Additive manufacturing system and method

Abstract

To provide improved liquid metal jet printing systems and methods for the same.SOLUTION: An additive manufacturing device may include a stage 106 configured to support a substrate 116, a printhead 104 disposed above the stage, and a targeted heating system 102 disposed proximally to the printhead. The printhead may be configured to heat a build material to a molten build material and deposit the molten build material on the substrate in the form of droplets to fabricate the article. The targeted heating system may be configured to control a temperature or temperature gradient of the droplets in a flight path interposed between the printhead and the substrate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments or implementations of the present disclosure are directed to additive manufacturing systems and methods. [Background technology]

[0002] Liquid metal jet printing, such as magnetohydrodynamic (MHD) liquid metal jet printing, involves ejecting liquid or molten metal droplets from a printhead onto a substrate, which may be a heated stage or pre-deposited metal, to form a workpiece or article. Generally, liquid metal jet printing involves utilizing direct current pulses applied by an electromagnetic coil to eject molten metal droplets toward the substrate. Once the droplets contact the substrate, they cool to form the article. While liquid metal jet printing has made significant advancements, articles produced from conventional liquid metal jet printing systems often exhibit inconsistencies with respect to build strength, adhesion, porosity, surface finish, cracks, fractures, z-height error, etc. Summary of the Invention [Problem to be solved by the invention]

[0003] In view of the foregoing, secondary or post-printing processes, such as machining and finishing, are often implemented to address inconsistencies in articles produced from conventional liquid metal jet printing systems. However, post-printing processes significantly reduce productivity and correspondingly increase the cost of producing articles by liquid metal jet printing.

[0004] What is needed, then, is an improved liquid metal jet printing system and method.

[0005] The following presents a simplified summary in order to provide a basic understanding of some aspects of one or more embodiments of the present teachings. This summary is not an extensive overview and is not intended to identify key or critical elements of the present teachings or to delineate the scope of the disclosure. Rather, its primary purpose is merely to present one or more concepts in a simplified form as a prelude to the more detailed description that is presented later.

[0006] The present disclosure may provide an additive manufacturing device for manufacturing an article. The additive manufacturing device includes a stage configured to support a substrate, a print head disposed above the stage, and a targeted heating system disposed proximate to the print head. The print head may be configured to heat a build material into molten build material and deposit the molten build material in the form of droplets onto the substrate to create the article. The targeted heating system may be configured to control a temperature or a temperature gradient of the droplets in a flight path interposed between the print head and the substrate.

[0007] In some embodiments, the target heating system can be configured to heat the droplets to a temperature between about ±10% and about ±40% of the melting point of the build material.

[0008] In some embodiments, the print head and the target heating system may be coupled to one another.

[0009] In some embodiments, the target heating system may include one or more lasers.

[0010] In some embodiments, the one or more lasers have a power output of about 1 W / cm 2 ~Approx. 10,000W / cm 2 The irradiation dose may include:

[0011] In some embodiments, the one or more lasers may include a high-power laser imager.

[0012] In some embodiments, the high power laser imager may include a 1D imager or a 2D imager.

[0013] In some embodiments, the target heating system can be configured to operate at temperatures between about 300°C or more and about 600°C or less.

[0014] In some embodiments, the target heating system may include a laser system.

[0015] In some embodiments, the laser system may include a fiber laser, a fiber-coupled laser module, an output fiber coupled to the fiber-coupled laser module, a collimator disposed downstream of the fiber output, a polarization rotator disposed downstream of the collimator, a variable retarder disposed downstream of the collimator, and a wavelength retarder disposed downstream of the variable retarder.

[0016] In some examples, the additive manufacturing system may further include a first polarizer positioned between the collimator and the polarization rotator, a second polarizer positioned between the polarization rotator and the variable retarder, and a third polarizer positioned downstream of the wavelength retarder.

[0017] In some embodiments, the polarization rotator may be positioned upstream of the variable retarder and the wavelength retarder.

[0018] In some examples, the additive manufacturing system may further include a first polarizer positioned between the collimator and the variable retarder, a second polarizer positioned between the wavelength retarder and the polarization rotator, and a third polarizer positioned downstream of the polarization rotator.

[0019] In some embodiments, the variable retarder and the wavelength retarder may be positioned upstream of the polarization rotator.

[0020] In some embodiments, the target heating system can include a monogon system, which can include one or more monogon scanners, one or more galvanometer mirrors, or a combination thereof.

[0021] In some examples, the monogon system may include a monogon scanner, which may be substantially free of a reflective coating.

[0022] In some examples, the additive manufacturing device may further include a monitoring system configured to monitor a portion of the additive manufacturing device.

[0023] In some examples, the monitoring system may be configured to measure the temperature of the droplets in the flight path.

[0024] In some examples, the additive manufacturing device may further include a computing system operably coupled to the print head and the target heating system, and a monitoring system operably coupled to the computing system and configured to monitor the additive manufacturing device.

[0025] In some examples, the additive manufacturing device may further include a beam dump positioned proximate to the print head and incident on the beam generated by the target heating system, the beam dump configured to absorb at least a portion of the energy from the beam generated by the target heating system.

[0026] In some examples, the target heating system may be further configured to control the temperature or temperature gradient of the droplets deposited on the substrate, the area proximate to the substrate, or a combination thereof.

[0027] In some examples, the build material may include one or more metals or metal alloys, which may include one or more of aluminum, aluminum alloys, brass, bronze, chromium, cobalt chromium alloys, copper, copper alloys, iron alloys, nickel, nickel alloys, nickel titanium alloys, stainless steel, tin, titanium, titanium alloys, gold, silver, molybdenum, tungsten, or combinations thereof.

[0028] In some examples, the build material may include one or more polymers, such as acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polylactic acid (PLA), high density polyethylene (HDPE), polyphenylsulfone (PPSU), poly(meth)acrylate, polyetherimide (PEI), polyetheretherketone (PEEK), high impact polystyrene (HIPS), thermoplastic polyurethane (TPU), polyamide, composites thereof, or combinations thereof.

[0029] The present disclosure can provide a method for making an article using an additive manufacturing device, which can include heating a build material in a print head to a molten build material, ejecting the molten build material from the print head toward a substrate, at least partially heating droplets in a flight path, and depositing the molten build material on the substrate. [Brief explanation of the drawings]

[0030] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present teachings. These and / or other aspects and advantages of embodiments of the present disclosure will become apparent and more readily understood from the following description of various embodiments taken in conjunction with the accompanying drawings.

[0031] [Figure 1] FIG. 1 illustrates a schematic cross-sectional view of an exemplary additive manufacturing layering device or 3D printer incorporating a targeted heating system according to one or more embodiments disclosed.

[0032] [Figure 2] FIG. 2 illustrates a schematic diagram of another exemplary additive manufacturing layering device or 3D printer incorporating an exemplary targeted heating system, according to one or more embodiments disclosed.

[0033] [Figure 3]FIG. 3 illustrates a schematic diagram of another exemplary additive manufacturing layering device or 3D printer incorporating an exemplary targeted heating system, according to one or more embodiments.

[0034] [Figure 4] FIG. 4 illustrates an exemplary fiber-coupled laser that may be utilized as part of the laser system of the target heating system of FIG. 2, FIG. 3, FIG. 7, or FIG. 8, according to one or more disclosed embodiments.

[0035] [Figure 5] FIG. 5 illustrates another exemplary fiber-coupled laser that may be utilized as part of the laser system of the target heating system of FIG. 2, 3, 7, or 8, according to one or more disclosed embodiments.

[0036] [Figure 6] FIG. 6 illustrates a schematic diagram of another exemplary additive manufacturing device or 3D printer incorporating an exemplary targeted heating system, according to one or more embodiments disclosed.

[0037] [Figure 7] FIG. 7 illustrates a schematic diagram of another exemplary additive manufacturing device or 3D printer incorporating an exemplary targeted heating system, according to one or more embodiments disclosed.

[0038] [Figure 8] FIG. 8 illustrates a schematic diagram of another exemplary additive manufacturing device or 3D printer incorporating an exemplary targeted heating system, according to one or more embodiments disclosed. DETAILED DESCRIPTION OF THE INVENTION

[0039] The following description of various exemplary embodiments is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses.

[0040] As used throughout, ranges are used as a shorthand to describe each and every value within the range. Any value within a range may be selected as an endpoint of the range. Additionally, all references cited herein are incorporated by reference in their entirety. In the event of a conflict between a definition in this disclosure and a cited reference, the present disclosure controls.

[0041] Additionally, all numerical values ​​are "about" or "approximately" the indicated value, taking into account experimental error and variations that would be expected by one of ordinary skill in the art. All numerical values ​​and ranges disclosed herein are understood to be approximations, regardless of whether "about" is used in conjunction with them. As used herein, the term "about," in conjunction with a number, is also understood to refer to a value that may be ±0.01% of that number (inclusive), ±0.1% (inclusive), ±0.5% (inclusive), ±1% of that number (inclusive), ±2% of that number (inclusive), ±3% of that number (inclusive), ±5% of that number (inclusive), ±10% of that number (inclusive), or ±15% of that number (inclusive). It should be further understood that when a numerical range is disclosed herein, any number falling within that range is also specifically disclosed.

[0042] As used herein, the term "or" is an inclusive operator and is equivalent to the term "and / or" unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for based on additional unrecited factors unless the context clearly dictates otherwise. As used herein, reference to "at least one of A, B, and C" includes embodiments including multiple instances of A, B, or C, A, B, or C, or combinations such as A / B, A / C, B / C, A / B / B / B / C, A / B / C, etc. Additionally, throughout this specification, the meanings of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on."

[0043] Reference will now be made in detail to the exemplary embodiments of the present teachings, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same, similar or like parts.

[0044] The present disclosure is directed to additive manufacturing devices or 3D printers and methods thereof. In particular, the present disclosure is directed to targeted heating systems and methods for 3D printers. Forming structures with molten metal droplets is a complex thermal-fluid process involving remelting, coalescence, cooling, and solidification. Voids and cold laps (lack of melting) are caused by insufficient remelting and insufficient metallurgical bonding at the interface formed between the molten metal droplet and a previously deposited material or substrate (e.g., droplet) under inappropriate temperatures. The interface temperature is primarily determined by the droplet temperature and the surface temperature of the previously deposited material or substrate. Obtaining and maintaining accurate part geometry and z-height are also adversely affected by the same factors. Too low an interface temperature results in the formation of voids and cold laps from insufficient remelting and coalescence. If the interface temperature is too high, new droplets will flow away from the surface of the previously deposited material before solidifying, resulting in misshapen part geometry and z-height errors. The interface temperature can be affected by the initial drop temperature, build part surface temperature, build plate temperature, drop frequency, and part z-height. While this can be controlled to some degree by optimizing process parameters, the thermal processes involved may be excessively slow due to changes and dynamics that occur during part printing, which can result in unacceptable interface temperatures. As described further herein, the target heating system may be capable of or configured to modify the interface temperature and / or temperature gradient of the substrate and / or areas proximal to the substrate to control the grain size, growth, and / or structure of the metal forming the article prepared by the 3D printer to address the aforementioned issues. For example, the target heating system may be capable of or configured to modify the interface temperature and / or temperature gradient of the melt pool to control the grain size, growth, and / or structure of the metal forming the article, thereby improving build strength, adhesion, porosity, and / or surface finish and preventing cracks and fractures within the article.

[0045] FIG. 1 illustrates a schematic cross-sectional view of an exemplary additive manufacturing layering device or 3D printer 100 incorporating a target heating system 102, according to one or more embodiments. The 3D printer 100 may be a liquid metal jet printing system, such as a magnetohydrodynamic (MHD) printer. However, it should be understood that any additive manufacturing device may utilize the target heating system 102 and methods disclosed herein. The 3D printer 100 may include a print head 104, a stage 106, a computing system 108, the exemplary target heating system 102, or any combination thereof. The computing system 108 may be operatively and / or communicatively coupled to any one or more of the components of the 3D printer 100. The computing system 108 may be capable of or configured to operate, modulate, receive instructions, data, etc. from any one or more of the components of the 3D printer 100. The print head 104 may include a body 110, which may also be referred to herein as a pump chamber, one or more heating elements (one shown at 112), one or more metal coils 114, or any combination operatively coupled to one another. As illustrated in FIG. 1 , the heating element 112 may be disposed at least partially around the body 110, and the metal coil 114 may be disposed at least partially around the body 110 and / or the heating element 112. As used herein, a substrate 116 may refer to the surface of the stage 106, previously deposited metal (e.g., metal droplets), an article 118 fabricated from the 3D printer 100 or a portion thereof, a platen 128, such as a heated platen or build plate, disposed on the stage 106, and / or their respective surfaces. As illustrated in FIG. 1 , the substrate 116 may be disposed on or above the stage 106 and below the body 110. The body 110 may have an inner surface 120 defining an interior volume 122 thereof. The body 110 may define a nozzle 124 disposed at a first end of the body 110 .

[0046] With continued reference to FIG. 1 , in an exemplary operation of the 3D printer 100, a build material (e.g., metal) from a source 126 may be directed into the interior volume 122 of the body 110. The heating element 112 may at least partially melt the build material contained within the interior volume 122 of the body 110. For example, the build material may be a solid, such as a solid metal, and the heating element 112 may heat the body 110, thereby heating the build material from a solid to a liquid (e.g., molten metal). The metal coil 114 may be coupled to a power source (not shown) capable of or configured to facilitate deposition of the build material onto the substrate 116. For example, the metal coil 114 and the power source coupled thereto may be capable of or configured to generate a magnetic field, which may generate an electromotive force within the body 110, thereby generating induced currents in the molten metal disposed within the body 110. The magnetic field and induced currents in the molten metal may generate a radially inward force on the liquid metal, known as the Lorentz force, which creates pressure at the nozzle 124. The pressure at the nozzle 124 may eject the molten metal in the form of one or more droplets from the nozzle 124 toward the substrate 116 and / or the stage 106 , thereby forming at least a portion of the article 118 .

[0047] The target heating system 102 may be capable of or configured to heat at least a portion of the substrate 116 and / or an area proximate to the substrate 116. For example, the target heating system 102 may be capable of or configured to heat a portion of the article 118, its respective surface, and / or an area proximate to the substrate 116, at least a portion of the platen 128. The target heating system 102 may heat a portion of the substrate 116 and / or an area proximate to the substrate 116 before, during, and / or after deposition of one or more droplets of molten metal on the substrate 116. In an exemplary embodiment, the target heating system 102 heats a portion of the substrate 116 before and / or during deposition of a liquid on the substrate 116. It should be understood that the deposition of liquid on the substrate 116 may generate or form a melt pool on the substrate 116, and that the target heating system 102 may be capable of, or may be configured to, at least partially modulate (e.g., increase, decrease, alter, etc.) the interfacial temperature or temperature gradient of the melt pool, thereby controlling one or more properties of the resulting solid metal forming the article 118. For example, modulating the temperature gradient of the melt pool may enable the 3D printer 100 to control the grain size, grain growth, grain structure, grain orientation, and / or grain boundaries of the resulting solid metal forming the article 118. It should be understood that the metal grain formation, structure, and / or properties (e.g., size, growth, orientation, boundaries, etc.) may at least partially determine one or more mechanical properties of the resulting portion of the article 118. For example, the grain formation and / or structure may at least partially determine the yield stress, ductility, hardness, fatigue life, or a combination thereof, of the resulting solid metal forming the article 118. Thus, the targeted heating system 102 may be capable of or configured to at least partially heat portions of the substrate 116, thereby controlling one or more properties of the solid metal forming the article 118.

[0048] The target heating system 102 may also be capable of, or may be configured to, reheat or remelt previously deposited liquid or sections of the article 118 to control the interfacial temperature and / or temperature gradient of the melt pool so that the molten metal liquid and the previously deposited metal coalesce, thereby improving the mechanical and / or build qualities of the article 118. It should be understood that the amount of heat or thermal energy required to sufficiently control the temperature gradient of the melt pool may be minimal as the temperature of the article 118 and / or the melt pool, or the melt pool or its coalesced region, is already maintained at a relatively high temperature. Thus, the target heating system 102 may be operated cost-effectively and provide sufficient thermal energy to control the temperature gradient of the melt pool. Furthermore, it should be understood that the target heating system 102 may be operated in an in-line manner so as not to reduce productivity. For example, the target heating system 102 may be operated along with other components of the 3D printer 100 to provide an article 118 with improved properties and without an offline secondary or post-printing process.

[0049] In addition to the foregoing, the target heating system 102 may be capable of or configured to at least partially heat a portion of the substrate 116 near or proximate the deposition of the droplets and / or melt pool. For example, the target heating system 102 may be capable of or configured to at least partially heat a portion of the substrate 116 adjacent to or outside of the deposition of the droplets and / or melt pool. It should be understood that heating a portion of the substrate 116 near, proximate, or adjacent to the deposition of the droplets and / or melt pool may reduce surface roughness and / or provide improved surface finish capabilities compared to a surface not heated by the target heating system 102.

[0050] The target heating system 102 may directly heat an area having a diameter of about 0.025 mm to about 1.0 mm. For example, the output (e.g., laser beam) of the target heating system 102 may have a diameter or major axis of about 0.025 mm to about 1.0 mm. In at least one embodiment, the output of the target heating system 102 may have a diameter or major axis of about 0.025 mm, about 0.03 mm, about 0.04 mm, about 0.05 mm, about 0.1 mm, about 0.2 mm, about 0.3 mm, or about 0.4 mm to about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 0.95 mm, or about 1 mm.

[0051] The substrate 116, in the area proximate the substrate 116 and / or near the fabricated article 118, may be maintained at a temperature of about 200°C to about 600°C. For example, the temperature may be about 200°C or higher, about 250°C or higher, about 300°C or higher, about 350°C or higher, about 400°C or higher, about 450°C or higher, about 500°C or higher, or about 550°C or higher, and about 600°C or lower. In other examples, the temperature may be about 200°C or higher, or about 300°C or higher, and about 350°C or lower, about 400°C or lower, about 450°C or lower, about 500°C or lower, about 550°C or lower, or about 600°C or lower. It should be understood that all or substantially all components of the target heating system 102 may be capable of or configured to operate at the temperature of the substrate 116, the area proximate the substrate 116, and / or near the article 118.

[0052] The target heating system 102 may be capable of or configured to heat the substrate 116 and / or a proximal area of ​​the substrate 116 to a temperature of at least 60% to about 100% of the melting point of the build material. For example, the target heating system 102 may be capable of or configured to heat the substrate 116 and / or a proximal area of ​​the substrate 116 to a temperature of at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95% to about 100% of the melting point of the build material. In another embodiment, the target heating system 102 may be capable of or configured to increase the temperature of the substrate 116 and / or the temperature of an area proximate to the substrate 116 (e.g., a coalescence region or melt pool) by approximately ±10%, ±15%, ±20%, ±25%, ±30%, ±35%, ±40%, ±45%, or ±50% of the melting point of the build material.

[0053] In at least one embodiment, the build material can be or include one or more metals and / or alloys thereof. Illustrative build materials can be or include, but are not limited to, aluminum, aluminum alloys, brass, bronze, chromium, cobalt-chromium alloys, copper, copper alloys, iron alloys (Invar), nickel, nickel alloys (Inconel), nickel-titanium alloys (Nitinol), stainless steel, tin, titanium, titanium alloys, gold, silver, molybdenum, tungsten, etc., or alloys thereof, or any combination thereof. It should be understood that droplet and substrate temperatures will be different for different metals.

[0054] In another embodiment, the build material can be or include one or more polymeric materials or polymers, or composites thereof. The polymer can be or include a functional polymer. Illustrative functional polymers can include, but are not limited to, heat-resistant polymers, conductive polymers, piezoelectric polymers, photosensitive polymers, or any combination thereof. The polymer can also be or include, but is not limited to, polyolefin-based polymers, acrylic-based polymers, polyurethane-based polymers, ether-based polymers, polyester-based polymers, polyamide-based polymers, formaldehyde-based polymers, silicone-based polymers, or any combination thereof. For example, polymers include poly(ether ether ketone) (PEEK), TORLON®, polyamideimide, polyethylene (PE), polyvinyl fluoride (PVF), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polyvinylidene chloride (PVDC), polychlorotrifluoroethylene (PCTFE), polytetrafluoroethylene (PTFE), polypropylene (PP), poly(1-butene), poly(4-methylpentene), polystyrene, polyvinylpyridine, polybutadiene, polyisoprene, polychloroprene, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene terpolymer, ethylene-methacrylic acid copolymer, These may include, but are not limited to, styrene-butadiene rubber, tetrafluoroethylene copolymers, polyacrylates, polymethacrylates, polyacrylamides, polyvinyl acetates, polyvinyl alcohols, polyvinyl butyrals, polyvinyl ethers, polyvinylpyrrolidones, polyvinylcarbazoles, polyurethanes, polyacetals, polyethylene glycols, polypropylene glycols, epoxy resins, polyphenylene oxides, polyethylene terephthalates, polybutylene terephthalates, polyhydroxymethylcyclohexyl terephthalates, cellulose esters, polycarbonates, polyamides, polyimides, any copolymers thereof, or any combinations thereof.In at least one embodiment, the polymer may be or include an elastomer, a synthetic rubber, or any combination thereof. Illustrative elastomeric materials and synthetic rubbers may include, but are not limited to, VITON®, nitrile, polybutadiene, acrylonitrile, polyisoprene, neoprene, butyl rubber, chloroprene, polysiloxane, styrene butadiene rubber, hydrin rubber, silicone rubber, ethylene-propylene-diene terpolymer, any copolymer thereof, or any combination thereof.

[0055] In exemplary embodiments, the polymer may include acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polylactic acid (PLA), high density polyethylene (HDPE), polyphenylsulfone (PPSU), poly(meth)acrylate, polyetherimide (PEI), polyetheretherketone (PEEK), high impact polystyrene (HIPS), thermoplastic polyurethane (TPU), polyamide (nylon), composites thereof, or combinations thereof.

[0056] In at least one embodiment, 3D printer 100 may include a monitoring system 130 that may be capable of or configured to control and / or monitor one or more components or portions of 3D printer 100, the formation of article 118, one or more portions of substrate 116, one or more areas proximate substrate 116, and / or droplet deposition. For example, monitoring system 130 may include one or more illuminators (not shown) that may be capable of or configured to measure droplet, build part, build plate, and substrate temperature, measure build part shape and z-height, measure droplet size and velocity, etc., or any combination thereof. Illustrative illuminators may be or include, but are not limited to, lasers, LEDs, various types of lamps, fiber optic light sources, etc., or combinations thereof. In another example, monitoring system 130 may include one or more sensors (not shown) that may be capable of or configured to measure the temperature of one or more components or portions of 3D printer 100. Illustrative sensors may be or include, but are not limited to, heat meters, thermistors, imaging cameras, photodiodes, etc., or combinations thereof. The monitoring system 130 may also be capable of or configured to provide feedback or communicate with the computing system 108.

[0057] In at least one embodiment, any one or more components of the 3D printer 100 may move independently relative to one another. For example, any one or more of the print head 104, the stage 106, and the platen 128 coupled thereto, the target heating system 102, the monitoring system 130, or any combination thereof may move independently in the x-axis, y-axis, and / or z-axis relative to any one or more of the other components of the 3D printer 100. In another embodiment, any two or more of the components of the 3D printer 100 may be coupled to one another and thus may move relative to one another. For example, the print head 104 and the target heating system 102 may be coupled to one another via mounts (not shown) such that movement or translation of the print head 104 in the x-axis, y-axis, and / or z-axis results in corresponding movement of the target heating system 102 in the x-axis, y-axis, and / or z-axis, respectively. Similarly, the target heating system 102 and the stage 106 may be coupled to each other via mounts (not shown) such that movement of the target heating system 102 in the x-axis, y-axis, and / or z-axis results in corresponding movement of the stage 106 in the x-axis, y-axis, and / or z-axis, respectively.

[0058] 2 illustrates a schematic diagram of another exemplary additive manufacturing layering device or 3D printer 200 incorporating an exemplary targeted heating system 102, according to one or more embodiments. The 3D printer 200 illustrated in FIG. 2 may be similar in some respects to the 3D printer 100 described above, and therefore may best be understood with reference to the description of FIG. 1, where like numerals indicate like components and will not be described in detail.

[0059] As illustrated in FIG. 2 , the target heating system 102 of the 3D printer 100 can include one or more lasers (two are shown at 202). The laser 202 can include external optical components such as filters, collimating optics, focusing optics, and beam shaping optics to achieve a desired dose level, dose pattern (i.e., circular, elliptical, etc.), and irradiation profile (i.e., Gaussian, top hat, donut mode, multimode, etc.). As further illustrated in FIG. 2 , the laser 202 can be coupled to the print head 104 via a mount 204. While FIG. 2 illustrates the laser 202 of the target heating system 102 coupled to the print head 104, it should be understood that the target heating system 102 or its laser 202 can be coupled to any other component of the 3D printer 200, as discussed above. As illustrated in FIG. 2, any one or more of the lasers 202 may be capable of or configured to direct a laser beam onto or proximate the substrate 116, thereby heating the substrate 116 or a portion thereof.

[0060] The laser 202 of the targeted heating system 102 may be or include any suitable laser that may be capable of or configured to sufficiently heat the substrate 116 and / or areas proximate to the substrate 116. In at least one embodiment, the type of laser 202 utilized may depend at least in part on the build material, such as the type of metal, being deposited to create the article 118. In another embodiment, the type of laser 202 utilized may depend at least in part on the rate at which drops are deposited on the substrate 116, or the deposition rate.

[0061] In at least one embodiment, the laser 202 may be or include an in-line high-power laser imager that may be capable of or configured to deliver targeted high-power laser energy to the substrate 116 and / or an area proximate to the substrate 116. The high-power laser imager may be a 1D imager or a 2D imager. The in-line high-power laser imager may utilize one or more of a high-power laser, an independently addressable diode laser or vertical cavity surface-emitting laser (VCSEL), an illumination optics system, a spatial light modulator, a pixelated spatial light modulator, projection optics, or a combination thereof. The illumination optics system may be capable of or configured to shape the laser emission and deliver it onto the spatial light modulator. The projection optics may be capable of or configured to image the spatial light modulator onto the substrate 116 and / or an area proximate to the substrate 116. The pixelated line image or 1D image may be generated with a linear spatial light modulator or a linear array of diode lasers or VCSELs. Illustrative linear spatial light modulators may be or include, but are not limited to, a galvanic light valve (GLV), a digital micromirror device (DMD), a liquid crystal on silicon (LCOS) spatial light modulator, or the like, or a combination thereof. Pixelated area images or 2D images may be generated with a spatial light modulator or 2D array of VCSELs. Illustrative spatial light modulators for generating 2D images may be or include, a 2D digital micromirror device (DMD), a 2D liquid crystal on silicon (LCOS) spatial light modulator, or the like, or a combination thereof. The 1D or 2D imager may be capable of or configured to pattern over a line or area to deliver targeted laser energy to two or more droplet locations on the substrate 116 and / or to areas proximate the substrate 116. The 1D or 2D imager may be capable of or configured to shape a laser beam profile within one or more droplet locations to alter local thermal gradients within the molten pool of one or more droplets at and / or near regions of the substrate 116.This is especially important for systems that use printheads with multiple independent ejectors, which allows for faster build part production and parallel printing for higher throughput.

[0062] In an exemplary embodiment, the laser 202 has a power of approximately 1 W / cm 2 ~Approx. 10,000W / cm 2 For example, any one or more of the lasers 202 may have an irradiance of about 1 W / cm 2 ~Maximum 1,000W / cm 2 , about 2,000W / cm 2 , approx. 3,000W / cm 2 , approx. 4,000W / cm 2 , or about 4,500 W / cm 2 ~Approx. 5,500W / cm 2 , about 6,000W / cm 2 , about 7,000W / cm 2 , about 8,000W / cm 2 , about 9,000W / cm 2 , or about 10,000 W / cm 2 It should be understood that much lower power lasers or laser arrays may be used depending on the application, metal, configuration, and spot size. It should further be understood that any one or more of the lasers 202 may include a combination of power and optical configurations, including collimated and non-collimated lasers, that can achieve the desired irradiance.

[0063] 2, the monitoring system 130 may include a pyrometer 206 that may be capable of or configured to measure the temperature of the substrate 116 or an area near or proximal to the substrate 116. For example, the pyrometer 206 may be capable of or configured to measure the temperature at and / or an area proximal to the substrate 116 heated by the laser 202 of the targeted heating system 102. In another example, the pyrometer 206 may be capable of or configured to measure the temperature of droplets from the print head 104 or any other component of the 3D printer 200.

[0064] 3 illustrates a schematic diagram of another exemplary additive manufacturing layering device or 3D printer 300 incorporating an exemplary targeted heating system 102, according to one or more embodiments. The 3D printer 300 illustrated in FIG. 3 may be similar in some respects to the 3D printers 100, 200 described above, and therefore may best be understood with reference to the description of FIG. 1 or 2, where like numerals indicate like components and will not be described in detail.

[0065] As illustrated in FIG. 3 , the target heating system 102 can include one or more fiber lasers 302, such as fiber-coupled lasers. As further illustrated in FIG. 3 , the fiber lasers 302 can be coupled to the print head 104 via a mount 204. The fiber lasers 302 of the target heating system 102 can be or include any suitable fiber lasers 302 that can be capable of or configured to sufficiently heat the substrate 116 and / or areas proximate to the substrate 116. In at least one embodiment, the fiber laser 302 utilized can depend at least in part on the build material, such as the type of metal, being deposited to create the article 118. In another embodiment, the fiber laser 302 utilized can depend at least in part on the rate at which drops are deposited on the substrate 116, or the deposition rate.

[0066] The fiber laser 302 may be capable of or configured to output a continuous wave (CW) beam. The fiber laser 302 may also be capable of or configured to output a pulsed beam. The fiber laser 302 may be polarized or unpolarized. The output light of the fiber laser 302 may be delivered by an optical single-mode or optical multimode output fiber. The output light of the fiber laser 302 may be collimated and / or shaped by an external optical system. The fiber laser 302 may be capable of or configured to operate at high ambient temperatures, such as the temperatures of the 3D printers described herein. In at least one embodiment, at least a portion of the fiber laser 302 may be cooled, such as by water cooling. In yet another embodiment, at least a portion of the fiber laser 302 may be located outside of a high temperature area of ​​the 3D printers described herein. For example, at least a portion of the fiber laser 302 may be located in an area having a temperature below 550°C, below 400°C, below 300°C, or below 200°C. It should be understood that the operating temperature of a 3D printer may depend at least in part on the metal being deposited.

[0067] Fiber laser 302 may provide or generate a laser or output having a wavelength of about 600 nm to about 1200 nm. However, it should be understood that other wavelengths may be used as commercially available from laser suppliers and manufacturers. For example, the output from fiber laser 302 may be about 600 nm, about 700 nm, about 750 nm, about 780 nm, or about 800 nm to about 850 nm, about 900 nm, about 950 nm, about 1000 nm, about 1050 nm, about 1070 nm, about 1100 nm, about 1150 nm, or about 1200 nm.

[0068]

[0023] Figure 4 illustrates an exemplary laser system 400 that may be utilized in place of the fiber laser 302 of the target heating system 102 of Figure 3, according to one or more embodiments. The laser system 400 illustrated in Figure 4 may utilize a fiber-coupled laser. The laser system 400 may include a fiber-coupled laser module 402, an output fiber 404, one or more collimators (one shown at 406), one or more polarizers (three shown at 408, 410, 412), one or more polarization rotators (one shown at 414), one or more variable retarders (one shown at 416), one or more wavelength retarders (one shown at 418), or a combination thereof. In an exemplary embodiment, the laser system 400 may consist of or consist essentially of a fiber coupled laser module 402, a fiber output 404, a collimator 406, one or more polarizers 408, 410, 412, a polarization rotator 414, a variable retarder 416, and a wavelength retarder 418.

[0069] The one or more polarizers 408, 410, 412 may be or include, but are not limited to, a polarizing beam splitter (PBS), a linear polarizer, or a combination thereof. The polarization rotator 414 may be or include, but is not limited to, a ferroelectric liquid crystal polarization rotator. The variable retarder 416 may be or include, but is not limited to, a nematic liquid crystal (LC) variable retarder. The wavelength retarder 418 may be or include, but is not limited to, a quarter wave retarder.

[0070] As illustrated in FIG. 4 , a fiber-coupled laser module 402 may be coupled to an output fiber 404. The fiber-coupled laser module 402 and the coupled output fiber 404 may be capable of generating and outputting unpolarized light or a laser, or may be configured to do so. A collimator 406 may be disposed downstream of the output fiber 404. One or more polarizers 408, 410, 412 may be disposed downstream of the collimator 406. For example, as illustrated in FIG. 4 , a first polarizer 408, a second polarizer 410, and a third polarizer 412 may be disposed downstream of the collimator 406. A polarization rotator 414 may be disposed downstream of any one or more of the polarizers 408, 410, 412 and / or upstream of any one or more of the polarizers 408, 410, 412. 4, the polarization rotator 414 may be interposed between the first polarizer 408 and the second polarizer 410. In another embodiment described further herein, the polarization rotator 414 may be interposed between the second polarizer 410 and the third polarizer 412. The variable retarder 416 may be disposed upstream of the wavelength retarder 418. Similarly, the wavelength retarder 418 may be disposed downstream of the variable retarder 416. In at least one embodiment, the variable retarder 416 and the wavelength retarder 418 may be disposed downstream of any one or more of the polarizers 408, 410, 412 and / or upstream of any one or more of the polarizers 408, 410, 412. For example, as illustrated in FIG. 4, the variable retarder 416 and the wavelength retarder 418 may be interposed between the second polarizer 410 and the third polarizer 412.

[0071] In at least one embodiment, the polarization rotator 414, which may be a ferroelectric LC polarization rotator, may be operatively coupled to any one or more of the polarizers 408, 410, 412 (e.g., PBS or linear polarizers) to form a liquid crystal shutter. The combination of the polarization rotator 414 and one or more of the polarizers 408, 410, 412 may form a liquid crystal shutter that may operate at an approximately 50% duty cycle with rise and fall times of approximately 100 microseconds. The liquid crystal shutter may modulate the beam "on" by allowing the beam to remain P-polarized and pass through the polarizing beam splitters 408, 410, 412, or modulate the beam "off" by switching the beam to an S-polarized state, thus reflecting from the polarizers 408, 410, 412 to the beam dump 420.

[0072] The liquid crystal shutters formed from the polarization rotator 414 and any one or more of the polarizers 408, 410, 412 may be capable of or configured to have various shutter speeds to match the droplet velocity of the print head 104. Matching the droplet velocity may allow the liquid crystal shutters to deliver laser energy to the substrate 116 and / or areas proximate to the substrate 116 just before or as the droplets are deposited. The ability to change or modify the shutter speed of the liquid crystal shutters may also reduce the amount of error in the shutter speed.

[0073] In at least one embodiment, variable retarder 416, which may be a nematic liquid crystal variable retarder, may be combined with wavelength retarder 418, which may be a quarter-wave retarder, to form nematic liquid crystal variable polarization rotator 422. In operation, wavelength retarder 418 may be capable of, or configured to, convert elliptically polarized light from variable retarder 416 to form linearly polarized light.

[0074] The nematic liquid crystal variable polarization rotator 422 may be operatively coupled to any one or more of the polarizers 408, 410, 412. The combination of the nematic liquid crystal variable polarization rotator 422 and any one or more of the polarizers 408, 410, 412 may be capable of, or may be configured to, vary the amplitude and / or power level of the laser directed at the article 118 (see FIGS. 1-3). Nematic liquid crystal variable polarization rotator 422. It should be understood that the drive current directed to the fiber coupled laser module 402 may also be adjusted to modulate the output power level of the laser system 400.

[0075] The laser system 400 may include one or more additional accessories and / or optics that may be capable of or configured to adjust, focus, and / or shape its beam profile. The beam profile may have a Gaussian, top-hat, or multimode profile. Illustrative accessories may be or include lenses, axes, collimators, phase plates, beam expanders, etc., or combinations thereof.

[0076] Figure 5 illustrates another exemplary laser system 500 that may be utilized in place of the fiber laser 302 of the target heating system 102 of Figure 3, according to one or more embodiments. The laser system 500 illustrated in Figure 5 may be similar in some respects to the laser system 400 described above, and therefore may best be understood with reference to the description of Figure 4, where like numerals indicate like components and will not be described in detail.

[0077] As illustrated in Figure 5, laser system 500 may include similar components to laser system 400 illustrated in Figure 4. However, a nematic liquid crystal variable polarization rotator 422 in laser system 500 is interposed between first polarizer 408 and second polarizer 410. Additionally, a polarization rotator 414 is interposed between second polarizer 408 and third polarizer 412.

[0078] It should be understood that any one or more of the lasers described herein may be substituted or used in combination with other types of lasers, such as gas lasers, diode lasers, VCSELs, diode laser arrays, VCSEL arrays, diode-pumped solid-state lasers, lasers in the near-ultraviolet wavelength range (i.e., violet and blue), or lasers in the visible wavelength range, or combinations thereof.

[0079] The adhesion of the 3D printed part or article 118 to the build plate or platen 128 must be strong enough to prevent the part from separating from the build plate or platen 128. During the printing process, the build part 118 is subjected to shear forces caused by acceleration due to changes in direction and speed as the part 118 moves under the print head 104. On the other hand, if the adhesion between the 3D printed part 118 and the build plate 128 is too strong, a secondary machining operation must be performed to cut or remove the part 128 from the build plate. The secondary operation increases costs and reduces productivity. Therefore, another use of the targeted heating system 102 disclosed herein is to deliver laser energy to a localized area of ​​the build plate 128, followed by a molten metal droplet, to promote stronger adhesion or create weaker adhesion, depending on what is required for the particular type of deposited metal and coating or material of the build plate 128. For example, a higher local build plate temperature can induce greater wetting of the droplet onto the surface of the build plate 128 to increase adhesion. For some materials, increasing the temperature can cause more oxidation on the droplet surface, decreasing adhesion. This effectively creates a release layer that can be used to separate the 3D printed part 118 from the build plate 128 by applying a shear mechanical or thermal shock. This eliminates the need for a secondary operation to remove the part 118 from the build plate 128.

[0080] 6 illustrates a schematic diagram of another exemplary additive manufacturing device or 3D printer 600 incorporating an exemplary targeted heating system 102, according to one or more embodiments. The 3D printer 600 illustrated in FIG. 6 may be similar in some respects to the 3D printers 100, 200, 300 described above, and therefore may best be understood with reference to the description of each figure, where like numerals indicate like components and will not be described in detail.

[0081] 6, the target heating system 102 may include one or more monogon systems (one shown at 602). The monogon system 602 may be capable of or configured to sufficiently heat the substrate 116 and / or areas proximate to the substrate 116. In at least one embodiment, the monogon system 602 and / or its components utilized may depend at least in part on the material of construction, such as the type of metal, being deposited to create the article 118. In another embodiment, the monogon system 602 and / or its components used may depend at least in part on the rate at which droplets are deposited on the substrate 116, or the deposition rate.

[0082] The monogon system 602 may include one or more monogon scanners (one shown at 604), one or more mirrors (one shown at 608), or a combination thereof. The mirror 608 may be capable of or configured to receive a power source, such as a high-power laser beam, and reflect or redirect the power source to the monogon scanner 604. The monogon scanner 604 may be capable of or configured to receive a power source from a mirror or another light source and reflect or redirect the power source to the substrate 116 and / or an area proximate to the substrate 116.

[0083] Any suitable monogon scanner 604 may be utilized. In at least one embodiment illustrated in FIG. 6 , the monogon scanner 604 may be or include a rotating monogon total internal reflection (TIR) ​​scanner capable of or configured to rotate about its axis (e.g., a vertical axis). The monogon scanner 604 may be rotated about an axis to direct or control the position of the output beam on the substrate 116 and / or on an area proximate to the substrate 116. An illustrative monogon scanner 604 may be or include, but is not limited to, a fused silica monogon optical scanner, or the like. The monogon scanner 604 may be capable of or configured to scan in an orientation greater than 360° by axial rotation of the monogon scanner 604. The monogon scanner 604 may also be capable of or configured to scan approximately 20° in altitude when utilized with a mirror 608 (e.g., a galvanometer mirror). The monogon scanner 604 may be capable of or configured to operate under high ambient temperatures of about 300° C. or 500° C. to about 1200° C., or about 600° C. to about 1000° C. The monogon scanner 604 may be capable of or configured to operate at high laser powers (e.g., 1 W to several kW).

[0084] In at least one embodiment, the monogon scanner 604 may be free of or substantially free of coatings, such as reflective or anti-reflective coatings. Additionally, it should be further understood that the monogon system 602 may utilize a power source (e.g., a laser source or optical beam) outside of the hot area of ​​the 3D printer 600. While Figure 6 illustrates a single monogon system 602, it should be understood that multiple monogon systems 602 may be independently operated to heat the substrate 116 and / or areas proximate to the substrate 116.

[0085] In at least one embodiment, the target heating system 102 may also be capable of, or configured to, heat the ejected droplets at one or more points along their flight or descent path between ejection and deposition. For example, the target heating system 102 may be capable of, or configured to at least partially heat the droplets of build material after ejection from the print head 104 and before deposition on the substrate 116. It should be understood that the target heating system 102 may heat the droplets along their flight path in addition to (or in combination with) or instead of heating the substrate 116 and / or areas proximate to the substrate 116. For example, the target heating system 102 may be configured to heat the droplets along their flight path.

[0086] Figure 7 illustrates a schematic diagram of another exemplary additive manufacturing device or 3D printer 700 incorporating an exemplary targeted heating system 102, according to one or more embodiments. The 3D printer 700 illustrated in Figure 7 may be similar in some respects to the 3D printers 100, 200 described above, and therefore may best be understood with reference to Figures 1 and 2, where like numerals indicate like components and will not be described in detail.

[0087] As illustrated in Figure 7, the target heating system 102 can include one or more lasers (one shown at 702). The laser 702 can be similar to any one of the lasers discussed herein. For example, the laser 702 can be similar to the laser 202 discussed above with respect to Figure 2. The laser 702 can be coupled to the print head 104 via a mount (not shown), such as the mount 204 of Figure 2. Alternatively, the laser 702 can be coupled to any other component of the 3D printer 700.

[0088] The laser 702 may be capable of or configured to heat the ejected droplets at one or more points along their flight or fall path 704 between ejection and deposition. The flight or fall path 704 may be defined as any portion or the entire length between the print head 104 and the substrate 116. As discussed above, the substrate 116 may refer to the surface of the stage 106, previously deposited metal (e.g., metal droplets), the article 118 or a portion thereof, the platen 128 on the stage 106, and / or their respective surfaces. As illustrated in FIG. 7 , the laser 702 may be positioned or oriented such that its beam 706 propagates in a direction parallel to the surface of the stage 106. For example, the beam 706 generated by the laser 702 may be in a horizontal orientation. In another example, the laser 702 may be positioned or oriented such that the beam 706 does not impinge on the surface of the stage 106.

[0089] The target heating system 102 illustrated in Figure 7 may also include a beam dump 708. The beam dump 708 may be capable of or configured to absorb at least a portion of the energy (e.g., photons or other particles) from the beam 706 generated by the laser 702. As illustrated in Figure 7, the beam dump 708 may be positioned proximate the article 118 and be incident on the beam 706 generated by the laser 702. Illustrative beam dumps may be or include, but are not limited to, a beam block, a beam trap, a charged particle beam dump, the like, or a combination thereof.

[0090] Figure 8 illustrates a schematic diagram of another exemplary additive manufacturing device or 3D printer 800 incorporating an exemplary targeted heating system 102, according to one or more embodiments. The 3D printer 800 illustrated in Figure 8 may be similar in some respects to the 3D printers 100, 200, 700 described above, and therefore may best be understood with reference to Figures 1, 2, and 7, where like numerals indicate like components and will not be described again in detail.

[0091] As illustrated in FIG. 8 , the target heating system 102 can include one or more lasers (one shown at 802). The laser 802 can be similar to any one of the lasers discussed herein. For example, the laser 802 can be similar to the laser 202 discussed above with respect to FIG. 2 . The laser 802 can be coupled to the print head 104 via a mount 204. While FIG. 8 illustrates the laser 802 of the target heating system 102 coupled to the print head 104 via a mount 204, it should be understood that the laser 802 can be coupled to any other component of the 3D printer 800. The laser 802 can be capable of, or configured to, heat the ejected droplets at one or more points along the flight path 704 between ejection and deposition.

[0092] Laser 802 may be operatively coupled to a reflector 804 capable of, or configured to, direct a beam 806 of laser 802 to a droplet in flight path 704 and ultimately to a beam dump 708. For example, as illustrated in FIG. 8 , laser 802 may be positioned or oriented such that its beam 806 propagates in a direction toward reflector 804, which may be positioned or oriented to direct the reflected beam 806 to and through flight path 704 toward beam dump 708. While FIG. 8 illustrates laser 802 in a vertical orientation such that the unreflected beam 806 is directed toward stage 106, it should be understood that laser 802 and reflector 804 may be positioned in any orientation that allows the unreflected beam 806 to traverse flight path 704 toward beam dump 708.

[0093] It should be appreciated that utilizing any one of the lasers 702, 802 and / or reflector 804 of the target heating system 102 may simplify the manufacture, assembly, and / or optimization (e.g., fine-tuning angles) of the 3D printer 700. For example, adjustments to the orientation of any one of the lasers 702, 802 and / or reflector 804 may be simplified. For example, the laser 702 illustrated in FIG. 7 need only be planarized against the surface of the substrate 116, the stage 106, or any surface thereof, simplifying the manufacture, assembly, and / or optimization of the 3D printer 700. In another example, the laser 802 and reflector 804 may be mounted to the print head 104, thereby simplifying the manufacture, assembly, and / or optimization of the 3D printer 700. It should further be appreciated that directing the beams 706, 806 to and through the flight path 704 reduces concerns about energy “spill” onto other areas of the substrate. For example, heating only the droplets in flight path 704 eliminates the variable of heating unintended portions of substrate 116. Thus, the size and / or shape of beams 706, 806 may not need to be tightly controlled.

[0094] It should be understood that the target heating system 102 may heat the droplets along their flight path 704 in addition to (or in combination with) or instead of heating the substrate 116 and / or areas proximal to the substrate 116, as discussed above. For example, the target heating system 102 may be configured to heat the droplets along their flight path, the substrate 116, areas proximal to the substrate 116, or a combination thereof. For example, the target heating system 102 may incorporate components capable of or configured to heat the substrate 116 or areas proximal to the substrate 116, as discussed with reference to FIGS. 2, 3, and / or 4, as discussed with reference to FIGS. 7 and 8, with components that can heat the droplets along their flight path 704. Specifically, embodiments disclosed herein may include an exemplary target heating system 102 that may incorporate a combination of two or more components or features from any of the 3D printers 100, 200, 300, 600, 700, 800, together.

[0095] With continued reference to FIG. 1 , in an exemplary operation of the 3D printer 100, the stage 106 and substrate 116 may be configured to move relative to the print head 104 in the x-axis, y-axis, and / or z-axis. For example, the stage 106 and substrate 116 may be configured to move relative to the print head 104 in the x-axis, y-axis, and z-axis while the print head 104 remains stationary. In another example, the print head 104 may be configured to move in the x-axis, y-axis, and z-axis while the stage 106 and substrate 116 remain stationary. In yet another example, the print head 104 may move in the z-axis, and the stage 106 and substrate 116 may move in the x-axis and y-axis. Similarly, the stage 106 and substrate 116 may move in the z-axis while the print head 104 may move in the x-axis and y-axis.

[0096] The print head 104 may direct droplets of build material along a build path on the platen 128 or substrate 116 to form the article 118 layer by layer. The time between a currently jetted droplet and a previously jetted droplet, at which the currently jetted droplet coalesces as it travels along the build path, may vary, and this may be determined at least in part by the shape and / or design of the article 118. The currently jetted droplet may be directed toward a previously jetted droplet, which may be surrounded by different amounts of previously jetted material (e.g., below and / or adjacent). It should be understood that the currently and / or previously jetted droplets may therefore be maintained at different temperatures. For example, the thermal conduction path may depend at least in part on the shape and / or design of the article 118. Thus, the temperatures of the previously jetted droplet and / or the currently jetted droplet may be maintained at different temperatures. During operation, the target heating system 102 may be capable of or configured to adjust the temperature of the substrate 116 and / or areas proximate to the substrate 116. The target heating system 102 may also be capable of or configured to heat the droplets at one or more points along the flight path between the print head 104 and the substrate 116 or its surface. The target heating system 102 may be operated to depend at least in part on one or more of the time difference between the trailing droplet and the current droplet of build material, the thermal conduction differences along various portions of the article 118, the build path, the type of build material utilized, or a combination thereof.

[0097] In at least one embodiment, the energy or power of the target heating system 102 may be predetermined from one or more of the shape and / or design of the article 118, the thermal environment in which the build path is formed or printed along with the layers of the article 118, material parameters, printing parameters utilized, the length of the flight path 704, or combinations thereof. Illustrative printing parameters may be or include, but are not limited to, drop frequency, drop temperature, platen 128 temperature, or combinations thereof. In an exemplary embodiment, the energy or power of the target heating system 102 may be determined according to equation (1): Laser output (t)=A1 Δ(t)+A2(t)t+A3(t) x position(t)+A4(t) y position(t)+A5(t) z position(t)+ΣB i (t) Printing parameters (t) i +ΣC j (t) Material parameters j +ΣD k (t) · Environmental parameters (t) k +... (1) During the ceremony, A1,A2,A3,...A N are the coefficients or weights for the various part shape parameters, B1...B N are the coefficients or parameter weights of the various printing process parameters, C1...C N are coefficients or parameters of various material parameters, D1...D N are the coefficients or parameters of the various environmental parameters, Δt is the time between the previous deposited material or droplet and the next droplet; x position is the x coordinate of a particular point on a build part or article relative to the build plate or other coordinate system origin; y position is the y coordinate of a particular point on a build part or article relative to the build plate or other coordinate system origin; The z position is the z coordinate of a particular point on a build part or article relative to a build plate datum or other coordinate system origin. The parameters or printer parameters may be or include, but are not limited to, initial drop temperature, build plate or platen temperature, drop frequency, initial drop ejection height, laser wavelength, etc., or combinations thereof. Material parameters may be or include, but are not limited to, melting temperature, optical absorption coefficient, density, specific heat, thermal conductivity, enthalpy, solidus temperature, liquidus temperature, etc., or combinations thereof. Environmental parameters may be or include, but are not limited to, ambient temperature, humidity, sheath gas concentration, etc., or combinations thereof. It should be understood that other or additional parameters and weights may be used in the equations to further optimize and refine the amount of laser power or energy to the build part or article 118 and / or build plate 128.

[0098] The heat provided by the target heating system 102 and directed to the substrate 116 and / or proximal areas of the substrate 116 may be utilized to heat, soften, re-melt, or any combination thereof, previous and / or current droplets or layers of build material. The heat provided by the target heating system 102 may also be capable of, or may be configured to, affect thermal gradients in the cooling droplet melt pool to control various characteristics of the article 118. For example, the heat provided by the target heating system 102 may affect one or more of build strength, adhesion, porosity, surface finish, crack and / or fracture formation, grain size, grain orientation, structure, etc. within the article 118.

[0099] The heat provided by the targeted heating system 102 and directed at the ejected droplets in the flight path 704 may be utilized to heat, soften, re-melt, or any combination thereof, the droplets of build material.

[0100] The present disclosure has been described with reference to exemplary embodiments. While a limited number of implementations have been shown and described, those skilled in the art will understand that changes can be made in these implementations without departing from the principles and spirit of the foregoing detailed description. It is intended that the present disclosure be construed as including all such modifications and variations as come within the scope of the appended claims or equivalents thereof.

Claims

1. 1. An additive manufacturing device for making an article, comprising: a stage configured to support a substrate; a print head disposed above the stage, the print head configured to heat a build material into a molten build material and deposit the molten build material in the form of droplets onto the substrate to create the article; a target heating system disposed proximate the print head, the target heating system including a laser system configured to control a temperature or a temperature gradient of the droplets in a flight path interposed between the print head and the substrate; the laser system: A fiber laser; a fiber-coupled laser module; an output fiber coupled to the fiber-coupled laser module; a collimator positioned downstream of the fiber output; a polarization rotator disposed downstream of the collimator; a variable retarder disposed downstream of the collimator; a wavelength retarder positioned downstream of the variable retarder.

2. The additive manufacturing device of claim 1 , wherein the print head and the target heating system are coupled to one another.

3. 10. The additive manufacturing device of claim 1, wherein the target heating system is configured to operate at a temperature of 300°C or higher and 600°C or lower.

4. a first polarizer disposed between the collimator and the polarization rotator; a second polarizer disposed between the polarization rotator and the variable retarder; and a third polarizer positioned downstream of the wavelength retarder.

5. The additive manufacturing device of claim 4 , wherein the polarization rotator is located upstream of the variable retarder and the wavelength retarder.

6. a first polarizer disposed between the collimator and the variable retarder; a second polarizer disposed between the wavelength retarder and the polarization rotator; and a third polarizer positioned downstream of the polarization rotator.

7. The additive manufacturing device of claim 6 , wherein the variable retarder and the wavelength retarder are located upstream of the polarization rotator.

8. The additive manufacturing device of claim 1 , further comprising a monitoring system configured to monitor a portion of the additive manufacturing device.

9. a computing system operatively coupled to the print head and the target heating system; The additive manufacturing device of claim 1 , further comprising: a monitoring system operably coupled to the computing system and configured to monitor the additive manufacturing device.

10. 10. The additive manufacturing device of claim 1, further comprising a beam dump positioned proximate to the print head and incident on a beam generated by the target heating system, the beam dump configured to absorb at least a portion of energy from the beam generated by the target heating system.

11. 10. The additive manufacturing device of claim 1, wherein the targeted heating system is further configured to control a temperature or temperature gradient of the droplets deposited on the substrate, an area proximate to the substrate, or a combination thereof.

12. The additive manufacturing device of claim 1 , wherein the build material comprises one or more metals or metal alloys.

13. 13. The additive manufacturing device of claim 12, wherein the one or more metals or metal alloys comprise one or more of aluminum, aluminum alloys, brass, bronze, chromium, cobalt chromium alloys, copper, copper alloys, iron alloys, nickel, nickel alloys, nickel titanium alloys, stainless steel, tin, titanium, titanium alloys, gold, silver, molybdenum, tungsten, or combinations thereof.

14. The additive manufacturing device of claim 1 , wherein the build material comprises one or more polymers.

15. 15. The additive manufacturing device of claim 14, wherein the one or more polymers comprise one or more of acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polylactic acid (PLA), high density polyethylene (HDPE), polyphenylsulfone (PPSU), poly(meth)acrylate, polyetherimide (PEI), polyetheretherketone (PEEK), high impact polystyrene (HIPS), thermoplastic polyurethane (TPU), polyamide, composites thereof, or combinations thereof.

16. 10. A method for making an article using the additive manufacturing device of claim 1, comprising: heating the build material in the print head to the molten build material; ejecting the molten build material from the printhead toward the substrate; at least partially heating the droplets within the flight path; depositing the molten build material onto the substrate.

17. The additive manufacturing device of claim 8 , wherein the monitoring system is configured to measure a temperature of droplets within a flight path.

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