Mounting system, pin support system, and directed energy deposition method for manufacturing a metal workpiece to reduce distortion - Patents.com

Abstract

The present application relates to a mounting system (100) for fabricating objects, particularly titanium and titanium alloy objects, on a substrate (300) by directed energy deposition, and to a system and method using the mounting system (100). The method includes thermally pre-bending a substrate (300) on which an object is to be fabricated to form a pre-bent substrate (300), attaching the pre-bent substrate (300) to a fixture using the mounting system (100) as an underlying support, pre-heating the substrate (300), and forming the object on the pre-heated pre-bent substrate (300) using directed energy deposition techniques.

Description

[Technical field]

[0001] The present invention relates to devices and methods for reducing distortion in metal objects, particularly titanium and titanium alloy objects, manufactured using a directed energy deposition additive manufacturing process, also known as solid freeform fabrication. [Background technology]

[0002] Structural metal parts, such as those made of titanium or titanium alloys, are made by conventional manufacturing methods such as casting, forging, or machining from a solid billet. These techniques often suffer from the drawbacks of large amounts of material waste of expensive titanium metal that is machined out, and the long lead times associated with manufacturing the metal parts.

[0003] Overall dense physical objects can be made by a manufacturing technique known as Directed Energy Deposition (DED), rapid prototyping, rapid manufacturing, layered manufacturing, additive layer manufacturing, shaped metal deposition, or additive manufacturing. Metal DED is an additive manufacturing process that uses focused thermal energy to melt and fuse materials together to form a deposit. Additive manufacturing builds up near-net-shape products in layers, allowing greater manufacturing flexibility and potentially reducing costs. It is also desirable to match material properties of traditional bulk forming processes such as forging while utilizing the same established metal alloys. DED is used for repair, rapid prototyping, and low / high volume part manufacturing.

[0004] DED systems include several categories of machines that use one or a combination of laser beam (LB), electron beam (EB), or arc-based energy sources such as plasma arc (PA), gas tungsten arc (GTA), gas metal arc (GMA). The metal feedstock used in DED systems typically includes metal in the form of powder and / or wire. DED is typically performed under an inert gas (e.g., DED using arc-based or LB systems) or vacuum (EB systems) atmosphere. While these are the main methods employed in practice, any combination of other energy sources, feedstocks, and atmospheres may also be used.

[0005] Residual stresses can be defined as self-balancing stresses that exist in an elastic body even in the absence of external loads, such as thermal and / or mechanical. Large amounts of weld-induced residual stresses can be generated and accumulated during DED of metal preforms due to localized heating and cooling cycles in which a heat source melts the metal material, deposits each new metal layer, and remelts the previously solidified metal layer. Incompatible elastic and / or plastic strain fields that arise during DED of metals caused by non-uniform thermal loading near the processing zone result in the inevitable accumulation of complex thermally induced residual stresses and distortions during layer-by-layer manufacturing. Thermal expansion and contraction can occur as a result of transient thermal expansions and steep thermal gradients that can exist during DED. The formation and relaxation of residual stresses during DED of metals can cause undesirable plastic deformations in areas adjacent to the processing zone, which can be carried over to the as-deposited preform. Retained residual stresses in the as-deposited DED preform can lead to permanent loss of tolerances of the workpiece. This is because the workpiece self-equilibrates the residual stress fields still present in the structure when released from the clamping fixture platform or jig. Residual stress induced deformation is more of a concern for larger components because larger temperature differences coexist along the DED build-up process. Improper distribution of residual stresses in the engineered components can also lead to unexpected or premature failure, i.e., in areas of high tensile stresses prone to fracture and fatigue. Stress relief heat treatments are commonly used to relieve stresses retained in the as-deposited preform by the DED manufacturing sequence. However, tolerance loss remains one of the major concerns in most DED processes.

[0006] Residual stresses during DED of metals generally result from the fact that different regions of the part being produced experience different thermal expansion and contraction cycles. The resulting thermal stresses can cause a non-uniform distribution of irreversible material deformation, some of which may remain after the material has cooled, resulting in an internal, completely self-equilibrated stress field within the workpiece. This self-equilibration can result in geometrically out-of-tolerance metal structures due to distortion and warping. All forms of DED processing involve a large amount of localized heat supply to the top of the newly deposited layer (exposed to the heat source), the interface between the newly deposited layer and the previous layer, and / or the substrate in order to achieve a properly fused interface.

[0007] Typically, DED manufacturing processes use a heat source with a high heat concentration to generate rapid heating. The generated heat can cause thermal expansion of the material with a gradual decrease in yield strength. The heat generated by the heat source is utilized to melt powder and / or wire feedstock and form a weld pool in a portion of the workpiece. This locally applied energy causes the weld area to heat up rapidly and fuse locally relative to the surrounding areas, which remain relatively cool throughout. The melted material does not support any load, so the stress below the heat source is close to zero. At some distance from the energy application area, i.e., in the material immediately adjacent to the melt pool and in the build layers below it, the material expands as a result of heating, but is restrained by the adjacent materials and the lower temperature material below it, resulting in an elastic compressive strain. As a result, the stress in the areas adjacent to the heat source is compressive. Because the temperature of the areas adjacent to the heat source is high and the yield strength of the material is low, the stress in these areas can be as high as the yield strength of the material at the corresponding temperature. As the thermal energy source moves away from the energy application area, the heated molten material cools and contracts as a solid, but the contracting metal is mechanically restrained by the adjacent underlying material. As cooling continues, the residual stresses within the object are distributed, typically resulting in large tensile stresses in the top layers where the material is prevented from shrinking, and equilibrium compressive stresses in the underlying layers. In some applications, the tensile stresses developed in the top layers may approach the yield strength of the material. Equilibrium compressive forces can cause buckling of metallic structural members when the strains and compressive loads they contain exceed the critical buckling load.

[0008] Due to the layer-by-layer nature of the DED process, the differential heating and cooling loads imposed by each successive layer create a spatial competition between material expansion and contraction, ultimately resulting in the accumulation of residual stresses in the object being produced. Because a hot layer of molten metal is deposited on a previous cooler layer of the object being built up, large local thermal gradients and large contractions can occur as heat from the heat source passes across the workpiece, introducing residual stresses in the workpiece caused by incompatible strain fields. The longitudinal and transverse contractions that occur during solidification of layer on layer can amplify the accumulation of residual stresses in the as-deposited preform. This stress is a function of the material's tensile modulus, coefficient of thermal expansion, and rate of contraction on cooling. If the stresses resulting from such incompatible strains remain in the finished product and are not relieved, the residual stresses can combine and react to generate internal forces that cause undesirable distortion of the object, such as bending, buckling, or rotation of the object. Residual stresses that can form during conventional additive manufacturing processes are sometimes large enough to cause significant distortion, misalignment, tearing, or the formation of stress-induced cracks in the additively manufactured object (see Figures 1A-1H).

[0009] Methods for measuring or modeling to predict stress induction in molded parts are known in the art (see, for example, U.S. Patent No. 6,233,663 (Sidhu et al., 2017); U.S. Patent No. 6,233,663 (Nguyen et al., 2018)). Prior art developed to address these shortcomings has met with limited success. For example, post-weld high-pressure mechanical rolling has been used to plastically deform the consolidated material prior to the formation of subsequent layers (see, for example, Colegrove et al., U.K. Patent Application No. 6,233,663 (2012)). Peening processes such as those taught in U.S. Patent No. 6,233,663 (Sidhu et al., 2015) are taught to be useful for relieving distortions in each metal layer deposited during the construction of an additively manufactured part. In these processes, one or more impact treaters are used to peen or strike a common point on a workpiece to plastically deform at least a portion of the deposited layers after cooling. Each impact treater may strike the workpiece one or more times and may strike at a frequency of up to 20 Hz. Laser peening has also been used to impart residual compressive stresses to workpieces (see Kramer et al. (2014)). These methods are not suitable for relieving residual stresses in areas inaccessible to peening or rolling tools for parts with complex geometries. These methods may also increase the time and complexity to manufacture the workpiece and therefore may be overly costly or impractical to utilize.

[0010] These methods also increase latency between layers, which can negatively impact productivity and limit manufacturing flexibility. Excessive cooling between layer depositions can also increase temperature differences between layers, further exacerbating the development of residual stresses. For methods that physically modify the deposited layers, contamination from tooling is also a concern, as the build-up process can introduce contaminants between layers in the final product.

[0011] Thus, there is a need in the art for an economical method of performing direct metal deposition at a metal deposition rate in an additive manufacturing system that results in a metal product having reduced or minimized residual stresses, or distortion, or both, than is achieved in conventional additive manufacturing processes. It would be desirable to provide a DED process that reduces the incidence of residual stresses or cracks in DED-produced objects. It would also be desirable to provide a DED process that reduces the incidence of localized distortion of the object being built as additional metal layers are deposited. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] U.S. Patent No. 9,555,475 [Patent Document 2] U.S. Pat. No. 9,950,476 [Patent Document 3] GB2491472 Specification [Patent Document 4] US Patent Application Publication No. 2017 / 0326681 [Patent Document 5] US Patent Application Publication No. 2014 / 0367894 Summary of the Invention [Means for solving the problem]

[0013] Accordingly, embodiments provided herein are directed to the manufacture of workpieces having reduced or minimized residual stresses, or distortion, or both, using additive manufacturing processes that substantially avoid one or more of the problems resulting from limitations and shortcomings of the related art. As embodied and broadly described, apparatus, systems, and methods are provided that reduce or minimize residual stresses or distortion, or both, during metal additive manufacturing to achieve products with improved material quality. DED manufactured products having such reduced residual stresses or distortion exhibit improved strength, fatigue resistance, and durability. In examples, the apparatus, systems, and methods provided can increase throughput and yield of DED formed products, resulting in workpieces within specified tolerances.

[0014] In examples, provided herein are methods and systems that may mitigate undesirable heat transfer without imparting substantial defects or any defects to the workpiece. In examples, methods and systems as described may be configured to control the substrate contact interface of structures underlying the substrate during DED manufacturing to reduce heat transfer from the substrate to a welding fixture or other underlying structure. In examples, reduced heat transfer may be achieved by reducing the surface area through which thermal energy may be transferred, increasing a solid / gas / solid thermally insulating boundary between the substrate and the underlying structure, or a combination of both. In examples, methods and systems as described may avoid or minimize undesirable defects on the workpiece.

[0015] In examples, the methods and systems provided herein may also improve DED manufacturing by promoting an atmosphere with reduced oxidant and contaminant particle content. In examples, the methods and systems provided herein may reduce or eliminate the need for ceramic sheets, plates, or pylons as part of the support. In examples, the thermal insulation that ceramic sheets, plates, or pylons can provide can be achieved by increasing the presence of solid / gas / solid interfaces that can take advantage of the low thermal conductivity of the inert atmosphere used during DED manufacturing. In examples, by not using ceramic sheets, plates, or pylons as supports, it may be possible to reduce the amount of moisture in the DED manufacturing atmosphere. In examples, by eliminating the use of ceramic sheets, plates, or pylons, it may be possible to avoid the introduction of unwanted ceramic particulates into the DED manufacturing atmosphere.

[0016] In examples, the methods and systems provided herein may also provide a resilient and durable system that can provide repeatable and predictable manufacturing uniformity.

[0017] In examples, the methods provided herein can be used to manufacture medium to large (e.g., up to 3 m) DED formed components that cannot be readily manufactured using conventional additive manufacturing processes. In addition, the large amounts of residual stress, distortion, or combinations thereof typical of conventional DED metal structures are reduced or eliminated, allowing the manufacture of metal structures that are geometrically within tolerances and specifications.

[0018] Because residual stress and distortion are often viewed as a significant barrier to mainstream acceptance of DED technology for metals, especially in safety-critical applications, the apparatus, systems, and methods provided herein that can minimize residual stress or distortion can open new markets or encourage wider acceptance of DED manufactured components. Additionally, the apparatus, systems, and methods provided herein can effectively control residual stress and distortion in DED metal structures, thereby improving material utilization efficiency of both the substrate and the DED material. Such improved material utilization, coupled with the production of within-tolerance DED manufactured products, can result in less waste and rework, significantly reducing DED manufacturing costs.

[0019] In an example, a DED manufacturing method is provided that includes pre-bending a metal substrate to form a plastically pre-bent substrate prior to DED of a single-sided metal structure. Also provided is a DED manufacturing method that includes pre-bending a metal substrate to form a plastically pre-bent substrate and pre-heating the pre-bent substrate prior to DED of the metal structure. Also provided is an apparatus for manufacturing components with reduced residual stresses and distortions by DED. The apparatus can be used with a conventional DED energy source used to melt metal powder and / or wire feedstock. The apparatus can include a mounting system as a support structure underlying the plastically pre-bent substrate. Also provided is a system that uses a conventional DED energy source modified using CAD-CAM program instructions that, when executed, cause the DED process to follow the shape of the underlying mounting system.

[0020] DED manufacturing methods are provided that minimize or prevent distortion of DED manufactured products. This can increase the efficiency of the manufacturing process, such as by minimizing substrate waste and the amount of deposition material that must be used. In particular, since the highest thermally induced stress fields may be introduced in the first deposition layer and distortion effects may be especially seen in the substrate, the methods provided herein may save substrate material that is sacrificed or lost in conventional additive manufacturing processes. The methods can result in improved material utilization efficiency of both the substrate and the DED material compared to conventional methods. The methods provided herein can effectively control residual stresses and distortions in the DED structures. This can reduce material waste and can bring the buy-to-fly or BTF ratio closer to unity. By reducing material waste and reducing or eliminating rework time, manufacturing costs can be significantly reduced.

[0021] A mounting system is provided that may include a first side configured to interface with a welding fixture. The mounting system may include a second side defining a curved profile and configured to interface with a substrate. The second side may include a substrate interface area sized to correspond to a surface of the substrate with which the second side is configured to interface. The second side may also include a substrate contact area configured for the mounting system to physically contact the substrate when the second side interfaces with the substrate. The mounting system may have a substrate contact interface defined as a ratio of the substrate contact area to the substrate interface area. The substrate contact interface may be defined in terms of a percentage of the substrate interface area occupied or constituted by the substrate contact area. In an example, the substrate contact area may constitute or be equal to 0.1 to 20 percent of the substrate interface area.

[0022] In examples, the percentage of the substrate interface area constituted by the substrate contact area may be greater than or equal to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1, and may be less than or equal to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. In examples, the second side is configured such that the percentage of the substrate interface area constituted by the substrate contact area may be in the range of 0.1 to 15, 0.1 to 10, 0.1 to 5, or 0.1 to 1. In examples, the second side is configured such that the percentage of the substrate interface area constituted by the substrate contact area may be in the range of 0.1 to 15, 0.1 to 10, 0.1 to 5, or 0.1 to 1. In examples, the second side is configured such that the percentage of the substrate interface area constituted by the substrate contact area can be in the range of 0.2 to 20, 0.2 to 15, 0.2 to 10, 0.2 to 5, or 0.2 to 1. In examples, the second side is configured such that the percentage of the substrate interface area constituted by the substrate contact area can be in the range of 0.3 to 20, 0.3 to 15, 0.3 to 10, 0.3 to 5, or 0.3 to 1. In examples, the second side is configured such that the percentage of the substrate interface area constituted by the substrate contact area can be in the range of 0.4 to 20, 0.4 to 15, 0.4 to 10, 0.4 to 5, or 0.4 to 1. In examples, the second side is configured such that the percentage of the substrate interface area constituted by the substrate contact area can be in the range of 0.5 to 20, 0.5 to 15, 0.5 to 10, 0.5 to 5, or 0.5 to 1. In examples, the second side is configured such that the percentage of the substrate interface area constituted by the substrate contact area can be in the range of 0.6 to 20, 0.6 to 15, 0.6 to 10, 0.6 to 5, or 0.6 to 1. In examples, the second side is configured such that the percentage of the substrate interface area constituted by the substrate contact area can be in the range of 0.7 to 20, 0.7 to 15, 0.7 to 10, 0.7 to 5, or 0.7 to 1. In examples, the second side is configured such that the percentage of the substrate interface area constituted by the substrate contact area can be in the range of 0.8 to 20, 0.8 to 15, 0.8 to 10, 0.8 to 5, or 0.8 to 1.In examples, the second side is configured such that the percentage of the substrate interface area that is constituted by the substrate contact area is in the range of 0.9-20, 0.9-15, 0.9-10, 0.9-5, or 0.9-1.

[0023] The mounting system can include or be made of a non-magnetic metal. The mounting system can include or be made of a metal having a melting point of 1350°C or higher. The mounting system can include or be made of a metal that is or includes an austenitic stainless steel. The austenitic stainless steel can include carbon, chromium, copper, manganese, molybdenum, nickel, nitrogen, phosphorus, silicon, or a combination of any two or more thereof. The austenitic stainless steel can include at least 18% chromium. The austenitic stainless steel can be a 300 series stainless steel. The austenitic stainless steel can include a 304 series stainless steel, a 309 series stainless steel, a 310 series stainless steel, a 316 series stainless steel, a 318 series stainless steel, a 321 series stainless steel, or a 330 series stainless steel, or a combination thereof.

[0024] The ceramic coating of the mounting system can be applied to any one or more surfaces. The ceramic coating can include zirconium dioxide, zirconium dioxide stabilized by the addition of yttrium oxide, yttrium aluminum oxide, alkaline earth metal silicates, ZrV2O7, Mg3(VO4)2, or combinations thereof. The mounting system can include a nominal curve profile deflection of about 3 mm to about 35 mm. The mounting system can include a bond coat to which the ceramic coating is applied.

[0025] In examples, the mounting system may be reconfigurable. In examples, the curvature profile may be defined by one or more pins. In examples, the mounting system may include at least a first pin of the one or more pins arranged to have a first substrate support height and at least a second pin of the one or more pins arranged to have a second substrate support height, where the first substrate support height is different from the second substrate support height.

[0026] In examples, the curved profile may be defined by a lattice support structure. In examples, the curved profile may be defined by a curved clamping die. Also provided is a pin support system having one or more pins in a reconfigurable arrangement on a welding fixture, the one or more pins having a variable substrate support height and arranged to define the curved profile.

[0027] In examples, at least one of the one or more pins includes a pin head portion including a substrate contact area, a collar portion, and a base portion configured to engage a weld fixture. In examples, the pin head portion may include a flat portion on at least a portion of a lateral profile. In examples, the pin head portion may include a weld fixture interface area. In examples, the one or more pins include austenitic stainless steel.

[0028] Also provided is a directed energy deposition method for manufacturing a metal workpiece, the method including pre-bending a substrate of a metallic material with thermal energy by forming a plurality of molten tracks on a first surface of the substrate of a metallic material using a first fusion tool to produce a pre-bent substrate; using a mount system or pin support system described herein as an underlying support structure for supporting the pre-bent substrate while securing the pre-bent substrate to a fixture; and securing the pre-bent substrate and the mount system or pin support system supporting the pre-bent substrate to the fixture using a plurality of clamps. After the pre-bent substrate and the mounting system or pin support system are secured to the fixture, the method includes forming a metal workpiece on the second surface of the substrate by an additive manufacturing process that can a) deposit a layer of molten metal on the second surface of the substrate to form a base material, and deposit a subsequent layer of molten metal on the base material to form a metal workpiece, or b) deposit a layer of metal powder, melt the metal powder on the second surface of the substrate to form a base material, and deposit a subsequent layer of metal powder, melt the powder on the base material to form a workpiece, the second surface of the substrate being opposite the first surface of the substrate. The method can include pre-heating the pre-bent substrate while secured to the fixture to a temperature of about 400° C. to about 900° C. by applying thermal energy to the second side of the substrate. Pre-bending the substrate can include inducing a thermal gradient in the substrate. The method can use a melting tool that includes a heat source selected from among a laser beam, an electron beam, a plasma arc, a gas tungsten arc, a gas metal arc, and any combination thereof. During the pre-bending of the first surface of the substrate, the application area of ​​the thermal energy can reach a temperature that is the melting point of the metallic material, or a temperature that is about 5° C. to about 50° C. lower or higher than the melting point of the metallic material.During the pre-bending of the first surface of the substrate, the formation of the melt tracks can result in the formation of tensile stresses at the centerlines of each of the melt tracks and compressive stresses in areas away from the centerlines of each of the melt tracks upon cooling of the substrate. The tensile stresses at the centerlines of the melt tracks can be within about 10% of the yield strength of the substrate. The tensile stresses at the centerlines of the melt tracks can exceed the magnitude of the yield strength of the substrate.

[0029] The pre-bending step can include directing cooling gas at the melt track using a gas jet device to enhance cooling of the melt track. Directing the cooling gas at the melt track can create a thermal gradient in the substrate and can impart residual stresses to the substrate as it cools. The gas jet device can direct the cooling gas at a rate of about 50 L / min to about 500 L / min. The cooling gas can be applied in a constant stream, intermittently, or in a pulsed stream. The cooling gas can include an inert gas selected from among argon, helium, neon, xenon, krypton, and combinations thereof. The cooling gas can be applied at a temperature of 100° C. or less. The cooling gas can be applied at a temperature of 25° C. or less. The gas jet device can generate a turbulent flow of the cooling gas, a laminar flow of the cooling gas, or a combination of turbulent and laminar flow of the cooling gas. The gas jet device can include a plurality of nozzles, the nozzles can direct the cooling gas away from the heat source of the melt tool, and at least one nozzle can direct the cooling gas at the as-solidified metal of the melt track.

[0030] In the methods provided herein, the melt tracks can be produced equidistant from each other. The distance between the melt tracks can be about 10 mm to about 60 mm. The method can include determining a centerline of each wall of the preform formed on the second surface of the substrate, and positioning the melt tracks on the first surface of the substrate about 10 mm to about 20 mm away from the centerline of the majority of the walls of the preform or workpiece formed on the second surface of the substrate. The majority of the melt lines can be formed on the first surface at one or more locations other than the location corresponding to the area or areas occupied by one or more walls of the workpiece formed on the second side of the substrate.

[0031] In the method, the pre-bending can form a pre-bent substrate having a uniform elastic-plastic bend. The pre-bending of the substrate can be performed while the substrate is clamped to a fixture and thermally isolated from the fixture. The substrate can be clamped to the fixture using a plurality of clamps, one or more of the clamps can include an insulating coating on each surface that contacts the pre-bent substrate. The insulating coating can include a ceramic material, silicon carbide, silicon nitride, boron carbide, or a combination thereof. The ceramic material can include alumina, zirconia, titanium oxide, alkaline earth metal silicate, aluminum titanate, zirconium dioxide, zirconium dioxide stabilized by the addition of yttrium oxide, yttrium aluminum oxide, ZrV2O7, Mg3(VO4)2, or a combination thereof. The insulating coating can have a thickness of 0.1 mm to 5 mm. The clamp can include a knurled pattern or corrugations on the surface that contacts the pre-bent substrate. The clamps can be tightened to conform the pre-bent substrate to a curved profile defined by the mounting or pin support system. Each of the clamps can be tightened to a torque of about 10 N·m to about 100 N·m. The clamps can be positioned so that they meet at the beginning or end of a wall of the workpiece being fabricated.

[0032] In the methods provided herein, pre-heating of the pre-bent substrate can be performed using one or more melting tools including a DED heat source under conditions that a) form a melt track but do not melt the surface of the pre-bent substrate, or b) form a melt track and melt the surface of the pre-bent substrate with the melt track. The melting tool can be positioned at a stand-off position that is further away than the stand-off position used to form the workpiece.

[0033] The method can include preheating a pre-bent substrate including a first short side and an opposing second short side and a first long side and an opposing second long side by: a) positioning a melting tool including a DED heat source at the first short side and within about 10 mm to about 60 mm from the first long side of the pre-bent substrate secured to a fixture; b) applying heat energy from the DED heat source of the melting tool to a surface of the pre-bent substrate starting from the first short side and in a direction opposite to the first short side. c) repositioning the DED heat source of the melting tool relative to the first short side and displaced from the first energy application line toward the second long side a distance of about 10 mm to about 60 mm; and d) repeating steps b) and c) until the energy application line is applied across the surface of the pre-bent substrate to a position about 10 mm to about 60 mm from the second opposite long side. The pre-heating can raise the temperature of the pre-bent substrate to a temperature of about 350° C. to about 650° C.

[0034] Forming a metal workpiece can include providing a metal material in the form of a wire; using a single melting tool to heat and melt the metal material such that the molten metal material is deposited on an area of ​​a substrate to form a base material; and moving the base material in a predetermined pattern relative to the position of the melting tool such that successive deposits of the molten metal material on the base material solidify to form a three-dimensional object.

[0035] Forming the metal workpiece may include: a) providing a metal material in the form of a wire; b) using a first melting tool to heat at least a portion of a surface of the substrate to form a pre-heated area on the substrate; c) using a second melting tool to heat and melt the metal material such that the molten metal material is deposited on the pre-heated area to form a base material; d) moving the base material relative to positions of the first melting tool and the second melting tool in a predetermined pattern; e) using the first melting tool to heat at least a portion of a surface of the base material to form a pre-heated area on the base material and depositing the molten metal material produced by the second melting tool melting the metal material on the pre-heated area on the base material; and f) repeating steps d) and e) such that successive depositions of molten metal material on the pre-heated area on the base material solidify to form the three-dimensional object.

[0036] The method can include using a gas jet device to direct a cooling gas to impinge on a surface of the as-solidified material adjacent a liquid-solid boundary of the molten metallic material, or any combination thereof; and moving the base material relative to the position of the melting tool and the gas jet device in a predetermined pattern such that successive deposits of the molten metallic material solidify to form the three-dimensional object. The first melting tool can include a PTA torch, a laser device, a coaxial powder feed nozzle laser system, an electron beam device, or any combination thereof, and the second melting tool can include a PTA torch, a laser device, a coaxial powder feed nozzle laser system, an electron beam device, or any combination thereof. The first melting tool can include a first PTA torch and the second melting tool can include a second PTA torch. The first melting tool can include a laser device and the second melting tool can include a PTA torch. The first melting tool can include a PTA torch and the second melting tool can include a laser device. The first melting tool can include a coaxial powder feed nozzle laser system and the second melting tool can include a laser device. The first melting tool can include a coaxial powder feed nozzle laser system and the second melting tool can include a PTA torch. The first melting tool can include a PTA torch and the second melting tool can include an electron beam device. The first melting tool can include an electron beam device and the second melting tool can include a PTA torch. The first melting tool can include an electron beam device and the second melting tool can include a laser device. The first melting tool can include a laser device and the second melting tool can include an electron beam device. When the second melting tool includes a PTA torch, the PTA torch can be electrically connected to a DC power source such that the electrode of the PTA torch is the cathode and the metal material is the consumable electrode that is the anode.

[0037] In the methods provided herein, each step of the method, including pre-bending the substrate, pre-heating the pre-bent substrate, and forming the metal workpiece, can be performed in an enclosed chamber containing an inert atmosphere, which can include argon, neon, xenon, krypton, helium, or combinations thereof.

[0038] Also provided is a system for directed energy deposition that can include a fixture for securing a pre-bent substrate, a mounting system or pin support system as described herein positioned between the fixtures and when the pre-bent substrate is secured to the fixture, an insulating clamp for securing the pre-bent substrate to the fixture, one or more melting tools with a DED heat source for melting a metal source into a metal melt that is deposited on a surface of a base material, a gas jet device for directing cooling gas to impinge on the as-solidified material adjacent the liquid-solid boundary of the liquid melt pool, or any combination thereof, a supply of cooling gas, and an actuator for positioning and moving the base material relative to the melting tools and the gas jet device.

[0039] Additional features and advantages of the embodiments described herein will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the illustrative embodiments will be realized and attained by the structure particularly pointed out in the written description and claims hereof, as well as the appended drawings.

[0040] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

[0041] The accompanying drawings, which are included to provide a further understanding of the invention, and which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. [Brief description of the drawings]

[0042] [Figure 1A] Photograph of a workpiece manufactured using conventional DED additive manufacturing without stress relief. [Figure 1B] The misconformity is shown (the arrow points to the location of the misconformity). [Figure 1C] The misconformity is shown (the arrow points to the location of the misconformity). [Figure 1D] A crack in the workpiece is shown (arrow points to the crack). [Figure 1E] A crack in the workpiece is shown (arrow points to the crack). [Figure 1F] A crack in the workpiece is shown (arrow points to the crack). [Figure 1G] A tear in the workpiece is shown (arrow points to the tear). [Figure 1H] A tear in the workpiece is shown (arrow points to the tear). [Figure 2A] 1A-1C illustrate exemplary curvature profiles that may be defined by the mounting systems described herein. [Figure 2B] FIG. 2 illustrates a substrate interface area of ​​a mounting system as described herein. [Figure 2C] FIG. 1 illustrates an example of knurling and knurling spaces or valleys coated with a bond coat and a ceramic coating. [Figure 3A] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3B] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3C] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3D] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3E]1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3F] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3G] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3H] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3I] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3J] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3K] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3L] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 3M] 1 illustrates an example mounting system that may be implemented as an example of the pin support system described herein. [Figure 4A] 1 illustrates an example mounting system implemented with the example lattice support structures described herein. [Figure 4B] 1 illustrates an example mounting system implemented with the example lattice support structures described herein. [Figure 4C] 1 illustrates an example mounting system implemented with the example lattice support structures described herein. [Figure 4D] 1 illustrates an example mounting system implemented with the example lattice support structures described herein. [Figure 5A] FIG. 13 is a side view of a curved clamp die showing an embodiment having a knurled curved surface. [Figure 5B]FIG. 1 is a side view of the same curved clamp mold showing the ceramic coating by dashed lines (exaggerated in the figure) on the curved surface that contacts the DED substrate (plate). The nominal mold deflection hmold is also shown in the figure. [Figure 5C] An exemplary cross-sectional shape (enlarged view) is shown, which is a frustum shape, specifically a truncated pyramidal shape. [Figure 5D] FIG. 2 is a top view of the same curved clamp die. [Figure 5E] FIG. 13 is an isometric view of the same curved clamp die. [Figure 5F] 1 is a bottom view of a curved clamping mold having four triangular cavities with peripheral rims separated by X-shaped stiffening members, the peripheral rims and the X-shaped stiffening members sharing a common plane, when the curved clamping member is placed on a fixture or welding table, only the peripheral rims and stiffening members contact the fixture platform for clamping, such as a fixture or welding table. [Figure 6] 1 illustrates an exemplary rapid cooling gas jet device. [Figure 7A] Illustrated are melt tracks formed on a first or backside of a substrate to pre-bend the substrate, and a DED back wall of the workpiece formed on a second or front side of the substrate. [Figure 7B] 1A-1C illustrate an exemplary process for pre-bending a substrate by creating a molten track on a first or backside of the substrate. [Figure 7C] 1 illustrates an exemplary heating path that can be used to move a DED energy source to form a melt track on the backside or top surface of a first side of a substrate to pre-bend the substrate towards the heat source. [Figure 7D] Schematically illustrates the relative position of the thermally induced pre-bending melt track formed by the heating path on the backside or first side of the substrate with respect to the overlaid (grey dashed line) DED workpiece fabricated on the frontside or second side of the substrate. [Figure 8A] 1 shows the uniform longitudinal bow that occurs in a substrate when the substrate is heated to induce a melt track and prebend the substrate. [Figure 8B] In the depicted substrate, the maximum nominal substrate deflection 410 perpendicular to the plane of the plate was approximately 15 mm. In both figures, the pre-bent substrate is placed on a fixture 400. [Figure 9A] FIG. 1 illustrates a bottom view of an exemplary insulated high strength steel clamp. [Figure 9B] FIG. 1 illustrates a side view of an exemplary insulated high strength steel clamp. [Figure 9C] 1A-1D are perspective overhead three-dimensional views of an exemplary insulated high strength steel clamp, showing exemplary surfaces that may be coated with a ceramic coating to minimize heat flow by conduction between the insulated high strength steel clamp and a pre-bent substrate when the clamp is used to join a fixture with a plastically pre-bent substrate. [Figure 10] FIG. 6 shows an example clamping arrangement using insulated or corrugated clamps to mount the pre-bent substrate in the fixture. The figure shows that the clamps can be positioned such that the centerline of the clamp (or clamping entity, such as that shown in the solid box outline around the clamps when multiple clamps are used in combination) intersects as closely as possible with the centerline of the DED wall start / end locations. Such substrate clamping constraint can significantly reduce deformation effects that arise primarily from longitudinal residual stresses. Non-optimal clamping can result in localized deformation or buckling due to lack of clamping constraint. For illustrative purposes, a non-optimal clamping arrangement 650 is shown in the dashed box of the drawing. Only one clamp is used in an off-center position to axially constrain the upward movement of the base plate. This is a non-optimal clamping arrangement because the centerline of the clamp / entity does not intersect with the centerline of the DED wall start / end locations. [Figure 11]The relative positions of the black faded pre-heat paths on the front side of the substrate prior to DED deposition are shown in a schematic diagram, superimposed with the shape of the workpiece to be formed. The exemplary embodiment shows the application of a low energy density applied by a heat source in the x direction from short side to short side over the entire surface of the substrate, which is pre-bent in the y direction. The figure shows, for example, solid and dashed faded black lines representing the tool paths and pre-heat sequence of two melting tools running in parallel. [Figure 12A] FIG. 1 shows a schematic diagram of a conventional directed energy deposition configuration in which the workpiece is fabricated layer-by-layer, with the substrate separated from the fixture, e.g., using an alumina insulating sheet or other substrate support mechanism. This configuration minimizes heat flow from the DED substrate to the fixture, while preventing extraction of heat generated by the DED process. [Figure 12B] 1 is a y-direction view of an exemplary configuration for directed energy deposition using a mounting system 100 including a pin support system 110 provided herein. The mounting system serves as a support structure that underlies the pre-bent substrate as it is attached to a fixture. The workpiece is manufactured in a layer-by-layer fashion. [Figure 12C] 12B illustrates an exemplary configuration for directed energy deposition using a mounting system 100 including a pin support system 110 provided herein as shown in FIG. 12B, but viewed in the X direction. The mounting system serves as a support structure that underlies the pre-bent substrate as it is attached to a fixture. The workpiece is manufactured in a layer-by-layer fashion. [Figure 13A] Figure 1 shows the deformation induced by DED deposition forming a workpiece on a first substrate having a thickness of 9.5 mm that has not undergone any type of stress relief. Distortion is evident on the short edge of the substrate, which bows upwards compared to the flat profile of the substrate before deposition. [Figure 13B] 1 shows the deformation caused by DED deposition on a second substrate having a thickness of 12.7 mm and not subjected to any type of stress relief. [Figure 13C] 1 shows a third substrate, 9.5 mm thick, that was used to form the object by undergoing thermal pre-bending, pre-heating and DED treatments. [Figure 14A] Figure 1 shows a non-optimal setup of the individual clamps, with the dashed circles indicating areas of uneven pressure and heat transfer distribution. [Figure 14B] An individual clamp setup is shown showing evenly distributed load across the clamp / base plate contact area ensuring uniform pressure and heat transfer distribution. [Figure 15] 1 shows comparative data on the heat retained by a substrate during a DED manufacturing process using a conventional ceramic pylon versus a mounting system embodied as a pin support system as described herein. [Figure 16A] 13 shows comparative data illustrating the reduction in moisture content in a DED atmosphere that can be achieved by eliminating ceramic in lieu of a mounting system embodied as a pin support system as described herein. [Figure 16B] 13 shows comparative data illustrating the reduction in moisture content in a DED atmosphere that can be achieved by eliminating ceramic in lieu of a mounting system embodied as a pin support system as described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] Detailed Description of the Preferred Embodiments Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings.

[0044] A.Definition

[0045] All technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs, unless otherwise defined.All patents, patent applications, published applications and publications, websites, and other published materials referenced throughout this disclosure are incorporated by reference in their entirety unless otherwise stated.In the present specification, in the event that there are multiple definitions of terms, the definitions in this section shall prevail.

[0046] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0047] As used herein, ranges and amounts can be expressed as "about" a particular value or range. "About" includes the exact amount. Thus, "about 5%" means "about 5%" and also "5%." "About" means within typical experimental error for the intended use or purpose.

[0048] As used herein, "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances in which the event or circumstance occurs and instances in which it does not occur. For example, an optional component in a system means that the component may or may not be present in the system.

[0049] As used herein, "combination" refers to any association between two items or between more than two items, which may be spatial or may refer to the use of two or more items for a common purpose.

[0050] As used herein, the terms "comprising, including, and containing" are synonymous and are inclusive or open-ended. Each term indicates that additional, unmentioned elements or method steps may optionally be included.

[0051] As used herein, "and / or" refers to "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with "and / or" should be interpreted similarly, i.e., as "one or more" of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the "and / or" clause, whether or not related to those elements specifically identified. Thus, as a non-limiting example, a reference to "A and / or B," when used in conjunction with open-ended language such as "comprising," can refer in one embodiment to only A (optionally including elements other than B); in another embodiment to only B (optionally including elements other than A); in yet another embodiment to both A and B (optionally including other elements), etc.

[0052] As used herein, "additive manufacturing," also known as "additive manufacturing," "additive layer manufacturing," "solid freeform manufacturing," "shaped metal deposition," or "layered manufacturing," refers to a layered process that effects the building of successive layers of an object. The process can employ 3D model data, a metal feedstock source such as wire or powder, a heat source (such as a plasma arc, laser, or electron beam) to melt the metal feedstock, or a combination thereof.

[0053] As used herein, "additive manufacturing system" refers to a system used for additive manufacturing.

[0054] As used herein, "Directed Energy Deposition" or "DED" refers to an additive manufacturing process in which a heat source is used to fuse materials, particularly metals, by melting them as they are deposited.

[0055] The terms "plasma transferred arc torch" or "PTA torch," as used interchangeably herein, refer to any device capable of heating and exciting a stream of inert gas into a plasma by an electric arc discharge, and then transferring the stream of plasma gas containing the electric arc outwardly through an orifice (such as a converging nozzle) to form a highly collimated arc column of ionized plasma gas that exits the nozzle orifice at high velocity and transfers the intense heat of the arc to a target area, such as a metal wire or substrate.

[0056] The term "metallic material" as used herein refers to any known or contemplated metal or metal alloy that can be employed in a directed energy deposition process to form a three-dimensional object. Examples of suitable materials include, but are not limited to, titanium and titanium alloys, such as Ti-6Al-4V alloy.

[0057] As used herein, a "heat source" refers to a piece of equipment by which thermal energy can be transferred to a metallic material, such as a metal wire or metal powder, or to a substrate or base material, or any combination thereof. Exemplary heat sources include plasma arcs, laser beams, and electron beams.

[0058] As used herein, "melting tool" refers to a device that generates a heat source to preheat or melt a metallic material and / or a portion of a surface of a workpiece in a DED additive manufacturing process. Examples include a PTA torch that generates an electric arc plasma as a heat source, a laser device that generates a laser beam as a heat source, and an electron beam device that generates an electron beam as a heat source.

[0059] The term "base material" as used herein refers to the target material onto which molten metal is deposited to form a workpiece. If one is depositing the first layer of metallic material, this is the substrate. If one or more layers of metallic material have been deposited on a substrate, the base material is the topmost layer of deposited metallic material onto which a new layer of metallic material is deposited.

[0060] As used herein, the term "workpiece" refers to a metal body or object that is manufactured using directed energy deposition.

[0061] The terms "computer-aided design model" or "CAD model," as used interchangeably herein, refer to any known or conceivable virtual three-dimensional representation of an object to be formed that may be employed in a DED system that coordinates the position and movement of a substrate and manipulates a DED heat source and a source of metallic material, such as a metal powder supply or a metal wire feeder, such that a physical object is constructed by fusing successive deposits of metallic material onto a substrate, such that a physical object is constructed according to the virtual three-dimensional model of the object. This may be obtained, for example, by first dividing the virtual three-dimensional model into a set of virtual parallel layers, and then dividing each of the parallel layers into a set of virtual quasi-one-dimensional pieces, thereby forming a virtual vectorized layered model of the three-dimensional model. A controller may then be engaged to deposit and fuse a series of quasi-one-dimensional pieces of metallic material feed onto a substrate in a pattern according to a first layer of the virtual vectorized layered model of the object, thereby forming the physical object.

[0062] The sequence is then repeated for the second layer of the object by depositing and fusing a succession of quasi-one-dimensional pieces of weldable material onto the previously deposited layer in a pattern that follows the second layer of the virtual vectorized layered model of the object. This repetition continues the deposition and fusing process layer by layer for each successive layer of the virtual vectorized layered model of the object until the entire object is formed. However, the invention is not bound to a particular CAD model and / or computer software for implementing a controller of the configuration according to the invention, nor is the invention bound to a particular type of controller. Any known or conceivable controller (such as CAD models, computer software, computer hardware, and actuators) capable of building a metal three-dimensional object by directed energy deposition can be used.

[0063] As used herein, a "cooling gas" is a gas that is directed toward an as-solidified surface, such as a melt track, to directly affect and accelerate the cooling and solidification of the as-solidified metal. The temperature of the gas can be any temperature that cools the surface with which it interacts. The temperature can be less than 100°C, or less than 50°C, or less than 30°C, or less than 25°C, or less than 10°C, or less than 5°C, or less than 0°C, or in the range of about -10°C to about 100°C, or about -5°C to about 90°C, or about 0°C to about 80°C. The temperature can be about 25°C or less.

[0064] As used herein, "residual stress" refers to stress that would be present in a structure even if all external loads were removed due to non-uniformity of residual strains. Residual stresses are typically self-equilibrating.

[0065] As used herein, a "fixture" refers to an apparatus used to hold or secure the workpiece, mounting system, and clamps in place during deposition. For example, a fixture can include a tray, pedestal, or platform on which a substrate or other portion of a workpiece can be secured during a DED process.

[0066] As used herein, a "preform" is a workpiece produced by an additive manufacturing process. A preform may be an intermediate to a final finished part or a semi-finished part. A preform may have a near net shape to a final finished part and may require some further processing, if minimal. For example, a preform may require final finishing processing for high tolerance configuration.

[0067] As used herein, "Buy-to-Fly Ratio" or "BTF Ratio" refers to the weight ratio of the weight of raw material used to produce a component to the weight of the finished product. This ratio may depend on how closely the shape of the initial as-deposited DED preform resembles the shape of the finished component. The more material that needs to be removed from the DED preform to produce the final component, the higher the BTF ratio.

[0068] As used herein, "length" or "lengthwise" with respect to a substrate refers to the direction along the largest of the substrate's three dimensions.

[0069] As used herein, "width" or "width direction" with respect to a substrate refers to the direction along the second-largest of the substrate's three dimensions, typically measured from one short side to the other short side.

[0070] As used herein, "thickness" or "thickness direction" with respect to a substrate refers to the direction along the smallest of the substrate's three dimensions.

[0071] As used herein, "high strength steel" refers to steel having a tensile strength of 300 MPa or greater.

[0072] As used herein, "high strength low alloy steel" refers to steel having a tensile strength of 370 MPa or greater.

[0073] As used herein, "ultra-high strength steel" refers to steel having a tensile strength of 780 MPa or greater.

[0074] As used herein, "warm forming temperature" is a temperature below the recrystallization temperature of a material that maximizes the malleability of the material without allowing recrystallization, grain growth, and metallurgical fracture. Warm forming temperatures can range from about 200°C to about 850°C depending on the material.

[0075] As used herein, a "hot forming temperature" is a temperature above the recrystallization temperature of a material. Hot forming temperatures can range from about 600° C. to about 2000° C. depending on the material.

[0076] As used herein, "backside of substrate" refers to the side of the substrate that faces away from the deposition apparatus during DED fabrication. For example, the backside of the substrate can face the fixture during deposition. The backside of the substrate is the side opposite to the side on which deposition occurs.

[0077] As used herein, "front side of a substrate" refers to the side of a substrate that faces a deposition apparatus. For example, the front side of a substrate can be the side on which molten material is deposited during DED. The front side of a substrate can be the side on which a workpiece is formed by DED. The front side of a substrate is the side opposite the back side of a substrate.

[0078] As used herein, "cavity" refers to an unfilled space or void in a mass that does not traverse the mass to form a hole. A cavity can be a hollowed out or cut out space, or a space created by adding additional material.

[0079] As used herein, the "nominal deflection" or "h" of a mounting system is the difference between the maximum height of the arcuate surface measured at the center of the arcuate surface and the top surface of the edge of the mounting system.

[0080] Also, unless expressly indicated to the contrary, it should be understood that in methods claimed herein that include multiple steps or acts, the order of the method steps or acts is not necessarily limited to the order in which the method steps or acts are described.

[0081] B. PCB Mounting System Conventional DED of metals to produce preforms can result in residual stresses in the preforms. Residual stresses during DED of metals typically result from the fact that different areas of the component being produced experience different thermal expansion and contraction cycles. The resulting thermal stresses can cause non-uniform distribution of irreversible material deformations, some of which may remain after the material cools, resulting in an internal completely self-equilibrated stress field within the workpiece. This stress, if not relieved, can promote numerous manufacturing defects. As shown in Figures 1A-1H, a workpiece produced using conventional DED additive manufacturing without stress relief (Figure 1A) can exhibit misalignments (Figures 1B and 1C), cracks (Figures 1D, 1E and 1F), and tears (Figures 1G and 1H). A substrate mounting system 100 is provided as a support structure underlying a pre-bent substrate for producing single-sided metal components with no residual stress and no distortion due to DED, or metal components with reduced residual stress or reduced distortion. The mounting system 100 can be used with conventional DED heat sources used to melt metal powder or wire feedstock, or a combination thereof.

[0082] In an example, the mounting system 100 can be employed as an intervening structure between a pre-bent substrate and a fixture. One or more clamps can be used to secure the pre-bent substrate to the fixture. As a result, the pre-bent substrate is pressed towards the fixture, so that the force required to secure the pre-bent substrate to the fixture is applied between the clamps and the fixture, and the mounting system 100 provides support between the substrate and the fixture. In an embodiment, the pre-bent substrate is pressed axially downward.

[0083] In examples, the mounting system 100 provided herein may allow for fixture redesign to be simpler, i.e., lighter, cheaper, and more versatile. Current fixtures may be over-designed to anticipate reaction forces and stresses encountered when clamping a substrate directly to the fixture and during DED. The mounting system 100 may reduce these anticipated forces and stresses. The mounting system 100 provided herein may also allow for changes in clamping arrangements compared to conventional clamping arrangements. In some applications, when the mounting system 100 is used, the entire perimeter of the substrate may be clamped to the fixture.

[0084] In examples, mounting system 100 can enable low or reduced thermal energy transfer between the substrate and the welding fixture during DED manufacturing, can reduce or eliminate the need for insulating ceramics, can result in defect-free or substantially defect-free manufactured products, or can achieve any combination thereof.

[0085] As previously mentioned, the ceramic sheets, plates, or pylons used as thermal insulation may absorb moisture released during DED manufacturing. Release of moisture in the environment increases the presence of oxygen, which may be detrimental to the process as it may result in oxidation of the deposited metal. In examples, the mounting system 100 may eliminate the ceramic sheets, plates, or pylons. In examples, the mounting system 100 may be used without ceramic. In examples, no ceramic coating is used in the mounting system 100. In examples, the mounting system 100 does not include any ceramic material. In examples, the mounting system 100 does not include any ceramic sheets, plates, pylons. In examples, the mounting system 100 may include ceramic materials and / or ceramic coatings.

[0086] The mounting system 100 may be configured to include a predetermined "substrate contact interface." As used herein, the term "substrate contact interface" with respect to the mounting system 100 refers to the ratio of the substrate contact area of ​​the mounting system 100 to the substrate interface area of ​​the mounting system 100. The "substrate interface area" of the mounting system 100 refers to the area of ​​one side of the mounting system 100 that is configured to be occupied by a surface of a substrate or pre-curved substrate that faces the mounting system 100 when in use, and thus corresponds to the area of ​​the surface of the substrate or pre-curved substrate that faces the mounting system 100 when in use. A diagram of an exemplary substrate interface area 106 (shown as a flat surface with dashed lines) of the mounting system 100 is shown in FIG. 2B (curvature omitted for clarity). In an example, the substrate interface area of ​​the mounting system 100 may be the same as or different from the surface area of ​​the physical surface of the mounting system 100 that is configured to face a substrate or pre-curved substrate when the mounting system 100 is in use. For example, in the example shown in FIG. 2B where the mounting system 100 may include a set of separate elements 101, the substrate interface area 106 may be greater than the collective surface area of ​​the elements 101 configured to face a substrate or pre-curved substrate when the mounting system 100 is in use. The term “substrate contact area” as used herein refers to the area where physical contact is made between the mounting system 100 and a substrate or pre-curved substrate when the mounting system 100 is in use. For purposes of this description, references to the “substrate contact area” of the mounting system 100 as a whole should be understood as the total surface area of ​​the mounting system 100 that is configured to physically contact a surface of a substrate or pre-curved substrate when the mounting system 100 is in use as described herein. Physical contact in this definition also includes contact with an intervening ceramic coating, bond coat, or both. For ease of reference, the ratio representing the substrate contact interface may be expressed as a percentage of the portion of the substrate interface area of ​​the mounting system 100 that is the substrate contact area of ​​the mounting system 100.In other words, as used herein, ratio may be expressed as a percentage or proportion of the area of ​​the side of mounting system 100 configured to be overlapped by a substrate or pre-bent substrate when mounting system 100 is in use that is occupied by the area configured to be in physical contact with a substrate or pre-bent substrate when mounting system 100 is in use. Substrate contact interface may similarly be understood to be the proportion of the surface area of ​​the side of the substrate or pre-bent substrate that mounting system 100 is configured to be in physical contact with when supporting the substrate or pre-bent substrate.

[0087] In examples, mounting system 100 may be configured to include a substrate contact interface that is greater than or equal to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 and less than or equal to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. In examples, mounting system 100 may be configured to have a substrate contact interface in the range of 0.1-15, 0.1-10, 0.1-5, or 0.1-1. In examples, mounting system 100 may be configured to have a substrate contact interface in the range of 0.1-15, 0.1-10, 0.1-5, or 0.1-1. In examples, the mounting system 100 may be configured to have a substrate contact interface in the range of 0.2-20, 0.2-15, 0.2-10, 0.2-5, or 0.2-1. In examples, the mounting system 100 may be configured to have a substrate contact interface in the range of 0.3-20, 0.3-15, 0.3-10, 0.3-5, or 0.3-1. In examples, the mounting system 100 may be configured to have a substrate contact interface in the range of 0.4-20, 0.4-15, 0.4-10, 0.4-5, or 0.4-1. In examples, the mounting system 100 may be configured to have a substrate contact interface in the range of 0.5-20, 0.5-15, 0.5-10, 0.5-5, or 0.5-1. In examples, the mounting system 100 may be configured to have a substrate contact interface in the range of 0.6-20, 0.6-15, 0.6-10, 0.6-5, or 0.6-1. In examples, the mounting system 100 may be configured to have a substrate contact interface in the range of 0.7-20, 0.7-15, 0.7-10, 0.7-5, or 0.7-1. In examples, the mounting system 100 may be configured to have a substrate contact interface in the range of 0.8-20, 0.8-15, 0.8-10, 0.8-5, or 0.8-1. In examples, the mounting system 100 may be configured to have a substrate contact interface in the range of 0.9-20, 0.9-15, 0.9-10, 0.9-5, or 0.9-1.

[0088] In an example, the mounting system 100 may be configured to have a desired substrate contact interface for a substrate or pre-curved substrate of a given size by controlling or adjusting the portion of the mounting system 100 configured to physically contact the substrate or pre-curved substrate. In an example, the substrate contact area of ​​the mounting system 100 may be controlled by making the surface of the mounting system 100 that faces and is configured to physically contact the substrate or pre-curved substrate during use (the "substrate contact surface") uneven or discontinuous. In an example, the substrate contact surface of the mounting system 100 may be corrugated, knurled, or otherwise include ridges and valleys or similar uneven surface contours, as described herein. In an example, the substrate contact surface of the mounting system 100 may be designed to have steps, curves, convexities, concavities, hollows, irregularities, or any other uneven profile that may result in a substrate contact area that is only a portion of the total area of ​​the substrate contact surface of the mounting system 100. In examples, mounting system 100 may be configured to support a substrate or pre-bent substrate only at spaced locations, such as by a set of pins or pin structure, or by a grid structure.

[0089] In an example, reducing the substrate contact area may result in reduced conductive heat transfer from the substrate or pre-bent substrate to the mounting system 100, the welding fixture, or both. In an example, this may promote heat accumulation in the substrate during the DED process, thus minimizing the extent of bounce. In an example, the thermal gradient across the thickness of the substrate or pre-bent substrate may be substantially smaller during deposition of the first layer, so that welding-induced residual stresses created during DED of the metal preform may be reduced. Also, because titanium and titanium alloys, such as Ti-6Al-4V, have high yield stresses and relatively low elastic moduli, these metals exhibit high bounce at room temperature.

[0090] In an example, the reduction in substrate contact area may result in the formation of one or more gaps or spaces between the substrate or pre-bent substrate and the mounting system 100, the welding fixture, or both. In an example, it may be possible to fill these gaps or spaces with the atmosphere of the DED chamber or a noble gas such as argon, which may act as a thermal insulator. Noble gases such as argon gas may be very effective thermal insulators. Also, because solid / gas / solid interfaces have fairly low thermal conductivity, these particular interfaces between the pre-bent substrate / argon gas / mounting system and / or the welding fixture may effectively function as a thermal barrier. Thus, in an example, the one or more gaps or spaces may also help minimize the average heat transfer rate between the substrate or pre-bent substrate and the mounting system 100.

[0091] In examples, mounting system 100 may include a single integral structure, an array of elements or structures, or a combination of both. Any structure that reflects the design characteristics of mounting system 100 described herein may be used to implement mounting system 100. In examples, mounting system 100 may include pin support system 110, one or more pins 112, grid support system 150, mold 170, any similar structure, or any combination thereof. These exemplary structures of mounting system 100 are provided by way of example and should not be considered limiting. In examples where mounting system 100 includes an array of elements or structures, each element or structure having its own substrate contact surface and substrate contact area, the substrate contact interface defined above when referring to mounting system 100 as a whole should be understood as a function of the total substrate contact area from all elements or structures in the array that are part of mounting system 100.

[0092] In examples, the mounting system 100 provided herein can be freestanding. In examples, the mounting system 100 can be separate and separate from a fixture. In examples, the mounting system 100 can be integrated as part of a welding fixture. In an exemplary embodiment, the mounting system 100 can be configured to be installed on a welding fixture.

[0093] In an example, the mounting system 100 can be configured to define a curved profile 102 on at least one side. In an example, the curved profile 102 corresponds to a surface profile of the mounting system 100. In an example, the curved profile 102 is a profile of a plane in which the mounting system 100 is defined. In an example, the curved profile 102 is a surface profile of the mounting system 100. In an example, if the mounting system 100 is a unitary structure such as a mold or may be disposed in a lattice as described herein, the curved profile 102 can be a surface profile of the mounting system 100. In an example, if the mounting system 100 includes discontinuous surfaces such as may be disposed in a lattice as described herein, or if the mounting system 100 includes an array of elements or structures 101 such as a pin support system as described, the curved profile 102 can be a profile defined as a plane that intersects the distal ends of each of the substrate contact areas on the discontinuous surfaces or on the elements or structures in the array, as shown in FIG. 2A.

[0094] In an example, the mounting system 100 may be configured to define a curved profile 102 at least on a side facing away from the welding fixture. In an example, the mounting system 100 may be configured to define a planar profile on one side. In an example, the mounting system 100 may be configured to define a planar profile on a first side and a curved profile on an opposite second side. In an example, the mounting system 100 may define a planar or flat profile on a first side intended to face or be oriented toward the welding fixture in use. In an example, the mounting system 100 may define a curved profile 102 on a second side opposite the first side. In an example, the mounting system 100 may define a curved profile 102 on a side intended to face away from the welding fixture or be oriented away from the welding fixture and face or be oriented toward the substrate or pre-bent substrate in use. In an example, the curved profile 102 of the mounting system 100 is configured to face a substrate or a pre-bent substrate when the mounting system 100 is in use. In an example, the curved profile 102 is provided on a side of the mounting system 100 that is configured to interface with a substrate or a pre-bent substrate when the mounting system 100 is in use. In an example, the curved profile 102 of the mounting system 100 is configured to interface with a substrate or a pre-bent substrate.

[0095] In an example, the curvature of the curved profile 102 of the mounting system 100 can be empirically determined based on data collected in initial testing conducted using ceramic plates. The ceramic plates were cut to different sizes and used to generate different current curvatures and tested for their ability to minimize distortion of preforms prepared on curved supports. Modeling was then used to confirm that the curvatures used in the experiments yielded close to the desired end result, i.e., distortion-free preforms. In cross-section as viewed from the side, the shape of the curved profile 102 of the mounting system 100 can resemble the upper half of an ellipse with a semi-minor axis much smaller than the semi-major axis. The ellipse can have an eccentricity close to but less than 1 (an eccentricity of 1 results in a flat surface).

[0096] In an example, the mounting system 100 can include a peripheral rim portion 104. An example of this is shown in FIG. 2A. In an example, the peripheral rim portion 104 can be present at least along a side edge or along a periphery of an area defined by the first side, the second side, or both the first and second sides of the mounting system 100. In an example, the peripheral rim portion 104 of the mounting system 100 can be configured to support at least a portion of the substrate or pre-bent substrate at a location where the substrate or pre-bent substrate is clamped to a welding fixture during use of the mounting system 100. In an example, at least a portion of the peripheral rim portion 104 of the mounting system 100 can be configured to support the substrate or pre-bent substrate at a location where the substrate or pre-bent substrate is clamped to a welding fixture during use of the mounting system 100.

[0097] In examples, contact between mounting system 100 and the substrate or pre-bent substrate may cause some compressive stress to be felt in mounting system 100. In examples, mounting system 100 may be made of a rigid material that is resistant to twisting and deformation to help maintain its shape. Additionally, mounting system 100 may be made of a material that is resistant to thermal shock, corrosion, and / or is non-magnetic.

[0098] In an example, mounting system 100 can serve as a support structure for a pre-bent DED substrate positioned between the pre-bent DED substrate and a fixture. An exemplary arrangement can include the fixture as the bottom surface against which mounting system 100 is positioned.

[0099] In an example, the backside (first side) of the pre-bent substrate, where the melt track may be present, may be positioned to face the side of the mounting system 100 facing away from the fixture. In this configuration, the backside of the pre-bent substrate faces downward toward the curved profile 102 of the mounting system 100 and fixture. In an example, one or more clamps may secure the pre-bent substrate to the fixture with the mounting system 100 sandwiched between the pre-bent substrate and the fixture. In an example, the force exerted by the clamps on the pre-bent substrate may straighten the pre-bent substrate to conform to the curvature of the curved profile 102 of the mounting system 100. One or more clamps around at least a portion of the periphery of the DED substrate may uniformly compress the pre-bent substrate downward toward the fixture and secure the pre-bent substrate to the fixture.

[0100] In an example, the mounting system 100 can help reduce or eliminate deformations, such as weld-induced buckling distortions caused by elastic instabilities caused by compressive residual stresses when a critical buckling stress of the substrate is exceeded. Due to the reduced contact interface that the mounting system 100 is configured to have with the substrate or pre-bent substrate, controlled substrate interface, or combinations thereof, in an example, the mounting system 100 may be able to minimize the occurrence of localized temperature gradients that can induce large localized stains and resulting deformation patterns. In an example, the mounting system 100 can maintain a consistent interface with the pre-bent substrate to optimize thermal and mechanical homogeneity across the pre-bent substrate.

[0101] In an example, the dimensions of the substrate can be selected to accommodate one or more workpieces to be built on the substrate. Typically, the only limitation on the size of the curved profile 102 defined by the mounting system 100 relative to the substrate is that the substrate or pre-bent substrate can be clamped to the fixture with the mounting system 100 positioned between the substrate and the fixture. The mounting system 100 can be designed to define a curved profile 102 that is the same size as the substrate or pre-bent substrate. In an example, the mounting system 100 can be configured to define a curved profile 102 that is 0.5% to 10% larger than the bonding surface of the substrate or pre-bent substrate, as long as the substrate or pre-bent substrate can be clamped to the fixture.

[0102] The mounting system 100 can be designed to define a curved profile 102 having a size that is 0.05% to 2.5% smaller than the substrate, so long as the substrate does not contact the fixture when clamped to the fixture with the mounting system 100 between the substrate and the fixture.

[0103] In the embodiments provided herein, the height of the curved profile 102 defined by the mounting system 100 at or near the center or apex of the curved profile 102, as measured from a surface of the welding fixture that faces the mounting system 100 when the mounting system 100 is placed on the welding fixture, may range from about 3 mm to about 60 mm, or from about 12 mm to about 50 mm, or from about 15 mm to about 45 mm. The height of the curved profile 102 measured at or near the outer edge or peripheral rim portion may range from about 0.5 mm to about 55 mm, or from about 3 mm to about 45 mm, or from about 10 mm to about 40 mm. The thickness profile of the curved profile 102 when viewed from the side has a maximum height at the center or apex, and the height may gradually decrease toward the outer edges or peripheral rim portion to from a curved surface. The height difference across the cross-section of the curved profile 102 defined by the mounting system 100 may result in a concave downward curvature in the upper surface of the curved profile 102. In cross-section as viewed from the side, the shape of the curved profile 102 may resemble the upper half of an ellipse with its semi-minor axis much smaller than its semi-major axis. The ellipse may have an eccentricity close to but less than 1 (an eccentricity of 1 is a flat surface).

[0104] In an example, the mounting system 100 can be constructed from any metal having sufficient strength and temperature resistance for use under typical conditions of DED processing. The mounting system 100 can be made from a corrosion resistant metal. The mounting system 100 can be made from a heat resistant metal. The mounting system 100 can be made from a non-magnetic metal. The mounting system 100 can be made from a metal having a melting point of 1350°C or higher. In some configurations, the mounting system 100 can include an austenitic stainless steel. The austenitic stainless steel can include carbon, chromium, copper, manganese, molybdenum, nickel, nitrogen, phosphorus, silicon, or combinations thereof. The austenitic stainless steel can include at least 18% chromium. The mounting system 100 can be made from a 300 series stainless steel. The mounting system 100 can be made from a 304, 309, 310, 316, 318, 321, or 330 series stainless steel. The mounting system 100 can be made from grade AISI 330 stainless steel. The mounting system 100 can be made of a non-magnetic metal to avoid the unbalanced magnetic field conditions surrounding the welding arc in arc-based DED systems, which can cause a number of processing problems, such as magnetic arc blow.

[0105] In an example, the mounting system 100 can be employed without the use of, i.e., omitting, ceramic sheets, plates, or pylons. As previously noted, elimination of ceramic elements such as ceramic sheets, plates, or pylons can be advantageous in maintaining a low level of oxygen or an oxygen-free atmosphere. In an example, replacing a conventional ceramic insulating sheet with the mounting system 100 can result in a significantly more stable processing chamber atmosphere, as less or no water vapor is released into the chamber from the ceramic coating of the mounting system 100 during DED processing, compared to the amount of water vapor released from a conventional alumina ceramic plate.

[0106] In examples, the use of a ceramic coating can be implemented in the mounting system 100 if desired. In examples, ceramic coatings as described herein may not present the same problems discussed with respect to ceramic sheets, plates, or pylons. An advantage of a ceramic coating would be to further minimize or better prevent thermal energy transfer from the substrate or pre-bent substrate to the mounting system 100, from the mounting system 100 to the welding fixture, or both, during the DED process. Further reduction in thermal energy transfer can lead to reduced heat loss from the substrate or pre-bent substrate during DED.

[0107] In examples, a ceramic coating may be applied to a portion or area of ​​the mounting system 101 configured to be a contact interface between the mounting system 101 and a substrate or a pre-bent substrate. In examples, a ceramic coating may be applied to a portion or area of ​​the mounting system 101 configured to be a contact interface between the mounting system 101 and a welding fixture. Any combination of the above may also be employed. Also, in examples, additional ceramic coatings or elements may be employed. In examples, the mounting system 100 may be contoured with a metallic material and not coated with a ceramic coating or bond coat at a periphery or peripheral rim of the curved profile 102 defined by the mounting system 100.

[0108] In examples, the ceramic coating 108 may be applied directly to the surface of the mounting system 100 , or the ceramic coating may be applied to a bond coat 107 that is applied directly to the surface of the mounting system 100 .

[0109] The ceramic coating can be applied using any process including atmospheric plasma spraying, magnetron sputtering, chemical or electrochemical vapor deposition such as electrophoretic deposition, or physical vapor deposition such as electron beam physical vapor deposition. Any high temperature ceramic coating known in the art can be used (see, for example, U.S. Pat. Nos. 4,321,310 (Ulion et al., 1982), 5,789,330 (Kondo et al., 1998), 5,304,519 (Jackson et al., 1994), 6,387,539 (Subramanian, 2002), and 6,998,064 (Gadow et al., 2006). Exemplary ceramic coatings include, but are not limited to, tungsten, titanium, tantalum, tantalum oxide, tantalum carbide ... Examples of suitable ceramic coatings include zirconium dioxide, zirconium dioxide stabilized by the addition of yttrium oxide, yttrium aluminum oxide, alkaline earth metal silicates, ZrVO, Mg(VO), and combinations thereof. The mounting system 100 can be coated with zirconium dioxide stabilized by the addition of yttrium oxide, such as plasma sprayed ZrOYO, such as those commercially available as Metco™ 22xx and 23xx powders, including Metco 222A, 231A, 233A, 233B, 233C, and 234A (available from Oerlikon Metco, Frankfurt, Germany). The coating can include multiple layers of different types of ceramics, or multiple layers of one type of ceramic.

[0110] The ceramic coating used in mounting system 100 can be selected to be less hygroscopic than conventional alumina insulation. The ceramic coating used in mounting system 100 can be selected to be non-hygroscopic compared to conventional alumina insulation.

[0111] In an example, the mounting system 100 can include a bond coat 107. A bond coat is a coating of a material that can enhance adhesion between a substrate and a ceramic coating. A bond coat can provide corrosion resistance to a substrate to which it is applied. A bond coat can be used alone or in combination with a ceramic coating. A bond coat can include chromium and aluminum. A bond coat can include MCrAlY, where M is a metal selected from the group consisting of Co, Ni, Fe, Cr, Co, and Ni / Co combinations. In some applications, the bond coat can include MCrAlY, where M is Ni, Co, or a combination thereof. Exemplary bond coat materials include Amdry™ powder products, such as Amdry™ 962, 9621, 9624, 9625, 963, and 964 (available from Oerlikon Metco, Frankfurt, Germany). The bond coat can be present at a thickness of about 1 to 250 μm.

[0112] The thickness of the ceramic coating applied to the mounting system 100 can vary depending on the type of ceramic used and its ability to support both mechanical and thermal loads. In some configurations, the thickness of the entire ceramic coating can be from about 0.1 mm to about 5 mm, or from about 0.25 to about 4 mm, or from about 0.3 to about 3 mm. Although each deposited layer can be thinner than the total amount of ceramic coating applied, all applied layers of ceramic taken together can form a ceramic coating that is at least 0.1 mm, or at least 0.25 mm, or at least 0.5 mm, or at least 0.75 mm, or at least 1 mm, or at least 1.25 mm, or at least 1.5 mm, or at least 2.0 mm, or at least 2.5 mm, or at least 3.0 mm, or at least 3.5 mm, or at least 4.0 mm, or at least 4.5 mm. The ceramic coating may have a thickness of 0.1 mm, or 0.25 mm, or 0.5 mm, or 0.75 mm, or 1 mm, or 1.25 mm, or 1.5 mm, or 2.0 mm, or 2.5 mm, or 3.0 mm, or 3.5 mm, or 4.0 mm, or 4.5 mm, or 5 mm.

[0113] In an example, the mounting system 100 may include knurling on at least a portion of a surface area configured to contact a substrate or a pre-curved substrate directly or through an intervening ceramic coating when the mounting system 100 is in use. The knurled surface may form a linear pattern, a diagonal pattern, a diamond pattern, or a combination thereof on the substrate contact surface. The diamond-shaped knurling may be performed to be a male or female knurling pattern. In a male diamond pattern, raised points are formed. In a female diamond pattern, diamond indentations are formed. The knurling may result in pillars, each having linear sides substantially perpendicular to the arc of the curved profile 102 defined by the mounting system 100. The pillars may have a planar top surface. The pillars may have a curved top surface. The pillars may have a cross section that is square, rectangular, circular, elliptical, diamond, trapezoidal, triangular, pentagonal, hexagonal, heptagonal, nonagonal, decagonal, frustum-shaped, truncated pyramid-shaped, or any combination thereof. The posts may be separated from one another by spaces. The spacing between the posts may be substantially constant.

[0114] In an example, the mounting system 100 can include a corrugated or wavy surface on at least a portion of a surface area configured to contact a substrate or pre-bent substrate directly or through an intervening ceramic coating 108 when the mounting system 100 is in use. In an example, the surface of the mounting system 100 can be corrugated to include alternating ridges and grooves. In an example, the corrugations can extend across the substrate contact surface of the mounting system 100. In an example, the corrugations can extend from one long side of the mounting system 100 to the other long side. In an example, the corrugations can extend from a first edge to a second edge of the mounting system 100. In an example, the corrugations can result in multiple columns perpendicular to the arc of the curved profile 102. In an example, the corrugations can extend along at least one edge of one or more elements or structures from an array of elements or structures that make up the mounting system 100.

[0115] In an example, the knurling 103 can be a post with a planar top surface, as illustrated in FIG. 2C. In an example, the ridges can be posts with a curved top surface. As also illustrated, the knurling spacing 105 can have a planar bottom surface. In an example, the grooves can have a curved or U-shaped bottom surface. The grooves can include rounded corners to protect against stress concentrations and crack propagation. Each of the ridges can have a taper that increases in cross section along its longitudinal axis. In cross section, the ridges can have a trapezoidal shape. In cross section, the ridges can have the shape of an isosceles trapezoid, where the longer base of the trapezoid forms the base of the ridge and the shorter base of the trapezoid forms the apex of the ridge. In cross section, the ridges can have the shape of a convex isosceles trapezoid. In cross section, the ridges can have the shape of a regular square pyramid.

[0116] A ridge having a frustum-shaped cross section, particularly a square pyramid-shaped cross section, can transfer stress from the top to the base of the ridge while avoiding stress deformation of the ridge caused by applying pressure to the curved profile 102 of the mounting system 100 when the pre-bent substrate is pressed against the fixture. A ridge having a frustum-shaped cross section can withstand loads, forces, and moments that may be applied during the DED process. Forces and moments acting on the plateau of the ridge can be transferred to the base of the ridge and ultimately to the backside of the mounting system 100. When the ridge has a frustum-shaped cross section, the applied load can be transferred to a larger surface area of ​​the base of the ridge. In an example, the knurled surfaces or valleys between the ridges can form additional clearance between the mounting system 100 and the substrate or pre-bent substrate when the mounting system 100 is contacted with the pre-bent substrate. As mentioned previously, the gap can be filled with the atmosphere of the DED chamber or with a noble gas such as argon, which can act as a thermal insulator. Argon gas is a very effective thermal insulator. Solid / gas / solid interfaces have fairly low conductivity and can therefore act effectively as a thermal barrier.

[0117] In an example, the knurling pattern or corrugations of the mounting system 100 can be covered by a ceramic coating layer 108 and optionally a bond coat 107, as described above and shown, for example, in FIG. 2C. In an example, the ceramic coating can also be present in the valleys of the knurling pattern or the valleys of the corrugations. The thickness of the ceramic coating alone is limited by the application limitations of the mounting system 100 and the ability of the ceramic thickness to support a pre-bent substrate and an axially downward clamping force without damaging the ceramic coating when the substrate is clamped in a fixture. Due to limitations in coating technology, thicker ceramic layers can be more difficult to achieve while maintaining the ability of the ceramic layer to support a pre-bent substrate without damaging the ceramic coating when the substrate is clamped in a fixture. The exact support strength and thermal conductivity of the ceramic can be determined by the composition of the ceramic. For example, a 2 mm coating of a ceramic based on zirconium dioxide stabilized by the addition of yttrium oxide can provide good thermal isolation as well as good mechanical support of the substrate without damaging the ceramic coating when the substrate is clamped in a fixture.

[0118] In an example, the mounting system 100 can function as a shaping back structure. In an example, the mounting system 100 can function as a support / shaping back structure. The mounting system 100 can be positioned between a pre-bent substrate and a fixture when the pre-bent substrate is secured to the fixture. In an example, when the DED fabrication process is complete, a self-balancing residual stress state can be achieved that allows the substrate and the DED structure built on the substrate to bounce back upward after the clamps that hold the substrate to the fixture are released. The substrate straightens out after being released from the clamps.

[0119] In the example, the nominal deflection provided by the mounting system 100, h mountThe arc degree may be the difference between the maximum height at the center of the curved profile 102 and the top surface of the edge or peripheral rim portion 104 of the curved profile 102, as measured from the surface of the welding fixture when the mounting system 100 is positioned on the welding fixture, as shown in FIG. 2A. In FIG. 2A, the difference between the maximum height 198 of the curved profile 102 and the edge or peripheral rim portion 104 is h mount The length ratio L r and the surface area defined by the mounting system 100 is determined by a new x-dimension L of the surface area defined by the mounting system 100. i and the original length L0 of the surface area defined by the mounting system 100. The predicted maximum deflection h Lr is the nominal deflection h mount and the surface area length ratio L defined by the mounting system 100 r is approximately proportional to the product of x and the square of x, which can be calculated according to the following formula: L r =L i / L0 therefore, h Lr ≒h mount ×L r 2 .

[0120] Thus, for example, for a mounting system 100 defining a surface area with xy dimensions of 635 mm by 190 mm (L x W), the maximum predicted deflection h Lr is approximately 3.8 mm. A surface area that is longer, such as one with xy dimensions of 1905 mm by 635 mm, has a length ratio of 3 (L r = 1905 / 635 = 3), which is 3.8 x 3 2 Maximum deflection h of ≒34.2 mm Lr The nominal deflection may be from about 3 mm to about 35 mm. Thus, the amount of deflection may depend on the characteristics of mounting system 100. The longer mounting system 100 needs to be to accommodate longer substrates, the higher / larger the deflection needs to be.

[0121] 1. Pin support system and pins In an example, the mounting system 100 may include a pin support system 110. In an example, the pin support system 110 may include one or more pin structures or other solid standoff structures (referred to herein as "pins") 112. An example of the mounting system 100 embodied as a pin support system 110 having one or more pins 112 is shown in FIGS. 3A-3M. In an example, the pin support system 110 may include a single pin 112. In an example, the pin support system 110 may include two or more pins 112. In an example, the one or more pins 112 of the pin support system 110 may be positioned to engage a surface of a structure. In an example, the one or more pins 112 of the pin support system 110 may be mounted on a structure configured to be used in DED manufacturing. In an example, the one or more pins 112 of the pin support system 110 may be positioned to engage a welding fixture. In an example, the one or more pins 112 of the pin support system 110 may be mounted on a welding fixture. In an example, one or more pins 112 of the pin support system 110 may be positioned on a weld fixture.

[0122] In examples, implementing mounting system 100 as pin support system 110 may provide one or more advantages. In examples, pin support system 110 may be implemented without the use of ceramic sheets and / or ceramic coatings while still achieving low thermal conduction. In examples, pin support system 110 may be implemented without the use of ceramic sheets. In examples, pin support system 110 may reduce costs. In examples, the use of an array of pins 112 may require less material than is required to form other types of support structures, such as grids or molds. In examples, pin support system 110 may exhibit an extended life span when compared to other types of support structures.

[0123] In an example, the pin support system 110 may be reconfigurable. In an example, one or more pins 112 may be installed and reinstalled as desired. In an example, the pin support system 110 may be reconfigured for use with different sized substrates or pre-bent substrates. In an example, the pin support system 110 may include an array of pins 112 configured to be removably installed. In an example, the pin support system 110 may include an array of pins 112 that can be installed and reinstalled to achieve any desired arrangement. In an example, the reconfigurability of the pin support system 110 due to the flexibility of the arrangement of the array of pins 112 may lead to improved or more effective distortion reduction when compared to other support structures such as grids or molds. In an example, the pins 112 may be arranged based on the design of the part being manufactured. In an example, by arranging the pins 112 based on the design of the part being manufactured, a user may be able to provide support where it is most needed to reduce distortion.

[0124] In examples, the spacing between the pins 112 can vary depending on the support desired. In examples, the pins 112 may be spaced 10 mm to 50 mm apart on the welding fixture, and in examples, the distance between two pins 112 may be 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, or 40 mm. These ranges and measurements are examples only. In examples, all pins 112 of a pin support system 110 may be equidistant from one another. In examples, the pins 112 of a pin support system 110 may not be equidistant from one another. In examples, two or more pins 112 of a pin support system 110 may be spaced closer to one another than two or more other pins 112 of the pin support system 110. Any combination or variation of these arrangements is also possible.

[0125] In an example, the pin support system 110 including one or more pins 112 may have advantages over other types of support structures by being able to provide increased space or clearance between the substrate or pre-bent substrate and the surface of the welding fixture. In an example, the pin support system 110 may be configured to occupy less space than other support structures because the one or more pins 112 may be placed only at the desired support locations without interconnect structures spanning other areas. In an example, the pin support system 110 may provide the flexibility to increase the space or clearance between the substrate or pre-bent substrate and the surface of the welding fixture by employing one or more pins 112 having a large pin support height.

[0126] As explained above, it may be possible to fill the gaps or spaces formed between the substrate or pre-bent substrate and the welding fixture with the atmosphere of the DED chamber or a noble gas such as argon, which may act as a thermal insulator. These gaps and spaces also provide a solid / gas / solid interface with a fairly low thermal conductivity. Thus, these interfaces between the pre-bent substrate / argon gas / mounting system and / or the welding fixture may effectively function as a thermal barrier. Thus, in examples, the gap or spaces may also help to minimize the average heat transfer rate between the substrate or pre-bent substrate and the welding fixture. In examples, this may help to retain more heat within the pre-bent substrate, thereby further reducing uneven temperature distribution and reducing thermal stresses within the pre-bent substrate.

[0127] In an example, one or more pins 112 of the pin support system 110 can be positioned to support the substrate or pre-bent substrate at a location proximate to the clamp. In an example, one or more pins 112 of the pin support system 110 can be positioned to support a central region of the substrate or pre-bent substrate. In an example, one or more pins 112 of the pin support system 110 can be positioned to support a central region of the substrate or pre-bent substrate to prevent warping.

[0128] In an example, one or more clamps can be used to secure the pre-bent substrate to the fixture. As a result, the substrate or pre-bent substrate is pressed toward the fixture so that the force required to secure the substrate or pre-bent substrate to the fixture exists between the clamp and the fixture, and the pin support system 110 has one or more pins 112 as support between the substrate or pre-bent substrate and the welding fixture. In an embodiment, the pre-bent substrate is pressed axially downward. In an example, the backside (first side) of the pre-bent substrate, where the melt track may be present, can be positioned to face the pin support system 110. In this configuration, the backside of the pre-bent substrate faces downward toward the pin support system 110 and the fixture. As previously described, one or more clamps can be used to secure the pre-bent substrate to the fixture, with the pin support system 110 sandwiched between the pre-bent substrate and the fixture.

[0129] In examples, the pins 112 of the pin support system 110 can be constructed from any metal having sufficient strength and temperature resistance for use under typical conditions of a DED process, as discussed above when discussing the mounting system 100. In examples, all of the pins 112 of the pin support system 110 are made from the same material. In examples, the material of each pin 112 can be independently selected. In examples, at least a first pin of the plurality of pins includes the same material as at least a second pin of the plurality of pins of the pin support system 110. In examples, at least a first pin of the plurality of pins includes a different material than the material included in at least a second pin of the plurality of pins of the pin support system 110.

[0130] As previously discussed, in examples, ceramic sheets, plates, and coatings are not used in the implementation of mounting system 100. In examples, pin support system 110, one or more pins 112, or both do not include ceramic and / or ceramic coatings. In examples, pin support system 110 may not include any ceramic sheets, plates, and pylons. In examples, one or more ceramic elements or coatings may be used in combination with pin support system 110, if desired. In examples, one or more pins 112 may include a coating of ceramic and / or bond coating as previously discussed. In examples, ceramic coating and / or bond coating may be applied to at least pin substrate contact surface 119. In examples, where one or more spacers 128 are ceramic spacers, ceramic coating spacers, or a combination of both, one or more 128 may be employed as described herein. The ceramic types, coating processes, and properties of ceramic elements and / or coatings previously discussed apply equally to mounting in pin support system 110 and / or mounting to one or more pins 112.

[0131] In examples, the pins can have any desired shape and size that enables the functionality described herein. In examples, the pins 112 can have shapes that are generally elongated, spherical, cubic, trapezoidal, cylindrical disk-shaped, conical, round, angular, annular, non-spherical, regular, irregular, and any combination thereof. FIG. 3A shows some exemplary shapes of the pins 112. In examples, the pins 112 can include an elongated shape as generally shown. In examples, the pins 112 can have a cross-sectional diameter, width, or thickness that is uniform over the length of the pin or pin structure 112, as shown, for example, by samples 114a, 114b, and 114c. In examples, the pins can include a tapered profile, as shown, for example, by samples 115a, 115b, and 116c. In an example, the pin 112 may include one or more portions having a cross-sectional diameter, width, or thickness greater than the cross-sectional diameter, width, or thickness of at least one other portion of the pin 112, for example, as illustrated by samples 115a, 115b, and 116a-116f. In an example, the pin 112 may have a mushroom shape, for example, as illustrated by samples 116a, 116b, 116d, 116e, 116f. In an example, one or more portions of the pin 112 may have a different shape than at least one other portion of the pin, for example, as illustrated by samples 116a-116f. In an example, one portion of the pin 112 may have a trapezoidal shape and a second portion may have a cylindrical shape, for example, as illustrated by samples 116c, 116d, 116e, 116f. In an example, one portion of the pin 112 may have a spherical or hemispherical shape and a second portion may have a cylindrical shape, for example, as shown by samples 116a and 116b. In an example, the pin 112 as shown may include a trapezoidal shape instead of a cylindrical shape. Any combination of two or more of the above shapes may be used for the shape of the pin 112. In an example, the pin 112 may include a conical shape, for example, as shown in FIG. 3B. In an example, the pin 112 may include a portion having a cylindrical shape and a portion having a conical shape, as shown in FIG. 3B.In an example, the cone shape may include a double cone shape oriented in opposite directions, as shown in FIG. 3B.

[0132] In an example, the pin 112 may include a pin head portion 118. In an example, the pin head portion 118 includes at least a portion of the pin 112 that is configured to remain exposed, i.e., extend beyond the surface of the device to which the pin 112 is connected, upon installation of the pin 112 in a welding fixture. In an example, the pin head portion 118 may have any shape or size. In an example, the pin head portion 118 may have a width or diameter ranging from 10 mm to 40 mm, and a length ranging from 0.05 mm to 10 mm. These dimensions are merely examples. In an example, the pin head portion 118 may have the same or different shape and / or size as the base portion or engagement portion 124. In an example, as shown in FIG. 3B, the pin head portion 118 may include a double cone shape. In an example, the pin 112 may include a double cone shape to function as a countersunk screw or bolt to help achieve a flush fit with the surface to which the pin 112 is installed. In an example, the pin head portion 118 of the pin 112 may be configured to sit flat on a surface of the weld fixture when contacted with the weld fixture.

[0133] In an example, the pin head portion 118 can include a substrate contact surface 119. In an example, the pin substrate contact surface 119 includes a surface area of ​​the pin 112 configured to contact a substrate or a pre-bent substrate during use of the pin support system 110. The pin substrate contact surface 119 can have any desired size. In an example, the pin substrate contact surface 119 is 15 mm 2 ~60mm 2 This range is merely an example.

[0134] In examples, pin substrate contact surface 119 can be flat, contoured, rounded, convex, concave, hollow, corrugated, knurled, or any combination thereof, as also shown in FIGURE 3B. The corrugations and / or knurling of pin substrate contact surface 119 can be accomplished in the same manner as any other surface, as described above in the discussion of mounting system 100.

[0135] In examples, the area of ​​the pin-substrate contact surface 119 of the pin 112 can be the substrate contact area of ​​the pin 112. In examples, the substrate contact area of ​​the pin 112 can be adjusted or configured to be different from or less than the area of ​​the pin-substrate contact surface 119. In examples, the substrate contact area of ​​the pin 112 can be a portion or fraction of the area of ​​the pin-substrate contact surface 119 of the pin 112. In examples, the substrate contact area of ​​a pin 112 configured to have a pin-head substrate contact surface 119 having a surface contour or profile that is uneven, rounded, convex, concave, hollow, corrugated, knurled, or any combination thereof can be less than the area of ​​the surface of the pin-head substrate contact surface 119. In an example, the substrate contact area of ​​a single pin 112 corresponds to the surface area of ​​the pin head substrate contact surface 119 if the pin head substrate contact surface 119 is a uniform, flat or planar surface that is configured to be parallel to a surface of the welding fixture that faces the substrate or pre-bent substrate in use and is configured to contact the substrate or pre-bent substrate when the pin support system 110 is used as the mounting system 100. In an example, the substrate contact area of ​​a single pin 112 will be less than the surface area of ​​the pin head substrate contact surface 119 if the pin head substrate contact surface 119 is uneven, rounded, convex, concave, hollow, corrugated, knurled, i.e., is not a uniform, flat or planar surface, and / or is not configured to be parallel to a surface of the welding fixture that faces the substrate or pre-bent substrate in use. In this latter case, the substrate contact area of ​​a pin 112 will be only that portion of the surface area of ​​the pin head substrate contact surface 119 that is configured to contact the substrate or pre-bent substrate in use.

[0136] In examples, the pin head portion 118 may include any lateral profile. In examples, the lateral profile of the pin head portion 118 may be tapered, linear, stepped, regular, irregular, rounded, planar, or flat, or any combination thereof. In examples, as shown in FIG. 3B, the pin head portion 118 may include one or more flat regions 120. In examples, the one or more flat regions 120 may be disposed across at least a portion of the lateral profile of the pin head portion 118. In examples, the flat regions 120 may aid in the attachment of the pin 112.

[0137] In an example, the pin head portion 118 can be configured to be wider than the base portion 124. In an example, the pin head portion 118 can include a wider pin head portion 118 that can be configured to contact a surface of a welding fixture when the pin 112 is installed. This can allow for more support and improved resiliency of the pin 112 when a substrate or pre-bent substrate is pressed against the pin support system 110.

[0138] In an example, as shown in FIG. 3B, the pin head portion 118 may include an area 121 that may contact or otherwise interface with a surface of a weld fixture to which the pin 112 is attached. In an example, the pin head portion 118 may include a weld fixture interface area 121 at an opposite end from where the pin head substrate contact surface 119 is located. The interface between the pin head portion 118 and the surface of the weld fixture may be affected by the contour of the surface of the pin head portion 118 that is configured to face the surface of the weld fixture when the pin 112 is attached to the weld fixture. In an example, the pin head portion 118 may be configured to have a flat, planar, tapered profile along the surface 121 that is intended to interface with the weld fixture. In an example, the surface 121 is flat and configured to be horizontal to the surface of the weld fixture when the pin 112 is attached. In an example, the surface 121 may be configured such that the pin head portion 118 may sit flat on the fixture when the pin 112 is attached. In an example, the surface 121 of the pin head portion 118 intended to interface with the weld fixture may be configured to have a bumpy, rounded, irregular shape, and / or may be knurled, corrugated, or may include ridges, valleys, or similar features as described with respect to the pin substrate contact area 119. In an example, having a smooth or more conforming profile in the area 121 of the pin head portion 118 configured to interface with the weld fixture may provide a flush installation. In an example, having a non-smooth, bumpy, corrugated, or knurled profile in the area 121 of the pin head portion 118 configured to interface with the weld fixture may provide an additional barrier against heat transfer from the pin 112 to the weld fixture and indirect heat transfer from the substrate or pre-bent substrate to the weld fixture. In an example, the weld fixture interface area 121 of all pins 112 of the pin support system 110 may define a side of the pin support system 110.

[0139] In an example, the pin 112 may include a collar portion 122 located between the pin head portion 118 and the pin base portion 124. In an example, the collar portion 122 may be below the weld fixture interface area 121, adjacent to the weld fixture interface area 121, and / or overlapping the weld fixture interface area 121. In an example, the collar portion 122 may have any desired size and / or profile. In an example, the collar portion 122 may have a width or diameter different from the pin base portion 124, the pin head portion 118, or both. In an example, the collar portion 122 may have a width or diameter in the range of 2 mm to 10 mm, and a length in the range of 5 mm to 10 mm. These size ranges are examples only. In an example, as shown in FIG. 3C, the collar portion 122 may be configured to accommodate one or more pin spacers 128 to provide support and / or add thermal insulation between the pin head portion 118 and the surface of the weld fixture on which the pin 112 is placed. In examples, pin spacer 128 can be configured in any size and shape that can fit into collar portion 122. In examples, pin spacer 128 can include a washer, ring, plate, or similar structure. In examples, pin spacer 128 can include a metal or similar material as described for pin or structure 112 or used in mounting system 100. In examples, pin spacer 128 can include a ceramic as described herein. In examples, pin spacer 128 can include a metal and a ceramic.

[0140] In an example, the pin 112 may include a base portion or engagement portion 124. In an example, the base portion or engagement portion 124 may refer to a portion of the pin 112 configured to engage an opening, fitting, bore, or threaded hole of a device to which the pin 112 is connected. In an example, the base portion or engagement portion 124 may be configured to have any desired shape and size. In an example, the base portion or engagement portion 124 may have a width or diameter ranging from 2 mm to 10 mm, and a length ranging from 10 mm to 50 mm. These size ranges are merely examples. In an example, the base portion or engagement portion 124 of the pin 112 may be configured to engage a welding fixture. In an example, the base portion or engagement portion 124 may be configured to removably engage a structure. In an example, the base portion or engagement portion 124 may be configured to be removably engaged to a welding fixture.

[0141] Any suitable means for engaging the base or engagement portion 124 with the weld fixture to allow installation of the pin 112 in the weld fixture may be employed. In an example, the base or engagement portion 124 may be configured as a bearing, screw, bolt, or similar structure. In an example, the weld fixture may provide a suitable opening, fitting, bore, threaded hole, or similar structure for engaging the base or engagement portion 124. In an example, the base or engagement portion 124 may be disengageable from one or more of a plurality of openings, fittings, bores, threaded holes, or similar structures provided in the weld fixture. In an example, the base or engagement portion 124 may be configured to permanently engage a fitting, bore, threaded hole, or similar structure provided in the weld fixture.

[0142] 3C illustrates an example of the installation of the pin 112 in a weld fixture 400. As shown, the weld fixture 400 may include a bore 126 configured to receive the base or engagement portion 124. As also shown, when the pin 112 is installed, the pin head portion 118 may be left exposed and extend from a surface of the weld fixture 400.

[0143] In an example, the base or engagement portion 124 may engage directly with the weld fixture, engage any structure attached to the surface of the weld fixture, or engage any combination thereof. This allows flexibility to place one or more pins 112 on any contour. Engagement of the pins 112 to structures provided on the surface of the weld fixture may be performed in a manner as described with respect to the weld fixture. In an example, the added structure may include one or more openings, fittings, bores, or threaded holes or fittings on one or more surfaces thereof. In an example, the bores of the fittings may be configured similarly to the bore or threaded hole structure 126 of the weld fixture 400.

[0144] In an example, the pin 112 may be configured to allow an adjustable distance between a surface of the welding fixture and a portion of the pin head substrate contact surface 119 that is configured to physically contact the substrate or pre-bent substrate in use. For purposes of this description, the perpendicular linear distance between the surface of the welding fixture that faces the substrate or pre-bent substrate in use and the portion of the pin substrate contact surface 119 that is configured to physically contact the substrate or pre-bent substrate in use is referred to as the "pin support height" (h pin support ) which we will call.

[0145] In an example, the pin 112 may be configured to allow adjustment of the pin support height independent of the degree of engagement by the base or engagement portion 124. In an example, the pin 112 may be configured to have an extendable portion. The adjustable portion may be the base or engagement portion 124, the pin head portion 118, or both. In an example, a portion of the pin 112 may be configured to slide in and out of another portion of the pin 112. In an example, a portion of the pin 112 may include a threaded bearing that allows the pin 112 to extend or retract by rotating a first end of the threaded bearing relative to a second end of the threaded bearing. In an example, the base or engagement portion 124 of the pin 112 may be configured to engage a fitting at various depths. In an example, the base or engagement portion 124 of the pin 112 may be configured to include an elongated thread configured to secure the pin to a threaded fitting of a weld fixture at various depths. In an example, as shown in FIG. 3D, rotating the base or engagement portion 124 of the pin or structure 112 in a clockwise direction may move it through the threaded joint in a first longitudinal direction, moving the pin head portion 118 closer to the surface of the weld fixture. Conversely, in an example, rotating the base or engagement portion 124 of the pin or structure 112 in a counterclockwise direction may move it through the threaded joint in a second longitudinal direction opposite the first longitudinal direction, moving the pin head portion 118 away from the surface of the weld fixture. In an example, the pin support height may be adjusted by translating the pin head portion 118 toward and away from the surface of the weld fixture. In an example, one or more spacers 128 may be employed when adjusting the pin support height. In an example, one or more spacers 128 may be introduced between the pin head portion 118 and the surface of the weld fixture facing the pin head portion 118, as described above. In examples, the spacer(s) 128 may be a washer or similar structure configured to fit around the collar 122 of the pin 112 .In an example, disposing one or more spacers 128 between the pin head portion 118 and the surface of the weld fixture, for example as shown in FIG. 3C, may position the pin head portion 118 further away from the surface of the weld fixture, resulting in an increased pin support height. In an example, removing one or more spacers 128 from the space between the pin head portion 118 and the weld fixture surface may position the pin head portion 118 closer to the weld fixture surface, resulting in a decreased pin support height. In an example, different numbers of spacers 128 may be used for different pins 112 to achieve different pin support heights across an array of pins 112. In an example, the spacers 128 may provide additional stability and / or support to the pin head portion 118 by filling the space between the pin weld fixture interface area 121 and the surface of the weld fixture. In an example, the spacers 128 may also help achieve a uniform pin support height and / or pin support height adjustment. In an example, any combination of the pin support height adjustment methods described above may be used.

[0146] 3D, the pin support height of the pin 112 may depend on the size of the pin 112 or the size of any portion of the pin 112. In an example, as shown in FIG. 3D, different pins 112 employed in the pin support system 110 may have different sizes and therefore different pin support heights.

[0147] In an example, mounting system 100 can be implemented using pin support system 110 by installing one or more pins 112 on weld fixture 400 and / or one or more structures provided on weld fixture 400. In an example, pin support system 110 can include an array of pins 112. The array can be two or more pins.

[0148] a. Multi-pin pin support system In examples, the pin support system 110 may include an array of two or more pins 112. In examples, the array of two or more pins 112 may be disposed on a surface of a structure, such as a welding fixture, as described above. In examples, the pin support system 110 may include any number of pins 112. In examples, the total number of pins 112 in the pin support system may be limited by the size of the pins 112, the size of the substrate or pre-bent substrate that the pin support system 110 is configured to contact, or a combination of both. Each of the two or more pins 112 may also have any desired size. In examples, the size of the one or more pins 112 may be limited by the number of pins employed, the size of the substrate or pre-bent substrate that the pin support system 110 is configured to contact, or a combination of both.

[0149] The pin support system 110 may be configured to include a predetermined substrate contact interface. In an example, the size and number of pins 112 may affect the total substrate contact area of ​​the pin support system 110 and therefore the substrate contact interface of the pin support system 110, as described above. For purposes of the substrate contact interface of the pin support system 110, the substrate interface area may be understood to be the substrate interface area 130, as described. In an example, the pin support system 110 may be configured to have an array of pins 112 arranged and configured to provide a controlled substrate contact interface that falls within the range of 0.1 to 20. In an example, the substrate interface of the pin support system 110 for a given substrate interface area 130 may be defined by the number of pins 112, the size of the substrate contact area of ​​the pins 112, or a combination of both. In an example, the pin support system 110 may provide increased flexibility in controlling the substrate contact interface by adding or removing pins 112 and / or by replacing one or more pins 112 with one or more pins 112 having a different sized substrate contact area.

[0150] In examples, the pin support system 110 can be configured to include a substrate contact interface that is greater than or equal to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 and less than or equal to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. In examples, the pin support system 110 can be configured to have a substrate contact interface in the range of 0.1-15, 0.1-10, 0.1-5, or 0.1-1. In examples, the pin support system 110 can be configured to have a substrate contact interface in the range of 0.1-15, 0.1-10, 0.1-5, or 0.1-1. In examples, the pin support system 110 may be configured to have a substrate contact interface in the range of 0.2-20, 0.2-15, 0.2-10, 0.2-5, or 0.2-1. In examples, the pin support system 110 may be configured to have a substrate contact interface in the range of 0.3-20, 0.3-15, 0.3-10, 0.3-5, or 0.3-1. In examples, the pin support system 110 may be configured to have a substrate contact interface in the range of 0.5-20, 0.5-15, 0.5-10, 0.5-5, or 0.5-1. In examples, the pin support system 110 may be configured to have a substrate contact interface in the range of 0.6-20, 0.6-15, 0.6-10, 0.6-5, or 0.6-1. In examples, the pin support system 110 can be configured to have a substrate contact interface in the range of 0.7 to 20, 0.7 to 15, 0.7 to 10, 0.7 to 5, or 0.7 to 1. In examples, the pin support system 110 can be configured to have a substrate contact interface in the range of 0.8 to 20, 0.8 to 15, 0.8 to 10, 0.8 to 5, or 0.8 to 1. In examples, the pin support system 110 can be configured to have a substrate contact interface in the range of 0.9 to 20, 0.9 to 15, 0.9 to 10, 0.9 to 5, or 0.9 to 1.

[0151] In an example, the pin support system 110 may be configured to include a first side 111 and a second side defined by one or more pins 112. In an example, the first side of the pin support system 110 may correspond to a side where the one or more pins 112 interface with a welding fixture. In an example, the one or more pins 112 may define a curved profile 102 as described above. In an example, the curved profile 102 may be on a second side 113 of the pin support system 110 opposite the first side. In an example, the second side 113 is also a side where the substrate contact interface 130 of the pin support system 110 is provided or defined. In an example, the curved profile 102 may be defined by one or more pins 112 on a side of the pin support system 110 configured to face a substrate or a pre-bent substrate in use. In an example, when the pin support system 110 includes two or more pins 112, the curved profile 102 may be a plane defined by the distal ends of the two or more pins 112, as discussed with reference to FIG. 2A where the two or more pins 112 are represented by element or structure 101. In an example, the distal ends of the pins 112 for purposes of defining the curved profile of FIG. 2A may include at least a portion of a pin substrate contact surface 119 configured to physically contact a substrate or pre-bent substrate in use. In an example, an area of ​​the mounting system 100 configured to receive a substrate or pre-bent substrate when the mounting system 100 is implemented as the pin support system 110 may be defined by one or more pins or pin structures 112 arranged to define a peripheral area of ​​the pattern when placed in a welding fixture.

[0152] In examples, it may be possible to arrange one or more pins 112 in any desired manner. In examples, one or more pins 112 may be configured to be arranged to have varying pin support heights. In examples, at least one or more pins 112 may be configured to have a pin support height that is greater than the pin support height of at least one other pin 112. In examples, the pin support height of one pin 112 may be differentiated from the pin support height of at least one other pin 112 by using a pin 112 configured to have an adjustable pin support height as described above, by using pins 112 having different sizes, or by a combination of both.

[0153] In an example, two or more pins 112 of the pin support system 110 may be arranged to define a curved profile 102, as described above. In an example, the pin support system 110 may be configured to include one or more pins 112 having a first pin support height disposed on the welding fixture at a first location and one or more pins 112 having a second pin support height disposed on the welding fixture at a second location. In an example, the first pin support height is different from the second pin support height. In an example, the first pin support height is less than the second pin support height. In an example, the one or more pins 112 having the smaller pin support height are arranged to surround the one or more pins 112 having the larger pin support height. In an example, the pin support system 110 may include one or more pins having a third pin support height. The third pin support height may be different from the first and second pin support heights. In an example, the pin support system 110 may include any number of one or more pins 112 having different pin support heights. In an example, the pin support system 110 may include an array of pins 112 arranged in a pattern, where one or more pins 112 located in a peripheral region of the pattern have a pin support height that is smaller than the pin support height of one or more pins 112 located in a central region of the pattern. In an example, the pin support system 110 may include an array of pins 112 arranged in a pattern such that the pin support height gradually increases from the peripheral region of the pattern toward the central region of the pattern. In an example, the gradually increasing pin support height toward the central region of the pattern of arranged pins 112 may define a curved profile 102 that can clamp a substrate or a pre-bent substrate.

[0154] 3E-3H show an exemplary implementation of the pin support system 110 as the mounting system 100 described above. FIGS. 3E and 3F show top views of an example of the pin support system 110 including an array of pins 112 arranged to define a substrate interface area 130. In an example, the substrate interface area of ​​the pin support system 110 is larger than a physical surface area of ​​the pin support system 110 configured to face a substrate or a pre-bent substrate when the pin support system 110 is in use. In an example, the physical surface area of ​​the pin support system 110 is limited to a surface of one or more pins 112 that constitute the pin support system 110, while the substrate interface area 130 should be understood to be an area on one side of the support system 110 that is intended to be occupied by a substrate or a pre-bent substrate when the pin support system 110 is in use. In an example, as shown, one or more pins 112 that are part of the pin support system 110 may be arranged to delineate a perimeter or boundary of the substrate interface area 130 intended for the pin support system 110. In an example, it may be possible to reconfigure the boundaries of the substrate interface area 130 of the pin support system 110 by repositioning one or more pins 112. In an example, the one or more pins 112 of the pin support system 110 that define the boundaries of the substrate interface area 130 may be one or more pins 112 located at the periphery of a set or cluster of one or more pins 112. In an example, the pins 112 in the peripheral region of the substrate interface area 130 may be close to where the clamp 500 is to be placed. This may allow the substrate or pre-bent substrate to be clamped when the pin system 110 is used. In an example, the pins 112 may also be located in a central region to support a central portion of the substrate or pre-bent substrate 300. In an example, the pins 112 located closest to the clamp 500 may have a pin support height that is smaller than the pin support height of the pins 112 located at the central portion of the substrate interface area 130, or may be adjusted to have a pin support height that is smaller than the pin support height of the pins 112 located at the central portion of the substrate interface area 130.As shown in Figures 3E and 3F, the pins 112 of the pin support system 110 may be provided in different numbers, different arrangements, different spacing, or any combination thereof to accommodate different sized substrates or pre-bent substrates.

[0155] In an example, the curved profile achieved by one or more pins 112 of the pin support system 110 can resemble the curved profile of a monolithic structure, such as a lattice or mold structure, described below. In an example, the one or more pins 112 can be positioned to define a curved profile 102 having a height measured at or near the center of the curved profile 102 in a range of about 3 mm to about 60 mm, or about 12 mm to about 50 mm, or about 15 mm to about 45 mm, as measured from the surface of the welding fixture, and their pin support heights can be adjusted or selected. Similarly, the one or more pins 112 of the pin support system 110 can be selected and / or adjusted to have a pin support height such that the height of the curved profile 102, as measured from the welding fixture surface facing the pre-bent substrate in use, at or near the outer edge of the curved profile 102, is in a range of about 0.5 mm to about 55 mm, or about 3 mm to about 45 mm, or about 10 mm to about 40 mm. In an example, when viewed from the side, the thickness profile of the curved profile defined by the one or more pins 112 of the pin support system 110 may have a maximum height at the center of the curved profile, the center of the substrate interface area 130 defined by the one or more pins 112, or both, and the height may gradually decrease toward the outer edge or periphery of the curved substrate interface area 130. In an example, the height difference across the cross section of the pin support system 100 may result in a concave downward curve. In a cross section viewed from the side, the shape of the curved profile defined by the pin support system 110 may resemble the upper half of an ellipse with its semi-minor axis much smaller than its semi-major axis. The ellipse may have an eccentricity close to but less than 1 (an eccentricity of 1 is a flat surface).

[0156] 3G and 3H show schematic side views of the pin support system 110 including an array of pins 112 in use mounted on a welding fixture 400 having a substrate or pre-bent substrate 300 clamped thereon by a clamp 500. As shown in FIGURES 3G and 3H, the pin support system 110 can be implemented with a variety of numbers of pins 112. FIGURE 3I shows additional examples of pins 112 having different shapes and sizes that can be used in the pin support system 110.

[0157] 3J-3M show schematic cross-sectional side views of a DED manufacturing process using a pin support system 110 as a mounting system 100. In an example, the clamps 500 can be positioned along the entire circumference of the substrate or pre-bent substrate 300. In the figures, the clamps 500 are only shown at the ends because they are cross-sectional side views to show the pin support system 110 that would otherwise be covered by the pre-bent substrate 300 and the clamps 500. As shown in FIG. 3J, the pre-bent substrate 300 can be clamped onto the pin support system 110, which includes one or more pins 112 disposed on a welding fixture 400, using the clamps 500. As shown in FIG. 3J, the array of pins 112 of the pin support system 110 can be configured and arranged to provide a curved profile on which the substrate or pre-bent substrate 300 is placed. In an example, the one or more clamps 500 can apply sufficient pressure to the substrate or pre-bent substrate to conform the substrate or pre-bent substrate to the curved profile defined by the array of pins 112. The pre-bent substrate 300 can then be heat treated as shown in FIG. 3K. In an example, after heat treatment, the DED fabrication can proceed as shown in FIG. 3L with deposition of one or more layers using a deposition device, such as a plasma arc torch 250. Once the deposition process is complete, the clamps 500 can be removed as shown in FIG. 3M. As shown, by using the pin support system 110 as the mounting system 100 in combination with a distortion relief process as described herein, the resulting workpiece is expected to have an improved profile.

[0158] As previously described for mounting system 100, in the example, the nominal deflection provided by pin support system 110, h pin supportThe arc degree may be the difference between the maximum height at the center of the curved profile 102 and the top surface of the edge or peripheral rim portion 104 of the curved profile 102, as measured from the surface of the welding fixture when the pin support system 110 is positioned on the welding fixture, as shown in FIG. 2A. In FIG. 2A, the difference between the maximum height 198 of the curved profile 102 and the edge or peripheral rim portion 104 is h pin support The length ratio L r and the surface interface area 130 defined by the pin support system 110 is a new x-dimension L of the surface area defined by the pin support system 110. i and the original length L0 of the surface area defined by the pin support system 110. The predicted maximum deflection h Lr is the nominal deflection h pin support and the surface area length ratio L defined by the pin support system 110 r is approximately proportional to the product of x and the square of x, which can be calculated according to the following formula: L r =L i / L0 therefore, h Lr ≒h pin support ×L r 2 .

[0159] Thus, for example, for a pin support system 110 defining a surface interface area 130 with xy dimensions of 635 mm by 190 mm (L×W), the maximum predicted deflection h Lr is approximately 3.8 mm. A surface area that is longer, such as one with xy dimensions of 1905 mm by 635 mm, has a length ratio of 3 (L r = 1905 / 635 = 3), which is 3.8 x 3 2 Maximum deflection h of ≒34.2 mm LrThe nominal deflection may be from about 3 mm to about 35 mm. Thus, the amount of deflection may depend on the characteristics of the pin support system 110. The longer the surface interface area 130 defined by the pin support system 110 needs to be to accommodate a longer substrate, the higher / larger the deflection needs to be.

[0160] b. Single pin support system In an example, the mounting system 100 may be implemented as a single pin pin support system 110. In an example, the single pin pin support system may include a single pin 112 as described. In an example, if the pin support system 110 is a single pin pin support system, the pin support system 110 may include a first side that interfaces or faces a welding fixture as described for the pin 112 when installed, and a second side that has or defines a curved profile 102. In an example, the curved profile 102 may be a profile of the top surface of the single pin 112. In an example, if the pin support system 110 is a single pin, the pin may be configured to include a curved physically modified surface configured to be oriented away from the fixture when installed in the fixture, as described for the curved clamping die 170 described below. The pin of the single pin pin support system may include a pin head 118 having a thicker center portion than the edges, as described for the clamping die 170, including dimensions. Also, similar to the clamping die 170, the pins used in the single pin pin support system can include a first side having a peripheral rim. In an example, the peripheral rim can have a flat or planar surface on at least one side. In an example, as discussed for the clamping die 170, for the single pin pin support system, the pins can include a structure configured to have a surface contact interface that falls within the range of 0.1 to 20 or any subrange thereof as discussed. Also, similar to the description of the curved clamping die 170, the single pin pin support system 110 can include one or more ceramic coatings and / or bond coatings and exhibit the same or similar nominal deflection as described for the curved clamping die 170.

[0161] 2. Lattice support structure In an example, the mounting system 100 may include as a lattice support structure 150. Examples of lattice support structures 150 are shown in Figures 4A-4D. In an example, the lattice support structure 150 may include a framework or structure of one or more metal elements 151. In an example, the lattice support structure 150 may be a frame.

[0162] In examples, the metal elements 151 can be any desired shape and size. In examples, the metal elements can be elongated, spherical, cubic, trapezoidal, and can have regular or irregular shapes, and any combination thereof. In examples, the metal elements 151 of the lattice support structure 150 include strips, rods, bars, or similar structures. As shown in the schematic perspective view provided in FIG. 4A, the top view in FIG. 4B, and the side view in FIG. 4C of the lattice support structure 150, the metal elements 151 can have uniform shapes and sizes, different shapes and sizes, and any combination thereof.

[0163] In examples, the metal elements 151 that make up the lattice support structure 150 can have any arrangement. As shown, the metal elements 151 are perpendicular and parallel to one another. In examples, the metal elements 151 can be at an angle to one another or can be randomly arranged. The metal elements 151 can be connected to one another by any known fasteners, such as bolts, screws, brackets, pins, bearings, or similar structures. In examples, the metal elements 151 can be attached to one another by welding, fusion, or adhesives. In examples, the metal elements 151 can all be part of one integral continuous structure. In examples, the lattice support structure 150 can include any one or more of the above-mentioned arrangements of metal elements 151 connected to one another in any one or more of the described manners and / or as part of a continuous integral structure.

[0164] The grating support structure 150 can be configured to include a predetermined substrate contact interface. In examples, the grating support structure 150 can be configured to have a substrate contact interface in the range of 0.1 to 20. In examples, the grating support structure 150 can be configured to include a substrate contact interface that is greater than or equal to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1, and less than or equal to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. In examples, the grating support structure 150 can be configured to have a substrate contact interface in the range of 0.1 to 15, 0.1 to 10, 0.1 to 5, or 0.1 to 1. In examples, the lattice support structure 150 may be configured to have a substrate contact interface in the range of 0.1-15, 0.1-10, 0.1-5, or 0.1-1. In examples, the lattice support structure 150 may be configured to have a substrate contact interface in the range of 0.2-20, 0.2-15, 0.2-10, 0.2-5, or 0.2-1. In examples, the lattice support structure 150 may be configured to have a substrate contact interface in the range of 0.3-20, 0.3-15, 0.3-10, 0.3-5, or 0.3-1. In examples, the lattice support structure 150 may be configured to have a substrate contact interface in the range of 0.4-20, 0.4-15, 0.4-10, 0.4-5, or 0.4-1. In examples, the lattice support structure 150 may be configured to have a substrate contact interface in the range of 0.5-20, 0.5-15, 0.5-10, 0.5-5, or 0.5-1. In examples, the lattice support structure 150 may be configured to have a substrate contact interface in the range of 0.6-20, 0.6-15, 0.6-10, 0.6-5, or 0.6-1. In examples, the lattice support structure 150 may be configured to have a substrate contact interface in the range of 0.7-20, 0.7-15, 0.7-10, 0.7-5, or 0.7-1. In examples, the lattice support structure 150 may be configured to have a substrate contact interface in the range of 0.8-20, 0.8-15, 0.8-10, 0.8-5, or 0.8-1. In examples, the grating support structure 150 may be configured to have a substrate contact interface in the range of 0.9-20, 0.9-15, 0.9-10, 0.9-5, or 0.9-1.

[0165] In examples, the lattice support structure 150 may include a peripheral region 154 as shown that defines a substrate interface area 155 (represented by a dashed line) of the lattice support structure 150. In examples, the substrate interface area of ​​the lattice support structure 150 may be different from, e.g., smaller than, the surface area defined by the peripheral region 154. As previously mentioned, the substrate interface area should be understood as the area that is configured to be overlaid by a substrate or a pre-bent substrate when the lattice support structure 150 is in use.

[0166] In an example, the substrate contact interface of the lattice support structure 150 for a given substrate interface area can be controlled by the configuration of the metal elements that define the substrate contact surface of the lattice support structure 150. In an example, the lattice support structure 150 can be configured to include a greater or lesser number of metal elements having one or more sizes and at various angles and spacings across a surface configured to interface with a substrate or pre-curved substrate. By controlling the number, size, and spacing of the metal elements of the lattice support structure 150 that are intended to contact the substrate or pre-curved substrate during use, it may be possible to affect the overall substrate contact area of ​​the lattice support structure 150. In an example, the substrate contact area of ​​one or more elements of the lattice support structure 150 can be affected. In an example, the substrate contact surface of one or more elements 151 of the lattice support structure 150 can be configured to be uneven, angular, rounded, concave, convex, irregular, planar, non-planar, or any combination thereof. For example, as shown in FIGS. 4A-4B, the metal element 151 may have a tapered profile that defines an element substrate contact surface 156 that is narrower than the overall width of the element. In an example, the narrower element substrate contact surface 156 may result in a reduced substrate contact area. In an example, the area of ​​the element substrate contact surface 156 may be equal to its element substrate contact area. In an example, the substrate contact area of ​​the element substrate contact surface 156 of one or more elements 151 of the lattice support structure 150 may be smaller than the area of ​​the element substrate contact surface 156. In an example, the element substrate contact surface 156 may be knurled, corrugated, or otherwise include ridges and valleys, as described herein. In an example, these surface effects may reduce the substrate contact area of ​​the substrate contact surface 156 of the element 151 by preventing the substrate or pre-bent substrate from fully contacting the substrate contact surface 156 of the element 151. In an example, the substrate contact surface 156 of one or more elements of the lattice support structure 150 may include one or more protrusions configured to space a surface of the clamped substrate or pre-bent substrate from one or more portions of the substrate contact surface 156 of the element 151.Any of these surface effects on the surface contact area of ​​one or more elements of the lattice support structure 150 can be employed to affect the substrate contact area and therefore the substrate contact interface of the lattice support structure 150.

[0167] In an example, the lattice support structure 150 may include one or more cavities 158 that may form one or more void areas in the lattice support structure 150. As previously described, it may be possible to fill the gaps or voids with the atmosphere of the DED chamber or a noble gas such as argon, which may act as a thermal insulator. These gaps or voids also provide a solid / gas / solid interface with a fairly low thermal conductivity. Thus, these interfaces between the pre-bent substrate / argon gas / mounting system and / or welding fixture may effectively function as a thermal barrier. Thus, in an example, the one or more gaps or voids may also help to minimize the average heat transfer rate between the substrate or pre-bent substrate and the welding fixture. In an example, this may help to retain more heat in the pre-bent substrate, thereby further reducing uneven temperature distribution and reducing thermal stress in the pre-bent substrate.

[0168] In an example, the lattice support structure 150 may provide the advantage of including a design that requires a reduced amount of material to fabricate. This may be cost-effective while still maintaining the physical stability of the integral free-standing structure. In addition to the cost reduction achieved by reducing the amount of non-magnetic metal required for fabrication, the lattice configuration of the lattice support structure 150 at the interface with the weld fixture may limit the surface contact area between the lattice support structure 150 and the weld fixture. In an example, the lattice support structure 150 may be configured to contact the weld fixture only at one or more elements 151 of the lattice structure that define the interface between the lattice support structure 150 and the weld fixture. In an example, the contact interface between the lattice support structure 150 and the weld fixture may be configured as desired in the same manner as the substrate contact interface of the lattice support structure 150 may be configured as described above. In an example, the lattice support structure 150 may be configured to include one or more elements 151 configured to engage a surface of the weld fixture. For example, one or more elements 151 may be configured as protrusions, as shown, for example, in Figures 4A, 4C, and 4D. In an example, the protruding elements 151 may be configured to mate with one or more fittings, openings, bores, or similar structures in a welding fixture. In an example, the reduced contact interface with the welding fixture may reduce conductive heat transfer from the lattice support structure 150 to the fixture while maintaining rigidity. This reduced heat transfer may also contribute to heat retention of the pre-bent substrate and minimize losses to the welding fixture.

[0169] In an example, the lattice support structure 150 may define a first, generally planar, smooth, or flat side 153 configured to face a welding fixture, for example as shown in dashed lines in FIG. 4C. In an example, the lattice support structure 150 may define a second side having a curved profile ("curved side") 152. The curved side 152 of the lattice support structure 150 may face away from the fixture, toward the pre-bent substrate, and may be positioned against the pre-bent substrate. The lattice support structure 150 may also include a peripheral region 154. One or more clamps may be used to secure the pre-bent substrate to the fixture. As a result, the substrate or pre-bent substrate may be pressed toward the fixture, so that the force required to secure the substrate or pre-bent substrate to the fixture is applied between the clamp and the fixture, where the lattice support structure 150 provides support between the substrate and the fixture. In an embodiment, the pre-bent substrate is pressed axially downward.

[0170] In an example, the backside (first side) of the pre-bent substrate, where the melt track may be present, may be positioned to face the side of the lattice support structure 150 (the side facing away from the fixture (second side)). In this configuration, the backside of the pre-bent substrate faces downward, toward the curved surface of the lattice support structure 150 and the fixture. As previously described, one or more clamps may secure the pre-bent substrate to the fixture, with the lattice support structure 150 sandwiched between the pre-bent substrate and the fixture.

[0171] The lattice support structure 150 may be configured to be thicker at the center than at the edges, such that the curved surface has a maximum height near its center. In embodiments provided herein, the height of the lattice support structure 150 measured at or near the center of the lattice support structure 150 may range from about 3 mm to about 60 mm, or from about 12 mm to about 50 mm, or from about 15 mm to about 45 mm. The height of the lattice support structure 150 measured at or near the outer edge of the lattice support structure 150 may range from about 0.5 mm to about 55 mm, or from about 3 mm to about 45 mm, or from about 10 mm to about 40 mm. In examples, the thickness profile of the lattice support structure 150 when viewed from the side may have a maximum height at the center of the lattice support structure 150, with the height gradually decreasing toward the outer edge of the curved surface. In examples, the height difference across the cross section of the lattice support structure 150 may result in a concave downward curvature in the upper surface of the lattice support structure 150. In cross-section as viewed from the side, the shape of the lattice support structure 150 may resemble the upper half of an ellipse with its semi-minor axis much smaller than its semi-major axis. The ellipse may have an eccentricity close to but less than 1 (an eccentricity of 1 is a flat surface).

[0172] The lattice support structure 150 may be constructed from any metal having sufficient strength and temperature resistance for use under typical conditions of DED processing, as previously described. In an example, one or more elements of the lattice support structure 150 may comprise a material that is the same or different from the material of at least one other element of the lattice support structure 150.

[0173] As previously mentioned, in examples, no ceramic sheets, plates, or pylons and / or ceramic coatings are used in the implementation of mounting system 100. In examples, lattice support structure 150 does not include ceramic sheets or pylons, ceramic coatings, or both. In examples, lattice support structure 150 may include ceramic coatings as described. In examples, lattice support structure 150 may use ceramic sheets, plates, or pylons.

[0174] In an example, the thickness of the lattice support structure 150 can be designed to mimic or provide the same or similar thermal insulation properties achieved with ceramic insulating sheets conventionally used in DED processes. For example, one or more sheets or plates of alumina (Al2O3) insulation are used in conventional DED processes to thermally isolate the substrate from a clamping fixture platform, such as a jig. The conventional use of insulating sheets contributes to a more uniform temperature distribution during the DED process while reducing the risk of potential thermal damage to the fixture. The thickness of the sheets or plates can vary, but conventionally used sheets can be about 3 mm to 3.5 mm thick. Multiple ceramic insulating sheets can be used in conventional DED processes. For example, in some conventional processes, about four ceramic insulating sheets or plates are used to provide an insulating layer of about 12 mm. More or fewer ceramic insulating sheets can be used in conventional ways. These alumina insulating plates can be cut to size. However, doing so can release alumina particles that can cause respiratory and eye irritation. In addition, the alumina insulating sheet tends to be hygroscopic and may release water vapor during the heating temperature of the DED process initially, which may cause the deposition environment to fluctuate during processing, which is unfavorable.In addition, the ceramic insulating sheet traditionally used between the substrate and the fixture is brittle and breaks easily, so it must be discarded after use, thus becoming a consumable item that increases the cost of DED manufacturing.

[0175] In an example, the lattice support structure 150 can be used in combination with a conventional ceramic insulating plate. The lattice support structure 150 can replace the conventional ceramic insulating plate and provide similar thermal insulation while maintaining the same height, so that minimal changes are required to the melting tool settings that provide the heat source or the CAD-CAM path plan that defines the piece to be manufactured by DED. As mentioned above, there are no physical limitations to the thickness of the lattice support structure 150 other than machine-dependent motion constraints. For example, the height stroke of the DED system can dictate the thickness of the lattice support structure 150 to be used. The thickness of the lattice support structure 150 can be selected to maximize the heat flow reduction at the lattice support / fixture interface while allowing sufficient clearance for the manufacture of the workpiece based on the height stroke of the system.

[0176] In an example, the lattice support structure 150 can include a ceramic coating. For example, a ceramic coating can be applied to a surface of the lattice support structure 150 that faces the DED substrate. As previously described, the ceramic coating can be applied directly to the curved surface, or the ceramic coating can be applied to a bond coat that is applied directly to a second curved surface. The ceramic coating can be applied directly to either surface of the lattice support structure 150, with or without a bond coat. In an example, the ceramic coating can provide thermal insulation to minimize or prevent thermal contact between the lattice support structure 150 and the substrate or pre-bent substrate.

[0177] The processes and properties of the ceramic coating that may be applied to the mounting system 100 are described above and may also be applied to the lattice support structure 150. Also, as previously described, in examples, the mounting system 100 may include a bond coat. Similarly, in examples, the lattice support structure 150 may include a bond coat, as previously described.

[0178] In examples, the mounting system 100 may include a corrugated surface and / or a knurled surface. Similarly, in examples, the lattice support structure 150 may define a curved surface and physically modify portions of the lattice support structure 150 that are in physical contact with the substrate and / or the pre-bent substrate during use to further minimize or prevent thermal conduction between the lattice support structure 150 and the pre-bent substrate.

[0179] A knurled surface can be cut into the portion of the lattice support structure 150 that is configured to contact a substrate or pre-bent substrate in use. The knurled surface can be cut before application of the ceramic coating layer. A corrugated surface including a combination of ridges and valleys can be cut before application of the ceramic coating layer. A corrugated surface including a combination of ridges and valleys, where the surface of one or more ridges has a knurled surface, can be cut before application of the ceramic coating layer.

[0180] In an example, the surface of the lattice support structure 150 that is configured to contact the substrate or pre-bent substrate during use may include a knurled surface. The knurled surface of the lattice support structure 150 may be manufactured as described above with respect to the mounting system 100.

[0181] In an example, the surface of the lattice support structure 150 configured to contact the substrate or pre-bent substrate in use can include corrugations or be corrugated. In an example, the corrugated surface can include alternating ridges and grooves. The corrugations can extend along the length or width of one or more elements that make up the lattice surface of the lattice support structure 150 configured to contact the substrate or pre-bent substrate in use. The ridges can be rows and can have the same properties and advantages as described above.

[0182] As described with mounting system 100, the knurled pattern or corrugations on the surface of grid support structure 150 may have a ceramic coating layer thereon.

[0183] As previously described for mounting system 100, the nominal grid deflection h of grid support structure 150 lattice The arcuate degree may be the difference between the maximum height of the curved surface of the lattice support structure 150 at the center and the top surface of the edge of the lattice support structure 150. The difference between the maximum height of the curved surface of the lattice support structure 150 and the edge may be h lattice The length ratio L of the lattice support structure 150 may be r is the new x-dimension L of the lattice support structure 150 i and the length L0 of the original lattice support structure 150. The predicted maximum lattice deflection h Lr is the nominal grid deflection h lattice and the length ratio L of the lattice support structure 150 r is approximately proportional to the product of x and the square of x, which can be calculated according to the following formula: L r =L i / L0 therefore, h Lr ≒h lattice ×L r 2 .

[0184] Therefore, for a grid support structure 150 with xy dimensions of 635 mm × 190 mm (L × W), the maximum predicted grid deflection h Lr is approximately 3.8 mm. A longer lattice support structure 150, such as a lattice support structure 150 with xy dimensions of 1905 mm by 635 mm, has a length ratio of 3 (L r = 1905 / 635 = 3), which is 3.8 x 3 2 Maximum grid deflection h ≒ 34.2 mm Lr The nominal grating deflection may be from about 3 mm to about 35 mm. Thus, the amount of deflection of the grating support structure 150 may depend on the properties of the grating support structure 150. The longer the grating support structure 150 needs to be to accommodate a longer substrate, the higher / larger the deflection of the grating support structure 150 needs to be.

[0185] As previously described with respect to the mounting system 100, in examples, the lattice support structure 150 provided herein may be freestanding. The lattice support structure 150 may be separate and separate from the fixture. In an exemplary embodiment, the lattice support structure 150 may rest flat on the fixture. The exemplary lattice support structure 150 may include a rim having a flat surface or plane around its periphery. The curvature of the surface of the lattice support structure 150 may be empirically determined based on data collected in initial testing performed with a ceramic plate, as discussed with respect to the curved clamping mold 170 below. In cross section as viewed from the side, the profile defined by the lattice support structure may resemble the upper half of an ellipse with its semi-minor axis much smaller than its semi-major axis. The ellipse may have an eccentricity close to but less than 1 (an eccentricity of 1 is a flat surface).

[0186] 3. Curved clamp mold In an example, the mounting system 100 may include a curved clamp die 170 .

[0187] In an example, the curved clamping die 170 may include one or more of the same or similar features as discussed in International Application No. PCT / EP2020 / 082678, which is incorporated herein by reference in its entirety. The curved clamping die 170 may be configured to include a predetermined substrate contact interface. In an example, the clamping die 170 may be configured to have a substrate contact interface that falls within the range of 0.1 to 20. In an example, the clamping die 170 may include one or more of the same or similar features as discussed in International Application No. PCT / EP2020 / 082678, which is incorporated herein by reference in its entirety.

[0188] In examples, the curved clamping mold 170 can be configured to include a substrate contact interface that is greater than or equal to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 and less than or equal to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. In examples, the curved clamping mold 170 can be configured to have a substrate contact interface in the range of 0.1-15, 0.1-10, 0.1-5, or 0.1-1. In examples, the curved clamping mold 170 can be configured to have a substrate contact interface in the range of 0.1-15, 0.1-10, 0.1-5, or 0.1-1. In examples, the curved clamping mold 170 may be configured to have a substrate contact interface in the range of 0.2-20, 0.2-15, 0.2-10, 0.2-5, or 0.2-1. In examples, the curved clamping mold 170 may be configured to have a substrate contact interface in the range of 0.3-20, 0.3-15, 0.3-10, 0.3-5, or 0.3-1. In examples, the curved clamping mold 170 may be configured to have a substrate contact interface in the range of 0.4-20, 0.4-15, 0.4-10, 0.4-5, or 0.4-1. In examples, the curved clamping mold 170 may be configured to have a substrate contact interface in the range of 0.5-20, 0.5-15, 0.5-10, 0.5-5, or 0.5-1. In examples, the curved clamping mold 170 may be configured to have a substrate contact interface in the range of 0.6-20, 0.6-15, 0.6-10, 0.6-5, or 0.6-1. In examples, the curved clamping mold 170 may be configured to have a substrate contact interface in the range of 0.7-20, 0.7-15, 0.7-10, 0.7-5, or 0.7-1. In examples, the curved clamping mold 170 may be configured to have a substrate contact interface in the range of 0.8-20, 0.8-15, 0.8-10, 0.8-5, or 0.8-1. In examples, the curved clamping mold 170 may be configured to have a substrate contact interface in the range of 0.9-20, 0.9-15, 0.9-10, 0.9-5, or 0.9-1.

[0189] In an example, the curved clamp mold 170 can include a top surface 174 as shown that defines a substrate interface area of ​​the curved clamp mold 170. In an example, the substrate interface area of ​​the curved clamp mold 170 can be different from, e.g., smaller than, a surface area of ​​the top surface 174. As previously mentioned, the substrate interface area should be understood as the area configured to be overlaid by a substrate or pre-bent substrate when the curved clamp mold 170 is in use.

[0190] In an example, the substrate contact interface of the curved clamping mold 170 for a given substrate interface area can be adjusted by modifying the curved surface of the curved clamping mold 170 that is configured to face the substrate or pre-curved substrate in use. In an example, as described herein, the curved surface of the curved clamping mold 170 may be configured to have a planar profile, an irregular profile, one or more protrusions extending therefrom, and / or may be configured to include a knurled surface, corrugations, or other ridges and valleys as described herein, and any similar structure that can affect the size of the substrate contact area of ​​the curved clamping mold 170.

[0191] In examples, the clamping mold 170 may include a first side including a peripheral rim. In examples, the peripheral rim may have a flat or planar surface on at least one side. In examples, the peripheral rim may have a flat or planar surface, a cavity or recess forming one or more void areas, and one or more reinforcing members. The planar perimeter and the reinforcing members share a common plane. In examples, only the peripheral rim and the reinforcing members contact the fixture or clamping platform. The curved clamping mold also includes a second side opposite the first side, the second side having a curved surface, as shown in FIGS. 5A-5B.

[0192] In use, the first side of the clamping die can be directed towards the welding fixture. The curved surface of the clamping die can be directed away from the fixture, towards the pre-bent substrate, and positioned against the pre-bent substrate. The planar surfaces of the peripheral rim and stiffening member of the curved clamping die can be laid flat on the fixture surface. The pre-bent substrate can be secured to the fixture using one or more clamps. This presses the substrate or pre-bent substrate towards the fixture, so that the force required to secure the substrate or pre-bent substrate to the fixture is applied between the clamp and the fixture, and the curved clamping die provides support between the substrate and the fixture. In an embodiment, the pre-bent substrate is pressed axially downwards.

[0193] The curved clamping mold can be positioned such that a first surface of the curved clamping mold faces the fixture. In an example, the planar surface of the peripheral rim and stiffening member of the first side of the curved clamping mold can be laid flat on the fixture surface. The backside (first side) of the pre-bent substrate, where the melt track may be present, is positioned to face the side of the curved clamping mold (the side facing away from the fixture (second side)). In this configuration, the backside of the pre-bent substrate faces downward toward the curved surface of the curved clamping mold and the fixture. As previously described, one or more clamps can secure the pre-bent substrate to the fixture, with the curved clamping mold sandwiched between the pre-bent substrate and the fixture.

[0194] In an example, the curved clamping mold can be configured to have a greater thickness at the center than at the edges, such that the curved surface has a maximum height near its center. In embodiments provided herein, the height of the curved clamping mold measured at or near the center of the curved clamping mold can range from about 3 mm to about 60 mm, or about 12 mm to about 50 mm, or about 15 mm to about 45 mm. The height of the curved clamping mold measured at or near the outer edge of the curved clamping mold can range from about 0.5 mm to about 55 mm, or about 3 mm to about 45 mm, or about 10 mm to about 40 mm. In an example, the thickness profile of the curved clamping mold when viewed from the side can have a maximum height at the center of the curved clamping mold, with the height gradually decreasing toward the outer edge of the curved surface. In an example, the height difference across the cross section of the curved clamping mold can cause a concave downward curvature in the top surface of the curved clamping mold. In a cross section viewed from the side, the shape of the curved clamping device can resemble the upper half of an ellipse with a semi-minor axis much smaller than the semi-major axis. An ellipse can have an eccentricity close to but less than 1 (an eccentricity of 1 is a flat surface).

[0195] The curved clamping mold can be constructed from any metal that has sufficient strength and temperature resistance for use under typical conditions of DED processing as described above. In an example, the curved clamping mold can be made from a rigid material that is resistant to twisting and deformation to help maintain its shape. In addition, the curved clamping mold can be made from a material that is resistant to thermal shock, corrosion, and is non-magnetic.

[0196] As previously discussed, in examples, no ceramic sheets, plates, or pylons and / or ceramic coatings are used in the implementation of mounting system 100. In examples, curved clamp mold 170 does not include ceramic sheets or pylons, ceramic coatings, or both. In examples, curved clamp mold 170 may include ceramic coatings as described. In examples, curved clamp mold 170 may be used in conjunction with ceramic sheets, plates, or pylons.

[0197] In an example, the thickness of the curved clamping die 170 can be designed to mimic or provide the same or similar thermal insulation properties achieved with ceramic insulating sheets conventionally used in DED processes. For example, one or more sheets or plates of alumina (Al2O3) insulation are used in conventional DED processes to thermally isolate the substrate from a clamping fixture platform, such as a fixture. The conventional use of insulating sheets reduces the risk of potential thermal damage to the fixture while contributing to a more uniform temperature distribution during the DED process. The thickness of the sheets or plates can vary, but conventionally used sheets are about 3 mm to 3.5 mm thick. Multiple ceramic insulating sheets can be used in conventional DED processes. For example, in some conventional processes, about four ceramic insulating sheets or plates are used to provide about a 12 mm layer of insulation. More or fewer ceramic insulating sheets can be used in conventional methods. These alumina insulating plates can be cut to size. However, doing so can release alumina particles that can cause respiratory and eye irritation. Alumina insulating sheets also tend to be hygroscopic and may release water vapor during the heating temperature of the DED process initially, which may lead to fluctuations in the deposition environment during processing, which is unfavorable. Also, ceramic insulating sheets traditionally used between the substrate and the fixture are brittle and easily broken, so they must be discarded after use, thus becoming consumables that increase the cost of DED manufacturing.

[0198] In an example, the curved clamping mold 170 can be used in combination with a conventional ceramic insulating plate. The curved clamping mold can replace the conventional ceramic insulating plate and provide similar thermal insulation while maintaining the same height, so minimal changes are required to the melting tool settings that provide the heat source or the CAD-CAM path plan that defines the piece to be manufactured by DED. As mentioned above, there are no physical limitations to the thickness of the curved clamping mold other than machine-dependent motion constraints. For example, the height stroke of the DED system can dictate the thickness of the curved clamping mold used. The thickness of the curved clamping mold can be selected to maximize the heat flow reduction at the mold / fixture interface while ensuring sufficient clearance for the manufacture of the workpiece based on the height stroke of the system.

[0199] In an example, the curved clamp mold 170 can include a ceramic coating. For example, as shown in FIG. 5B, a ceramic coating can be applied to the surface of the curved clamp mold that faces the DED substrate (the second curved surface that includes knurling or corrugations). The ceramic coating can be applied directly to the curved surface, or the ceramic coating can be applied to a bond coat that is applied directly to the second curved surface. The ceramic coating can be applied directly to the first flat surface on the opposite side of the mold, or the ceramic coating can be applied to a bond coat that is applied directly to the first flat surface. The ceramic coating can provide thermal insulation to minimize or prevent thermal contact between the curved clamp mold and the pre-bent substrate.

[0200] The process and properties of the ceramic coating that may be applied to the mounting system 100 have been described above and are similarly applicable to the curved clamping die 170. Also, in examples, the mounting system 100 may include a bond coat, as discussed above. Similarly, in examples, the curved clamping die 170 may include a bond coat, as discussed above. An example of an applied bond coat is shown diagrammatically in FIG. 5C. The knurling 178 is coated with a bond coat 186, which is then coated with a ceramic coating 184.

[0201] In examples, the mounting system 100 may include a corrugated and / or knurled surface. Similarly, in examples, the curved surface of the curved clamping mold 170 may be physically modified to further minimize or prevent thermal conduction between the curved clamping mold 170 and the pre-bent substrate.

[0202] A knurled surface can be cut into the curved surface of the curved clamping mold before applying the ceramic coating layer. A corrugated surface including a combination of ridges and valleys can be cut into the curved surface of the curved clamping mold before applying the ceramic coating layer. A corrugated surface including a combination of ridges and valleys, where the surface of one or more of the ridges has a knurled surface, can be cut into the curved surface of the curved clamping mold before applying the ceramic coating layer. Exemplary embodiments are shown in Figures 5A, 5B, 5D and 5E. The embodiment shown in Figure 5A shows a curved clamping mold 100 including a top surface 174 that is knurled and includes a combination of knurls 178 at intervals 180, and a bottom surface with a flat or planar rim 182. The curved clamping mold can include edges 176 on each side as shown in Figure 5B. The edges 176 on each side of the mold can help support and / or limit the downward movement of the short edges of the plate (substrate) during clamping.

[0203] In an example, the curved surface of the curved clamping mold 170 may include knurling, as shown in Figures 5D and 5E. The knurled surface on the curved surface of the curved clamping mold 170 may be fabricated as described above with respect to the mounting system 100.

[0204] In the embodiments provided herein, the curved surface of the curved clamp mold 170 can include or be corrugated. The curved surface of the mold can be corrugated to include alternating ridges and grooves. The corrugations can extend from one long side of the curved clamp mold 170 to the other long side. The corrugations can extend from one short side of the curved clamp mold to the other short side. The corrugations result in multiple columns perpendicular to the arc of the curved clamp mold. The periphery of the mold at the curved surface can be contoured with a metallic material and is not coated with a ceramic coating or bond coat.

[0205] The ridges can be in rows and can have the same properties and advantages as described above. Exemplary ridges implemented in a curved clamp die 170 are shown in Figures 5A, 5B, 5C, and 5E.

[0206] As also described above with respect to mounting system 100, in an example, the knurling pattern or corrugations on the curved surface of curved clamping mold 170 can have a ceramic coating layer thereon. An exemplary embodiment showing curved clamping mold 170 with a ceramic coating 184 is shown in FIG.

[0207] As previously described for mounting system 100, the nominal mold deflection h of the curved clamp mold mold The arc degree is the difference between the maximum height at the center of the curved surface of the curved clamping mold and the upper surface of the edge of the curved clamping mold, as shown in FIG. 5B. In FIG. 5B, the difference between the maximum height 198 of the curved surface of the curved clamping mold and the edge 176 is h mold The length ratio of the mold L r is the new x dimension of the mold L iis the ratio between the length of the original mold and the length of the mold L0. The predicted maximum mold deflection h Lr is the nominal deflection h mold and the length ratio L r is approximately proportional to the product of x and the square of x, which is calculated according to the formula: L r =L i / L0 therefore, h Lr ≒h mold ×L r 2 .

[0208] Therefore, for a curved clamp mold with xy dimensions of 635 mm × 190 mm (L × W), the predicted maximum mold deflection h Lr is approximately 3.8 mm. A longer mold, such as a curved clamp mold with xy dimensions of 1905 mm × 635 mm, would have a mold length ratio (L r = 1905 / 635 = 3), which is 3.8 x 3 2 Maximum deflection h of ≒34.2 mm Lr The nominal mold deflection may be from about 3 mm to about 35 mm. Thus the amount of mold deflection may depend on the mold properties. The longer the curved clamp mold needs to be to accommodate a longer substrate, the higher / larger the curved clamp mold deflection needs to be.

[0209] In an example, the curved clamp mold 170 can also be designed to include cavities or depressions on the underside of the mold while retaining the mold's rigidity and resistance to deformation. An exemplary design is shown in FIG. 5F. A segment of non-magnetic metal on the bottom surface of the curved clamp mold can be machined to create two or more cavities or depressions. The cavities or depressions can be separated from each other by unmilled areas of metal that can act as reinforcing members. There can also be unmilled metal areas on the periphery of the bottom surface of the mold to form a rim. This design reduces the amount of material required to manufacture the curved clamp mold 170 while still maintaining the physical stability of the mold. By reducing the need for a full block of material used to form the mold, the weight of the mold can be reduced while maintaining the rigidity of the mold's structure. Instead of milling metal to achieve the desired cavities and reinforcing members, the curved clamp mold 170 can be made by casting it to include these attributes using a mold, minimizing the amount of material that needs to be removed to achieve the desired final design. Additionally, reinforcing members can be added, such as by attaching a separate reinforcing member to the bottom surface of the curved clamp mold 170. The reinforcing members may be attached in any suitable manner, with exemplary methods including welding, screws, bolts, adhesives, or combinations thereof.

[0210] The cavities can have any shape. In an example, the cavities can be four triangular cavities separated by mold material to form X-shaped reinforcing members that separate the cavities from one another. An exemplary embodiment is shown in FIG. 5F. In the configuration shown, the substrate is machined to form triangular cavities 188, 190, 192, 194 while leaving material to form X-shaped reinforcing member 196 and flat peripheral rim 182. The outer surfaces of flat peripheral rim 182 and X-shaped reinforcing member 196 are coplanar and can sit flat on the fixture surface when secured to a fixture. The cavities can be four square or rectangular cavities separated by mold material to form H-shaped reinforcing members that separate the cavities from one another. The cavity can be any shape selected from the group consisting of a square, a rectangle, an oval, an ellipse, a trapezoid, a parallelogram, a pentagon, a hexagon, a heptagon, a star, a cross, a multi-pointed star, an intersecting geometric shape, a polygon, a geometric shape, an irregular shape, a regular shape, a symmetric shape, an asymmetric shape, and combinations thereof.

[0211] In addition to the cost savings achieved by reducing the amount of non-magnetic metal required for fabrication, the cavity + stiffener + peripheral rim design offers several functional advantages. One advantage is that only the unmilled portion of the bottom surface of the mold comes into contact with the high strength steel fixture. This reduces conductive heat transfer from the curved clamping mold to the fixture while maintaining the rigidity of the curved clamping mold. This reduction in heat transfer also contributes to the retention of heat in the pre-bent substrate, minimizing losses to the fixture.

[0212] Additionally, the cavity on the bottom surface of the curved clamping mold 170 can hold atmosphere or argon gas. Argon can be effectively used as a thermal insulator under most of the mold due to the presence of the cavity and the peripheral rim. Argon is a very effective thermal insulator. Heat flow from the curved clamping mold 170 to the steel fixture underneath occurs exclusively at the solid / solid contact interface by conductive heat transfer as a result of the thermal gradient. Since the solid / gas / solid interface has a fairly low thermal conductivity, the cavity on the bottom surface of the curved clamping mold 170 can effectively act as a thermal barrier (e.g., air or inert gas gap) between the curved clamping mold 170 and the fixture. Air or inert gas gaps can be utilized at the interface between the base plate and the clamping mold 170 and / or at the interface between the clamping mold 170 and the fixture to help reduce heat transfer from the base plate to the fixture. In this way, the curved clamping mold 170 can help retain more heat in the pre-bent substrate, thereby further reducing non-uniformity in temperature distribution and reducing thermal stress in the pre-bent substrate.

[0213] In an example, the curved clamp mold 170 can exhibit high durability. After repeated use, the curved clamp mold 170 can experience thermal stresses that can accumulate and result in some small bow distortion of the mold (e.g., 0.05 mm to about 0.5 mm lift at the edges after repeated use). The degree of bow distortion observed in the curved clamp mold 170 after repeated use is not expected to significantly change the distortion relief effect produced in the DED preform. Different object designs may require the use of curved clamp molds 170 of different sizes to accommodate substrates of different sizes. Similar curved clamp molds 170 can be used to manufacture objects having similar shapes and / or substrate sizes. For example, objects having similar shapes and / or substrate sizes can be grouped into families and the same curved clamp mold design can be used within the same object family.

[0214] As previously described with respect to the mounting system 100, in an example, the curved clamping mold 170 provided herein can be freestanding. The curved clamping mold 170 can be separated and separated from the fixture. In an exemplary embodiment, the curved clamping mold 170 can be placed flat on the fixture. The exemplary clamping mold 170 can include a rim with a flat or planar surface around its periphery. The mold curvature can be empirically determined based on data collected in initial tests performed with ceramic plates. Different sizes of ceramic plates were cut and used to generate different current curvatures and tested for their ability to minimize distortion of preforms prepared on the curved mold. Modeling was then used to confirm that the curvature used experimentally resulted in something close to the desired end result, i.e., a distortion-free preform. In cross section from the side, the shape of the curved clamping device can resemble the upper half of an ellipse with a semi-minor axis much smaller than the semi-major axis. The ellipse can have an eccentricity close to but less than 1 (an eccentricity of 1 is a flat surface).

[0215] 4. Modified fixture design In an example, the mounting system 100 can be integrated into a welding fixture. In an example, any of the exemplary structures described above, the pins 112, the pin support system 110, the lattice support structure 150, and / or the curved clamping die 170, can be an integral part of the welding fixture. In an example, the surface of the welding fixture 400 can be configured to mimic a curved surface or substrate contact area as described for any of the pin support system, the pins, the lattice support structure, and / or the curved clamping die. Any of these discussed features can be implemented in the surface of the welding fixture 400 to achieve the same or similar benefits.

[0216] C. Methods of Directed Energy Deposition Provided herein is a method of directed energy deposition that alleviates or reduces distortion in objects fabricated using directed energy deposition, particularly titanium and titanium alloy objects. The method includes thermally pre-bending a substrate on which the object is to be fabricated, attaching the pre-bent substrate to a mounting system provided herein, pre-heating the substrate prior to DED deposition, and fabricating the object by layer-by-layer deposition of a metal layer. Pre-bending the substrate includes inducing a steep through-thickness thermal gradient in the substrate.

[0217] In the thermally induced pre-bending step, a heat source can be used to apply thermal energy at a high energy density to a first side or backside surface of the substrate. The thermal energy can be applied to a defined portion of the backside of the substrate to form a large thermal gradient in the substrate. The large thermal gradient can introduce a high residual stress field in the substrate. After the thermal energy is applied, the temperature of the surface to which the thermal energy was applied can be reduced. In an embodiment, a gas jet device can be used to apply a cooling gas. The application of the cooling gas can increase the cooling rate, thereby further increasing the stress imparted to the substrate. For example, the heat source can include an electric arc of a plasma torch, such as a PTA torch, and the gas jet device can be mounted on a support relative to the plasma torch, as shown in FIG. 6. In FIG. 6, the gas jet device 200 is mounted on a support 230, and a nozzle 210 of the gas jet device 200 can apply a cooling gas to an area heated by the PTA torch 250.

[0218] In contrast, in the preheating step, thermal energy is applied uniformly to the surface of the substrate to minimize temperature gradients along the x, y, and z directions. Thermal energy is applied as uniformly as possible to the front side of the substrate, as long as the heating device allows. Preheating can use any heating device or method that provides uniform heating. For example, direct heating can be used using a heater positioned to apply heat to the entire surface of the substrate. The heating device can be or include an infrared heater, an induction heater, a resistance heater, or a combination thereof. Exemplary heaters include conductor-in-conduit heat sources, heater strips, resistance heating strips, infrared heaters, positive heat coefficient ceramic heaters, thick film ceramic heaters, resistance wire or resistance ribbon heating devices, infrared heaters, and induction heaters. Preheating can also be accomplished using one or more melting tools to apply thermal energy to the surface of the substrate. The melting tools can be used alone or in combination with infrared heaters, induction heaters, resistance heaters, or combinations thereof. The melting tools can include electric arc plasma, laser beams, or electron beams as heat sources, and multiple melting tools including the same or different heat sources can be used. The heated area can be maximized by using a lower energy density and applying more heat energy to a larger area. Multiple heat sources can be used in tandem, series or parallel to create multiple "lines" of heat energy applied to the front surface of the substrate to heat the substrate more uniformly. This allows a lower energy density of heat to be used to raise the temperature of the substrate more uniformly, with little or minimal thermal gradients, especially through the thickness. By applying heat energy using one or more melting tools during a dry run of preheating (application of heat without adding molten metal), residual contaminants, such as those left by ultrasonic / hand wipe cleaning procedures, can be effectively removed from the substrate surface. Preheating is performed until the target temperature of the substrate is reached.

[0219] In some applications, the target temperature achieved by the preheating process is the DED process temperature, such as the DED deposition temperature, or is within ±25°C of the DED process temperature. In some applications, the target temperature is within ±25°C of the plastic deformation temperature of the substrate. In some applications, preheating is performed until the substrate temperature is about 400-900°C. In some applications, preheating is performed until the substrate is at a temperature of about 500-850°C. Other authors report that warm forming can also be performed between 200-300°C to reduce flow stresses and minimize titanium bounce. In some applications, preheating is performed until the substrate is at a temperature of about 595-815°C.

[0220] Mounting system 100 can act as a support for the pre-bent substrate as it is clamped in a fixture. Among other advantages, mounting system 100 provides a more consistent and repeatable edge residual stress distribution, helping to minimize distortion of the workpiece during and after manufacturing.

[0221] DED can be performed after the substrate has been preheated (and remains heated) to mitigate the development of thermal gradients during the DED process, especially in the thickness direction (z-direction). Although it is optimal to not introduce stresses into the object being manufactured, the DED process is in effect a welding process, and welding-induced residual stresses and deformations typically accumulate during manufacture. Reducing such residual stresses and deformations results in objects with improved dimensional accuracy and superior mechanical properties. Below, the steps of the method are described in more detail.

[0222] 1. Pre-bending the board In the methods provided herein, the substrate can be pre-bent prior to deposition. This pre-bending of the substrate can be a separate step of the DED process. In the methods provided herein, thermal energy can be applied to a first side of the substrate to plastically deform the substrate, thus pre-bending the substrate permanently and uniformly. In an embodiment, when thermal energy is applied across the surface of the first side of the substrate, one or more autogenous melt tracks or weld lines can be formed. This is significantly different from mechanical pre-bending by mechanical stress, which uses a clamp to physically restrain the substrate. Although mechanical pre-bending can be used to bend the substrate, the mechanical stress is usually not accompanied by local melting of planned segments of the substrate surface and is insufficient to introduce the desired uniform plastic deformation in the substrate. The mechanical force introduces a different stress redistribution pattern than that introduced by applying localized heating after the substrate is released from the clamp. For example, when a substrate pre-bent with mechanical force is released, the substrate bounces back to a state much higher than the thermal pre-bending.

[0223] In an embodiment, the substrate can have a first side and an opposing second side. The first side can be the side that faces the fixture during DED manufacturing, and the second side can be the side on which the workpiece is formed by DED. For pre-bending, the substrate can be clamped to the fixture with the first side facing up and the backside facing down toward the fixture.

[0224] The pre-bending of the substrate can be performed while the substrate is flat. The pre-bending of the substrate can be performed while the substrate is firmly connected to the fixture using a number of clamps. The pre-bending of the substrate can be performed while the substrate is thermally isolated from the fixture. The substrate can be thermally isolated from the fixture by including one or more alumina insulating sheets having the same dimensions as the substrate. In an embodiment, four alumina insulating sheets can be used. Other materials that can thermally isolate the substrate from the fixture can be used. Devices having similar thermo-physical properties to the mounting system 100 can be used, such as corrugated surfaces with a series of ridges and valleys that define a flat profile instead of a curved profile, pin support systems, grid systems, forms, etc., with or without a ceramic coating to provide thermal insulation. The use of such devices can eliminate the need to use alumina insulating sheets or sheets of other insulating materials.

[0225] The substrate can be clamped to the fixture using clamps at the entire perimeter of the substrate along all four sides of the substrate. In some applications, the substrate can be attached to the fixture using clamps only along the two longest opposing sides of the substrate. This configuration allows a heat source, such as an electric arc plasma, laser, electron beam device, or any combination thereof, to travel lengthwise to the edge of the substrate. This clamping arrangement can allow edge-to-edge energy delivery, which can generate a stress field all the way to the edge of the substrate, which helps to counteract subsequent residual stresses introduced during DED fabrication in this particular area.

[0226] It has been found that applying high heat energy all the way to the edge or to within about 5 mm of the edge can minimize or prevent twisting of the substrate. As the distance from the edge to where the high heat energy ends is increased, twisting also increases. The thermal stresses created when the DED heat source is applied 10 mm from the edge are significantly different than those achieved when the heat source is applied up to the edge or only 20 mm from the edge. It has been found that the thickness of the substrate is almost the same when considering the distance from the edge that can be tolerated without stress formation being a concern. For thicker substrates, it may be necessary to provide a higher arc energy (or heat input) during pre-bending, thereby achieving a wider and deeper fusion profile. This can be achieved, for example, by reducing the traverse speed, increasing the amount of heat energy applied, or a combination of both. In the example, taller DED preform builds also warp less compared to shorter builds, meaning that the radius of curvature of the curved profile can be increased for shorter builds.

[0227] Clamps can be used to attach the board to the fixture, and a constant clamping force can be applied to all clamps. This can be achieved by torque-controlled tightening of the bolts connecting the clamps to the fixture. During the pre-bending stage, a force of 10 Newton meters (N·m) to 20 N·m, for example 15 N·m, can be used to tighten the bolts connecting the clamps to the fixture. Higher torques can be used for thicker boards.

[0228] The DED heat source generates thermal energy to melt planned segments of the substrate surface in a predetermined sequence and / or location sufficiently to form an autogenous melt line on the substrate surface. To rapidly cool the melt track, a gas jet device can be used to direct cooling gas at the melt track. The heating or heating / cooling thermal cycle can induce controlled formation and development of residual stresses in the substrate. As a result, uniform thermally induced pre-bending of the substrate can be achieved or controlled to a predetermined level as required.

[0229] The DED heat source can be configured to provide sufficient thermal energy to induce a melt track on the DED substrate at a relatively fast rate. If used, a gas jet device can provide large volumes of cooling gas, such as 100 L / min to 200 L / min, to impose rapid heating / cooling cycles on the substrate surface. For example, using a plasma transferred arc system and a substrate thickness of 9.5 mm to 10 mm, a current of 190 amps, a voltage of 25.5 V, and a traverse speed of 10 mm / s, a melt track about 3 mm wide and up to 1 mm deep can be formed. This can correspond to an arc energy delivery of about 485 J / mm. The energy and traverse speed can be adjusted for thicker substrates. An exemplary embodiment is shown in FIG. 7A. In the embodiment shown, a substrate 300 having a first side 310 is shown having melt tracks 350 and 360 on the first side 310 with a spacing 355 between the melt tracks 350 and 355, and a DED backwall of a preform 330 on a second side 320 of the substrate 300.

[0230] The rapidly applied high temperatures, along with the cooling gas from the gas jet device, which promotes fast cooling rates, can result in the formation of very steep thermal gradients around the molten track and towards the substrate (along the x, y and z directions). A high stress state approaching the material yield strength of the substrate material can be achieved.

[0231] Any gas jet device that can be configured to deliver cooling gas to the molten surface of the substrate to rapidly cool the molten surface can be used. In the case of Ti or Ti alloy materials, an inert gas can be used as the cooling gas. The inert gas can be argon, helium, krypton, xenon, or combinations thereof. The gas jet device can include a pipe, tube, or other conduit, or combinations thereof, that can carry the cooling gas from the gas supply to the application area. The gas jet device can include a first end attached to the gas supply and a second end positionable to direct the cooling gas exiting the second end to a desired location on the substrate such that the cooling gas impinges on the substrate surface, particularly the area of ​​molten metal in the melt track. To enhance or accelerate the cooling of the melt track, multiple gas jet devices can be utilized. The second end of the gas jet device can include one or more nozzles that are adjustably positionable to direct the cooling gas to the target location. The effect of the cooling gas impinging on the substrate surface can be greatest in the vicinity of the direct impingement of the cooling gas, but surrounding areas of the substrate can also be advantageously affected to reduce the temperature in the vicinity of the cooling gas. The cooling gas supply can be a pulsed gas flow. A fully turbulent gas flow can be used to increase the cooling efficiency. Cooling gas jet devices are known in the art (see, for example, U.S. Pat. Nos. 4,090,697 (Perrine, 1978); 6,390,115 (Rohwer et al., 2002); and 7,381,364 (Yamashita, 2008)). An exemplary gas jet device is described in U.S. Patent Application Serial No. 16 / 019,460 (filed June 26, 2018).

[0232] The pipe, tube, or conduit of the gas jet apparatus can be of any material having channels extending therethrough that are compatible with the conditions expected to be present during DED deposition. The gas source can be any source of cooling gas, such as a compressor or a container of high pressure gas, in fluid communication with the gas jet apparatus. Methods of supplying pressurized gas to the gas conduits are known in the art.

[0233] The cooling gas can be supplied to provide a target flow rate of gas impinging on the substrate surface. The gas flow rate can be greater than 50 L / min, or greater than 100 L / min, or greater than 150 L / min, or greater than 200 L / min. The gas flow rate can be between 50 L / min and 500 L / min. The gas flow rate can be between 50 L / min and 250 L / min. The gas flow rate can be between 50 L / min and 100 L / min. The flow rate can be selected for fast cooling and thus creating high thermal and stress gradient conditions in the substrate.

[0234] The cooling gas may include an inert gas, such as argon, helium, neon, xenon, krypton, and combinations thereof. The cooling gas may be applied in a constant stream, intermittently, or in a pulsed stream. The temperature of the cooling gas is optional. The temperature of the cooling gas may be the ambient temperature of the additive manufacturing process. The cooling gas temperature may be applied at a gas temperature of about 100° C. or less. The cooling gas temperature may be about room temperature or less, for example, about 25° C. or less. The cooling gas temperature may range from about −10° C. to about 80° C.

[0235] For a preform or workpiece formed on the second surface of the substrate, the number of DED walls having a centerline parallel to the short side of the substrate and the number of DED walls having a centerline parallel to the long side of the substrate can be determined. If the majority of the DED walls of the preform or workpiece have centerlines parallel to the short side of the substrate, melt tracks parallel to the short side of the substrate can be formed. In general, for substrates with a large length-to-width aspect ratio, melt tracks should be formed along the longest axis, i.e., the axis where distortion effects are expected to be greatest. If the majority of the DED walls of the preform or workpiece have centerlines parallel to the long side of the substrate, melt tracks can be preferentially formed parallel to the long side of the substrate to counteract the greatest effects of distortion along the long axis of the substrate.

[0236] The thermally induced pre-bending on the first side or backside of the substrate can be applied such that the resulting melt track, and the typical distribution of longitudinal and transverse residual stresses caused by welding, is positioned about 10 mm to about 20 mm away from the centerline of the majority of the DED walls of the preform or workpiece that will be deposited on the second side or frontside of the substrate. The pre-bending forming technique applied to the first side of the substrate can be performed such that the resulting melt track is positioned about 10 mm, or 11 mm, or 12 mm, or 13 mm, or 14 mm, or 15 mm, or 16 mm, or 17 mm, or 18 mm, or 19 mm, or 20 mm away from the centerline of the DED walls of the workpiece that will be deposited parallel to the long side of the substrate on the second side or frontside of the substrate. The melt track can be positioned such that it can be under the minimum area of ​​the DED walls of the workpiece. An exemplary embodiment is shown in FIG. 7A.

[0237] Previous knowledge of the shape of the DED workpiece to be deposited on the second side of the substrate can be used to determine the pre-bend heating procedure to be applied to the first side of the substrate. The heating procedure can be designed to result in a minimum number of melt tracks under the area where the DED workpiece will be built up. The final aggregate residual stress distribution resulting from the combination of both DED and melt tracks has a lower tensile peak at the DED centerline and lower balancing compressive stresses away from the DED centerline compared to the original residual stress profile of DED without the pre-bend melt tracks (i.e., a high tensile peak at the DED centerline and balancing compressive stresses further away).

[0238] Exemplary embodiments illustrating the application of thermal energy to form a melt track on a substrate are shown in Figures 7A-7D. The diagram in Figure 7B shows a diagram of a process for forming a melt track 350. As shown, a substrate 300 can be placed on a welding fixture 400 and clamped with one or more clamps 500. In this step, a mounting system 100 is not used and the substrate 300 can be placed flat against the welding fixture 400. A DED such as a plasma torch 250 can then also be used to form a melt track on the surface of the clamped substrate 300. In an example, the melt track extends from a first end of the substrate 300 to a second, opposite end of the substrate 300. Figure 7D shows a schematic of an exemplary heating path that can be used to move a DED energy source to form a melt track on the backside or top surface of the first side of a substrate to preliminarily bend the substrate towards the heat source. The black arrow indicates the direction / path of the DED energy source and the X ES The circle containing represents a sequence X, where X is 1 to 6, across the surface of the first side 310 of the substrate 300, with S representing the start of an energy application path resulting in a heating path, and E representing the end of the path. In the pattern shown, heating can begin at the top edge across the x direction (1 ES ), then the heat source can be moved in the y direction less than halfway across the substrate and heat can be applied in the y direction from short side to short side (2 ES ). Repeat this step 3 ES , 4 ES , 5 ES , and 6 ES The first heating path 370 can be repeated for 1 ES The second heating path 371 corresponds to ES The third heating path 372 corresponds to ES The fourth heating path 373 corresponds to ES The fifth heating path 374 corresponds to ES The sixth heating path 375 corresponds to ES Corresponds to.

[0239] A predetermined DED heating / cooling thermal cycle can induce a controlled formation and development of residual stresses in the substrate. Application of cooling gas using a gas jet device (not shown) can be used to accelerate cooling. As a result, uniform thermally induced pre-bending of the substrate can be achieved / controlled to a predetermined level.

[0240] FIG. 7D shows heating paths 370-375 (1 ES ~6 ES 6 shows a schematic of the relative position of a thermally induced pre-bending melt track formed by a heat transfer path (shown as a radiator) relative to an overlaid (grey dashed line) DED workpiece preform 600 fabricated on the opposite front or second side of the substrate. The melt track can result from the application of thermal energy in a heating path.

[0241] The heat source of the melting tool can heat the backside of the substrate to form a melt track at a predetermined location on the substrate, imparting thermal stress to the substrate. This thermal stress can cause the substrate to bend. The substrate can be clamped tightly to the fixture, so the bending of the substrate is not noticeable while the substrate is attached to the fixture. When the clamp is removed, the substrate can bow upward away from the fixture, i.e., toward the heat source. A uniformly deformed pre-bent substrate can be defined by a well-defined radius of the bow. After removing the clamp from the fixture, the resulting uniform elastic-plastic pre-bending effect on the substrate caused by the application of thermal energy is shown in Figures 7B and 8A. The resulting substrate 300 bows upward away from the fixture 400, exhibiting the nominal substrate deflection. In Figure 8B, the substrate is upside down. As seen in Figure 8B, the pre-bent substrate has a uniform elastic-plastic bend (arc) caused by the application of intense thermal energy and cooling gas to induce large temperature and stress gradients on the backside of the substrate, where the nominal substrate deflection 410 is shown.

[0242] The thermally induced board pre-bending procedure can result in a longitudinal residual stress distribution. Comparing the residual stress maps of multiple pre-bent boards thermally pre-bent as described herein, it was found that large tensile stresses developed at the weld centerline (up to 600 MPa +σ L ), and further away compressive stresses (up to -σ of -300 MPa L ) was demonstrated.

[0243] Nominal board deflection h along the z-direction for a board having dimensions 635 mm x 190 mm x 9.5 mm (L x W x T) sub (Arc shape)(h sub =z max -z min ) can be 15 mm after applying the thermally induced substrate pre-bending. This is an actual measurement and was also verified by modeling. r is the new x dimension of the board, L i is the ratio between the length of the board L0 (635 mm) and the expected maximum board deflection h Lr is the nominal board deflection h sub and the length ratio L of the board r is approximately proportional to the product of x and the square of x, which is calculated according to the formula: L r =L i / L0 therefore, h Lr ≒h sub ×L r 2 .

[0244] As an example, a substrate length ratio of 3 (i.e., L r The longer board size (15×3) is 1905 / 635=3 after the thermally induced board pre-bending is applied. 2 = 135mm bow. Thus, the amount of board deflection may depend on the board properties. The longer the board, the higher / larger the deflection needs to be.

[0245] The heat source for providing thermal energy to form a melt track on the backside of the substrate can be any energy source capable of providing sufficient thermal energy to melt the substrate at the heat application area to form a melt track. Exemplary heat sources that can be used include electric arc plasma, laser beam, electron beam, and any combination thereof. In some configurations, two or more melting tools providing separate heat sources can be used. For example, one melting tool providing a heat source can be used to preheat the substrate and a second melting tool providing a heat source can be used to melt the preheated substrate to form a melt track. When multiple melting tools providing separate heat sources are used, they can be the same or different from each other. Examples of combinations of multiple melting tools providing DED heat sources include two PTA torches generating electric arc plasma, two laser devices generating laser beams, two electron beam devices generating electron beams, a PTA torch generating electric arc plasma and a laser heat source generating laser beams, a PTA torch generating electric arc plasma and an electron beam heat source generating electron beams, and a laser device generating electron beams and an electron beam device generating electron beams.

[0246] To form the melt track, sufficient heat can be applied to the substrate surface to heat the substrate to melt at least a portion of the substrate at the heat application area. The target temperature provided by the heat source can be the melt temperature of the substrate material, or 5°C to 50°C above the melt temperature of the substrate, or 10°C to 20°C above the melt temperature of the substrate. The localized heating of the substrate can help induce stresses in the substrate to create a highly stressed substrate in an elastic-plastic state, and when the substrate is unclamped from the fixture, the substrate bows to form a pre-bent substrate, stabilizing or equilibrating the residual stresses imparted by the pre-bending step. In general, the highest stresses can be induced in the melt track, with a tensile stress peak occurring at the centerline of the melt track. The peak of the tensile residual stress can be close to the yield strength of the material. As the distance from the centerline increases, the residual stress becomes compressive. Whether sufficient stress has been induced can be confirmed by observing the amount of upward displacement (i.e., the degree of arching). The greater the displacement, the higher the residual stress introduced during the pre-bending. For most substrates, the maximum tensile residual stress is close to the yield strength of the base material. The sequence and location of these melt tracks relative to the DED can be varied to achieve the targeted residual stress redistribution.

[0247] The amount of heating required to induce the targeted stress and the number of melt tracks formed on the backside of the substrate can be determined experimentally. For example, an object can be fabricated on a first substrate using DED without preliminarily bending the first substrate, and the resulting distortion of the substrate can be measured. A second substrate having similar properties to the first substrate can then be preliminarily bent by forming an amount of melt tracks on the backside of the second substrate that is required to fully or partially compensate for the amount of distortion measured on the first substrate. The amount of heating required to induce the targeted stress and the number of melt tracks formed on the backside of the substrate can also be determined based on modeling predictions, modeling, calculations, or a combination thereof. Modeling can be used, for example, to predict the development of distortion and residual stress in the substrate, and experiments can be used to confirm the modeling predictions. Simulations have also been found to match experimental data very well. In some embodiments, in addition to the pre-determined placement of melt tracks from about 10 mm to about 20 mm from the centerline of the preform, melt tracks can also be formed along the longest substrate length on parts having high aspect ratios. Assuming one fabricates a square, relatively symmetric preform shape on a square substrate, a crisscross pre-bending heat energy application pattern can be used on the underside of the substrate to induce bending in both the longitudinal and lateral directions, resulting in a mounting system that can assume a dome shape.

[0248] After formation, the pre-bent substrate can be handled in a consistent manner as can be done with conventional substrates. To maintain consistency, the temperature of the pre-bent substrate can be selected and the same temperature can be used to form similar preforms. The temperature of the pre-bent substrate can be room temperature when used and when fixed to a jig. The temperature of the pre-bent substrate can be 50° C. or higher when used fixed to a jig. In a typical additive manufacturing process, the number of substrates required to produce a target number of preforms can be determined and a sufficient number of pre-bent substrates can be produced one by one and then each can be individually fixed to a jig at a target temperature, such as room temperature.

[0249] 2. Fixing the pre-bent board to the jig After the pre-bending of the substrate is completed, the pre-bent substrate can be attached to a fixture or welding table. For example, the pre-bent substrate can be attached to the fixture using clamps attached to the fixture. The mounting system 100 can be used as an underlying support between the pre-bent substrate and the fixture. The pre-bent substrate can have the same curvature as the mounting system 100. The pre-bent substrate can have a curvature different from that of the mounting system 100. The pre-bent substrate can be positioned so that the backside having the molten track can contact the curved surface of the mounting system 100. The clamps attached to the fixture can apply a force to the pre-bent substrate to elastically deform the pre-bent substrate. The clamps can force the pre-bent substrate to conform to the curvature of the mounting system 100. The clamps can be made of high strength steel, ultra high strength steel, or high strength low alloy steel.

[0250] As the clamps progress to secure the pre-bent substrate to the fixture, the curvature of the pre-bent substrate will gradually resemble the curvature of the curved profile defined by the mounting system 100, and as a result of the clamps, the curvature of the pre-bent substrate may be the same as the maximum deflection of the curved profile defined by the mounting system 100. Sufficient force may be applied by the clamps to conform the surface of the pre-bent substrate to the curved profile defined by the mounting system 100. Thicker substrates have more resistance and may require the clamps to apply more force to overcome the elastic response of the pre-bend. The amount of force required for the clamps to attach the pre-bent substrate to the fixture and conform the pre-bent substrate to the curved profile defined by the mounting system 100 may be from about 10 Nm to about 120 Nm. For example, for a Ti-6Al-4V substrate having a thickness of approximately 9.5 mm to 10 mm, the pre-bent substrate can be mounted in a fixture and a torque of only 40 Nm can be exerted by the clamps to conform the pre-bent substrate to the curvature profile defined by the mounting system 100.

[0251] The clamps can be torqued to apply an initial clamping force to the substrate, and then additional torque can be applied to apply a final torque to the substrate. The initial clamping can be accomplished by tightening the clamps sequentially, or by tightening clamps positioned opposite one another. The curvature of the pre-bent substrate can gradually resemble the curvature of the curved profile defined by the mounting system 100.

[0252] Due to the curvature of the curved profile defined by the mounting system 100, in an example, the torque applied to the substrate through the clamps can be significantly less than the torque that would be required to mount a pre-curved substrate flat in a fixture without the use of the mounting system 100. The curvature of the curved profile defined by the mounting system 100 can be mimicked by plate boundary conditions. To achieve satisfactory clamping, (a) a consistent clamping force can be used by tightening the bolts attaching the clamps in a torque-controlled manner, (b) consistent dimensions can be selected from the clamps, (c) the clamps can be applied symmetrically, (d) even pressure and heat transfer distribution can be ensured by properly mounting the clamps to avoid gaps and uneven pressure application, or (e) any combination of (a)-(d). For example, the clamps can be attached to the base plate via countersunk screws that are flush with the top surface of the clamps to ensure even distribution between the clamps and the base plate. The bottom and side contact facets of the clamps can be constructed and arranged to contact flush with the base plate to ensure even pressure and even heat transfer distribution. See, for example, Figures 14A and 14B. Dashed circles 544, 545, 546, 547, 548, 549 in Figure 14A indicate areas of uneven pressure and heat transfer distribution due to the way bolts 520, adjusted via countersunk screws 510 and nuts 525, adjust clamp 500 to attach base plate 550 to fixture surface 530. In the example shown, base plate 550 is thermally insulated from fixture surface 530 by layers of alumina insulating plates 540-543.

[0253] To avoid uneven pressure and heat transfer distribution, the flat head screw 510 can be adjusted so that its tip 515 is flush with the top surface 507 of the clamp 500, as shown in Figure 14B. By doing so, uniform pressure and heat transfer distribution is obtained. Boxes 575, 576, 577, 578 in Figure 14A show areas of uniform pressure and heat transfer distribution achieved because of the way the bolts 520, adjusted via the flat head screw 510 and nuts 525, adjust the clamp 500 to attach the base plate 550 to the fixture surface 530. In the embodiment shown, the bottom contact facet 505 and side contact facets 507 of the clamp 500 are shown to be flush with the top and side surfaces of the base plate, respectively, to ensure uniform pressure and heat transfer distribution.

[0254] Fixturing a pre-bent substrate using the mounting system 100 as an underlying support can result in a slight redistribution of longitudinal residual stresses. L The tensile stress peak can increase from about 600Mpa to about 700Mpa, and -σ away from the centerline L The compressive stress can be reduced from about -300 MPa to about -200 MPa.

[0255] The clamping of the pre-bent substrate to the mounting system can be performed in an elastic mode. The curvature imposed by clamping the substrate to the mounting system can be fully reversible if the substrate is unclamped from the mounting system 100 at this point. This is especially true for metallic substrates that have a high bounce at room temperature. The elastic deformation imposed by the clamping force can be distinguished from the plastic deformation introduced into the substrate in the pre-bending step.

[0256] The clamps used to secure the substrate to the fixture or welding table can typically be made from materials that exhibit high strength and low deformability. Steel can be used as the clamp material due to its high strength, thermal stability, and resistance to deformation. Steel can typically have a higher thermal conductivity than the substrate. For many substrates, the heat transfer of the steel in the clamp can be orders of magnitude higher than the substrate. This difference in thermal conductivity between the clamp and the substrate can cause the clamp to act as a heat sink. As a heat sink, the clamp in direct contact with the substrate during the DED process can result in a rapid flow of thermal energy from the area of ​​the substrate adjacent or proximate to the clamp attachment point to the clamp and from the clamp to the fixture or welding table. As a result, high thermal gradients can be created in the pre-bent substrate during the DED process. High thermal gradients can impose stresses and strains on the substrate during the deposition process.

[0257] The clamps can be thermally insulated to reduce or prevent the formation of thermal gradients due to the clamps acting as a heat sink. Thermal insulation can reduce or prevent the transfer of heat from the substrate through the clamps to the fixture. An insulating coating can be applied to all surfaces of the clamps. An insulating coating can be applied to all surfaces of the clamps that may come into contact with the substrate. The insulating coating can be any coating that does not effectively transfer thermal energy. The insulating coating can be made of a ceramic material, silicon carbide, silicon nitride, boron carbide, or any combination thereof. The ceramic material can be or include alumina, zirconia, titanium oxide, alkaline earth metal silicates, aluminum titanate, zirconium dioxide, zirconium dioxide stabilized by the addition of yttrium oxide, yttrium aluminum oxide, ZrV2O7, Mg3(VO4)2, or combinations thereof. Any high temperature ceramic coating known in the art can be used (see, for example, U.S. Pat. Nos. 4,321,310 (Ulion et al., 1982), 5,789,330 (Kondo et al., 1998), 5,304,519 (Jackson et al., 1994), 6,387,539 (Subramanian, 2002), and 6,998,064 (Gadow et al., 2006)). The clamps can be coated with zirconium dioxide stabilized by the addition of yttrium oxide, such as plasma sprayed ZrO28Y2O3. The insulating coating can include multiple layers of different types of ceramics, carbides, nitrides, or combinations thereof, or multiple layers of one type of ceramic, carbide, nitride, or combinations thereof.

[0258] Many of these materials are commercially available and can be applied using a variety of techniques known in the art. For example, the insulating coating can be applied using any process including atmospheric plasma spraying, magnetron sputtering, chemical or electrochemical vapor deposition such as electrophoretic deposition, or physical vapor deposition such as electron beam physical vapor deposition, or any combination thereof.

[0259] The thickness of the insulating coating applied to the clamp may vary depending on the type of insulating material used and its ability to support a load without damage from the application of a compressive force. In some configurations, the insulating coating may be 0.1 mm to 5 mm, or 0.25 mm to 4 mm, or 0.3 mm to 3 mm, 0.4 mm to 2 mm, or 0.5 mm to 1.5 mm thick. The insulating coating may be at least 0.1 mm, or at least 0.25 mm, or at least 0.5 mm, or at least 0.75 mm, or at least 1 mm, or at least 1.25 mm, or at least 1.5 mm, or at least 2.0 mm, or at least 2.5 mm, or at least 3.0 mm, or at least 3.5 mm, or at least 4.0 mm, or at least 4.5 mm thick. The insulating coating can have a thickness of 0.1 mm, or 0.25 mm, or 0.5 mm, or 0.75 mm, or 1 mm, or 1.25 mm, or 1.5 mm, or 2.0 mm, or 2.5 mm, or 3.0 mm, or 3.5 mm, or 4.0 mm, or 4.5 mm, or 5 mm. The insulating coating layer can reduce heat transfer from the DED substrate to the fixture, thereby reducing heat loss from the DED substrate. One example of an insulating coating is 0.5 mm to 1.5 mm of ZrO28Y2O3 that is plasma sprayed onto the contact surface of the clamp to help reduce conductive heat transfer from the DED substrate to the clamp. This can increase thermal insulation and reduce thermal conductivity.

[0260] To further reduce heat conduction from the substrate through the clamp to the fixture, the surface of the clamp in thermal communication with the substrate can be modified to have a knurled pattern. The knurling of the surface can reduce the amount of the surface of the clamp in contact with the substrate. The knurling can reduce the possibility of heat conduction between the clamp and the substrate. Any knurling pattern known in the art can be used on the surface of the clamp that may be in contact with the substrate. Exemplary knurling patterns include diagonal patterns, such as diagonal patterns, linear patterns, diamond patterns, or any combination thereof. The knurled pattern can also have an insulating coating layer on its surface.

[0261] To reduce heat transfer from the substrate through the clamp to the fixture, the surface of the clamp in thermal communication with the substrate can be modified to have a corrugated surface that includes a series of ridges and valleys. The corrugated surface can reduce the amount of the clamp in contact with the substrate. The corrugated surface can reduce the possibility of heat transfer between the clamp and the substrate. Any corrugation pattern known in the art can be used. The corrugations can be in any direction on the surface of the clamp. Exemplary configurations include diagonal corrugations, such as diagonal corrugations, straight corrugations parallel to the long sides, straight corrugations parallel to the short sides, or any combination thereof. The corrugated surface can also have an insulating coating layer on its surface.

[0262] Due to limitations in coating technology, thicker layers of insulating coatings capable of withstanding the compressive forces required to clamp the pre-bent substrate to the fixture may be more difficult to achieve. The specific compressive strength of the insulating coating may be determined by the composition of the insulating coating. For example, a 0.5-2.0 mm coating of a ceramic based on zirconium dioxide stabilized by the addition of yttrium oxide has been found to provide good thermal isolation along with good compression resistance when clamps are used to connect the substrate to the fixture, without damaging the insulating coating.

[0263] Exemplary configurations of clamps are shown in Figures 9A, 9B, and 9C. Figure 9A shows a bottom surface of clamp 500 with a screw hole 501 for accepting a countersunk screw and a hole 502 to accommodate a bolt. Top surface 507 can include a ceramic coated surface 509 on the edge that contacts the base plate. Top surface 507 can be corrugated. Figure 9B shows a side view of clamp 500 showing the ceramic coated surfaces 509 of bottom contact facet 505 and side contact facet 506 that contact the base plate. Figure 9C shows a perspective overhead view showing a three-dimensional view of clamp 500, showing screw hole 501 and ceramic coated bottom contact facet 505 and side contact facet 506 of clamp 500. Clamps of the same design can be used (e.g., all the same length, or the same width, or the same length and width). Clamps with different lengths and / or widths can also be used.

[0264] In an example, thermally insulated clamps can be placed around the entire periphery of the pre-bent substrate. An exception to using only insulated clamps can be when using a PTA torch as the DED melting tool to provide the electric arc plasma as the heat source. In such a configuration, one or more non-insulated clamps can be used to provide a path for the current. For example, in an exemplary configuration, two or three non-insulated clamps can be used to ensure a stable current path from the power source. In such a configuration, one or two non-insulated clamps can be positioned on the short sides of the base plate and one non-insulated clamp can be positioned in the mid-section of the longest dimension of the base plate. Other configurations can also be used.

[0265] To reduce stress and distortion of the substrate during metal deposition and object fabrication, the clamps can be positioned on the substrate such that, as much as possible, the centerlines of the clamps intersect at the beginning / end of the DED strings / walls. An exemplary configuration is shown in FIG. 10. In the configuration shown, the clamps 500 are positioned around the preform 600 such that substantially all of the periphery of the substrate 300 is clamped to the fixture 400, and are positioned such that, as much as possible, the centerlines of the clamps 500 intersect with the centerlines of the beginning / end of the DED strings / walls of the preform 600 (shown as clamping entities 610, 615, 620, 625, and 630). Such substrate clamping constraints can significantly reduce deformation effects that arise primarily from longitudinal residual stresses during deposition. Suboptimal clamping can result in localized deformations or buckling due to lack of clamping constraints, as shown in the dashed box outline 650.

[0266] Different clamping arrangements can be used during pre-bending and while mounting the pre-bent substrate in the fixture for the DED process. The different clamping arrangements can be selected because during pre-bending, when applying thermal energy to the backside of the substrate using a melting tool providing the DED heat source, it is necessary to increase the access of the heat source to the entire or nearly entire length of the substrate to produce a uniform deflection along the longest substrate length. Insulating clamps may not be used at the edges to allow the melting tool providing the DED heat source to apply thermal energy to the entire length of the substrate. During object building by metal deposition on the front side of the substrate, insulating clamps can be placed around the periphery of the substrate, especially at the beginning / end of the DED wall, to help reduce localized deformations resulting from the development of residual stresses. The clamping configurations (1) promote symmetry across the plate, (2) use identically shaped clamps when possible, (3) allow the desired access to the substrate by the melting tool providing the DED heat source, and (4) can meet the torque requirements required to mount the pre-bent substrate in the fixture.

[0267] While the use of the mounting system 100 can significantly improve the manufacturing process, it is possible to perform the DED process on the front side of the pre-bent substrate by using a sheet of insulating material, such as a conventional alumina (Al2O3) insulating sheet or plate, cut to form a curvature that closely matches the arc of the pre-bent substrate. This is significantly more laborious than using the mounting system 100 provided herein. Furthermore, there may be variations in thickness of the alumina insulating sheet, and variations may occur between workpieces as the layers of the pre-cut sheet are formed to match the curvature of the pre-bent substrate. The various mounting systems 100 provided herein can reduce or prevent such part-to-part variations by providing a structure with consistent physical and mechanical properties that can be used multiple times. Furthermore, in examples, the mounting system 100 can eliminate ceramic sheets, plates, or pylons, thus providing the added benefit of less moisture in the DED atmosphere.

[0268] 3. Preheating the board Once the pre-bent substrate is secured to the fixture using the mounting system 100 and insulating clamps, the pre-bent substrate can be pre-heated before starting the DED process. This pre-heating step is intended to treat a majority of the front surface of the substrate with a heat source to uniformly heat the entire substrate to a target temperature, and then use the DED process to build the workpiece while the pre-bent substrate is still hot.

[0269] In the pre-bending step, steep thermal gradients and high cooling rates are selected to generate higher internal tensile and compressive stresses, and as opposed to the application of energy to the backside of the substrate, in the pre-heating step, energy is applied toward the front side of the substrate in a more gentle and consistent manner. During the pre-heating step, energy can be directed toward the front side of the substrate using a heat source under conditions that do not locally melt the substrate surface. During the pre-heating step, energy can be directed toward the front side of the substrate using a heat source under conditions that do not form a continuous melt track. Since nearly uniform heating is desired, energy from the heat source can be applied at a relatively low rate of the melting tool providing the heat source, which is positioned at a higher standoff distance (further from the substrate) to apply heat energy with a lower energy density. Furthermore, since the pre-heating step is intended to heat the substrate prior to workpiece construction using the DED process, no cooling gas is applied using a gas jet device. Thus, the cooling rate is significantly lower than that which may occur in the pre-bending step.

[0270] This slow heating / cooling cycle during pre-heating can promote a slow cooling rate and low thermal gradient formation in the substrate along the x, y and z directions. The application of energy during pre-heating can be done in a manner that allows for a slow build-up of residual heat, since the heat can be dissipated throughout the pre-bent substrate volume by conduction. For example, a lower energy density can impart a lower thermal gradient to the substrate. These conditions generate a "near" uniform temperature distribution throughout the base plate, allowing for a slow build-up of residual heat, since the heat can be dissipated throughout the base plate volume by conduction. The pre-bent substrate is thermally isolated from the mounting system 100, and insulating clamps are used to secure the pre-bent substrate to the fixture, so that the residual heat can be more easily retained in the substrate.

[0271] The low energy density can be delivered to the substrate in a continuous manner to generate a substantially uniform temperature distribution both over the surface of the substrate and over the thickness of the substrate. To avoid exposing an area to accumulated thermal energy, the application of energy can begin at a first edge of the substrate and continue across the surface of the substrate along the x-direction until the opposite second edge of the substrate is reached. The melting tool providing the heat source can then be returned to the first edge and repositioned in the y-direction some distance away from the first energy application path, and energy can be applied along the x-direction. This process is repeated until the temperature of the pre-bent substrate reaches the target temperature. The more uniform the temperature distribution of the substrate, the better it is for reducing the effects of stresses and distortions induced in the substrate.

[0272] An exemplary pattern of energy application during preheating is shown in FIG. 11. The black faded arrows indicate the direction / path of the DED energy source, and the X ES The circle containing the sigma indicates a sequence X across the surface of the second side 320 of the substrate 300, where X is 1 to 8, S indicates the start of a path of energy application resulting in a heating path, and E indicates the end of the path. In the pattern shown, heating begins at the bottom edge across the x-direction (1 ES ), then move the heat source in the y direction to a point about one-ninth of the way up from the first heating pass and apply heat in the y direction from short side to short side (2 ES This procedure is repeated for 30 minutes until heat is applied to the entire surface of the substrate 300. ES , 4 ES , 5 ES , 6 ES , 7 ES , and 8 ES The first heating path 700 is ES The second heating path 705 corresponds to ES The third heating path 710 corresponds to ES The fourth heating path 715 corresponds to ES The fifth heating path 720 corresponds to ES The sixth heating path 725 corresponds to ES The seventh heating path 730 corresponds toES The eighth heating path 735 corresponds to ES . The pre-heating path can use a single energy source or multiple energy sources. The figure shows solid and dashed black faded lines representing the tool path and pre-heating sequence of two melting tools operating in parallel. Although the illustrated embodiment describes heating using a DED energy source, other energy sources can be used. Exemplary alternative energy sources include, for example, one or more lasers, one or more induction heaters, or any combination of lasers, DED energy sources, and induction heaters. Additionally, other methods and devices capable of uniformly heating the base plate can also be used, such as induction heating, resistive heating, and others.

[0273] The direction of pre-heating can be the same as the actual DED process forming the preform, such that the temperature and residence time in the area below the DED deposition area can be similar. For example, as shown in FIG. 11, the start (S) and end (E) positions of pre-heating thermal energy application (indicated by the faded black arrows and labeled with circles, respectively) are in the same direction of metal deposition during the DED process.

[0274] The thermal energy application can be applied using any source that generates thermal energy. For example, electric arc-based, laser beam, and electron beam heat sources can be used alone or in combination to achieve the preheating effect. For example, one or more thermal arc welding sources, such as a preheat PTA torch and a melting PTA torch, can heat the substrate laterally across the substrate. The PTA torch can be positioned to reduce the formation of a temperature gradient and reduce the total preheating time. Other heat sources based on laser or electron beam energy can also be used for the same purpose, but with an appropriate set of parameters to achieve similar heating of the substrate. The spacing between the preheating thermal energy application areas can depend on the amount of heat provided by the heat source. The spacing between the preheating thermal energy application areas can depend on the heat distribution provided by the heat source.

[0275] For example, two PTA thermoelectric arc plasma welding torches can be used to heat the substrate simultaneously, transversely. The two torches can have a relative (fixed) distance from each other, such as about 20 mm to 40 mm. This configuration allows the application of heat energy along the x direction and across the y direction, without overlapping the centerlines of the heat sources, so that the heat is delivered and spread as evenly as possible. On the other hand, for a fixed substrate width, the amount of preheating can be differentiated if a more focused heat source, such as laser energy or electron beam energy, is used for this purpose. The spot of the laser or electron beam can be designed to be larger to affect a larger heating area on the substrate. The substrate can also be heated evenly by other methods and devices, including induction heaters and resistance heaters.

[0276] A melting tool providing a DED heat source can be used to perform uniform preheating. The positioning, sequence and parameters used to perform preheating using a melting tool providing a DED heat source can be controlled such that the application of energy to the substrate can result in the development of a lower thermal gradient than that imposed on the substrate during the prebending step. Preheating can be performed to uniformly increase the temperature of the substrate. In an exemplary embodiment, preheating can be performed to uniformly increase the temperature of the substrate to a temperature ranging from about 350°C to about 650°C, depending on the substrate material. For example, a substrate including Ti can be preheated to a temperature ranging from about 400°C to about 550°C. For some Ti alloys, the substrate can be preheated to a temperature ranging from about 450°C to about 500°C to reduce the formation of thermal gradients during DED. Preheating can reduce the buildup of internal stresses during DED processing by reducing localized stresses due to heating during deposition of molten metal to build the workpiece. By pre-heating the substrate to an elevated temperature, such as a warm or hot forming temperature, the weld bead formed on the substrate during DED workpiece formation may result in near-zero distortion because the resulting thermal gradient may be significantly less than the thermal gradient through the thickness that occurs when depositing a weld on a substrate at room temperature. The pre-heating does not significantly modify or fuse the substrate surface and may result in the formation of a weld seam without the addition of metal.

[0277] Preheating can use indirect heating, such as heating a pre-bent substrate clamped in a fixture in an oven to uniformly raise the temperature of the substrate. In some applications, this is not feasible or practical. The time required to move the substrate and fixture combination from the oven to a chamber where the DED process can take place can lead to significant loss of residual heat from the substrate, defeating the purpose of the preheating step. This system can be modified to include an oven accessible through the deposition chamber so that the oven can be used to preheat the substrate.

[0278] Direct heating can be used using a heating device positioned to apply heat to the entire surface of the substrate when the substrate is mounted in the fixture. Any method and heating device capable of uniformly heating the substrate prior to deposition can be used. The heating device can be or include an induction heater, a resistive heater, or a combination thereof. Exemplary heating devices include heaters that can include conductor-in-conduit heat sources, heater strips, resistive heating strips, infrared heaters, positive heat coefficient ceramic heaters, thick film ceramic heaters, resistive wire or resistive ribbon heating devices, and induction heaters, as well as any combination thereof.

[0279] 4. DED process to build the workpiece Immediately after the substrate is preheated to the target temperature, a DED process can be performed to form a workpiece on the substrate. During the building of an object by metal deposition on the front side of the substrate, clamps can typically be positioned at the start / end of the DED walls to help reduce localized deformations resulting from the development of residual stresses.

[0280] Prior to pre-heating, the pre-bent substrate may be in contact with the mounting system 100 via an insulating / non-insulating clamp attached to the fixture. In an example, the substrate may be thermally isolated from the fixture. In an example, the mounting system 100 may be ceramic-free or may include an insulating ceramic coating on surfaces that may be in contact with the pre-bent substrate. The pre-bent substrate does not adhere to the mounting system. Additionally, as can be seen from this arrangement, a workpiece may be built on the surface of the pre-bent substrate while the pre-bent substrate is secured to the fixture. Although the pre-bent substrate may become part of the workpiece, no part of the mounting system 100 becomes part of the workpiece.

[0281] The pre-curved substrate has an arc and is coupled to a mounting system that also has an arc, but the tilt of the curvature of the pre-curved substrate fixed to a fixture with the mounting system as a support between the pre-curved substrate and the fixture does not affect the overall deposition conditions. The radius of curvature of the curvature profile defined by the mounting system can be large enough that the effects of gravity do not adversely affect the mechanics of the weld pool, and deposition on the pre-curved substrate in contact with the mounting system can obtain similar results as deposition on a substrate in a flat position. The radius of curvature of the curvature profile defined by the mounting system can be selected such that the effects of gravity due to the tilt do not affect the behavior of the liquid melt pool deposited or formed on the surface of the pre-curved substrate. Furthermore, a controller used in the DED process for building the workpiece can adapt the z-coordinate to the curvature of the curvature profile defined by the mounting system to ensure that consistent energy / processing conditions are delivered by the DED process during the production of the workpiece. CAD-CAM program instructions can be executed to result in a melting tool providing a DED heat source that follows the exact shape of the curvature profile defined by the mounting system to ensure that the overall processing conditions, especially the standoff distance, are not affected.

[0282] The design of the workpiece constructed by the DED process can be positioned on the front side of the substrate such that the majority of the walls of the workpiece formed by the deposition of molten metal are between adjacent molten tracks on the back side of the substrate, and preferably equally spaced from adjacent molten tracks. This positioning allows non-uniform plastic deformation and high tensile stresses that may occur in the molten regions during DED fabrication of the workpiece to occur in areas of high compressive stress imposed by the pre-bending process, and compressive stresses that may form as the welds of the workpiece cool to occur in areas of high tensile stress imposed by the pre-bending process. Thus, the positioning of the walls of the workpiece on the front side of the substrate relative to the molten tracks on the back side of the substrate can balance the residual stress field and reduce the overall distortion of the as-deposited preform.

[0283] An exemplary deposition pattern for preform formation is shown in Figure 11. As shown, the preform 600 is positioned on the front or second side 320 of the substrate 300 such that the majority of walls, such as 380, 382, ​​and 384, of the workpiece preform 600 formed by deposition of molten metal are between and preferably equally spaced from adjacent preheat passes 700, 705, 710, 715, 720, 725, 730, and 735 on the back or first side 310 of the substrate 300. An exemplary DED sequence path layer by layer is shown sequentially by boxes S1-S5, with arrows indicating the DED direction layer by layer.

[0284] In the method of manufacturing a metal workpiece using the DED process provided herein, a three-dimensional object of a metal material can be manufactured by fusing successive deposits of the metal material on a substrate. Any DED process can be used to build the workpiece. The DED process can use one or more melting tools that provide an energy source, alone or in combination. Exemplary melting tools that can be used include a PTA torch that provides an electric arc plasma as a heat source, a laser device that provides a laser beam as a heat source, an electron beam device that provides an electron beam as a heat source, and any combination thereof. In some configurations, two or more melting tools that provide a heat source can be used. For example, one melting tool that provides a DED heat source can be used to preheat the substrate, and a second melting tool that provides a DED heat source can be used to melt the metal material to form a molten metal that can be deposited on the preheated area. When multiple melting tools that provide a DED heat source are used, they can be the same or different from each other. Exemplary combinations of multiple melting tools include two PTA torches, two laser beam devices, two electron beam devices, a PTA torch and a laser beam device, a PTA torch and an electron beam device, and a laser beam device and an electron beam device.

[0285] In some methods, the first melting tool can be used to deliver energy to at least a portion of the surface of the base material, e.g., the location where the metal material is to be deposited, for surface heating of the substrate. This is distinct from a pre-heating step to raise the temperature of the entire substrate to a target temperature to minimize thermal gradients during the DED process. In contrast, for surface heating of the base material, whether it is a substrate or a layer of previously deposited metal, the first melting tool delivers high intensity energy to a limited area of ​​the base material, raising the temperature of the base material in the energy application area to a temperature slightly below the melting temperature, e.g., 0.1% to 10% below the melting temperature, or to the melting temperature. The surface heating of the base material can improve the wetting and spreading characteristics of the weld bead. The surface heating of the base material can improve the contact angle of the weld bead. The surface heating of the base material can make the surface more receptive to the molten metal that is to be deposited on the heated surface.

[0286] A second melting tool can be used to heat and melt the metallic material such that the molten metallic material is deposited on the surface heated areas of the base material heated by the first melting tool. A gas jet device can be used to direct a cooling gas across the surface of the liquid melt pool, impinge on the surface of the liquid melt pool, impinge on the surface of the solidified material adjacent the liquid-solid boundary of the liquid melt pool, or any combination thereof. The base material can be moved relative to the positions of the first and second melting tools and the gas jet device in a predetermined pattern such that successive deposits of the molten metallic material solidify to form the three-dimensional workpiece. Alternatively, the first and second melting tools and the gas jet device can be moved relative to the position of the base material in a predetermined pattern such that successive deposits of the molten metallic material solidify to form the three-dimensional workpiece.

[0287] In the methods provided herein, the cooling gas can be or include an inert gas, such as argon, helium, neon, xenon, krypton, and combinations thereof. The cooling gas can have a flow rate measured at the inlet of about 1 L / min to about 300 L / min. The cooling gas can be applied in a constant stream, intermittently, or in a pulsed stream. The flow of the cooling gas can be adjusted to create a turbulent flow of the cooling gas in the vicinity of the melt pool. For example, the velocity of the cooling gas flowing through the gas jet device can be increased so that the cooling gas exiting the gas jet device exhibits a turbulent flow rather than a laminar flow. The cooling gas can be delivered using multiple nozzles on a single gas jet device, or using multiple gas jet devices, such that a combination of laminar and turbulent flow of the cooling gas can be directed in the vicinity of the melt pool.

[0288] The temperature of the applied cooling gas can be any temperature. The cooling gas temperature can be the ambient temperature of the chamber in which the lamination process is carried out. The cooling gas temperature can be below room temperature, for example below about 25°C. The cooling gas can be at a refrigerated temperature, such as about -150°C to about 4°C, or about -10°C to about 10°C.

[0289] The number and configuration of nozzles of the gas jet device, and / or the number of gas jet devices, and their configuration and arrangement, can be selected to provide cooling gas to cover the length of the workpiece, such as a distance of about 5 mm to about 50 mm, or about 10 mm to about 40 mm, or about 15 mm to about 30 mm along the direction of movement at or around the thermal energy impingement area.

[0290] In the methods provided herein, a melting tool providing a DED heat source can be used in combination with a gas jet device to control the melt pool conditions, which generates a cooling gas that results in a temperature reduction from about 1200° C. to about 600° C., or from about 1000° C. to about 800° C. In some methods where the workpiece is formed of a Ti alloy, a temperature reduction from 1000° C. to 800° C. can be used.

[0291] The methods provided herein can be implemented in any additive manufacturing system. The methods can be implemented in a system where the inert gas contains only a heat source such as an electric arc plasma, contains a melting tool containing a heat source, or contains a melting tool and a workpiece. The methods can be implemented in a system that contains a sealed chamber filled with an inert gas to provide an inert atmosphere where the entire process is carried out in an inert atmosphere. The inert atmosphere can be or contain argon, xenon, neon, krypton, helium, or combinations thereof, allowing for inert atmosphere deposition.

[0292] Exemplary differences between a conventional substrate configuration for the DED process and the process provided herein using mounting system 100 implemented as pin support system 110 are shown in Figures 12A and 12B. Figure 12A shows the conventional configuration from the y-direction, where substrate 300 is secured to fixture 400 (via clamps, not shown) but thermally isolated from fixture 400 by alumina insulating plates 540, 541, 542, 543 positioned between substrate 300 and fixture 400. Substrate 300 that has not been stress relieved is flat, and during the DED process, metal material is deposited on the top surface of substrate 300 to produce preforms 600 and 600'.

[0293] In contrast, FIG. 12B illustrates an exemplary embodiment of a substrate configuration using the mounting system 100 implemented as the pin support system 110 viewed in the y direction for comparison with the illustration of FIG. 12A. FIG. 12C illustrates an exemplary embodiment of a substrate configuration using the mounting system 100 implemented as the pin support system 110 of FIG. 12B, but viewed in the x direction to illustrate that the preform 600 may be deposited along the length of the substrate 300. In the configuration shown, the pin support system 110 may function as a support underlying the substrate 300 once the substrate 300 is secured to the fixture 400 (via clamps, not shown). The pin support system 110 may eliminate the need to use alumina insulating plates, or other substrate support devices, that are conventionally used to thermally isolate the substrate from the fixture, since the mounting system 100 may be configured to thermally isolate the substrate 300 from the fixture 400. The substrate 300 may be subjected to a stress relief process as disclosed herein, which may result in pre-bending of the substrate 300. The pre-bent substrate 300 can be clamped to the pin support system 110 using insulating clamps (not shown). In an example, the radius of curvature of the curve defined by the pin support system 110 can be large enough that the effects of gravity do not adversely affect the mechanics of the weld pool, so that deposition is accomplished similarly to deposition in a flat position. Metallic material is deposited on the top surface of the substrate 300 during a DED process to produce preforms 600 and 600'.

[0294] D. System Also provided is a system for constructing a metal workpiece by a DED process, comprising a fixture to which a pre-bent substrate is secured, a mounting system 100 capable of serving as a support underlying the pre-bent substrate as it is secured to the fixture, insulating clamps for securing the pre-bent substrate to the fixture, one or more melting tools with a DED energy source for melting a metal source into a metal molten material that can be deposited on a surface of a base material (for a first layer, the base material is the surface of the substrate; for subsequent layers, the base material is the surface of a previously deposited metal layer), a cooling gas across a liquid melt pool, or impinging on a liquid melt pool, or adjacent a liquid-solid boundary of the liquid melt pool, and a DED energy source for melting a metal source into a metal molten material that can be deposited on a surface of a base material (for a first layer, the base material is the surface of the substrate; for subsequent layers, the base material is the surface of a previously deposited metal layer), and a cooling gas across a liquid melt pool, or impinging on a liquid melt pool, or adjacent a liquid-solid boundary of the liquid melt pool. The system can include a gas jet apparatus capable of directing a cooling gas, a cooling gas impinging on the solidified material, or any combination thereof; a supply of cooling gas; a system for positioning and moving a base material relative to the melting tool and gas jet apparatus; and a controller capable of reading a design model, such as a computer-aided design (CAD) model, of the metal workpiece to be formed and using the design model to adjust the position and movement of the system for positioning and moving the base material and operate the melting tool and gas jet apparatus such that the workpiece is built up by fusing the metal material onto the base material to form a continuous deposit of metal material that forms the workpiece.

[0295] A single melting tool can be used or two melting tools can be used, for example a first preheating torch generating a single preheating electric arc plasma and a second torch generating a dual electric arc plasma. The two torches can be used simultaneously in a tandem configuration. The preheating arc can supply thermal energy to a portion of the surface of the base material for surface heating or preconditioning of the substrate, for example at the location where the metal DED material is deposited. Furthermore, the dual electric arc plasma can be powered by a separate electric supply. The dual electric arc plasma can be used to resistively heat and melt the metal to the surface heating area of ​​the base material. The dual electric plasma arc can ensure sufficient fusion between the base material of the workpiece and the molten metal generated by the action of the electric arc plasma arc on the metal, such as a metal wire feedstock. For example, the second melting tool can be a torch generating a dual electric arc plasma, whereby one arc burns between the tungsten electrode of the torch and the workpiece (PTA) and the other arc burns between the tungsten electrode of the torch and the wire feedstock (main arc), both using linear polarity. The PTA electric arc plasma can deepen the fusion properties of the molten metal into the preheated surface of the base material, which can be controlled independently of the main electric arc plasma. The main electric arc plasma can be established between the torch and a wire feedstock through which current flows. The wire feedstock can be melted by the heat generated by the column of the PTA electric arc plasma transferred to the workpiece and by the heat generated by the main electric arc plasma circuit. The wire feedstock can generate molten metal that can be deposited on the workpiece. The superheat from the droplets of molten metal can maintain a molten pool in the vicinity of the surface heated area of ​​the base material. The surface heating of the base material can enhance fusion and improve the wetting and spreading properties of the liquid pool, thus resulting in overall better DED properties. With regard to the deposition profile, it may be possible to obtain a shallower and wider deposition profile by surface heating the substrate.The improved weld bead properties can result in a shape with a beneficial weld bead contact angle to the base material, which can promote sufficient fusion to the base material and adjacent weld beads. Improved weld bead and fusion properties can result in a product with improved mechanical integrity.

[0296] Each melting tool can be controlled separately and therefore individually adjusted to generate separate fields of temperature and pressure. An advantage of this arrangement may be that the amount of heat energy applied to the melted metal feedstock on the surface heating area of ​​the base material can be greater than the heat energy applied to the surface of the base material, avoiding overheating of the base material.

[0297] The DED manufacturing system provided herein may include a PTA torch, a laser device, an electron beam device, or any combination thereof as a melting tool. In some configurations, a first PTA torch electrically connected to a base material surface may heat a target deposition area on the base material to form a surface heated area, and a second PTA torch electrically connected to a consumable electrode may heat and melt the consumable electrode, resulting in droplets of molten metal that may fall onto the surface heated area of ​​the target deposition area. In some configurations, the PTA torch may surface heat a target deposition area on the base material to form a surface heated area, and the laser device may heat and melt a metal wire or metal powder, resulting in molten metal that may be deposited onto the surface heated area of ​​the target deposition area. In some configurations, the PTA torch may heat a target deposition area on the base material to form a surface heated area, and the electron beam device may heat and melt a metal wire, resulting in droplets of molten metal that may fall onto the surface heated area of ​​the target deposition area.

[0298] In some configurations, a laser device can spot heat a target deposition area on a base material to form a spot heated area, and a PTA torch electrically connected to a consumable electrode can heat and melt the consumable electrode, resulting in droplets of molten metal that can fall onto the spot heated area of ​​the target deposition area. In some configurations, a first laser device can spot heat a target deposition area on a base material to form a spot heated area, and a second laser device can heat and melt a metal wire or metal powder, resulting in the formation of molten metal that can be deposited onto the spot heated area of ​​the target deposition area. In some configurations, a laser device can spot heat a target deposition area on a base material to form a spot heated area, and an electron beam device can heat and melt a metal wire, resulting in droplets of molten metal that can fall onto the spot heated area of ​​the target deposition area.

[0299] In some configurations, the electron beam device can spot heat the target deposition area on the base material to form a spot heated area, and a PTA torch electrically connected to the consumable electrode can heat and melt the consumable electrode, resulting in droplets of molten metal that can fall onto the spot heated area of ​​the target deposition area. In some configurations, the electron beam device can spot heat the target deposition area on the base material to form a preheated area, and a laser device can heat and melt a metal wire or metal powder, resulting in droplets of molten metal that can fall onto the spot heated area of ​​the target deposition area. In some configurations, a first electron beam device can spot heat the target deposition area on the base material to form a spot heated area, and a second electron beam device can heat and melt a metal wire or metal powder, resulting in droplets of molten metal that can fall onto the spot heated area of ​​the target deposition area.

[0300] In some configurations, the DED manufacturing system can include a laser device or a PTA torch that can be positioned to direct energy (e.g., laser energy or a plasma transferred arc, respectively) to a target area of ​​the base material to form a surface heated area, and the PTA torch or laser device can be positioned to direct energy to an end of a consumable electrode or metal wire positioned above the surface heated area of ​​the base material. The energy can melt the end of the consumable electrode or metal wire and form droplets of molten metal that can fall onto the surface heated area of ​​the base material below the end of the consumable electrode or metal wire. The melting tool that directs energy to the target deposition area can promote fusion between the base material and the molten metal material deposited thereon by deepening the penetration of the molten metal droplets into the base material. The melting tool used to melt the consumable electrode or metal wire can also contribute heat energy in the vicinity of the spot heated area of ​​the target deposition area, contributing to the heat energy provided by the melting tool directed at the base material. The superheat from the molten metal droplets can help maintain a melt pool in the vicinity of the spot heated area of ​​the base material.

[0301] The consumable electrode or metal wire can be or include Al, Cr, Cu, Fe, Hf, Sn, Mn, Mo, Ni, Nb, Si, Ta, Ti, V, W, or Zr, or a composite or alloy thereof. In some embodiments, the consumable electrode can be a wire including Ti or a Ti alloy. The consumable electrode or metal wire can be or include a titanium alloy including Ti in combination with one or a combination of Al, V, Sn, Zr, Mo, Nb, Cr, W, Si, and Mn. For example, exemplary titanium alloys include Ti-6AI-4V, Ti-6AI-6V-2Sn, Ti-6AI-2Sn-4Zr-6Mo, Ti-45AI-2Nb-2Cr, Ti-47AI-2Nb-2Cr, Ti-47AI-2W-0.5Si, Ti-47AI-2Nb-1Mn-0.5W-0.5Mo-0.2Si, and Ti-48AI-2Nb-0.7Cr-0.3Si. Consumable electrodes or metal wires can include aluminum, iron, cobalt, copper, nickel, carbon, titanium, tantalum, tungsten, niobium, gold, silver, palladium, platinum, zirconium, alloys thereof, and combinations thereof. Consumable electrodes can include solid wire electrodes, cored wire electrodes, or strip electrodes.

[0302] A typical cross section of the consumable electrode or metal wire is circular. The diameter of the consumable electrode or metal wire can be up to about 10 mm and can range from about 0.8 mm to about 5 mm. The consumable electrode or metal wire can have any cross-sectional size that is practically feasible, for example, 1.0 mm, 1.6 mm, and 2.4 mm, or from about 0.5 mm to about 3 mm. The feed rate and positioning of the consumable electrode or metal wire can be controlled and adjusted to the effect of the power supply to the PTA torch, laser device, electron beam device, or any combination thereof, to ensure that the consumable electrode or metal wire is continuously heated and melted when it reaches its intended position above the preheated area of ​​the base material.

[0303] The laser device can generate a laser beam of sufficient energy to transfer thermal energy to the base material to preheat a surface area of ​​the base material or to melt the metal wire. Preheating the base material via energy from the laser beam can promote fusion between the base material and the molten metal material by deepening melting features in the base material. In some embodiments, at least a portion of the base material can be melted by energy from the laser beam of the laser device. In some embodiments, sufficient heat can be applied by the laser beam of the laser device to form a melt pool in the base material at the location where the metal material is to be deposited, produced by a PTA torch, or another laser device, or an electron beam device.

[0304] Examples of suitable laser devices include ytterbium (Yb) lasers, Yb fiber lasers, Yb fiber-coupled diode lasers, Yb:glass lasers, diode-pumped Yb:YAG lasers, neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers, CO2 lasers, CO lasers, Nd:glass lasers, neodymium-doped yttrium orthovanadate (Nd:YVO4) lasers, Cr:ruby lasers, diode lasers, diode-pumped lasers, excimer lasers, gas lasers, semiconductor lasers, solid-state lasers, dye lasers, X-ray lasers, free electron lasers, ion lasers, gas mixture lasers, chemical lasers, and combinations thereof. Preferred lasers include Yb lasers, particularly Yb fiber lasers. In many applications, the wavelengths used by Yb fiber lasers may have lower reflectance compared to other laser wavelengths.

[0305] The PTA torch can be any configuration capable of generating an electric arc plasma to resistively heat and melt a consumable electrode, such as gas metal arc welding (GMAW), particularly welding using a non-reactive gas to establish an arc (metal inert gas welding or MIG welding), or to heat a target area on the surface of a base material. The consumable electrode can be melted in the plasma generated by the PTA torch using an electric arc, and the melted consumable electrode can be deposited in a molten pool on the workpiece to add to the near-net-shape metal body to form the near-net-shape metal body. Preheating the base material via the energy from the PTA torch can promote fusion between the base material and the molten metal material by deepening the melting characteristics in the base material. In some embodiments, at least a portion of the base material can be melted by the energy from the plasma of the PTA torch. In some embodiments, sufficient heat can be applied by the plasma of the PTA torch to form a molten pool in the base material at a location where a melted metal material is to be deposited by a different PTA torch or laser device.

[0306] The combination of thermal pre-bending of the substrate by inducing a melt track, use of mounting system 100, and pre-heating of the substrate prior to forming the workpiece using the DED process enables the formation of near net shape metal workpieces that significantly reduce the problems associated with internal residual stresses and distortions that are prominent in many conventional additively manufactured products, resulting in improved manufacturing repeatability and the production of workpieces with improved dimensional accuracy, strength, fatigue resistance, and durability. EXAMPLES

[0307] E. Example The following examples are included for illustrative purposes only and are not intended to limit the scope of the embodiments provided herein.

[0308] Example 1 The first base plate substrate, with dimensions (L x W x T) of 635 mm x 190 mm x 9.5 mm and made of Ti-6Al-4V, was used as the first test substrate to measure the deflection without residual stress relief. The workpiece was fabricated by clamping this substrate to a fixture or welding table, preheating the base material with a first PTA torch, melting the Ti-6Al-4V wire with a second PTA torch to form molten metal and depositing it on the preheated base material. The deposition rate was 7.5-10 mm / s, and a high flow rate of cooling gas was used to direct the cooling gas using an inert gas to impinge on the as-solidified material adjacent to the liquid-solid boundary of the liquid melt pool. After deposition was completed, the component was cooled and removed from the fixture, and the deformation of the substrate was examined.

[0309] Distortion was evident on the short sides of the substrate, causing the substrate to bow upwards compared to the flat profile of the substrate prior to deposition. The observed deformation is shown in Figure 13A.

[0310] A second base plate substrate made of Ti-6Al-4V with dimensions (L×W×T) of 635 mm×190 mm×12.7 mm was used as the second test substrate. The same workpieces were fabricated using the same conditions as described above. Figure 13B shows the deformation caused by DED deposition on a substrate with a thickness of 12.7 mm that has not undergone any type of residual stress relief, showing upward bowing at the short sides of the substrate, with the left edge bowing upwards by approximately 7 mm and the right edge bowing upwards by approximately 6.0 mm, compared to the flat profile of the substrate before deposition.

[0311] FIG. 13C shows a third base plate substrate made of Ti-6Al-4V with dimensions (L×W×T) of 635 mm×190 mm×9.5 mm that was used to form the object by subjecting it to thermal pre-bending, pre-heating and DED processing as described herein. The substrate was securely clamped to the fixture using insulating clamps along the entire length of the long side of the substrate, while no clamps were used on the short side of the substrate. The substrate was thermally isolated from the fixture using four layers of alumina insulating plates (RS-1200 Keranova) between the substrate and the fixture, each about 3.2 mm thick with the same dimensions as the substrate.

[0312] A PTA torch was used to provide thermal energy to the first side of the substrate to form a melt track in the substrate. The final aggregate residual stress distribution determined by the combination of DED and melt track has a lower tensile peak at the centerline of the DED and a lower equilibrated compressive stress at locations away from the centerline of the DED compared to the original residual stress profile of DED without the pre-bending melt track (i.e., high tensile peak at the centerline of the DED and high equilibrated compressive stress at locations away). The pattern used to form the melt track is shown in Figures 7C and 7D. As shown in the figures, the PTA torch, which serves as the DED heat source, was positioned at one edge of the substrate. The spacing between the melt tracks may be subject to the shape of the workpiece to be fabricated. For example, the melt track may be formed in an area that is not an area under the wall of the workpiece to be formed in order to minimize the final aggregate residual stress distribution in the workpiece. For example, the majority of the melt line on the first surface may be formed at one or more locations other than the locations corresponding to the area or areas occupied by one or more walls of the workpiece to be formed on the second side of the substrate. To induce maximum thermal stress in the substrate, a high energy density (e.g., arc energy delivered at about 450 J / mm to about 550 J / mm) was applied at a speed of 6 to 16 mm / s to rapidly melt a portion of the substrate surface to form an autogenous weld line, which was then rapidly cooled using a gas jet device to direct a high flow rate of cooling gas at a temperature of 25° C. toward the weld line, thereby forming a molten track with high tensile stress near the centerline of the molten track and high compressive stress at a distance away from the centerline. In an exemplary embodiment, for a substrate thickness of 9.5 to 10 mm, a single heat source with a current of about 150 A to about 250 A, a voltage of about 20 V to about 30 V, and a traverse speed of 6 mm / s to 16 mm / s was used to form a molten track with a width of about 3 mm and a depth of up to 1 mm.

[0313] Upon release from the fixture, the pre-bent substrate bowed upwards, exhibiting a deflection of approximately 15 mm as shown in Figure 8A. This pre-bent substrate was then mounted in a fixture using the described curved clamping die and insulating clamps as the underlying supports, and the pre-bent substrate was attached to the fixture. The pre-bent substrate was positioned so that the side with the melt track was facing the curved clamping die. Pre-heating of the pre-bent substrate was achieved using two PTA torches delivering a lower energy density to the pre-bent substrate surface by positioning the PTA torches at a higher stand-off distance to reduce the risk of generating localized melt tracks that could cause fusion issues at the baseplate interface during DED metal deposition. For example, pre-heating was performed using two PTA torches using a range of 150–250 A and an arc voltage of 20–30 V. The traverse speed was 6–12 mm / s. For example, the arc energy delivered by the first PTA torch could be 460 J / mm and the arc energy delivered by the second PTA torch could be 430 J / mm. Another important aspect is the fact that the pre-bending of the track was performed with a higher plasma gas flow compared to that used in the pre-heating. A higher plasma gas flow rate generates a harder electric arc and therefore a higher energy density. Regarding the stand-off distance, a 25%-50%, or 30%-40% higher stand-off distance can be used during the pre-heating compared to the stand-off distance used in the pre-bending. No cooling gas was used during the pre-heating process.

[0314] After the substrate reached a temperature of 450°C-550°C, DED deposition of the metal to form the object was performed in a sealed chamber containing an argon inert atmosphere. The DED process used two PTA torches. The first PTA torch directed thermal energy to a target area of ​​the base material, forming a preheated area, and the second PTA torch directed thermal energy (1) to an end of a consumable electrode or metal wire positioned above the preheated area of ​​the base material, and (2) toward the preheated area. The energy from the second PTA torch melted the end of the consumable electrode or metal wire, forming droplets of molten metal that fell onto the preheated area of ​​the base material below the end of the consumable electrode or metal wire. The process also included using a gas jet device to direct a high flow rate of cooling gas at a temperature of 25°C toward the as-solidified material adjacent the liquid-solid boundary of the molten metal. Deposition continued until the workpiece was completed. The workpiece was cooled in the deposition chamber to a temperature of 400°C or less. The workpiece is then removed from the deposition chamber and the pre-bent substrate is removed from the fixture. Depending on how quickly the operator removes the workpiece, the pre-bent substrate can be removed from the fixture at a temperature of 200-300°C or less. In this example, the pre-bent substrate was removed from the fixture at a temperature of approximately 250°C.

[0315] As shown in FIG. 13C, the workpiece exhibited slight upward movement (only about 0.5 mm) on the short side of the substrate, indicating that a significant amount of residual stress observed in the test substrate when using the conventional DED process was eliminated using the curved clamping die in combination with pre-bending and pre-heating.

[0316] Repeatability was tested under the same conditions as described above using similar substrates and the same workpiece design. The method showed consistent and repeatable results across all three workpieces produced. The deviation in substrate deformation between workpiece #1 and workpiece #2 was approximately 0.5 mm, and the deviation in substrate deformation between workpiece #2 and workpiece #3 was approximately 0.1 mm.

[0317] The stress relief heat treatment did not significantly affect the overall dimensions of the workpieces, e.g., only a slight upward shift of about 0.5 mm occurred on the short side of the plate after stress relief, which means that the as-deposited workpieces have very low residual stresses as a result of the described stress relief.

[0318] Example 2 A comparative experiment was conducted to compare the temperature gradient of the substrate during DED fabrication using a ceramic sheet support known in the art versus using the pin support system described herein. The same DED fabrication process was performed on two identical titanium substrates. In the first example, the substrate was clamped to a set of pins during the DED process described herein, whereas in the second example, the substrate was clamped on a set of ceramic pylons during the DED process described herein. The total thickness of the ceramic pylons was greater than the substrate support height of the pins. Thermocouples were used to measure the heat transfer and heat of the various components. Data was collected and plotted across various positions of the substrate being processed. The results are shown in FIG. 15. As shown, the rotational average temperature of the substrate during the DED process clamped to a set of pins remained higher throughout the DED process than when the substrate was clamped to a set of ceramic pylons. This indicates that reduced heat loss from the substrate may be obtained by using a pin support system as described herein as a support structure compared to the known ceramic pylon support.

[0319] Example 3 A comparative experiment was also conducted to demonstrate the reduction in moisture content achieved during the DED process when using a support system without ceramic sheets, plates, or pylons, such as the pin support system as described herein, versus a support formed with ceramic pylons. In the example, the DED process was performed on two equal substrates as in Example 2. During the first experiment, the substrate was clamped to the pin support system described herein without ceramic sheets, plates, or pylons. During the second experiment, the substrate was clamped to a ceramic pylon support. The moisture and oxygen content in the atmosphere was monitored, and the measurements are reflected in FIG. 16A when the substrate was supported with a ceramic free pin support system and in FIG. 16B when the substrate was supported with a ceramic pylon. The measurement data shows that the moisture content in the DED atmosphere is much lower throughout the process when using a pin support system as described herein without any ceramic sheets, plates, or pylons, versus when using a ceramic pylon support.

[0320] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Thus, it is intended that the present invention cover the modifications and variations of the present invention provided they come within the scope of the appended claims and their equivalents.

[0321] Below is a list of reference numbers used in the description and accompanying drawings. [Explanation of symbols]

[0322] 100 PCB Mounting System 101 Mounting System Elements 102 Mounting System Curved Profile 103 Knurling 104 Peripheral rim area 105 knurling interval 106 Mounting System Board Interface Area 107 Bond Court 108 Ceramic Coating 110 Pin Support System 112 pin 114 Pin with uniform width 115 Pins with non-uniform width 116 Pin with combined shape 118 Pinhead part 119 pin board contact surface 120 Pinhead Flat Area 122 Colored part of pin 124 Pin base or engagement part 126 Pin structural welding fixture joint 128 Pin Spacer 130 Pin Support System Board Interface Area 150 Lattice Support System 151 Lattice Elements 152 Curved Surfaces of Lattice Support Systems 153 Flat surface of grid support system 154 Area around the grid support system 155 Substrate surface interface of the grid support system 156 Grid element substrate contact surface 158 Lattice Cavity 170 Curved clamp mold 172 Knurled or corrugated surface 174 Top / Substrate Interface Area 176 Mold edge 178 Knurling 180 knurling interval 182 Flat Rim 184 Ceramic Coating 186 Bond Court 188 Cavity 190 Cavity 192 Cavity 194 Cavity 196 Reinforcement members 198 Maximum height 200 Gas jet device 210 Nozzle 230 Support 250 PTA torch 300 Substrates 310 First Side 320 Second Side 330 Preform DED back wall 350 Melting Truck 355 Spacing between melting tracks 370 First preliminary bend heating path 371 Second preliminary bend heating path transfer distribution 372 Third preliminary bend heating path 373 Fourth preliminary bend heating path 374 5th preliminary bend heating path 375 6th preliminary bend heating path 380 Preform Wall 382 Preform Wall 384 Preform Wall 400 Jig 410 Nominal Board Deflection 500 Clamp 501 screw hole 502 holes 505 Bottom contact facet 506 Side contact facet 540 Alumina Insulation Plate 541 Alumina Insulation Plate 507 Clamp top 509 Ceramic Coating Surface 510 Flat head screw 515 Flat head screw tip 520 Volts 525 Nut 530 Top of the jig 542 Alumina Insulation Plate 543 Alumina Insulation Plate 544 Areas of Uneven Pressure and Heat Transfer Distribution 545 Areas of Uneven Pressure and Heat 546 Areas of Uneven Pressure and Heat Transfer Distribution 547 Areas of Uneven Pressure and Heat Transfer Distribution 548 Areas of Uneven Pressure and Heat Transfer Distribution 549 Areas of Uneven Pressure and Heat Transfer Distribution 550 Base Plate 575 Frame showing areas of non-uniform pressure and heat transfer distribution 576 Frame showing areas of non-uniform pressure and heat transfer distribution 577 Frame showing areas of non-uniform pressure and heat transfer distribution 578 Frame showing areas of non-uniform pressure and heat transfer distribution 600 Preforms 600' Preform 610 Clamp entity 615 Clamp entity 620 Clamp entity 625 Clamp entity 630 Clamp entity 650 Non-optimal clamping area 700 First preliminary heating path 705 Second preliminary heating path 710 Third preliminary heating path 715 Fourth preliminary heating path 720 Fifth preliminary heating path 725 6th preliminary heating path 730 Seventh preliminary heating path 735 8th preliminary heating path

Claims

1. 1. A system for directed energy deposition, comprising: A welding fixture for fixing the pre-bent substrate; a pin support system positioned between the fixtures and when the pre-bent substrate is secured to the fixture; a clamp for fixing the pre-bent substrate to the fixture; one or more melting tools comprising a DED heat source for melting a metal source into a metal melt that is deposited on a surface of the base material; a gas jet apparatus for directing cooling gas to impinge on the as-solidified material adjacent the liquid-solid boundary of the liquid melt pool to affect a temperature gradient; The cooling gas supply unit, and an actuator for positioning and moving the base material relative to the melt tool and the gas jet device; Including, the pin support system comprising one or more pins in a reconfigurable arrangement on the weld fixture; The one or more pins have a variable substrate support height and are arranged to define a curved profile.

2. At least one of the one or more pins: a pin head portion including a substrate contact area; The color part and a base portion configured to engage the weld fixture. The system of claim 1 .

3. The system of claim 2 , wherein the pin head portion further comprises a flat portion on at least a portion of its lateral profile.

4. The pin support system of claim 2 , wherein the pin head portion includes a weld fixture interface area.

5. The system of any one of claims 1 to 3, wherein the one or more pins comprise austenitic stainless steel.

6. 1. A directed energy deposition method for manufacturing a metal workpiece, comprising: pre-bending a substrate of metallic material with thermal energy by forming a plurality of fusion tracks on a first surface of the substrate of metallic material using a fusion tool to produce a pre-bent substrate; using a pin support system of the system for directed energy deposition of any one of claims 1 to 5 as an underlying support structure for supporting the pre-bent substrate, and fastening the pre-bent substrate and the mounting system or pin support system supporting the pre-bent substrate to a fixture using a plurality of clamps; forming the metal workpiece on the second surface of the substrate by an additive manufacturing process that includes melting a metal feedstock to deposit a layer of molten metal on the second surface of the substrate to form a base material, and depositing subsequent layers of molten metal on the base material to form the metal workpiece; the second surface of the substrate is opposite the first surface of the substrate; method.

7. The method of claim 6 , wherein the metal feedstock is metal in the form of a powder, a wire, or a combination thereof.

8. 8. The method of claim 6 or 7, further comprising pre-heating the pre-bent substrate to a temperature of about 400° C. to about 900° C. prior to fabricating the metal workpiece while clamped in the fixture by applying thermal energy to the second side of the substrate.

9. The method of any one of claims 6 to 8, wherein pre-bending the substrate comprises inducing a thermal gradient in the substrate.

10. The method of any one of claims 6 to 9, wherein the melting tool comprises a heat source selected from a laser beam, an electron beam, a plasma arc, a gas tungsten arc, a gas metal arc, and any combination thereof.

11. 11. The method according to any one of claims 6 to 10, wherein during pre-bending of the first surface of the substrate, the application area of ​​thermal energy reaches a temperature that is the melting point of the metallic material or a temperature that is about 5°C to about 50°C lower or higher than the melting point of the metallic material.

12. 12. The method according to claim 6, wherein the formation of the melt tracks during pre-bending of the first surface of the substrate results in the formation of tensile stresses at a centerline of each of the melt tracks and in the formation of compressive stresses in areas away from the centerline of each of the melt tracks upon cooling of the substrate.

13. The method of claim 12 , wherein the tensile stress at the centerline of the melt track is within about 10% of the yield strength of the substrate.

14. The method of claim 12 , wherein the tensile stress at the centerline of the melt track exceeds a magnitude of a yield strength of the substrate.

15. 15. The method of any one of claims 6 to 14, wherein the pre-bending step further comprises directing cooling gas at the molten track using a gas jet device to enhance cooling of the molten track.

16. 16. The method of claim 15, wherein directing the cooling gas at the melt track creates a thermal gradient in the substrate to impart residual stress to the substrate upon cooling.

17. The method of claim 15 or 16, wherein the gas jet device directs the cooling gas at the melt track at a rate of about 50 L / min to about 500 L / min.

18. A method according to any one of claims 15 to 17, wherein the cooling gas is applied in a constant stream, applied intermittently or applied in a pulsed stream.

19. The method of any one of claims 15 to 18, wherein the cooling gas comprises an inert gas selected from the group consisting of argon, helium, neon, xenon, krypton and combinations thereof.

20. The method according to any one of claims 15 to 19, wherein the cooling gas is applied at a temperature below 100°C.

21. A method according to any one of claims 15 to 20, wherein the cooling gas is applied at a temperature below 25°C.

22. The method of any one of claims 15 to 21, wherein the gas jet device generates a turbulent flow of the cooling gas, a laminar flow of the cooling gas, or a combination of turbulent and laminar flow of the cooling gas.

23. 23. The method of any one of claims 15 to 22, wherein the gas jet device comprises a plurality of nozzles, the nozzles directing the cooling gas away from a heat source of the melting tool, and at least one nozzle directing the cooling gas at as-solidified metal in the melting track.

24. The method according to any one of claims 6 to 23, wherein the melt tracks are formed equidistant from each other.

25. The method of any one of claims 6 to 24, wherein the distance between the melt tracks is from about 10 mm to about 60 mm.

26. determining a centerline of each wall of a preform formed on the second surface of the substrate; positioning the melt track on the first surface of the substrate about 10 mm to about 20 mm away from a centerline of a majority wall of the preform formed on the second surface of the substrate; The method of any one of claims 6 to 25, further comprising:

27. 27. The method of any one of claims 6 to 26, further comprising forming a majority of the fusion line on the first surface at one or more locations other than locations corresponding to one or more areas occupied by one or more walls of the workpiece formed on the second side of the substrate.

28. The method of any one of claims 6 to 27, wherein the pre-bending forms a pre-bent substrate having a uniform elastic-plastic bending.

29. The method of any one of claims 6 to 28, further comprising pre-bending the substrate while the substrate is clamped to a fixture and thermally insulated from the fixture.

30. The method of any one of claims 6 to 29, wherein one or more clamps include an insulating coating on each surface that contacts the pre-bent substrate.

31. 31. The method of claim 30, wherein the insulating coating comprises a ceramic material, silicon carbide, silicon nitride, boron carbide, or a combination thereof.

32. 32. The method of claim 31 , wherein the ceramic material comprises alumina, zirconia, titanium oxide, alkaline earth metal silicates, aluminum titanate, zirconium dioxide, zirconium dioxide stabilized by the addition of yttrium oxide, yttrium aluminum oxide, ZrVO, Mg(VO), or combinations thereof.

33. The method according to claim 31 or 32, wherein the insulating coating has a thickness of between 0.1 mm and 5 mm.

34. The method of any one of claims 30 to 33, wherein the clamp comprises a knurled pattern or corrugations on a surface that contacts the pre-bent substrate.

35. 35. The method of any one of claims 30 to 34, further comprising tightening the clamp to conform the pre-bent substrate to a curved profile defined by the mounting system or the pin support system.

36. The method of claim 35, wherein each of the clamps is tightened to a torque of about 10 N·m to about 100 N·m.

37. A method according to any one of claims 30 to 36, wherein the clamps are positioned such that they meet at the start or end of a wall of the workpiece being produced.

38. The pre-heating of the pre-bent substrate further comprises: a) forming a melt track but not melting the surface of the pre-bent substrate, or b) forming a melt track and melting a surface of the pre-bent substrate with the melt track; The method of any one of claims 6 to 37, performed using one or more melting tools comprising a DED heat source under the conditions:

39. 40. The method of claim 38, further comprising positioning the melt tool at a stand-off location that is further away than a stand-off location used to form the workpiece.

40. The method further includes pre-heating the pre-bent substrate, including a first short side and an opposing second short side and a first long side and an opposing second long side, prior to DED deposition to form a workpiece, the pre-heating including: a) positioning a melting tool including a DED heat source at the first short side and within about 10 mm to about 60 mm from the first long side of the pre-bent substrate secured to the fixture; b) applying thermal energy from the DED heat source of the melting tool across a surface of the substrate, beginning at the first short side across the surface of the pre-bent substrate to the opposing second short side, forming a first line of energy application on the surface; c) repositioning the DED heat source of the melting tool relative to the first short side and displaced from the first line of energy application toward the second long side a distance of about 10 mm to about 60 mm; and d) repeating steps b) and c) until a line of energy application is applied across the surface of the pre-bent substrate to a position between about 10 mm and about 60 mm from the second opposite long side; 40. The method of claim 39, comprising:

41. 41. The method of claim 39 or 40, further comprising pre-heating the pre-bent substrate prior to DED deposition to form a workpiece by applying thermal energy to a front side of the substrate with a heating device.

42. 42. The method of claim 41, wherein the heating device comprises an infrared heater, an induction heater, a resistive heater, or a combination thereof.

43. 42. The method of claim 41, wherein the heating device comprises a conductor-in-conduit heat source, a heater strip, a resistive heating strip, an infrared heater, a positive heat coefficient ceramic heater, a thick film ceramic heater, a resistive wire heater, a resistive ribbon heating device, an infrared heater, and an induction heater or a combination thereof.

44. The method of any one of claims 6 to 43, wherein the pre-heating increases the temperature of the pre-bent substrate to a temperature of from about 350°C to about 650°C.

45. forming the metal workpiece, Providing a metal feedstock in the form of a wire; using a single melting tool to heat and melt the wire such that molten metallic material is deposited on areas of the substrate to form a base material; and moving the base material in a predetermined pattern relative to a location of the melting tool such that successive deposits of molten metallic material on the base material solidify to form a three-dimensional object; The method according to any one of claims 7 to 44, comprising:

46. forming the metal workpiece, a) providing a metal feedstock in the form of a wire; b) heating at least a portion of a surface of the substrate using a first melting tool to form a pre-heated area on the substrate; c) using a second melting tool to heat and melt the wire such that molten metallic material is deposited on the pre-heated area to form a base material; d) moving the base material relative to the positions of the first melt tool and the second melt tool in a predetermined pattern; e) heating at least a portion of a surface of the base material using the first melting tool to form a pre-heated area on the base material and depositing a molten metallic material produced by the second melting tool melting the metallic material onto the pre-heated area on the base material; and f) repeating steps d) and e) such that successive deposits of molten metallic material on the pre-heated areas on the base material solidify to form a three-dimensional object; The method according to any one of claims 7 to 45, comprising:

47. using a gas jet device to direct a cooling gas across a surface of the molten metal material, or to impinge on the surface of the molten metal material, or to impinge on a surface of as-solidified material adjacent a liquid-solid boundary of the molten metal material, or any combination thereof; and moving the base material relative to the location of the melt tool and the gas jet in a predetermined pattern such that successive deposits of molten metallic material solidify to form a three-dimensional object; 47. The method of claim 45 or 46, further comprising:

48. the first melting tool comprises a PTA torch, a laser device, an electron beam device, or any combination thereof; the second melting tool comprises a PTA torch, a laser device, a coaxial powder delivery nozzle laser system, an electron beam device, or any combination thereof; 47. The method of claim 45 or 46.

49. the first melting tool comprises a first PTA torch and the second melting tool comprises a second PTA torch; or the first melting tool comprises a laser and the second melting tool comprises a PTA torch; or the first melting tool comprises a PTA torch and the second melting tool comprises a laser; or the first melting tool comprises a laser device and the second melting tool comprises a coaxial powder delivery nozzle laser system; or the first melting tool comprises a PTA torch and the second melting tool comprises a torch coaxial powder delivery nozzle laser system; or the first melting tool comprises a PTA torch and the second melting tool comprises an electron beam device; or the first melting tool comprises an electron beam device and the second melting tool comprises a PTA torch; or the first melting tool comprises an electron beam device and the second melting tool comprises a laser device; or the first melting tool comprises a laser device and the second melting tool comprises an electron beam device; 48. The method of claim 47.

50. 50. The method of claim 49, wherein when the second melting tool includes a PTA torch, the PTA torch is electrically connected to a DC power source such that an electrode of the PTA torch is a cathode and the metallic material is a consumable electrode that is an anode.

51. 51. The method of any one of claims 1 to 50, wherein each of pre-bending the substrate, pre-heating the pre-bent substrate, and forming a metal workpiece is performed in a sealed chamber containing an inert atmosphere.

52. 52. The method of claim 51, wherein the inert atmosphere comprises argon, neon, xenon, krypton, helium, or a combination thereof.

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