Systems and methods for controlling material deposition using magnetic fields

Abstract

Systems and methods for controlling deposition of additive manufacturing materials using magnetic fields are provided. The system may include a build surface; a material depositor through which magnetically responsive materials are deposited on the build surface; an energy source; and a magnet set. The magnet set applies a magnetic field to the build surface and / or the material depositor. The magnetic field is configured to attract the magnetically responsive material when the energy source melts the magnetically responsive material.

Description

Technical Field

[0001] The present invention relates generally to additive manufacturing, and more particularly to applying a magnetic field during a particle deposition process to improve the quality and properties of additively manufactured products, and more particularly to improving the quality and properties of additively manufactured products based on molten metals. Background Art

[0002] Additive manufacturing or 3D printing technology is widely used due to its desirable qualities such as efficiency and flexibility. One of the challenges of additive manufacturing processes using techniques such as directed energy deposition or powder bed fusion is controlling porosity. Directed energy deposition creates a product by melting and fusing material particles as they are deposited. Powder bed fusion creates a product by depositing a layer of material and melting and fusing the deposited material particles. When particles are exposed to the applied energy beam, their movement can be affected by many factors. Influencing factors such as airflow can cause particles to be more concentrated in certain areas of the product, leaving voids in other areas of the product. Precise control of the deposited particles is a challenge.

[0003] In addition to porosity, products produced with directed energy deposition or powder bed fusion can have low resolution and less than ideal material structures. For example, grain structure control is challenging. The "heat-affected zone" surrounding the melt pool is subject to large thermal gradients. During the build, the effects of temperature gradients on the structure being generated are difficult to overcome. In addition, due to the characteristics of fusion-based additive manufacturing, the products produced may have undesirable highly non-uniform characteristics in their microstructure and mechanical properties.

[0004] Therefore, it is desirable to provide systems and methods for improving the quality and properties of additively manufactured products.Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background. Summary of the invention

[0005] Many embodiments include systems and methods for controlling deposition of materials using magnetic fields. Embodiments include systems for controlling deposition of additive manufacturing materials using magnetic fields. A material depositor delivers a magnetically responsive material for deposition on a build surface. A magnet set applies a magnetic field to the build surface and / or the material depositor. The magnetic field is configured to generate an attractive force between the magnetically responsive material and the build surface while an energy source melts the magnetically responsive material.

[0006] In further embodiments, the material depositor includes a material conduit, and the magnet array is disposed around the material conduit.

[0007] In other embodiments, the array of magnets is disposed around the build surface.

[0008] In further embodiments, the magnet set comprises a plurality of electromagnets.

[0009] In further embodiments, a controller selectively energizes each of the plurality of electromagnets to vary the applied magnetic field.

[0010] In further embodiments, the controller is configured to control the magnet set in an on and off sequence.

[0011] In further embodiments, the controller is configured to vary an activation level of the magnet set during deposition of the material.

[0012] In further embodiments, an actuator is coupled to the magnet set, and the controller is configured to operate the actuator to reposition the magnet set.

[0013] In further embodiments, the controller suspends the magnetic field while the material depositor deposits the magnetically responsive material.

[0014] In further embodiments, the energy source is configured to generate a molten pool from the magnetically responsive material, and the controller is configured to control the magnet set to direct a magnetic field into the molten pool.

[0015] In various other embodiments, a method of controlling deposition of additive manufacturing materials using a magnetic field includes depositing a magnetically responsive material and focusing an energy source onto the deposited magnetically responsive material. A magnet array applies a magnetic field to a build surface and / or a material depositor. The magnetic field creates an attractive force between the magnetically responsive material and the build surface, including when the energy source melts the magnetically responsive material.

[0016] In further embodiments, the material depositor includes a material conduit, and the magnet array is disposed around the material conduit.

[0017] In other embodiments, the array of magnets is disposed around the build surface.

[0018] In further embodiments, the magnet set comprises a plurality of electromagnets.

[0019] In further embodiments, the controller energizes each of the plurality of electromagnets to vary the applied magnetic field.

[0020] In further embodiments, the controller turns the magnet groups on and off.

[0021] In further embodiments, the controller varies the excitation level of the magnet groups.

[0022] In further embodiments, the controller repositions the magnet set via an actuator.

[0023] In further embodiments, the controller suspends the magnetic field while the material depositor deposits the magnetically responsive material.

[0024] In a number of additional embodiments, a method of controlling deposition of additive manufacturing materials using a magnetic field includes depositing a magnetically responsive material onto a build surface via a material depositor. A controller focuses an energy source onto the deposited magnetically responsive material. A magnet set applies a magnetic field to the build surface and / or the material depositor. The magnetic field creates an attractive force between the magnetically responsive material and the build surface, including when the energy source melts the magnetically responsive material. The controller controls the magnet set to change the magnetic field to impart a target property therein as the magnetically responsive material solidifies. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Exemplary embodiments will be described below with reference to the following drawings, wherein like reference numerals represent like elements, and wherein:

[0026] Figure 1 is a schematic diagram of a system for controlling deposition of materials using a magnetic field acting on a build surface of a build plate or substrate according to various embodiments;

[0027] Figure 2 is a schematic diagram of a system for controlling material deposition using a magnetic field acting on a material delivery system according to various embodiments;

[0028] Figure 3 is a schematic diagram of a system for controlling material deposition using a magnetic field acting on a building surface of a building plate or substrate having a plurality of magnetic modules according to various embodiments;

[0029] Figure 4 According to various embodiments, a method for controlling Figure 1-3 A schematic diagram of a control system of the system;

[0030] Figure 5 is a flow chart illustrating a process for building a component using magnetic field controlled material deposition according to various embodiments. DETAILED DESCRIPTION

[0031] The following detailed description is merely exemplary in nature and is not intended to limit application and use. In addition, it is not intended to be bound by any express or implied theory presented in the previous technical field, background technology, invention content or the following detailed description. As used herein, the term module refers to any hardware, software, firmware, electronic control component, processing logic and / or processor device, alone or in any combination, including but not limited to: application-specific integrated circuits (ASICs), electronic circuits, processors (shared, dedicated or grouped) and memories that execute one or more software or firmware programs, combinational logic circuits and / or other suitable components that provide the functions.

[0032] Embodiments of the present disclosure may be described herein in terms of functional and / or logical block components and various processing steps. It should be understood that such block components may be implemented by any number of hardware, software, and / or firmware components configured to perform a specified function. For example, embodiments of the present disclosure may employ various integrated circuit components, such as storage elements, digital signal processing elements, logic elements, lookup tables, etc., which may perform various functions under the control of one or more microprocessors or other control devices. In addition, those skilled in the art will appreciate that embodiments of the present disclosure may be implemented in conjunction with any number of various systems, and the system described herein is merely an example embodiment of the present disclosure.

[0033] For the sake of brevity, conventional techniques related to signal processing, data transmission, signaling, control, and other functional aspects of the system (and the various operating components of the system) may not be described in detail herein. In addition, the connecting lines shown in the various figures included herein are intended to represent example functional relationships and / or physical couplings between various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in the embodiments of the present disclosure.

[0034] As disclosed herein, systems and methods for controlling deposited materials using magnetic fields as described herein can be used for magnetically assisted additive manufacturing processes and other applications. During material deposition, for example in directed energy deposition or powder bed fusion, an in-situ magnetic field is applied. The magnetic field can be applied with permanent magnets and / or electromagnets. In some embodiments, a magnetic field can be applied to a build surface of a build platform or substrate so that the deposited material adheres to the build surface when deposited on the build surface. In other embodiments, the deposited material can be magnetized during deposition to create an attractive force between the build surface and the material. The methods disclosed herein are applicable to a variety of magnetically responsive metallic materials.

[0035] The applied magnetic field can be controlled during deposition and post-deposition response of the particles, and in some embodiments can be cyclically turned on and off to achieve a localized or variable magnetic field in the molten pool. In some embodiments, such as in applications using powder bed fusion, the magnetic field can be paused during the process of adding layers of material to the bed to avoid disturbing the uniform distribution. In some embodiments, such as those using non-magnetic materials such as aluminum alloys, a coating or additive can be added to the powder so that the powder is magnetically attracted. An example of such a coating or additive material can be titanium boron. Various beneficial results can be obtained, such as in-situ powder condensation during laser deposition, reduced porosity, refined microstructure, reduced non-uniform characteristics of microstructure and mechanical properties, reduced powder waste, controlled deposition orientation, and / or others.

[0036] As described herein, the disclosed method may include cleaning a substrate and applying a magnetic field to the substrate. The substrate may be a build platform that supports a component during construction but is not part of the finished product. In some embodiments, metal powder is delivered during the application of energy, such as by a nozzle, or by other application mechanisms that spread the layer before applying the energy, such as by rolling the entire layer. Due to the effect of the magnetic field of the metal powder in the position and direction determined by the applied magnetic field during the deposition process, the metal powder adheres / attaches to the substrate, so the scattering of magnetic powder is minimized. Energy, such as energy from a laser beam, is focused on the substrate / component / powder layer and melts the powder to form a molten pool. In various embodiments, the energy / laser beam is focused on the metal powder after being transmitted to the substrate to reduce the thermal effect of the magnetic field. After a layer of the component being built is completed, the nozzle / energy source moves upward, and the component is built layer by layer of the deposited and melted material. When the component is built, the magnetic field can be redirected to obtain various results, and can be redirected upward close to the top surface (build surface) of the component to maximize its effect on the deposited particles. Multiple magnets can be used to provide a larger particle size for control purposes. Once parts are manufactured to final dimensions, they may be machined and cleaned as necessary to meet applicable specifications.

[0037] refer to Figure 1 , schematically illustrating a magnetic field controlled material deposition system 100. In general, the magnetic field controlled material deposition system 100 includes a laser type energy delivery system 102, a material depositor in the form of a material deposition system 104, a magnetic field transmission system 106, a build surface in the form of a build platform 108, and a gas delivery system 110 for delivering an inert gas to a build chamber 112. In the current embodiment, the magnetic field controlled material deposition system 100 is illustrated as a directed energy deposition additive manufacturing / 3D printing system. In other embodiments, other additive manufacturing methods may be used, such as powder bed fusion or other methods.

[0038] In this embodiment, the material deposition system 104 includes a powder supply source 114 for delivering material to the target area through a nozzle 116. During the construction of the part 109 one layer at a time, the nozzle 116 moves on the building platform 108. In the current embodiment, the powder flow is delivered through the same nozzle 116 as the laser beam, for example, through at least two concentric channels in the nozzle 116. In other embodiments, the powder flow and the laser beam can be delivered through separate nozzles or conduits. The energy delivery system 102 includes a laser source 118, a reflector 120 for guiding energy, and a nozzle 116 for guiding the laser beam. The magnetic field transmission system 106 includes at least one of a permanent magnet group 122 and / or an electromagnet group 124 for magnetizing the building platform 108 and / or the building surface of the part 109. In this way, the building platform 108 is composed of a magnetizable material such as a ferromagnetic material. As described in more detail below, the magnetic field can be suspended / removed from the building platform 108 for a variety of reasons. Therefore, the building platform itself may not be a permanent magnet. Build platform 108 includes the substrate upon which fabricated part 109 is built and is therefore not part of the finished product being manufactured. Gas delivery system 110 supplies an inert gas to a sealed build chamber 112 to better control material properties and protect the build material of part 109 from oxidation.

[0039] like Figure 1 As shown, the magnetic field control material deposition system 100 applies a controlled magnetic field to the building platform 108. The permanent magnet group 122 includes a plurality of permanent magnets / magnet parts 126, 128 to magnetize the building platform 108. In one embodiment, the magnet parts 126, 128 are elements of a magnet structure surrounding the building platform 108. In other embodiments, any number of permanent magnets 126, 128 can be used around the building platform 108. In some embodiments, the permanent magnets 126, 128 can be moved away from the building platform to reduce or eliminate its magnetization, and can be moved closer and / or increased in number to enhance the magnetic field. The electromagnet group 124 can include any number of separate electromagnets 131-137. In some embodiments, only one of the electromagnets 131-137 can be used. In the case of a large-sized building platform 108 and / or when more precise magnetic field control is required, a larger number of electromagnets 131-137 can be used to cover the entire area of ​​the building platform 108.

[0040] In operation, build chamber 112 is filled with an inert gas by gas delivery system 110. The build platform is selectively magnetized by magnetic field transmission system 106, which provides a magnetic field through permanent magnet group 122 and / or electromagnet group 124. Material deposition system 104 delivers material through nozzle 116, and energy delivery system 102 delivers energy through nozzle 116 to melt the delivered material. This creates a molten pool 125, which fuses to build part 109 when nozzle 116 is moved away. In general, the magnetic field applied to build platform 108 and / or injected into the deposited material particles creates an attractive force between the material powder particles and build plate 108, causing the particles delivered through nozzle 116 to adhere in place on previously built layers of the build platform or part 109. In various embodiments, the magnetic field can be controlled to provide additional effects on building part 109, as described in more detail below.

[0041] In the magnetic field controlled material deposition system 100, the magnetic field can be used to control the porosity in the part 109 being built, thereby increasing the density. Porosity can form during the build process, for example due to incomplete melting of the powder material or improper adhesion of two layers of material. Keyhole porosity may occur when bubbles are entrained in the part 109 during the build process. Keyhole porosity is characterized by the formation of pores inside the part 109. It has been found that during the build process, due to the flow of energy, the deposited particles flow / move within the molten pool 125 generated by the laser, which leads to increased porosity. The magnetic field attracts the deposited particles and holds them in place within the molten pool 125, thereby reducing the porosity. In this way, the deposited particles are ferromagnetic or other materials attracted by the magnetic field. In many embodiments, the deposited particles include aluminum, aluminum alloys, or other non-ferromagnetic materials. In the latter case, the powder particles are treated with a magnetically responsive material such as titanium-boron, such as by coating, and the magnetic field attracts and holds them in the molten pool 125.

[0042] In the magnetic field controlled material deposition system 100, the magnetic field can be used to refine the microstructure of the material forming the build part 109. For example, it has been found that the material can exist in a semi-solid form in areas of the material in and / or around the molten pool 125. If not handled, these semi-solid clusters may cause undesirable material properties, such as inhomogeneity. It has been found that the inhomogeneity characteristics are caused by semi-solid clusters located at the liquid-solid interface and / or within the liquid molten pool. Semi-solid clusters may cause non-equiaxed grains. It has also been found that columnar grain structures may be formed. Columnar grains are generally undesirable because they produce solidification defects and anisotropy of mechanical properties. A magnetic field can be used to effectively stir or mix the molten pool to break up semi-solid clusters and columnar grains. This results in a preferred equiaxed grain structure with reduced inhomogeneity and columnar grains.

[0043] In the magnetic field controlled material deposition system 100, the magnetic field can be used to reduce scattering. Scattering occurs when particles are blown away from or out of the molten pool 125 and thus lead to a number of undesirable results, such as material waste. By holding the deposited particles in place via the magnetic field, scattering is minimized and the majority of the deposited material is present in the part 109 being built.

[0044] In a magnetic field controlled material deposition system 100, a magnetic field can be used to control the deposition direction of a material. For example, during the construction of a complex part 109, such as an out-of-plane portion including a protruding angled portion or an overhanging cantilever portion, a support structure can typically be constructed to support the portion as the portion is built layer by layer. These support structures are typically not an integral part of the part 109 design, but can be removed in post-processing after the additive manufacturing build. The magnetic field can be directed to help support these parts while being built, thereby eliminating the need for some or all of the build support structures. Because the deposited particles are magnetically responsive, the magnetic field can be used to apply sufficient force to prevent the portion from bending or collapsing during the build.

[0045] refer to Figure 2 , schematically illustrating a magnetic field controlled material deposition system 200. Typically, the magnetic field controlled material deposition system 200 also includes a material deposition system 104, a laser type energy delivery system 102, a build platform 108, and a gas delivery system 110 for delivering an inert gas to a build chamber 112. In this embodiment, the magnetic field controlled material deposition system 200 is also illustrated as a directed energy deposition additive manufacturing / 3D printing system. In other embodiments, other additive manufacturing methods, such as powder bed fusion or other methods, may be used. In this embodiment, a magnetic field transmission system 206 is included.

[0046] like Figure 2As shown, the magnetic field controlled material deposition system 200 applies a controlled magnetic field to the material deposition system 104, in particular to the material particles supplied thereby. The magnetic field transmission system 206 includes at least one of a permanent magnet group 222 and / or an electromagnet group 224. The permanent magnet group 222 includes a plurality of permanent magnets / magnet parts 226, 228 to magnetize the particles supplied from the powder supply source 114 by the material deposition system 104 through a conduit including a conduit 230 and a nozzle 116. In one embodiment, the magnet parts 226, 228 are elements of a magnet structure surrounding the conduit 230. In other embodiments, any number of permanent magnets 226, 228 can be used around the conduit 230. In some embodiments, the permanent magnets 226, 228 can be moved away from the conduit 230 to reduce or eliminate its magnetization, and can be moved closer and / or increased in number to enhance the magnetic field. The electromagnet group 224 can include any number of individual electromagnets 231. In some embodiments, one electromagnet 231 can be used. One or more components of magnetic field transmission system 206, in this embodiment, an electromagnet array 224, can be disposed around powder supply 114. In some embodiments, electromagnet array 224 can be cycled on and off. In operation, magnetic field transmission system 206 magnetizes particles delivered through nozzle 116 so that they are attracted / adhered to previously deposited layers of build platform 108 or part 109, resulting in many of the same desired results as magnetic field controlled material deposition system 100.

[0047] refer to Figure 3 , schematically illustrating a magnetic field-controlled material deposition system 300. Typically, the magnetic field-controlled material deposition system 300 includes a material depositor in the form of a material deposition system 304, a laser-type energy delivery system 102, a build platform 108, and a build chamber 112. The material deposition system 304 is configured as a roller system that deposits a layer of material on the build platform 108 before applying energy from the laser beam. A gas delivery system (not shown) may be included in multiple embodiments. In this embodiment, the nozzle 316 guides the laser beam but does not guide the deposited material. In this embodiment, the magnetic field-controlled material deposition system 300 is illustrated as a powder bed fusion type additive manufacturing / 3D printing system. In other embodiments, other additive manufacturing methods may be used. In this embodiment, a magnetic field transmission system 306 is included.

[0048] The magnetic field controlled material deposition system 300 applies a controlled magnetic field to the building platform 108. The magnetic field transmission system 306 includes at least one of the permanent magnet group 322 and / or the electromagnet group 324. The permanent magnet group 322 includes a plurality of permanent magnets / magnet parts 326, 328 to magnetize the building platform 108 and / or the component 109. In one embodiment, the magnet parts 326, 328 are elements of a magnet structure surrounding the building platform 108. In other embodiments, any number of permanent magnets 326, 328 can be used around the building platform 108. The permanent magnets 326, 328 can be moved away from the building platform 108 to reduce or eliminate its magnetization, such as during the deposition of a material layer, and can be moved closer and / or increased in number to enhance the magnetic field. The electromagnet group 324 can include any number of individual electromagnets 331. In the illustrated embodiment, one electromagnet 331 is used. In the case of large-sized build platform 108 and / or when more precise magnetic field control is desired, a greater number of electromagnets 331 may be used to cover the entire area of ​​build platform 108. In operation, magnetic field delivery system 306 magnetizes build platform 108 such that deposited particles are attracted / adhered to previously deposited layers of build platform 108 or part 109, resulting in many of the same desired results as magnetic field controlled material deposition system 100.

[0049] refer to Figure 4, the control aspects applicable to the magnetic field controlled material deposition system 100, 200, 300 are shown in greater detail in a composite form, and generally control the energy delivery system 102, the material deposition system 104, the magnetic field transmission system 106, and the gas delivery system 110. The control system 400 includes a controller 404. In other embodiments, any number of controllers may be used in place of the controller 404. For the purposes of the current embodiment, the controller 404 controls the operation of the magnetic field controlled material deposition system 100, 200, 300, including controlling the material deposition system 104 through at least one actuator 408, controlling the energy delivery system 102 through at least one actuator 410, and controlling the gas delivery system 110 through at least one actuator 412. In addition, the controller 404 controls various aspects of the magnetic field transmission system 106, 206, 306. The controller 404 may also control the movement of the nozzle 116, for example, by operating the actuator 416. The actuator 416 may be a multi-axis positioning actuator to move the nozzle through various heights, positions, and orientations relative to the build platform 108. The controller 404 may include any number of electronic control modules and receive various input variables of current operating conditions and other parameters. The inputs are analyzed and operating parameters, such as operating parameters of the energy delivery system 102, the magnetic field transmission system 106, 206, 306, and others, are calculated from the data and applied to various actuators and other appropriate response devices. The controller 404 may receive various signals, including signals from the sensor group 414, analyze them, and send control signals to various destinations, including actuators 408, 410, 412, 416 and magnetic field transmission systems 106, 206, 306. The sensor group 414 may sense various aspects of the component 109 and its construction, including detecting the height of the construction through the position sensor 420 to determine the location of the current construction surface, and determining the position of the nozzle 116 through the position sensor 422. The sensor group 414 may include any number of additional sensors to monitor the operation / status of the component 109 and the magnetic field controlled material deposition system 100, 200, 300.

[0050] The controller 404 may include any number of electronic control modules. The controller 404 receives information from various sources, processes the information, and provides control signals / commands based thereon to implement the operation of the magnetic field controlled material deposition system 100, 200, 300. The controller 404 includes a processor 424 and a storage device 426, and is coupled to a storage device 428. The processor 424 performs the computational and control functions of the controller 404, and during operation executes one or more programs 430, and may use data 432, each of which may be contained in the storage device 428, so that the processor 424 controls the general operation of the controller 404 in performing the processes described herein, such as the processes further described below. The storage device 426 may be any type of suitable memory or combination of storage devices capable of storing data, some of which represent executable instructions used by the controller 404. In the illustrated embodiment, the memory device 426 may store the above-described programs 430 and one or more stored values ​​of the data 432, such as for short-term data access. The storage device 428 stores data, such as long-term data access for automatically controlling the magnetic field controlled material deposition system 100, 200, 300, and can be any suitable type of storage device. In an exemplary embodiment, the storage device 428 includes a source from which the storage device 426 receives a program 430 and data 432. The program 430 represents executable instructions used by the controller 404 for processing information and controlling the magnetic field controlled material deposition system 100, 200, 300, including the magnetic field transmission system 106, 206, 306. The processor 424 can generate control signals for the magnetic field transmission system 106, 206, 306 based on logic, calculations, methods and / or algorithms.

[0051] As the build progresses, powder for building part 109 is deposited in separate layers on build platform 108, and energy delivery system 102 selectively energizes the powder according to its design parameters to form part 109. Magnetic field transmission system 106, 206, 306 can be activated after material is deposited on the build or while deposition is occurring. The timing at which magnetic field transmission system 106, 206, 306 is actuated can be predefined and stored in memory, and can be called based on parameters such as the height of the build sensed by position sensor 420.

[0052] The magnetic field transmission system 106, 206, 306 may include any number of electromagnets, such as electromagnets 436, 438, which represent Figure 1-3 The electromagnets 436, 438 can be powered on and off to provide magnetic fields of different strengths and directions or no magnetic field. The magnetic field transmission system 106, 206, 306 can include any number of permanent magnets 440, 442, which represent Figure 1-3 Permanent magnet. Figure 4 As shown, the permanent magnets are mounted to be repositionable by actuators 444, 446, respectively. The actuators 444, 446 can be multi-axis positioning actuators to move the permanent magnets 440, 442 through various positions to change or eliminate the applied magnetic field, as described in more detail below. The controller 404 can receive various signals, including signals from the sensor group 414, analyze them, and send control signals to the actuators 444, 446. The controller 404 can control the magnetic field transmission system 106, 206, 306 to change the generated magnetic field, including directing the magnetic field into the molten pool 125.

[0053] refer to Figure 5 , a process 500 is shown, which can be performed using at least one of the magnetic field controlled material deposition systems 100, 200, 300. The process 500 begins by preparing 502 the build platform 108, and otherwise setting up the additive manufacturing machine. For example, the remnants of the previous build are removed, and the build platform 108 is cleaned, presenting a new build surface, in preparation for building a new one or more parts 109. The process 500 includes the selective application 504 of the magnetic field, such as by one of the magnetic field transmission systems 106, 206, 306. The application 504 may require fully or partially energizing the electromagnet group 124, 224, 324. When equipped with an actuator 444, 446, the application 504 may require moving the permanent magnet group 122, 222, 322 into position. The process 500 includes, for example, delivering 506 powder to the previously built layer of the build platform 108 or part 109 by the material deposition system 104, 304. Applying 504 may precede delivery 506, or delivery 506 may precede applying 504, or both may be initiated simultaneously. For example, for a directed energy deposition system, application 504 of a magnetic field may precede powder delivery 506 by a short time interval, or both may be initiated simultaneously. In another example, such as in the case of a powder bed fusion application, delivery 506 of a powder layer across build platform 108 may be performed prior to applying 504 to achieve a uniform distribution of the deposited layer.

[0054] Process 500 includes controlling 508 a magnetic field, such as by controller 404, which may be performed throughout the build phase. For example, in the case of a plurality of electromagnets 131-137, less than all of the electromagnets 131-137 may be energized at any particular time. This approach may be employed when building a large part 109, and only the electromagnets 131-137 in the area of ​​the build platform 108 where the nozzle 116 is currently operating may be energized. This approach may also be used to focus the magnetic field in the molten pool 125. In another example, individual electromagnets 131-131 may be energized or have their energization levels altered to correspond to the orientation of material deposition, such as to support features of the part 109 being built. In another example, individual electromagnets 131-131 may be energized or have their energization altered to mix / stir the molten pool 125, such as to break up columnar particles and / or semi-solid clusters. In another example, the magnetic field may be paused during the application of a layer of material, such as when building with powder bed fusion.

[0055] Process 500 includes focusing 510 an energy beam on a build surface of build plate 108 or an elevated level of part 109 being built, for example, during or after deposition, to melt the delivered 506 powder. In one embodiment, focusing 510 may be delayed after powder delivery 506 to reduce thermal effects on the magnetic field. For example, the heat applied by energy delivery system 102 may be intense enough to distort or weaken the magnetic field for an extended period of time.

[0056] After the layer of the part 109 being built is completed, the process 500 includes positioning the nozzle 116. For example, the nozzle 116 is raised, for example, by the control system 400, and is positioned at a specified starting point in preparation for building the next layer of the part 109. The process can return to the selective application of the magnetic field 504, and can cycle through steps 504-512 as the part 109 is built layer by layer to its designed dimensions. As the part 109 is built, the magnetic field moves upward near the upper surface of the part 109 in the process. For example, the magnetic field can be conducted through the building platform 108 and the part 109. In another example, as the height of the part 109 increases, the excitation level of the electromagnet group 124, 224, 324 can be increased, for example, by the control system 400. In another example, the magnet can be moved upward, for example, by the control system 400 and the actuators 444, 446. When the part 109 is fully built, post-processing 516 is performed. Post-processing 516 may include removing part 109 from build platform 108 , as well as any required machining and / or cleaning, and finishing part 109 .

[0057] Through the embodiments disclosed herein, magnetic fields are used to control deposited materials during additive manufacturing processes. The magnetic field can advantageously reduce porosity, refine the material microstructure of the component, reduce non-uniform properties, reduce scattering to improve powder usage, and / or control deposition orientation.

[0058] Although at least one exemplary embodiment has been given in the foregoing detailed description, it should be understood that there are a large number of variations. It should also be understood that one or more exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. On the contrary, the foregoing detailed description will provide a convenient roadmap for those skilled in the art to implement one or more exemplary embodiments. It should be understood that various changes may be made to the functions and arrangements of elements and / or steps without departing from the scope of the present disclosure as set forth in the attached claims and their legal equivalents.

Claims

1. A system for controlling deposition of additive manufacturing materials using a magnetic field, the system comprising: Build the surface; a material depositor by which the magnetically responsive material is deposited on the build surface, the material depositor comprising a conduit for supplying unmelted material from a material supply; Energy source; and A magnet array is disposed about the conduit to magnetize unmelted material supplied through the conduit so that the unmelted material is attracted or adhered to a build surface or a previously deposited layer of deposited material.

2. The system of claim 1 further comprising another set of magnets disposed around the building surface.

3. The system according to claim 1, wherein: The magnet group includes a plurality of electromagnets.

4. The system of claim 3, comprising a controller, wherein the controller is configured to selectively energize each of the plurality of electromagnets to vary the applied magnetic field.

5. The system of claim 1, comprising a controller, wherein: The controller is configured to control the magnet set in an on and off sequence.

6. The system according to claim 5, wherein: The controller is configured to vary an excitation level of the set of magnets.

7. The system of claim 5, comprising at least one actuator on the magnet set, wherein the controller is configured to operate the actuator to reposition the magnet set.

8. The system of claim 2, comprising a controller, wherein the controller is configured to pause the magnetic field generated by the another magnet set while the material depositor deposits the magnetically responsive material.

9. A method for controlling deposition of additive manufacturing materials using a magnetic field, the method comprising: depositing a magnetically responsive material on the build surface by a material depositor, the material depositor comprising a conduit for supplying unmelted magnetically responsive material from a material supply source, and a magnet array disposed around the conduit; magnetizing, by the magnet set, unmelted magnetically responsive material supplied through the conduit such that the unmelted magnetically responsive material is attracted or adhered to a build surface or a previously deposited layer of magnetically responsive material; focusing an energy source onto the deposited magnetically responsive material via a controller; Another set of magnets disposed about the build surface is controlled by a controller to vary the magnetic field generated by the other set of magnets to impart target properties therein as the magnetically responsive material is deposited.

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