Airflow Control for Additive Manufacturing

Abstract

To provide an improved method of controlling an airflow within an additive manufacturing apparatus.SOLUTION: The invention provides a method, an apparatus and a program for additive manufacturing. An additive manufacturing device 300 includes a positioning mechanism configured to provide independent movement of at least one build unit 302 in at least two dimensions. The build unit 302 may further include a gas flow device for providing a flow zone in a first direction with relation to the build unit 302. The build unit 302 may further include a powder delivery mechanism and an irradiation beam directing unit. The irradiation bean unit may follow a first irradiation path, where the first irradiation path forms at least a first solidification line and at least a second solidification line formed at an angle other than 0° and 180° to the first solidification line.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to an improved method for controlling air flow within an additive manufacturing device. [Background technology]

[0002] Additive manufacturing (AM) techniques include electron beam freeform manufacturing, laser metal deposition (LMD), laser wire metal deposition (LMD-w), gas metal arc welding, laser engineered net shaping (LENS), selective laser sintering (SLS), direct metal laser sintering (DMLS), electron beam melting (EBM), powder fed directed energy deposition (DED), and three-dimensional printing (3DP). In contrast to subtractive manufacturing methods, AM generally involves the deposition of one or more materials to create a net or near net shape (NNS) object. While "additive manufacturing" is the industry standard term (ASTM F2792), AM encompasses a variety of manufacturing and prototyping techniques known by a variety of names, including freeform manufacturing, 3D printing, rapid prototyping / tooling, etc. AM techniques can be used to create a wide variety of materials from a wide variety of materials. Complex components can be manufactured from these materials. Generally, free-standing objects can be created from computer-aided design (CAD) models. As an example, certain types of AM processes use an energy beam, e.g., electromagnetic radiation such as an electron beam or laser beam, to sinter or melt powder materials and / or wire stock to create a solid, three-dimensional object in which the materials are bonded together.

[0003] Selective laser sintering, direct laser sintering, selective laser melting, and direct laser melting are common industry terms used to refer to the production of three-dimensional (3D) objects by sintering or melting fine powders using a laser beam. For example, U.S. Pat. No. 4,863,538 and U.S. Pat. No. 5,460,758 describe conventional laser sintering techniques. More specifically, sintering involves fusing (agglomerating) particles of powder at temperatures below the melting point of the powder material, while melting involves melting the particles of powder sufficiently to form a solid homogenous mass. The physical process involved in laser sintering or laser melting involves the transfer of heat to the powder material, followed by sintering or melting the powder material. Electron beam melting (EBM) uses a focused electron beam to melt the powder. These processes involve successively melting layers of powder to build an object in a metal powder.

[0004] AM techniques, examples of which are discussed above and throughout this disclosure, can be characterized by the use of a laser or energy source to heat the powder to at least partially melt the material. Thus, a high concentration of heat is generated in the fine powder in a short period of time. High temperature gradients within the powder while building a part can have a significant effect on the microstructure of the finished part. Rapid heating and solidification can cause high thermal stresses and produce localized non-equilibrium phases throughout the solidified material. Furthermore, the orientation of the crystal grains in the finished AM part can be controlled by the direction of heat conduction in the material, making the scanning scheme of the laser in the AM equipment and techniques an important way to control the microstructure of the AM-built part. Control of the scanning scheme in the AM equipment is even more important to develop parts without defects of the material, examples of defects include lack of fusion porosity and / or boilover porosity.

[0005] 1 is a schematic diagram showing a cross-sectional view of an exemplary conventional system 110 for direct metal laser sintering (DMLS) or direct metal laser melting (DMLM). The apparatus 110 builds an object, such as a part 122, layer by layer (e.g., layers L1, L2, and L3, exaggerated for illustrative purposes) by sintering or melting a powder material (not shown) using an energy beam 136 generated by a source such as a laser 120. The powder melted by the energy beam is supplied by a reservoir 126 and evenly distributed on a build plate 114 using a recoater arm 116 moving in a direction 134 to maintain the powder at a level 118 and remove excess powder material extending above the powder level 118 to a waste container 128. The energy beam 136 sinters or melts a cross-sectional layer (e.g., layer L1) of the object being built under the control of a galvo scanner 132. The build plate 114 is lowered and another layer of powder (e.g., layer L2) is distributed onto the build plate and the object to be built, followed by successive melting / sintering of the powder by the laser 120. The process is repeated until the part 122 is fully built from the melted / sintered powder material. The laser 120 can be controlled by a computer system including a processor and memory. The computer system can determine a scanning pattern for each layer and control the laser 120 to irradiate the powder material according to the scanning pattern. After the fabrication of the part 122 is completed, various post-processing procedures may be applied to the part 122. Post-processing procedures include, for example, removal of excess powder by blowing or vacuuming, machining, sanding or media blasting. Additionally, conventional post-processing can include removing the part 122 from the build platform / substrate, for example, by machining. Other post-processing procedures include stress relief treatments. Additionally, thermal and chemical post-processing procedures can be performed to finish the part 122. It can be used to

[0006] The AM process described above is controlled by a computer that executes a control program. For example, the device 110 includes a processor (e.g., a microprocessor) that executes firmware, an operating system, or other software that provides an interface between the device 110 and an operator. The computer receives as input a three-dimensional model of the object to be formed. For example, the three-dimensional model is generated using a computer-aided design (CAD) program. The computer analyzes the model and proposes a toolpath for each object in the model. The operator can define or adjust various parameters of the scan pattern, such as power, speed, and spacing, but generally does not directly program the toolpath. One skilled in the art will appreciate that the control program described above is applicable to any of the AM processes described above. Additionally, the computer control described above may be applicable to any subtractive manufacturing or any pre- or post-processing technique used in any post- or hybrid processing.

[0007] The above additive manufacturing techniques can be used to form parts from stainless steel, aluminum, titanium, Inconel 625, Inconel 718, Inconel 188, cobalt chrome, among other metallic materials or alloys. For example, the above alloys can include materials having the trade names Haynes 188®, Haynes 625®, Super Alloy Inconel 625™, Chronin® 625, Altemp® 625, Nickelvac® 625, Nicrofer® 6020, Inconel 188, and any other material having material properties that make it attractive for forming parts using the above techniques.

[0008] In the above examples, the laser and / or energy source is generally controlled to form a series of solidified lines (hereinafter interchangeably referred to as hatch lines, solidified lines, and raster lines) in the powder layer based on a pattern. The pattern can be selected to reduce build time, to improve or control the material properties of the solidified material, to reduce stress in the finished material, and / or to reduce wear on the laser and / or galvanometer scanner and / or electron beam. In the past, various scanning schemes have been contemplated, including, for example, checkerboard and / or stripe patterns.

[0009] One attempt to control stress in the material of a built AM part involves rotating a stripe region that includes a plurality of adjacent parallel vectors as solidification lines that run perpendicular to the solidification lines that bound the stripe region for each layer in the AM build process. The solidification lines that are bounded by the stripes and perpendicular to the stripes are rotated for each layer of the AM build. One example of scanning-based control of an AM machine is disclosed in U.S. Patent No. 8,034,279 B2 to Dimter et al., entitled "Method and Device for Manufacturing a Three-dimensional Object," which is incorporated herein by reference in its entirety.

[0010] Figures 2 and 3 show the rotary striping method described above. A laser scans the surface of the powder to form a series of solidification lines 213A, 213B. The series of solidification lines form a build layer and are bounded by solidification lines in the form of stripes 211A, 212A, 211B, 212B perpendicular to the solidification lines 213A, 213B that form the boundaries of each stripe region. The stripe regions bounded by the solidification lines 211A, 212A form part of the larger surface of the layer being built. In forming the part, the bulk of the part cross section is divided into a number of stripe regions (the region between two solidified stripes containing transverse solidification lines). The orientation of the stripes is determined during the AM build process as shown in Figures 2 and 3. The solidification line 213B is rotated for each layer formed. The first layer may be formed by a series of parallel solidification lines 213A in the stripe area formed substantially perpendicular to and bounded by the solidified stripe 211A. In the next layer formed on the first layer, the stripe 211B is rotated as shown in FIG. 3. By forming the stripe boundaries of the solidification lines 213A, 213B through a set of solidified stripes 211B, 212B rotated relative to the previous layer, the solidification line 213B formed perpendicular to and bounded by the stripe 211B is also rotated relative to the solidification line 213A of the previous layer.

[0011] A typical powder bed AM machine requires a constant gas flow in the area of ​​melting and / or sintering of material. The process chamber of the AM machine is usually connected to a protective gas circuit that can supply a protective gas to the process chamber to establish a protective gas atmosphere in the process chamber. The protective gas circuit generally further includes a discharge region where gas containing particulate impurities, such as residual feed powder particles and welding smoke particles, can be removed from the process chamber.

[0012] Maintaining a particular orientation of the airflow relative to the solidification lines described above is advantageous in producing consistent metallurgy of the AM-built parts. For example, U.S. Patent Application 2014 / 0301883A1 to Wiesner et al., entitled "Method and Apparatus for Producing Three-dimensional Work Pieces," incorporated herein by reference in its entirety, discloses the need to control the gas flow in the AM machine relative to the solidification lines described above. In the '883 application, the AM machine is controlled to have an angle between 0° and 90°, or 270° and 360° relative to the direction of flow of the gas flow across the build surface. However, since the direction of the airflow is fixed, most AM machines require that maintaining the gas flow direction relative to the solidification lines involves determining an acceptable range of angles between the formation of the solidification lines and the gas flow, and only forming solidification lines whose orientations are within the acceptable range of angles relative to the provided gas flow. This severely limits the variation in the angle of the solidification lines formed in each layer, limiting the ability to control the microstructure of the finished part.

[0013] It is necessary to change the direction of the gas flow 290, which significantly increases the complexity of the AM apparatus. Furthermore, the change introduces delays and increases build time. Another method of maintaining the direction of the gas flow relative to the solidification lines involves determining an acceptable range of angles between the formation of the solidification lines and the gas flow, and only forming the solidification lines 213A and / or 213B at orientations that are within the acceptable range of angles relative to the provided gas flow.

[0014] For at least the above reasons, a need exists to control gas flow across the build surface in relation to the solidification line that forms during the building of an AM part. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] US Patent Application Publication No. 2016 / 0368053 Summary of the Invention

[0016] In one aspect, an additive manufacturing apparatus is disclosed, the additive manufacturing apparatus including a positioning mechanism configured to provide independent movement of at least one build unit in at least two dimensions. The build unit can further include a gas flow device for providing a flow zone along a first direction relative to the build unit. The build unit can further include a powder delivery mechanism and an irradiation beam directing unit. The irradiation beam unit can follow a first irradiation path, the first irradiation path including at least a first solidification line and a second solidification line. and forming at least a second coagulation line formed at an angle other than 0° and 180° relative to the first coagulation line. During formation of the first coagulation line, the building unit may be positioned in a first orientation such that a first direction of the flow zone is substantially perpendicular to the first coagulation line. During formation of the second coagulation line, the building unit may be positioned in a second orientation such that a flow zone along the first direction is substantially perpendicular to the second coagulation line.

[0017] The build unit may be rotatably mounted on the positioning system about an axis substantially perpendicular to the first direction and may be rotated from the first orientation to the second orientation. The apparatus may further include a movement platform configured to move independently of the build unit. For example, the build platform may be rotatable about an axis.

[0018] A method for manufacturing an object is further disclosed. The method may include positioning the building unit with a mechanism configured to provide independent movement of at least one building unit in at least two dimensions. The building unit may further include at least one gas flow device capable of providing a gas flow zone along a first direction relative to the building unit. The method may further include irradiating the powder along a first irradiation path to form at least partially a first solidification line at a first angle, and irradiating the powder along a second irradiation path to form at least partially a second solidification line at an angle other than 0° and 180° relative to the first solidification line. During the formation of the first solidification line, the building unit may be positioned such that a first direction of the flow zone is substantially perpendicular to the first solidification line. During the formation of the second solidification line, the building unit may be positioned such that a flow zone along the first direction is substantially perpendicular to the second solidification line.

[0019] A non-transitory computer readable medium storing a program configured to cause a computer to execute an additive manufacturing process using an additive manufacturing device is further disclosed. The additive manufacturing process may include forming at least one first solidification line. The gas flow device may be arranged in a first orientation such that the flow zone is along a first direction substantially perpendicular to the first solidification line. The non-transitory computer readable medium may be further configured to control the additive manufacturing device to form at least a second solidification line formed at an angle other than 0° and 180° with respect to the first solidification line. The gas flow device may be repositioned to a second orientation such that the flow zone is substantially perpendicular to the second solidification line.

[0020] Further, in any of the above embodiments or disclosures, any number of construction units can be used in parallel, i.e., substantially simultaneously, to construct one or more objects and / or envelopes, all on the same work surface.

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more exemplary aspects of the present disclosure and, together with the detailed description, serve to explain the principles and embodiments thereof. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a side view of a conventional additive manufacturing technique used to form at least a portion of a part. [Diagram 2] FIG. 1 is a top view showing a conventional hatch and stripe pattern used to form at least a portion of a part. [Diagram 3] FIG. 1 is a top view showing a conventional hatch and stripe pattern used to form at least a portion of a part. [Figure 4] FIG. 1 is a perspective view illustrating exemplary part build layers during a conventional AM process. [Diagram 5] FIG. 5 is a top view showing the hatch and stripe patterns used to form each layer and the gas flow direction of the part shown in FIG. 4 according to one embodiment of the present disclosure. [Figure 6] FIG. 2 is a side cross-sectional view of a building unit according to one aspect of the present disclosure. [Figure 7] FIG. 2 is a side cross-sectional view of a portion of a build unit and a rotating build platform of an additive manufacturing apparatus according to one aspect of the present disclosure. [Figure 8] 1A-1C are top views illustrating an exemplary orientation of a construction unit according to one aspect of the present disclosure. [Figure 9] 7 is a perspective view of the apparatus of FIG. 6, showing an exemplary orientation of a building unit according to one embodiment of the present disclosure. [Figure 10] 8 is a perspective view of the apparatus of FIG. 7, showing an exemplary orientation of a building unit according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Although the embodiments described herein are described in conjunction with the exemplary embodiments outlined above, various alternatives, modifications, variations, improvements, and / or substantial equivalents, whether known or currently unexpected or unexpected, will be apparent to those skilled in the art. Accordingly, the exemplary embodiments described above are illustrative and not limiting. Various changes can be made without departing from the spirit and scope of the present disclosure. Accordingly, the present disclosure is intended to encompass all known or later developed alternatives, modifications, variations, improvements, and / or substantial equivalents.

[0024] When using any of the above AM techniques to form a part by at least partially melting a powder, a hatch scan (hereinafter interchangeably referred to as hatch scan, raster, scan line, or solidification line) is formed using a laser scanning across the powder material in a raster scan manner. The above-mentioned solidification line is used to form the bulk of the part cross-section during the AM build. Contour scans may also be used to outline the edges of the part cross-section. During the raster scan process, the energy source or laser is turned on, increased in power, and / or focused in areas where a solid portion of the AM build is desired, and is turned off, defocused, and / or reduced in power where melt formation of the object's cross-section within that layer is not desired. During the raster scan process, at least partial melting and solidification formation of the powder is repeated along adjacent solidification lines, for example to form a single melted and fused cross-section of the object to be built, while the contour scan forms the individual boundaries or edges of the part. In the example of a powder-bed AM machine, once the fusion formation of one cross-section of the object to be built is complete, the machine coats the completed cross-sectional surface with an additional layer of powder, and the process is repeated until the object is complete.

[0025] For the above reasons, the laser and / or energy source is controlled to form a series of solidification lines in the powder layer with a pattern for at least the following reasons: to reduce build time, control heat accumulation in the powder and / or increase efficiency of the build, improve and / or control material properties of the solidified material, reduce stress in the finished material, and / or reduce wear on the laser and / or galvanometer scanner.

[0026] As shown in Figures 4 and 5, the built AM part includes multiple layers 215, 216, 217. An example of the above scheme is shown. For example, the first layer 217 may be divided by the software into several stripe regions bounded by stripes 257, 277 formed as solidified lines. The stripes 257, 277 may form boundaries of parallel adjacent vectors or solidification lines 267 formed individually. The surface of the part includes multiple stripes covering the surface to be built. As shown in Figure 5, each stripe region is bounded by solidified stripes 257, 277 in the layer 217 and forms boundaries of a series of parallel solidification lines 267. The parallel solidification lines 267 are formed by solidified stripes. The stripes are oriented at a first angle in layer 217 such that the vertical solidified lines 267 are formed substantially perpendicular to the stripes 257, 277. The stripe region bounded by the solidified stripes 256, 257 on the second layer 216 is angled relative to the solidified stripe boundaries 257, 277 on the previous layer 217. Thus, the solidified lines 266 extending perpendicular to the solidified stripes 256, 276 are also angled relative to the solidified lines 267 on the previous layer 217. As the build progresses, the next layer having the stripes 265, 275 on the third layer 215 is angled relative to the stripes 257, 277 on layer 217 and also relative to the stripes 256, 276 on layer 216.

[0027] Further details regarding scanning schemes that can be used in accordance with the present invention can be found in U.S. patent application Ser. No. 15 / 451,108, entitled "Triangle Hatch Pattern for Additive Manufacturing," filed Mar. 7, 2017, with Attorney Docket No. 037216.00070; U.S. patent application Ser. No. 15 / 451,043, entitled "Leg Elimination Strategy for Hatch Pattern," filed Mar. 6, 2017, with Attorney Docket No. 037216.00078; and U.S. patent application Ser. No. 15 / 459,941, entitled "Constantly Varying Hatch for Additive Manufacturing," filed Mar. 15, 2017, with Attorney Docket No. 037216.00077, the disclosures of which are incorporated herein by reference.

[0028] For the best possible build environment, powder bed additive manufacturing machines require constant gas flow in the areas of melting and / or sintering of material. The process chambers of the AM machines described above and below are typically connected to a protective gas circuit that can supply protective gas to the process chamber to establish a protective gas atmosphere in the process chamber. The protective gas circuit generally further includes a discharge area where gases containing particulate impurities, such as residual raw powder particles and welding smoke particles, can be removed from the process chamber. Using the apparatus and methods described herein, it is possible to provide gas flows 290A-C in a desired direction, for example, relative to solidification lines 255, 266, 267. As shown in FIG. 5, the apparatus and methods described below allow the direction of gas flow to be controlled relative to each layer 217, 216, 215 during AM build. For example, the build units (described below) can be positioned such that gas flow 290C is substantially perpendicular to solidification line 267 formed in layer 217. Once layer 217 is complete, powder is fed to the desired area and layer 216 is formed by the build units with gas flow 290B oriented substantially perpendicular to solidification line 266. Similarly, once layer 216 is complete, powder is fed to the desired area and layer 217 is formed by the build units with gas flow 290C oriented substantially perpendicular to solidification line 255. Note that throughout this disclosure, the gas flow areas are referred to as being substantially perpendicular, but the disclosure is not so limited. For example, it may be desirable to have gas flow at an angle other than 90 degrees to the solidification line without departing from the scope of the disclosure.

[0029] FIG. 6 shows an example of an embodiment of a large scale AM ​​apparatus according to the present invention. The apparatus includes a positioning system (not shown) and a build unit 400 including an irradiating radiation directing device 401, a laminar gas flow zone 404, and a build plate (not shown) below an object 415 to be built. The maximum build area, instead of being defined by a powder bed as in conventional systems, is defined by the positioning system (not shown) and the build region of a particular build can be limited to a build envelope 414 that can be dynamically built together with the object. In general, the positioning system used in the present invention can be any multi-dimensional positioning system such as a gantry system, delta robot, cable robot, robot arm, etc. The irradiating radiation directing device 401 is aligned with the build unit 400 by a second positioning system (not shown). The recoater 411 can move independently within the build unit 400. The atmospheric environment outside the build unit, i.e., the "build environment" or "containment zone", can be controlled such that the oxygen content is reduced relative to typical ambient air and the environment is at a reduced pressure. In some embodiments, the recoater used is a selective recoater. One embodiment of a selective recoater 411 is shown in FIG. 6.

[0030] Also, in the case of a laser source, there may be an illumination source that generates photons that comprise the laser illumination directed by the illumination radiation directing device. In the case where the illumination source is a laser source, the illumination radiation directing device may be, for example, a galvo scanner, and the laser source may be located outside the build environment. In such a situation, the laser illumination may be conveyed to the illumination radiation directing device by any suitable means, for example, a fiber optic cable. In the case where the illumination source is an electron source, the electron source generates electrons that comprise the electron beam that is directed by the illumination radiation directing device. In the case where the illumination source is an electron source, the illumination radiation directing device may be, for example, a deflection coil. In the case where the illumination radiation directing device directs a laser beam during operation of a large-scale additive manufacturing apparatus according to an embodiment of the present invention, it is generally advantageous to include a gas flow device 404 that provides a substantially laminar gas flow 403B zone. As shown in FIG. 6, the flow direction is represented by arrows 403B, which represent a flow along the X direction in the example shown in FIG. 6. Instead of or in combination with a laser, an electron beam may also be used. An electron beam is a well-known illumination source. For example, U.S. Patent No. 7,713,454 by Larsson, entitled "Arrangement and Method for Producing a Three-Dimensional Product," discusses electron beam systems and is incorporated herein by reference.

[0031] The gas flow device 404 can provide gas to a pressurized outlet portion (not shown) and a vacuum inlet portion (not shown) and can provide a gas flow in a direction 403B toward the gas flow zone 403 and the recoater 405. Above the gas flow zone 404 is an enclosure 418 that can contain an inert environment 419. The recoater 405 can include a hopper 406 that includes a back plate 407 and a front plate 408. The recoater 405 also has at least one actuating element 409, at least one gate plate 410, a recoater blade 411, an actuator 412, and a recoater arm 413. The recoater is mounted to a mounting plate 420. FIG. 6 also shows a build envelope 414, which can be formed, for example, by additive manufacturing or Mig / Tig welding, an object 415 to be formed, and a powder 416 contained in the hopper 406 that is used to form the object 415. In this particular example, the actuator 412 actuates the actuating element 409 to pull the gate plate 410 away from the front plate 408. In one embodiment, the actuator 412 may be, for example, a pneumatic actuator and the actuating element 409 may be a two-way valve. In one embodiment, the actuator 412 may be, for example, a voice coil and the actuating element 409 may be a spring. There is also a hopper gap 417 between the front plate 408 and the back plate 407 that allows powder to flow when the corresponding gate plate is pulled away from the powder gate by the actuating element. The powder 416, the back plate 407, the front plate 408, and the gate plate 410 may all be the same material. Alternatively, the back plate 407, the front plate 408, and the gate plate 410 may all be the same material, which may be a material compatible with any desired material, such as, for example, cobalt-chromium. In this particular example of an embodiment of the invention, the gas flow in the gas flow zone 404 flows in the x-direction, but may also flow in any desired direction relative to the build unit. The recoater blade 411 has a width in the x-direction. The direction of the illuminating radiation beam when θ2 is approximately 0 defines the z-direction in this illustration.The gas flow within gas flow zone 404 may be substantially laminar. The irradiating radiation directing device 401 may be independently movable by a second positioning system (not shown). The view shows a gate plate 4. 10 is shown in the closed position.

[0032] Additionally, it should be noted that while the selective powder recoating mechanism 405 described above includes only a single powder dispenser, the powder recoating mechanism may include multiple compartments containing multiple different material powders.

[0033] When the gate plate 410 is in the open position, powder in the hopper is deposited to create a fresh powder layer 521, which is smoothed by the recoater blade 511 to create a substantially uniform powder layer. In some embodiments of the invention, the substantially uniform powder layer may be irradiated simultaneously as the build units move, which allows for continuous operation of the build units and therefore faster production of objects.

[0034] FIG. 7 shows a side view of the manufacturing apparatus 300 including details of the build unit 302, which is depicted on the far side of the build platform. The moving build unit 302 includes an irradiation beam directing mechanism 506, a gas flow mechanism 532 having a gas inlet and a gas outlet (not shown) that provides gas flow in a direction 538 toward a gas flow zone, and a powder recoating mechanism 504. In this example, the flow direction is represented by an arrow head 538, which represents flow along the X direction in the example shown in FIG. 7. Above the gas flow zone 538 may be an enclosure 540 that contains an inert environment 542. The powder recoating mechanism 504 mounted on a recoater plate 544 has a powder dispenser 512 including a back plate 546 and a front plate 548. The powder recoating mechanism 504 also includes at least one actuating element 552, at least one gate plate 516, a recoater blade 550, an actuator 518, and a recoater arm 508. In this embodiment, the actuator 518 actuates the actuation element 552 to pull the gate plate 516 away from the front plate 548, as shown in Figure 7. There is a gap 564 between the front plate 548 and the gate plate 516 to allow powder to flow onto the rotating build platform 310 when the gate plate 516 is pulled away from the front plate 548 by the actuation element 552.

[0035] 7 shows the build unit 302 with the gate plate 516 in an open position. Powder 515 in the powder dispenser 512 is deposited to create a fresh powder layer 554, which is smoothed by the recoater blade 510 onto a portion of the upper surface (i.e., build surface or work surface) of the rotating build platform 310 to form a substantially uniform powder layer 556, which is then irradiated by an irradiation beam 558 to become a fused layer that is part of the printed object 330. In some embodiments, the substantially uniform powder layer 556 can be irradiated at the same time as the build unit 302 is moving, which allows for continuous operation of the build unit 302 and therefore more time-efficient production of printed or grown objects 330. The object 330 being built on the rotating build platform 310 is shown in a powder bed 314 constrained by an outer build wall 324 and an inner build wall 326. In this particular example of one embodiment of the present invention, the gas flow in gas flow zone 532 is in the x-direction, but may flow in any desired direction relative to the build units.

[0036] It should be noted that while the selective powder recoating mechanism 504 described above includes only a single powder dispenser, the powder recoating mechanism may include multiple compartments containing multiple different material powders.

[0037] Further details regarding construction units and positioning mechanisms for single units and / or multiple units that can be used in accordance with the present invention can be found in "Additive Manufacturing," filed on May 31, 2017, with attorney docket number 037216.00103. No. 15 / 610,177, entitled “Apparatus and Method for Continuous Additive Manufacturing,” filed on May 31, 2017 under Attorney Docket No. 037216.00102; U.S. Patent Application No. 15 / 609,965, entitled “Method for Real-Time Simultaneous Additive and Subtractive Manufacturing With a Dynamically Grown Build Volume,” filed on May 31, 2017 under Attorney Docket No. 037216.00108; No. 15 / 610,113 entitled "Apparatus and Method for Real-Time Simultaneous Additive and Subtractive Manufacturing with Mechanism to Recover Unused Raw Material," filed on May 31, 2017, with Attorney Docket No. 037216.00109; U.S. Patent Application No. 15 / 609,747 entitled "Apparatus and Method for Real-Time Simultaneous Additive and Subtractive Manufacturing with Mechanism to Recover Unused Raw Material," filed on January 13, 2017, with Attorney Docket No. 037216.00061; No. 15 / 406,444 entitled "Additive Manufacturing Using a Mobile Build Volume," filed on January 13, 2017 with Attorney Docket No. 037216.00059; U.S. Patent Application No. 15 / 406,467 entitled "Additive Manufacturing Using a Mobile Scan Area," filed on January 13, 2017 with Attorney Docket No. 037216.00060; and U.S. Patent Application No. 15 / 406,454 entitled "Additive Manufacturing Using a Mobile Scan Area," filed on January 13, 2017 with Attorney Docket No. 037216.No. 15 / 406,461, entitled "Additive Manufacturing Using a Selective Recoater," filed on January 13, 2017 under Attorney Docket No. 00062, and U.S. Patent Application No. 15 / 406,471, entitled "Large Scale Additive Machine," filed on January 13, 2017 under Attorney Docket No. 037216.00071, the disclosures of which are incorporated herein by reference.

[0038] As discussed above with respect to the exemplary solidification line orientations shown in Figures 4 and 5, with respect to the AM apparatus described above, as the angle of the solidification lines (e.g., reference numbers 255, 266, and / or 267) of each layer 215-217 changes, the moving construction units in the manufacturing apparatus described above are oriented to enable the desired gas flow direction and solidification line orientation.

[0039] FIG. 8 illustrates an example of gas flow orientation control according to one embodiment of the disclosure. For example, a single layer (e.g., as shown in FIG. 4) may be formed with solidification lines formed in a first orientation 606. In this example, a simplified version of any of the build units described above is shown at 616A. When building a part 610 using an AM process, the build unit 616A may be moved to a first position to form the solidification lines 606A. The build unit 616A may be oriented at the first position such that the gas flow is in a direction 608A that may be substantially perpendicular to the solidification lines 606A that are formed. In a second layer (e.g., L2 shown in FIG. 4), it may be desirable to form solidification lines 606B in a second orientation that is different from the orientation used to form the solidification lines 606A. The build unit may be moved via a path 612 to form at least a portion of the part 610 using the solidification lines 606B, and the build unit may be oriented at a position 616B such that the gas flow direction 608B is substantially perpendicular to the solidification lines 606B that are formed. Similarly, a third layer (e.g., L3 shown in FIG. 4) may form coagulation line 606C in a second orientation that is different from the orientation used to form coagulation line 606B. It may be desirable. The build unit can be moved via the path 614 to form at least a portion of the part 610 using the solidification line 606C, and the build unit can be oriented at the position 616C such that the gas flow direction 608C is substantially perpendicular to the solidification line 606C being formed. Although the above example discusses that the solidification lines 606A-606C are variations with each layer (e.g., L1-L3 as shown in FIG. 4), it is noted that the solidification lines 606A-606C can also vary while forming a single layer. In other words, each of the solidification lines 606A-C and the orientation of the build unit and the gas flow direction 608A-B, respectively, may occur in a single layer (e.g., only layers L1, L2, and / or L3 shown in FIG. 4). It is further noted that the positions and orientations shown in FIG. 8, as well as all the disclosed figures, are presented by way of example only, and one skilled in the art would understand that any orientation and / or solidification line and / or sequence of orientations are possible based on the present disclosure. Additionally, it should be noted that multiple building units can be used simultaneously to further increase building speed.

[0040] FIG. 9 is a perspective view of an exemplary application of the disclosed invention. For example, the gas flow control of the present disclosure may be applicable to a moving build unit 802 to form an AM part 810 in a grown build envelope 818 to contain powder 813 applied during the build process. A single layer (e.g., as shown in FIG. 4) may be formed with solidification lines formed in a first orientation 806A. In this example, a simplified version of any of the build units described above is shown at 802. When building a part 810 using an AM process, the build 802 may be moved to a first position and orientation 816A to form solidification lines 806A. The build unit 802 may be oriented in the first position 816A such that the gas flow zone 803 is positioned such that the gas flow is in a direction 808A that may be substantially perpendicular to the solidification lines 806A being formed. In a second layer (e.g., L2 as shown in FIG. 4), it may be desirable to form solidification lines 806B in a second orientation that is different from the orientation used to form the solidification lines 806A. The build unit can be moved through path 812 and rotated in direction R to form at least a portion of part 810 using solidification line 806B, and the build unit can be oriented in position 816B such that gas flow direction 808B is substantially perpendicular to the solidification line 806B being formed. Although the above example discusses that solidification lines 806A-B are variations with each layer (e.g., L1-L2 as shown in FIG. 4), it is noted that solidification lines 806A-B can also vary while forming a single layer. In other words, each of solidification lines 806A-B and the orientation of build units and gas flow direction 808A-B, respectively, may occur in a single layer (e.g., only layers L1, L2, and / or L3 shown in FIG. 4). It is further noted that the positions and orientations shown in FIG. 9, as well as all disclosed figures, are presented by way of example only, and one skilled in the art would understand that any orientation and / or solidification line and / or sequence of orientations are possible based on the present disclosure. Additionally, it should be noted that multiple building units can be used simultaneously to further increase building speed.

[0041] FIG. 10 is a perspective view of an exemplary application of the disclosed invention. For example, the gas flow control of the present disclosure may be applicable to a moving build unit 902 for forming an AM part 910 on a moving build platform 910. The AM part 910 may be built in a grown build envelope and / or a build envelope 818 to accommodate the powder 813 applied during the build process. In FIG. 10, the build unit 902 is shown in a single position to simplify the illustration, but the build unit may move to the positions represented by the dotted lines 916A, 916B and / or to any position within the apparatus 900. Additionally, it is noted that since a rotatable build platform 910 is used, the build unit may be stationary relative to the y direction, or may simply rotate and move in the z direction, and move radially (x direction in FIG. 10) inwards and outwards. Thus, the rotatable platform 910 may be used to move the AM part 910 inwards and outwards. The movement of the form 910 in conjunction with the rotation allows the build unit to build a portion of the AM part at substantially any location within the apparatus 900. Additionally, it should be noted that the build platform 910 can be moved in the z direction in combination with or instead of a build unit that is movable in the z direction. In one embodiment, for example, the build platform 910 is movable in the z direction and the build unit 901 is rotatable and movable inward and outward in the radial direction (i.e., the x direction shown in FIG. 10 ) while remaining stationary in the z direction. As yet another example, the build unit 902 may be large enough such that it only needs to be rotatable and movable in the z direction. In other words, if the build unit 902 is large enough to cover the full width of the radial portion being built, the build unit can scan the build material across the full width of the part, so the build unit only needs to be rotatable to redirect the airflow. Additionally, it should be noted that in the above embodiment, the build unit 902 may be moveable in each direction (i.e., rotatable, z, x, and y) such that a raster scan can be formed in any direction while the build platform 910 remains stationary. Those skilled in the art will appreciate that the process described below is applicable to any single or combination of the above movements to form an AM part.

[0042] A single layer (e.g., as shown in FIG. 4) may be formed with solidification lines formed in a first orientation 906A. In this example, a simplified version of any of the build units described above is shown at 902. When building a part 910 using an AM process, the build unit 902 may be moved to a first position and orientation 916A to form the solidification lines 906A. The build unit 902 may be oriented in the first position 916A such that a gas flow zone is positioned such that gas flow is in a direction 908A that may be substantially perpendicular to the solidification lines 906A being formed. In a second layer (e.g., L2 as shown in FIG. 4), it may be desirable to form solidification lines 906B in a second orientation that is different from the orientation used to form the solidification lines 906A. The build unit may be moved and / or rotated to form at least a portion of the part 810 using the solidification lines 906B, and the build unit may be oriented in the position 916B such that the gas flow direction 908B is substantially perpendicular to the solidification lines 906B being formed. Although the above example discusses that the solidification lines 906A-B are variations with each layer (e.g., L1-L2 as shown in FIG. 4), it is noted that the solidification lines 906A-B can also vary while forming a single layer. In other words, each of the solidification lines 906A-B and the orientation of the building units and the gas flow direction 908A-B, respectively, may occur in a single layer (e.g., only layers L1, L2, and / or L3 as shown in FIG. 4). It is further noted that the positions and orientations shown in FIG. 10, as well as all the disclosed figures, are shown by way of example only, and that a person skilled in the art would understand that any orientation and / or solidification lines and / or sequence of orientations are possible based on the present disclosure. It is further noted that multiple building units can be used simultaneously to further increase the building speed.

[0043] This specification uses examples to disclose the invention, including preferred embodiments. It also uses examples to enable any person skilled in the art to practice the invention, including making and using any device or system, and performing any incorporated method. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are encompassed within the scope of the claims if they have structural elements that do not differ from the language of the claims, or if they include equivalent structural elements that do not differ substantially from the language of the claims. The various embodiments described, as well as other known equivalents of each of these aspects, can be mixed and matched by those skilled in the art to construct further embodiments and techniques according to the principles of the present application. [Embodiment 1] 1. A system for manufacturing an additively manufactured part, the system comprising: a positioning mechanism configured to provide independent movement of at least one building unit (302, 400, 616A, 901) in at least one dimension, said building unit (302, 400, 616A, 901) comprising: a gas flow device (404) for providing a flow zone (803) along a first direction relative to said building unit (302, 400, 616A, 901); a powder delivery mechanism; and a beam directing unit (506) following a first irradiation path, the first irradiation path forming at least a first solidification line and at least a second solidification line formed at an angle other than 0° and 180° relative to the first solidification line, wherein during formation of the first solidification line, the building unit (302, 400, 616A, 901) is positioned in a first orientation such that the first direction of the flow zone (803) is substantially perpendicular to the first solidification line, and during formation of the second solidification line, the building unit (302, 400, 616A, 901) is positioned in a second orientation such that the flow zone (803) along the first direction is substantially perpendicular to the second solidification line. [Embodiment 2] A system for manufacturing an additively manufactured part as described in embodiment 1, wherein the building unit (302, 400, 616A, 901) is rotatably mounted to the positioning mechanism around an axis substantially perpendicular to the first direction and is rotated from the first orientation to the second orientation. [Embodiment 3] 3. A system for manufacturing an additively manufactured part as described in embodiment 2, wherein the powder delivery mechanism provides powder onto a rotatable build platform (910), and the build platform (910) is rotated after formation of the first solidification line. [Embodiment 4] 2. The system for manufacturing an additively manufactured part of claim 1, wherein the gas flow device (404) generates a laminar flow along the first direction. [Embodiment 5] 4. The system for manufacturing an additively manufactured part of embodiment 3, wherein the first solidification line comprises a plurality of parallel solidification lines (267). [Embodiment 6] 6. The system for manufacturing an additively manufactured part of embodiment 5, wherein the second solidification line comprises a plurality of parallel solidification lines (267). [Embodiment 7] 2. The system for manufacturing an additively manufactured part according to claim 1, wherein the build unit (302, 400, 616A, 901) further comprises a powder recoater (405). [Embodiment 8] 7. A system for manufacturing an additively manufactured part as described in embodiment 6, wherein the first series of solidification lines are formed on a first powder layer and the second set of solidification lines are formed on a second powder layer provided on the first powder layer by the powder delivery mechanism. [Embodiment 9] A system for manufacturing an additively manufactured part as described in embodiment 1, further comprising a moving build platform (910) configured to move independently of the build unit (302, 400, 616A, 901). [Embodiment 10] A method for manufacturing an object (330, 415), comprising: positioning at least one building unit (302, 400, 616A, 901) using a mechanism configured to provide independent movement of said building unit (302, 400, 616A, 901) in at least two dimensions, (302, 400, 616, 901) includes at least one gas flow device (404) capable of providing a gas flow zone (803) along a first direction relative to said building unit (302, 400, 616A, 901); irradiating the powder along a first irradiation path to form a first solidification line at least partially at a first angle; irradiating the powder along a second irradiation path to at least partially form a second solidification line at an angle other than 0° and 180° relative to the first solidification line, wherein during formation of the first solidification line, the building unit (302, 400, 616A, 901) is positioned such that the first direction of the flow zone (803) is substantially perpendicular to the first solidification line, and during formation of the second solidification line, the building unit (302, 400, 616A, 901) is positioned such that the flow zone (803) along the first direction is substantially perpendicular to the second solidification line. [Embodiment 11] 11. The method of claim 10, wherein the building unit (302, 400, 616A, 901) is rotated from the first orientation to the second orientation about an axis substantially perpendicular to the first direction. [Embodiment 12] 11. The method of embodiment 10, wherein the gas flow device (404) generates a laminar flow along the first direction. [Embodiment 13] 11. The method of embodiment 10, wherein irradiating the powder along the first irradiation path includes forming a plurality of parallel solidification lines (267) at the first angle. [Embodiment 14] 14. The method of embodiment 13, wherein irradiating the powder along the second irradiation path includes forming a plurality of parallel solidification lines (267) at the second angle. [Embodiment 15] 15. The method of claim 14, wherein the first set of solidification lines is formed on a first powder layer and the second set of solidification lines is formed on a second powder layer disposed on the first powder layer by the powder delivery mechanism. [Embodiment 16] A non-transitory computer-readable medium storing a program configured to cause a computer to execute an additive manufacturing process using an additive manufacturing device, the additive manufacturing process comprising: forming at least one first solidification line, the gas flow device (404) being disposed in a first orientation such that the flow zone (803) is along a first direction substantially perpendicular to the first solidification line; forming at least a second solidification line formed at an angle other than 0° and 180° relative to the first solidification line, the gas flow device (404) being repositioned to a second orientation such that the flow zone (803) is substantially perpendicular to the second solidification line; A non-transitory computer readable medium comprising: [Embodiment 17] A non-transitory computer-readable medium as described in embodiment 16, wherein during the additive manufacturing process, a construction unit (302, 400, 616A, 901) of the additive manufacturing apparatus is controlled to rotate from the first orientation to the second orientation around an axis substantially perpendicular to the first direction. [Embodiment 18] 17. The non-transitory computer readable storage medium of claim 16, wherein during the additive manufacturing process, the gas flow device (404) is controlled to generate a laminar flow along the first direction. Medium. [Embodiment 19] 17. The non-transitory computer-readable medium of embodiment 16, wherein during the additive manufacturing process, the irradiation beam directing unit (506) is controlled to form the first solidification line and a plurality of solidification lines parallel to the first solidification line, and the irradiation beam directing unit (506) is controlled to form the second solidification line and a plurality of solidification lines parallel to the second solidification line. [Embodiment 20] 20. The non-transitory computer-readable medium of embodiment 19, wherein the additive manufacturing apparatus is further controlled by the powder delivery mechanism to form a first series of solidification lines on the first powder layer and a second set of solidification lines on a second powder layer disposed on the first powder layer. [Embodiment 21] 17. The non-transitory computer-readable medium of embodiment 16, wherein the additive manufacturing apparatus is further controlled to rotate a moving build platform (910) after forming at least one of the first solidification line or the second solidification line. [Explanation of symbols]

[0044] 110 Equipment, conventional systems 114 Build Plate 116 Recoater Arm 118 Powder Level 120 Laser 122 parts 126 Reservoir 128 Waste Container 132 Galvo Scanner 134 directions 136 Energy Beam 188 Inconel 211A Stripe, Solidification Line 211B Stripe 212A Stripe, Solidification Line 212B Stripe 213A Coagulation Line 213B Coagulation Line 215 Third Layer 216 Second Layer 217 First Layer 255 Coagulation Line 256 Stripes 257 Stripe Border 265 Stripes 266 Coagulation Line 267 Solidification lines, equilibrium solidification lines, vertical solidification lines 277 Stripe Border 290 Gas Flow 290A Gas Flow 290B Gas flow 290C Gas flow 300 Manufacturing equipment 302 Construction Unit, Mobile Construction Unit 310 Rotating Build Platform 314 Powder Bed 324 External construction wall 326 Inner Construction Wall 330 Object 400 Building Units 401 Irradiation radiation directing device 403 Gas Flow Zone 403B Gas flow, direction, arrows 404 Gas flow device, gas flow zone 405 Recoater, selective powder recoating equipment 406 Hopper 407 Backplate 408 Front Plate 409 Actuation elements 410 Gate Plate 411 Recoater Blade, Selective Recoater 412 Actuator 413 Recoater Arm 414 Construction Envelope 415 Object 416 Powder 417 Hopper Gap 418 Enclosure 419 Inert environment 420 Mounting Plate 504 Powder recoating mechanism 506 Irradiation Beam Directing Mechanism 508 Recoater Arm 510 Recoater Blade 511 Recoater Blade 512 Powder Dispenser 515 Powder 516 Gate Plate 518 Actuator 521 Powder layer 532 Gas flow mechanism, gas flow zone 538 Arrow head, direction, gas flow zone 540 Enclosure 542 Inert environment 544 Recoater Plate 546 Backplate 548 Front Plate 550 Recoater Blade 552 Actuating Elements 554 Powder layer 556 Powder layer 558 Irradiation Beam 564 Gap 606 First Orientation 606A Coagulation Line 606B Coagulation Line 606C Coagulation Line 608A Gas flow direction 608B Gas flow direction 608C Gas flow direction 610 parts 612 Routes 614 Routes 616A Construction Unit 625 Inconel 718 Inconel 802 Mobile Construction Unit 803 Gas Flow Zone 806A Coagulation Line, 1st Orientation 806B Coagulation Line 808A Gas flow direction 808B Gas flow direction 810 AM Parts 812 Routes 813 Powder 816A First Position and Orientation 818 Construction Envelope 900 equipment 901 Building Unit 902 Mobile Construction Unit 906A Solidification Line, Orientation 906B Coagulation Line 908A Gas flow direction 908B Gas flow direction 910 Build platform, AM parts 916A First Position and Orientation, dotted line, 916B Dotted line

Claims

1. A program configured to cause a computer to execute an additive manufacturing process using an additive manufacturing device including an irradiation beam directing unit and a construction unit, the construction unit including an irradiation beam directing unit, the additive manufacturing process comprising: forming at least one first solidification line, the build unit including a gas flow device and arranged in a first orientation such that a flow zone is substantially perpendicular to the at least one first solidification line and along a first direction extending substantially parallel to a build platform or a powder layer disposed on the build platform; forming at least one second solidification line formed at an angle other than 0° and 180° relative to the at least one first solidification line, the gas flow device being repositioned to a second orientation such that the flow zone is substantially perpendicular to the at least one second solidification line; wherein, during execution of the additive manufacturing process, the build unit is controlled to rotate from the first orientation to the second orientation about an axis substantially perpendicular to the first direction, and during execution of the additive manufacturing process, the irradiation beam directing unit is controlled to form the at least one first solidification line and the at least one second solidification line.

2. The program of claim 1 , wherein during the additive manufacturing process, the gas flow device is controlled to generate a laminar flow along the first direction.

3. The program of claim 1 or 2, wherein the at least one first coagulation line comprises a first plurality of parallel coagulation lines.

4. The method of claim 1 , wherein the at least one second coagulation line comprises a second plurality of parallel coagulation lines.

5. 5. The program of claim 1, wherein the irradiation beam directing unit is controlled by a powder delivery mechanism to form a first plurality of solidification lines on a first powder layer and a second plurality of solidification lines on a second powder layer disposed on the first powder layer.

6. The program of claim 5 , wherein an orientation of the first plurality of coagulation lines is different from an orientation of the second plurality of coagulation lines.

7. The program of claim 5 or 6, wherein the first direction is different from a propagation direction of the illumination beam from the illumination beam directing unit.

8. The program of claim 7 , wherein the additive manufacturing apparatus is further controlled to rotate a moving build platform after forming at least one of the first solidification line or the second solidification line.

9. The program of claim 8 , wherein the additive manufacturing apparatus is controlled to operate the mobile build platform independently of the build unit.

Images