Apparatus, system, and method for in-situ alignment detection for additive manufacturing

Abstract

An apparatus (300) can include a processor (305), a memory module (340), and machine-readable instructions stored in the memory module. When executed by the processor, the instructions can cause the apparatus to receive image data of one or more laser shots on a build plane as a part is being built, the image data indicating locations of a first set of reference shots made by a first laser (120) on the build plane and locations of a second set of reference shots made by a second laser (121) on the build plane, determine relative locations of the first set of reference shots and the second set of reference shots from the received image data, compare the determined relative locations of the first set of reference shots and the second set of reference shots to expected relative locations, and determine whether the first laser and the second laser are misaligned relative to each other based on the comparison.

Description

Technical Field

[0001] This disclosure relates to additive manufacturing, and more specifically, to field alignment testing for additive manufacturing. Background Technology

[0002] Direct metal laser melting (DMLM) is an additive manufacturing process that uses lasers to melt ultrathin layers of metal powder to build three-dimensional objects or parts. During the operation of a DMLM machine that includes multiple lasers, one or more lasers may become misaligned relative to one or more other lasers. If this occurs, it can introduce seams or other material defects into the part being built. Attached Figure Description

[0003] Figure 1 An example additive manufacturing machine for constructing parts by additive manufacturing according to one or more embodiments shown and described herein is schematically depicted;

[0004] Figure 2 A system for performing field alignment for additive manufacturing according to one or more embodiments shown and described herein is schematically depicted;

[0005] Figure 3 An alignment device according to one or more embodiments shown and described herein is schematically depicted;

[0006] Figure 4 A description of one or more embodiments shown and described herein is provided. Figure 1 An example cross-section of layers of a part constructed by an additive manufacturing machine;

[0007] Figure 5 A description of one or more embodiments shown and described herein is provided. Figure 1 Another example of a cross-section of layers in a part constructed by an additive manufacturing machine;

[0008] Figure 6 A description of one or more embodiments shown and described herein is provided. Figure 2 The system uses images to perform field alignment; and

[0009] Figure 7 A flowchart is provided illustrating an illustrative method for performing field alignment in additive manufacturing according to one or more embodiments shown and described herein. Detailed Implementation

[0010] This disclosure generally relates to field alignment for additive manufacturing. In the example shown, this disclosure relates to direct metal laser melting (DMLM). However, in other examples, this disclosure can be used with other types of additive manufacturing.

[0011] Direct metal laser melting (DMLM) is an additive manufacturing process that uses lasers to melt ultrathin layers of metal powder to build three-dimensional objects or parts. During the operation of a DMLM machine that includes multiple lasers, one or more lasers may become misaligned relative to one or more other lasers. If this occurs, it can introduce seams or other material defects into the part being built.

[0012] Computer-aided design (CAD) software can be used to design 3D parts. The output files generated by the CAD software can then be converted into multiple slice files representing different layers of the part. These slice files are then loaded onto a DMLM machine to build the part.

[0013] During operation, the recoating machine moves across a build platform and evenly spreads a thin layer of fine metallic powder. A laser then melts the powder to form a cross-section of the part for each layer, based on a slice file. The build platform is then lowered, and the process is repeated for the next layer of the part. In some examples, DMLM machines may include multiple lasers. Each laser can operate on a different section of the build platform. Therefore, the part to be built can consist of multiple segments stitched together, with each laser used to build a different segment. This can allow for the construction of larger parts than possible using a single laser and / or allows for faster part formation relative to a single-laser process.

[0014] However, if the multiple lasers of a DMLM machine are misaligned relative to each other, the parts may not be properly stitched together. Therefore, in the embodiments disclosed herein, a camera can be positioned to capture images along the line of sight of one laser. Thus, the camera can capture images of laser illumination from the lasers on the build platform of the DMLM machine. If the camera is also able to capture images of one or more laser illuminations from another laser of the DMLM machine within the same frame, the expected relative position between the laser illuminations from the two lasers can be compared to the actual relative position between the laser illuminations from the two lasers. If the relative position between the illuminations from the two lasers is not as expected, it can be determined that the lasers are misaligned relative to each other, and corrective actions can be taken to properly align the lasers.

[0015] Figure 1 A schematic diagram of an illustrative apparatus for performing DMLM additive manufacturing is shown. As used herein, this apparatus may be referred to as DMLM machine 100. DMLM machine 100 constructs objects, such as part 122, in a layer-by-layer manner by sintering or melting powder material using energy beams 136 and 137 generated by one or more sources, such as lasers 120 and 121. As described above, multiple lasers can be used to construct different segments of part 122. Figure 1 In the example, the DMLM machine 100 includes two lasers 120, 121. However, it should be understood that in other examples, the DMLM machine 100 may include more than two lasers. Furthermore, while this disclosure relates primarily to field alignment for additive manufacturing using the DMLM machine 100, the various methods and processes described herein can also be implemented using another type of additive manufacturing apparatus instead of the DMLM machine 100.

[0016] The powder to be melted by the energy beam is supplied by a storage tank 126, and a recoating machine 116 (e.g., a recoating arm) traveling in direction 134 spreads the powder evenly onto a build plate 114 to maintain the powder at a certain level 118 and / or remove excess powder material extending above the powder level 118 to a waste container 128. Energy beams 136 and 137, under the control of galvanometer scanners 132 and 133, sinter or melt cross-sectional layers of the object being constructed. The build plate 114 is then lowered, and another layer of powder is spread onto the part 122 being constructed, subsequently melted / sintered by lasers 120 and 121. This process is repeated until the part 122 is entirely constructed from the molten / sintered powder material.

[0017] Since each layer of part 122 is constructed by DMLM machine 100, the top layer of the part being constructed at any given time is referred to herein as the build plane. Thus, as each successive layer of part 122 is constructed, a layer of powder is spread on the current build plane of part 122.

[0018] Lasers 120 and 121 can be controlled by a computer system including a processor and memory. The computer system can determine the scanning pattern for each layer and control the lasers 120 and 121 and the galvanometer scanners 132 and 133 to irradiate the powder material according to the scanning pattern. Each laser 120 and 121 can operate on different portions of the build plate 114 and can be used to build different segments of the part 122. In an embodiment, laser 120 and galvanometer scanner 132 may include a first laser channel 124, while laser 121 and galvanometer scanner 133 may include a second laser channel 125. Laser channels 124 and 125 may also include mirrors, lenses, or other optical devices for controlling energy beams 136 and 137.

[0019] After the manufacture of part 122 is completed, various post-processing procedures can be applied to it. Post-processing procedures may include removing excess powder by, for example, purging or vacuuming. Other post-processing procedures may include stress relief processes. In addition, thermal and chemical post-processing procedures can be used to finish part 122.

[0020] To construct part 122 in multiple segments using lasers 120 and 121, the laser channels are preferably calibrated relative to each other. That is, laser irradiation from lasers 120 and 121 ideally occurs at a desired location on the construction plane of part 122, such that the segments of part 122 constructed by laser 120 and the segments of part 122 constructed by laser 121 are correctly aligned. If the calibration or alignment between laser channels 124 and 125 is disturbed, the segments of part 122 constructed by lasers 120 and 121 may not be correctly aligned, and material defects may occur in part 122.

[0021] Therefore, the embodiments disclosed herein provide field alignment of a DMLM machine 100. Specifically, the embodiments disclosed herein provide alignment of laser channels 124, 125 of the DMLM machine 100. However, in other examples, the embodiments disclosed herein may provide alignment of a DMLM machine having more than two laser channels.

[0022] In the embodiments disclosed herein, the camera can monitor the position of laser illumination by lasers 120 and 121. By monitoring the position of laser illumination by lasers 120 and 121, the alignment of laser channels 124 and 125 relative to each other can be determined, as disclosed herein. If laser channels 124 and 125 become misaligned, they can be adjusted to ensure correct alignment. Figure 1 In the example, the camera can be positioned to capture images along the line of sight of one of the lasers 120, 121, as disclosed herein.

[0023] Figure 2 A schematic diagram of a system 200 for performing field alignment in DMLM additive manufacturing, as disclosed herein, is shown. Figure 2 In the example, system 200 includes Figure 1 The DMLM machine 100 and the alignment device 300, which are referred to below. Figure 3 This will be discussed in more detail. System 200 further includes a camera 202, a photodiode 204, and a beam splitter 206. The camera 202 and photodiode 204 may each contain multiple lenses and other optical components. Furthermore, as... Figure 2 As shown, the DMLM machine 100 also includes a laser deflector 208, a focusing lens 210, and mirrors 212 and 214 within the galvanometer scanner 133.

[0024] exist Figure 2 In the example, laser 121 is positioned such that the energy beam 137 emitted by laser 121 is deflected by laser deflector 208 through focusing lens 210 and then guided toward DMLM machine 100. Energy beam 136 can also be emitted by laser 120, such as... Figure 1 As shown. Therefore, in Figure 1 In the example, part 122 can be constructed using lasers 120 and 121, as described above.

[0025] Also in Figure 2 In one example, camera 202 is positioned to capture an image along the optical line of sight 205 of laser 121. Specifically, the energy beam 137 emitted by laser 121 can cause light to be reflected and / or scattered away from the build plane of part 122 and guided by galvanometer scanner 133 through focusing lens 210 toward laser deflector mirror 208. The light can then pass through laser deflector mirror 208 and be split by beam splitter 206, such that a portion of the light travels to camera 202 and a portion travels to photodiode 204. Camera 202 can then capture an image of the build plane of part 122 along the line of sight 205 of laser 121. In some examples, either camera 202 or photodiode 204 may not be included in system 200. In some examples, system 200 may include other arrangements of camera 202, photodiode 204, and / or laser 121 such that camera 202 is capable of capturing an image along the line of sight 205 of laser 121.

[0026] By capturing a series of images of reflected and / or scattered laser illumination from the build plane along the field of view of laser 121, system 200 can determine the position where the energy beam 137 emitted by laser 121 illuminates the build plane. This position can be compared to the expected position where the energy beam 137 illuminates the build plane. Furthermore, if the series of images along the field of view of laser 121 also includes laser illumination from energy beam 136 emitted by laser 120, system 200 can compare the position where energy beam 136 illuminates the build plane with the expected position. Therefore, the relative positions between the positions where energy beams 136 and 137 illuminate the build plane can be compared to the relative positions where energy beams 136 and 137 are expected to illuminate the build plane. If the relative illumination positions of energy beams 136 and 137 are within a threshold tolerance of the expected relative illumination positions, system 200 can determine that laser channels 124 and 125 are correctly aligned relative to each other. However, if the relative illumination positions of energy beams 136 and 137 are outside the threshold tolerance of the expected relative illumination positions, the system 200 can determine that laser channels 124 and 125 are misaligned relative to each other.

[0027] refer to Figure 3 The alignment device 300 can receive images captured by the camera 202 and can determine whether laser channels 124, 125 are misaligned relative to each other, as disclosed herein. Components of the alignment device 300 are schematically depicted. In some examples, the alignment device 300 may be a DMLM machine (e.g., Figure 1The alignment device 300 is part of the DMLM machine 100. In other examples, the alignment device 300 may be a separate computing device or part of a computing device separate from the DMLM machine 100. In other examples, the alignment device 300 may be part of a system including the DMLM machine 100 (e.g., Figure 2 Within the system 200).

[0028] like Figure 3 As shown, the alignment device 300 may include a processor 305, input / output hardware 310, network interface hardware 320, data storage unit 330, and non-transitory memory unit 340. The memory unit 340 may be configured as a volatile and / or non-volatile computer-readable medium, and therefore may include random access memory (including SRAM, DRAM, and / or other types of random access memory), flash memory, registers, optical disc (CD), digital versatile optical disc (DVD), and / or other types of storage units. Furthermore, the memory unit 340 may be configured as a storage operation logic 342, a build data receiving module 344, a reference illumination determination module 346, an image data receiving module 348, an alignment determination module 350, and an alignment correction module 352 (each of which, by way of example, may be embodied as a computer program, firmware, or hardware). Figure 3 It also includes a network interface 370, which can be implemented as a bus or other interface to facilitate communication between components of the alignment device 300.

[0029] Processor 305 may include any processing unit configured to receive and execute instructions (e.g., from data storage unit 330 and / or memory unit 340). Input / output hardware 310 may include a monitor, keyboard, mouse, printer, camera, microphone, speaker, touchscreen, and / or other devices for receiving input and output information. Network interface hardware 320 may include any wired or wireless network hardware, such as a modem, LAN port, Wi-Fi card, WiMax card, mobile communication hardware, and / or devices for connecting to other networks and / or devices (e.g., [missing information]). Figure 1 Other hardware for communication with the DMLM machine 100.

[0030] Still referencing Figure 3 The data storage unit 330 can store data received by the construction data receiving module 344 and / or the image data receiving module 348. The data storage unit 330 can also store other data used by the alignment device 300, as described herein.

[0031] The memory component 340 includes operating logic 342, a construction data receiving module 344, a reference illumination determination module 346, an image data receiving module 348, an alignment determination module 350, and an alignment correction module 352. The operating logic 342 may include an operating system and / or other software for managing components of the alignment device 300.

[0032] The data receiving module 344 can receive data from parts to be constructed by the DMLM machine 100 (e.g., Figure 1 The build data receiving module 344 receives build data associated with part 122. The data received by the build data receiving module 344 can indicate the shape of the part to be built by the DMLM machine 100. In some examples, the build data receiving module 344 can receive data generated by CAD software. However, in other examples, the build data receiving module 344 can receive build data from other types of software programs (e.g., slice files). In this embodiment, the data received by the build data receiving module 344 can indicate which parts of part 122 will be built by each of lasers 120, 121.

[0033] The reference illumination determination module 346 can determine the reference illumination caused by lasers 120 and 121 during the construction of part 122. As used herein, the reference illumination is laser illumination performed by a DMLM machine to determine the relative alignment between multiple lasers of the DMLM machine. Specifically, the reference illumination determination module 346 can determine the reference illumination to be used to determine whether laser channels 124 and 125 are aligned relative to each other. As discussed above, system 200 can determine whether lasers 120 and 121 are correctly aligned relative to each other. This can be achieved by analyzing a series of images captured by camera 202, which includes laser illumination performed by both lasers 120 and 121.

[0034] When the image captured by camera 202 includes the irradiation positions of the two lasers 120, 121, the image can be analyzed to determine whether the relative positions between the irradiations are as expected. Therefore, the reference irradiation determination module 346 can determine the reference irradiations to be used for calibrating the alignment of laser channels 124, 125. In some examples, reference irradiation can be performed on part 122 after a layer is completed and before the next recoating. In other examples, reference irradiation can be performed on the powder after recoating, before building the next layer, or afterward. In some examples, one or more reference portions can be built across the build plane of part 122, and reference irradiation can be performed on the reference portions. In some examples, multiple reference irradiations can be performed at multiple locations across the build plane, and images showing multiple reference irradiations can be analyzed to determine the alignment of laser channels 124, 125.

[0035] In some examples, system 200 can determine the alignment of laser channels 124, 125 at multiple layers of part 122 while building part 122. In some examples, system 200 can determine the alignment of laser channels 124, 125 at each layer of part 122 being built. In other examples, system 200 can determine the alignment of laser channels 124, 125 at a subset of layers of part 122. For example, the system can determine the alignment of laser channels 124, 125 for every n layers (e.g., every 2 layers, every 5 layers, every 10 layers, etc.). Therefore, the alignment of laser channels 124, 125 can be checked continuously while building the part. In these examples, reference illumination determination module 346 can determine reference illumination at each layer of part 122 where the alignment of laser channels 124, 125 will be checked. The build layer of part 122 for which the alignment of laser channels 124, 125 is determined can be specified by the user or can be specified in the configuration. In some examples, system 200 can monitor the alignment of laser channels 124, 125 at multiple layers of part 122 to determine whether the alignment changes over time.

[0036] In the first operating mode, the reference illumination determination module 346 can determine the reference illumination based on the laser illumination included in the build data receiving module 344. That is, the reference illumination determination module 346 can calibrate laser channels 124, 125 based on laser illumination that will be used as part of the build of part 122. Conversely, in the second operating mode, the reference illumination determination module 346 can determine additional laser illumination to add to the build data specifically intended for the calibration of laser channels 124, 125. That is, the reference illumination determination module 346 can add laser illumination that is not required to build part 122 but is used to determine the alignment of laser channels 124, 125.

[0037] In the first operating mode, the reference illumination determination module 346 can analyze the build data received by the build data receiving module 344 to determine an appropriate laser illumination as a reference. Specifically, the reference illumination determination module 346 can select laser illumination from two lasers 120, 121 within the field of view of the camera 202 as a reference, so that the relative positions of the laser illuminations can be compared with each other. In an example where the alignment of laser channels 124, 125 needs to be calibrated at multiple layers, the reference illumination determination module 346 can select the laser illumination as the reference for each layer of the build of part 122, at which the alignment of laser channels 124, 125 will be calibrated.

[0038] In the second operating mode, the reference illumination determination module 346 can determine reference illuminations not used for constructing part 122. Specifically, in some examples, the reference illumination determination module 346 can generate illumination positions for each of the lasers 120, 121, which can be used as references. The reference illumination determination module 346 can generate reference illuminations for the lasers 120, 121 within the field of view of the camera 202, thereby determining the alignment of laser channels 124, 125. In examples where the alignment of laser channels 124, 125 needs to be determined at multiple layers, the reference illumination determination module 346 can generate reference illuminations at each layer of part 122, where the alignment of laser channels 124, 125 needs to be determined. In the second operating mode, after determining the reference illumination positions for lasers 120, 121, the reference illumination determination module 346 can add the reference illumination positions to the build file and enable the network interface hardware 320 to transmit the modified build file with the reference illumination positions to the DMLM machine 100, thereby enabling the DMLM machine to perform reference illumination on lasers 120, 121. Therefore, after the DMLM machine 100 performs reference illumination on the lasers 120 and 121, the alignment device 300 can analyze the reference illumination to determine whether the laser channels 124 and 125 are correctly aligned, as disclosed herein.

[0039] In some examples, in the second operating mode, the reference illumination determination module 346 can determine the reference illumination position located on the part 122 being constructed. However, the reference illumination is typically small enough not to damage the structure of part 122. In some examples, the reference illumination may be located on a portion of the construction plane that does not include part 122. For example, Figure 4 A layer of part 122 is shown, having reference illumination positions 400, 402, 404, and 406 located on the build plane excluding the part itself. Therefore, reference illumination can be performed at positions 400, 402, 404, and 406 without affecting part 122. In other examples, reference illumination can be performed on lower layers of part 122. When building parts using DMLM, the first few layers of the build are typically discarded. Therefore, reference illumination can be performed on the layers of part 122 that are to be discarded without affecting the structure of part 122. For example, Figure 5 An example layer of part 122 to be discarded is shown. Figure 5 In the example, reference illumination can be performed at locations 500, 502, 504, 506, 508, 510, 512, 514, 516, 518, 520, 522, 524, 526, 528, 530, 532, 534, 536, 538, 540, 542, 544, 546, and 548 on the build plane without affecting part 122, because this layer will be discarded from the final build of part 122.

[0040] In some examples, lasers 120 and 121 may be out of sync with each other in either the first or second operating mode. That is, lasers 120 and 121 may each construct a corresponding portion of part 122 at a timing independent of the timing of the other laser. This may not cause any problems during the normal construction of part 122, as the two portions of the part can be constructed independently and then stitched together. However, if reference illuminations from the two lasers 120 and 121 do not occur simultaneously, this lack of time synchronization can make it difficult to determine the alignment of laser channels 124 and 125. Therefore, in some examples, the reference illumination determination module 346 may determine multiple reference illuminations for one or both of lasers 120 and 121. Camera 202 can then capture multiple images of each reference illumination and these images can be stacked together to determine the alignment of laser channels 124 and 125, as disclosed herein.

[0041] In one example, multiple reference illuminations may include parallel lines used for hashing or rasterization. For example, Figure 6 A stacked image 600 is shown, including a first parallel line and a second parallel line. The first parallel line includes multiple laser irradiations 602 from laser 120, and the second parallel line includes multiple laser irradiations 604 from laser 120. A laser irradiation 606 from laser 121 can then be a midpoint between the parallel lines of laser irradiations 602 and 604. If laser channels 124, 125 are correctly aligned, laser irradiation 606 will be positioned at the midpoint between laser irradiations 602 and 604 in the stacked image 500. However, if laser channels 124, 125 are misaligned, laser irradiation 606 may deviate from the midpoint between laser irradiations 602 and 604. Figure 6 In the example, laser illumination 606 is located 188.477 pixels from laser illumination 602 but 105.712 pixels from laser illumination 604, which corresponds to a misalignment of 278.4 micrometers.

[0042] Return to reference Figure 3 The image data receiving module 348 can receive data from... Figure 2 The system 200 captures image data from camera 202 and / or photodiode 204. The image data received by image data receiving module 348 may include images of laser illumination from lasers 120 and 121. Specifically, the image data sequence received by image data receiving module 348 may display a reference illumination from lasers 120 and 121, and the stacked images may be generated by, for example... Figure 6The image sequence of the stacked images 600 is used to generate the image. After the image data receiving module 348 receives the image data of the reference illumination, the alignment determination module 350 can analyze one or more of the received images to determine the alignment of the laser channels 124, 125, as disclosed below.

[0043] Still referencing Figure 3 The alignment determination module 350 can analyze one or more images of reference illumination received by the image data receiving module 348 to determine the alignment of laser channels 124, 125, as disclosed herein. Specifically, the alignment determination module 350 can compare the relative position between the reference illuminations performed by laser channels 124, 125 with the expected relative position of the reference illuminations determined by the reference illumination determination module 346. That is, the alignment determination module 350 can first determine the relative position between the reference illuminations performed by laser channels 124 and 125. Then, the alignment determination module 350 can determine the expected relative position between the reference illuminations based on the output of the reference illumination determination module 346. Then, the alignment determination module 350 can compare the actual relative position with the expected relative position.

[0044] In one example, the alignment determination module 350 can compare one or more distances between reference illuminations performed by laser channels 124, 125 with a desired distance between the reference illuminations, for example in... Figure 6 In the example, for instance, the alignment determination module 350 can compare the actual distance between laser illumination 602 and laser illumination 606 with the expected distance between them. If the expected distance between the reference illuminations performed by the two lasers 120, 121 differs from the actual distance between the laser illuminations, the alignment determination module 350 can determine that the laser channels 124, 125 are not correctly aligned.

[0045] In one example, the alignment determination module 350 can analyze the received image to determine the pixel-level distance between two reference illuminations made by laser 120. This pixel-level distance between the two reference illuminations can be compared to a known nominal distance between the two reference illuminations (e.g., based on build data of part 122) to determine the pixel ratio per micrometer (or some other unit distance) of the received image. The alignment determination module 350 can further analyze the received image to determine the pixel difference between the expected and actual positions of the reference illumination made by laser 121 relative to the reference illumination made by laser 120. The alignment determination module 350 can then use the pixel ratio per micrometer determined for the received image to determine the relative error value of the alignment between laser channels 124, 125.

[0046] In some examples, the alignment determination module 350 can determine the alignment between laser channels 124, 125 for a single layer of the construction of part 122 at one or more locations on the construction plane. In other examples, the alignment determination module 350 can determine the alignment between laser channels 124, 125 for multiple layers of the construction of part 122 at one or more locations on the construction plane. In some examples, the alignment determination module 350 can determine whether the alignment of laser channels 124, 125 has changed across multiple layers of the construction of part 122.

[0047] Still referencing Figure 3 The alignment correction module 352 can take certain actions in response to misalignment of laser channels 124, 125 identified by the alignment determination module 350. In some examples, the alignment correction module 352 can output a warning to the operator of system 200 indicating misalignment of laser channels 124, 125. The warning may include the amount of relative error in alignment between laser channels 124, 125 determined by the alignment determination module 350. In other examples, the alignment correction module 352 may take certain remedial measures to correct the misalignment of laser channels 124, 125, as described below.

[0048] In some examples, the alignment correction module 352 can perform software corrections to realign laser channels 124, 125. For instance, the alignment correction module 352 can, based on the misalignment determined by the alignment determination module 350, cause the DMLM machine 100 to modify the future laser illumination position of one of the lasers 120 or 121. This allows the DMLM machine 100 to adjust the future laser illumination to compensate for the misalignment between laser channels 124, 125.

[0049] In some examples, the alignment correction module 352 can adjust the build plate 114 up or down by a certain amount based on the relative misalignment of the laser channels 124, 125 determined by the alignment determination module 350. This can move the lasers 120, 121 away from each other to compensate for the misalignment of the laser channels 124, 125.

[0050] In some examples, the alignment correction module 352 can take remedial action whenever the alignment determination module 350 determines that the amount of misalignment between laser channels 124, 125 exceeds a predetermined threshold. In other examples, the alignment correction module 352 can take remedial action to correct the misalignment between laser channels 124, 125 only when the alignment correction module 352 detects misalignment on multiple layers. This prevents unnecessary corrections due to measurement or other errors that could lead to inaccurate misalignment determinations in a single layer of part 122.

[0051] Now for reference Figure 7The operation is shown Figure 2 and Figure 3 A flowchart of an example method for alignment device 300 is provided. In step 700, build data receiving module 344 receives a build file containing build data associated with part 122. The build data may indicate laser irradiation performed by lasers 120 and 121 of DMLM machine 100.

[0052] In step 702, the reference illumination determination module 346 determines the reference illumination for lasers 120 and 121 based on the build data received by the build data receiving module 344. In a first operating mode, the reference illumination determination module 346 can select laser illumination that is part of the build data as the reference illumination. In a second operating mode, the reference illumination determination module 346 can modify the build file to add additional reference illumination by lasers 120 and 121. The reference illumination determination module 346 can then transmit the modified build file back to the DMLM machine 100.

[0053] In step 704, the image data receiving module 348 receives image data of the part 122 during its construction. The image data can be captured by the camera 202. The image data may include images of light reflected and / or scattered from the construction plane of the part 122 under the beam from the laser 121, such that the field of view of the image includes the laser illumination from the laser 121. Therefore, the image data of the part can indicate the positions of a first set of reference illuminations from the laser 120 and a second set of reference illuminations from the laser 121.

[0054] In step 706, the alignment determination module 350 determines the relative positions of the reference illuminations performed by lasers 120 and 121 based on the image received by the image data receiving module 348. In some examples, the alignment determination module 350 may determine the pixel distance between the reference illuminations and then determine the nominal distance between the reference illuminations based on that pixel distance.

[0055] In step 708, the alignment determination module 350 compares the determined relative positions of the reference illuminations performed by lasers 120 and 121 with the expected relative positions of the reference illuminations performed by lasers 120 and 121. In step 710, the alignment determination module 350 determines whether laser channels 124 and 125 are correctly aligned relative to each other based on the comparison between the relative positions of the reference illuminations and the expected positions of the reference illuminations. If the alignment determination module 350 determines that laser channels 124 and 125 are correctly aligned (yes in step 710), control proceeds to step 714. If the alignment determination module 350 determines that laser channels 124 and 125 are not correctly aligned (no in step 710), control proceeds to step 712.

[0056] In step 712, the alignment correction module 352 takes remedial action. In some examples, the alignment correction module 352 issues a warning to notify the operator of the DMLM machine 100 that laser channels 124, 125 are misaligned. In other examples, the alignment correction module 352 may take remedial action to correct the misalignment of laser channels 124, 125, as described above. Control then proceeds to step 714.

[0057] In step 714, the alignment device 300 determines whether to receive the image of the additional layer. If the image of the additional layer is to be received (yes in step 714), control returns to step 704, and the image data receiving module 348 receives the image data of the next layer for checking the alignment of laser channels 124, 125. Alternatively, if no additional image data is to be received from the additional layer (no in step 714), then... Figure 7 The method ends here.

[0058] It should now be understood that the apparatus, systems, and methods described herein provide on-site alignment for DMLM additive manufacturing using multiple lasers. In the embodiments disclosed herein, build data associated with a part to be built via additive manufacturing can be received by an alignment device, and the alignment device can determine a reference illumination based on the build data. In a first operating mode, the reference illumination can be laser illumination caused by a laser of the DMLM machine as part of the build data. In a second operating mode, the build file can be modified to include new laser illumination used as the reference illumination.

[0059] During part construction, a camera with a field of view consistent with one of the lasers can capture images of laser illumination on the construction plane by more than one laser channel, and these images can be transmitted to an alignment device. The alignment device can determine the positions of reference illuminations based on these images and compare these positions with the expected positions of the reference illuminations. Based on this comparison, the alignment device can determine whether the laser channels are correctly aligned relative to each other. If the laser channels are not correctly aligned, remedial measures can be taken to notify the operator and / or correct the alignment.

[0060] In examples where more than two laser channels are used to construct part 122, the above techniques can still be used to determine the alignment of the laser channels. In these examples, camera 202 can capture images showing the laser illumination from each laser channel, as long as the laser illumination is entirely within the field of view of camera 202. In some examples, other cameras can capture images showing the laser illumination from one or more of the multiple laser channels, which can be used to determine the alignment of the laser channels.

[0061] Further aspects of this disclosure are provided by the subject matter of the following clauses.

[0062] An apparatus includes: one or more processors; one or more memory modules; and machine-readable instructions stored in the one or more memory modules, the machine-readable instructions, when executed by the one or more processors, causing the apparatus to: receive image data of one or more laser illuminations on a construction plane, the image data indicating positions of a first set of reference illuminations performed by a first laser on the construction plane and positions of a second set of reference illuminations performed by a second laser on the construction plane; determine, from the received image data, the relative positions of the first set of reference illuminations and the second set of reference illuminations relative to each other; compare the determined relative positions of the first set of reference illuminations and the second set of reference illuminations relative to each other with expected relative positions of the first set of reference illuminations and the second set of reference illuminations relative to each other; and, based on the comparison, determine whether the first laser and the second laser are misaligned relative to each other.

[0063] According to any of the preceding clauses of the device, the image data includes a plurality of images, the plurality of images including a first set of reference illuminations and a second set of reference illuminations performed at a plurality of time steps.

[0064] According to any of the preceding clauses of the device, wherein the first set of reference illuminations comprises two parallel lines, and the second set of reference illuminations comprises one or more reference illuminations between the two parallel lines.

[0065] According to any of the preceding clauses, the instructions further cause the device to: receive a build file associated with the part, the build file indicating a first plurality of laser irradiations to be performed by the first laser and a second plurality of laser irradiations to be performed by the second laser; and, based on the build file, determine a first set of reference irradiations from the first plurality of laser irradiations and determine a second set of reference irradiations from the second plurality of laser irradiations.

[0066] According to any of the preceding clauses, the device further enables the device to determine reference irradiation at multiple layers of the part.

[0067] According to any of the preceding clauses, the first set of reference illuminations and the second set of reference illuminations are within the field of view of the camera, the camera having a line of sight along the propagation direction of the first laser or the second laser.

[0068] According to any of the preceding clauses, the camera has a line of sight along the propagation direction of the first laser or the second laser.

[0069] According to any of the preceding clauses, the instructions further cause the device to: determine laser irradiation not included in the build file as the first set of reference irradiation and the second set of reference irradiation; and modify the build file to include the first set of reference irradiation and the second set of reference irradiation.

[0070] According to any of the preceding clauses, the instructions further enable the device to determine the positions of the first set of reference irradiations and the second set of reference irradiations on the layers of the build file that will not be included in the final version of the part.

[0071] According to any of the preceding clauses of the device, wherein the instructions further cause the device to determine the positions of the first set of reference irradiations and the second set of reference irradiations at locations outside the part.

[0072] According to any of the preceding clauses, the instruction further causes the device to output a warning when it determines that the first laser and the second laser are misaligned relative to each other.

[0073] According to any of the preceding clauses, the instructions further cause the device to take remedial measures to correct the alignment of the first laser or the second laser when it is determined that the first laser and the second laser are misaligned.

[0074] According to any of the preceding clauses, the instructions further cause the device to receive second image data of the build plane as a part is being built on the build plane, the second image data being captured at a second position on the build plane, the second position being different from the position where the image data was captured, the second image data indicating the positions of a third set of reference irradiations performed by the first laser on the build plane and the positions of a fourth set of reference irradiations performed by the second laser on the build plane; determine the relative positions of the third set of reference irradiations and the fourth set of reference irradiations from the received second image data; compare the determined relative positions of the third set of reference irradiations and the fourth set of reference irradiations with expected relative positions; and based on the comparison, determine whether the first laser and the second laser are misaligned relative to each other at the second position.

[0075] A method includes: receiving image data of one or more laser illuminations on a construction plane, the image data indicating positions of a first set of reference illuminations performed by a first laser on the construction plane and positions of a second set of reference illuminations performed by a second laser on the construction plane; determining relative positions of the first set of reference illuminations and the second set of reference illuminations relative to each other from the received image data; comparing the determined relative positions of the first set of reference illuminations and the second set of reference illuminations relative to each other with expected relative positions of the first set of reference illuminations and the second set of reference illuminations relative to each other; and determining, based on the comparison, whether the first laser and the second laser are misaligned relative to each other.

[0076] According to the method of any of the preceding clauses, the image data includes a plurality of images, the plurality of images including a first set of reference illuminations and a second set of reference illuminations performed at a plurality of time steps.

[0077] According to the method described in any of the preceding clauses, the first set of reference irradiations comprises two parallel lines, and the second set of reference irradiations comprises one or more reference irradiations between the two parallel lines.

[0078] The method according to any of the preceding clauses further includes: receiving a build file associated with the part, the build file indicating a first plurality of laser irradiations to be performed by the first laser and a second plurality of laser irradiations to be performed by the second laser; and, based on the build file, determining a first set of reference irradiations from the first plurality of laser irradiations and determining a second set of reference irradiations from the second plurality of laser irradiations.

[0079] The method according to any of the foregoing clauses further includes determining reference irradiation at multiple layers of the part.

[0080] According to the method described in any of the preceding clauses, the first set of reference illuminations and the second set of reference illuminations are within the field of view of a camera associated with the additive manufacturing equipment.

[0081] According to any of the preceding clauses of the method, the camera has a line of sight along the propagation direction of the first laser or the second laser.

[0082] The method according to any of the preceding clauses further includes: identifying laser irradiation not included in the build file as the first set of reference irradiation and the second set of reference irradiation; and modifying the build file to include the first set of reference irradiation and the second set of reference irradiation.

[0083] The method according to any of the foregoing clauses further includes determining the positions of the first set of reference irradiations and the second set of reference irradiations on layers of the build file that will not be included in the final version of the part.

[0084] The method according to any of the foregoing clauses further includes determining the positions of the first set of reference irradiations and the second set of reference irradiations at locations outside the part.

[0085] The method according to any of the foregoing clauses further includes outputting a warning when it is determined that the first laser and the second laser are misaligned relative to each other.

[0086] The method according to any of the foregoing clauses further includes taking remedial measures to correct the alignment of the first laser or the second laser when it is determined that the first laser and the second laser are misaligned relative to each other.

[0087] The method according to any of the preceding clauses further includes: receiving second image data of the build plane while a part is being built on the build plane, the second image data being captured at a second position on the build plane, the second position being different from the position where the image data was captured, the second image data indicating the positions of a third set of reference irradiations performed by the first laser on the build plane and the positions of a fourth set of reference irradiations performed by the second laser on the build plane; determining the relative positions of the third set of reference irradiations and the fourth set of reference irradiations from the received second image data; comparing the determined relative positions of the third set of reference irradiations and the fourth set of reference irradiations with expected relative positions; and based on the comparison, determining whether the first laser and the second laser are misaligned relative to each other at the second position.

[0088] A system includes: an apparatus for additive manufacturing of a part using at least a first laser and a second laser, the apparatus including a build plane on which the part is built; a camera having a line of sight along the propagation direction of the first laser or the second laser; and an alignment device configured to: receive image data of one or more laser irradiations on the build plane, the image data being captured by the camera, indicating positions of a first set of reference irradiations performed by the first laser on the build plane and positions of a second set of reference irradiations performed by the second laser on the build plane; determine, based on the received image data, the relative positions of the first set of reference irradiations and the second set of reference irradiations relative to each other; compare the determined relative positions of the first set of reference irradiations and the second set of reference irradiations relative to each other with expected relative positions of the first set of reference irradiations and the second set of reference irradiations relative to each other; and, based on the comparison, determine whether the first laser and the second laser are misaligned relative to each other.

[0089] According to any of the preceding clauses of the system, the image data includes a plurality of images, the plurality of images including a first set of reference illuminations and a second set of reference illuminations performed at a plurality of time steps.

[0090] According to any of the preceding clauses of the system, wherein the first set of reference illuminations comprises two parallel lines, and the second set of reference illuminations comprises one or more reference illuminations between the two parallel lines.

[0091] According to any of the preceding clauses of the system, wherein the alignment device is further configured to receive a build file associated with the part, the build file indicating a first plurality of laser irradiations to be performed by the first laser and a second plurality of laser irradiations to be performed by the second laser; and based on the build file, to determine a first set of reference irradiations from the first plurality of laser irradiations and to determine a second set of reference irradiations from the second plurality of laser irradiations.

[0092] According to any of the preceding clauses, the alignment device is further configured to determine reference irradiation at multiple layers of the part.

[0093] According to any of the preceding clauses of the system, wherein the first set of reference illumination and the second set of reference illumination are within the field of view of the camera.

[0094] According to any of the preceding clauses of the system, the alignment device is further configured to determine laser irradiation not included in the build file as the first set of reference irradiation and the second set of reference irradiation; and to modify the build file to include the first set of reference irradiation and the second set of reference irradiation.

[0095] According to any of the preceding clauses of the system, the alignment device is further configured to determine the positions of the first set of reference irradiations and the second set of reference irradiations on the layers of the build file that will not be included in the final version of the part.

[0096] According to any of the preceding clauses of the system, the alignment device is further configured to determine the positions of the first set of reference irradiations and the second set of reference irradiations at locations outside the part.

[0097] According to any of the preceding clauses of the system, the alignment device is further configured to output a warning when it is determined that the first laser and the second laser are misaligned relative to each other.

[0098] According to any of the preceding clauses of the system, the alignment device is further configured to take remedial measures to correct the alignment of the first laser or the second laser when it is determined that the first laser and the second laser are misaligned relative to each other.

[0099] According to any of the preceding clauses of the system, wherein the alignment device is further configured to receive second image data of the build plane as a part is being built on the build plane, the second image data being captured at a second position on the build plane, the second position being different from the position where the image data was captured, the second image data indicating the position of a third set of reference irradiations performed by the first laser on the build plane and the position of a fourth set of reference irradiations performed by the second laser on the build plane; determine the relative positions of the third set of reference irradiations and the fourth set of reference irradiations from the received second image data; compare the determined relative positions of the third set of reference irradiations and the fourth set of reference irradiations with expected relative positions; and based on the comparison, determine whether the first laser and the second laser are misaligned relative to each other at the second position.

Claims

1. A device for on-site alignment inspection in additive manufacturing, characterized in that, include: One or more processors; One or more memory modules; and Machine-readable instructions stored in the one or more memory modules, which, when executed by the one or more processors, cause the device to: During the process of constructing a part on a construction plane using a first laser and a second laser, image data of one or more laser irradiations on the construction plane are received, the image data indicating the positions of a first set of reference irradiations performed by the first laser on the construction plane and the positions of a second set of reference irradiations performed by the second laser on the construction plane; The relative positions of the first set of reference illuminations and the second set of reference illuminations with respect to each other are determined from the received image data; The determined relative positions of the first set of reference irradiations and the second set of reference irradiations relative to each other are compared with the expected relative positions of the first set of reference irradiations and the second set of reference irradiations relative to each other. and Based on the comparison, it is determined whether the first laser and the second laser are misaligned relative to each other.

2. The device according to claim 1, characterized in that, The image data includes multiple images, which include a first set of reference illuminations and a second set of reference illuminations performed at multiple time steps.

3. The device according to claim 1, characterized in that, The instructions further enable the device to: Receive a build file associated with the part, the build file indicating a first plurality of laser irradiations to be performed by the first laser and a second plurality of laser irradiations to be performed by the second laser; and Based on the constructed file, the first set of reference irradiations is determined from the first plurality of laser irradiations and the second set of reference irradiations is determined from the second plurality of laser irradiations.

4. The device according to claim 3, characterized in that, The first set of reference illuminations and the second set of reference illuminations are within the field of view of the camera, and the camera has a line of sight along the propagation direction of the first laser or the second laser.

5. The device according to claim 3, characterized in that, The instructions further enable the device to: Laser irradiation not included in the build file is identified as the first set of reference irradiations and the second set of reference irradiations; and Modify the build file to include the first set of reference illuminations and the second set of reference illuminations.

6. A method for on-site alignment inspection in additive manufacturing, characterized in that, include: During the process of constructing a part on a construction plane using a first laser and a second laser, image data of one or more laser irradiations on the construction plane are received, the image data indicating the positions of a first set of reference irradiations performed by the first laser on the construction plane and the positions of a second set of reference irradiations performed by the second laser on the construction plane; The relative positions of the first set of reference illuminations and the second set of reference illuminations with respect to each other are determined from the received image data; The determined relative positions of the first set of reference irradiations and the second set of reference irradiations relative to each other are compared with the expected relative positions of the first set of reference irradiations and the second set of reference irradiations relative to each other. and Based on the comparison, it is determined whether the first laser and the second laser are misaligned relative to each other.

7. The method according to claim 6, characterized in that, The image data includes multiple images, which include a first set of reference illuminations and a second set of reference illuminations performed at multiple time steps.

8. The method according to claim 6, characterized in that, The first set of reference illuminations includes two parallel lines, and the second set of reference illuminations includes one or more reference illuminations between the two parallel lines.

9. The method according to claim 6, characterized in that, Further includes: Receive a build file associated with the part, the build file indicating a first plurality of laser irradiations to be performed by the first laser and a second plurality of laser irradiations to be performed by the second laser; and Based on the constructed file, the first set of reference irradiations is determined from the first plurality of laser irradiations and the second set of reference irradiations is determined from the second plurality of laser irradiations.

10. The method according to claim 9, characterized in that, This further includes determining reference irradiation at multiple layers of the part.

11. The method according to claim 9, characterized in that, The first set of reference illuminations and the second set of reference illuminations are within the field of view of a camera associated with the additive manufacturing equipment.

12. The method according to claim 11, characterized in that, The camera has a line of sight along the propagation direction of the first laser or the second laser.

13. The method according to claim 9, characterized in that, Further includes: Laser irradiation not included in the build file is identified as the first set of reference irradiation and the second set of reference irradiation. and Modify the build file to include the first set of reference illuminations and the second set of reference illuminations.

14. The method according to claim 13, characterized in that, Further, it includes determining the positions of the first set of reference illuminations and the second set of reference illuminations on layers in the build file that will not be included in the final version of the part.

15. The method according to claim 13, characterized in that, Further, it includes determining the positions of the first set of reference irradiations and the second set of reference irradiations at locations outside the part.

16. The method according to claim 6, characterized in that, It further includes issuing a warning when it is determined that the first laser and the second laser are misaligned relative to each other.

17. The method according to claim 6, characterized in that, Further, it includes taking remedial measures to correct the alignment of the first laser or the second laser when it is determined that the first laser and the second laser are misaligned relative to each other.

18. The method according to claim 6, characterized in that, Further includes: Receive second image data of the construction plane as the part is being constructed on the construction plane, the second image data being captured at a second position on the construction plane, the second position being different from the position where the image data was captured, the second image data indicating the position of a third set of reference illuminations performed by the first laser on the construction plane and the position of a fourth set of reference illuminations performed by the second laser on the construction plane; The relative positions of the third set of reference illuminations and the fourth set of reference illuminations are determined from the received second image data; The determined relative positions of the third set of reference irradiations and the fourth set of reference irradiations are compared with the expected relative positions; and Based on the comparison, it is determined whether the first laser and the second laser are misaligned relative to each other at the second position.

19. A system for on-site alignment inspection in additive manufacturing, characterized in that, include: An apparatus for constructing parts using additive manufacturing with at least a first laser and a second laser, the apparatus comprising a construction plane on which the parts are constructed; A camera having a line of sight along the propagation direction of the first laser or the second laser; and Alignment device, the alignment device being configured to: During the construction of the part on the construction plane using the first laser and the second laser, image data of one or more laser irradiations on the construction plane are received, the image data being captured by the camera, indicating the positions of a first set of reference irradiations performed by the first laser on the construction plane and the positions of a second set of reference irradiations performed by the second laser on the construction plane; Based on the received image data, determine the relative positions of the first set of reference illuminations and the second set of reference illuminations with respect to each other; The determined relative positions of the first set of reference irradiations and the second set of reference irradiations relative to each other are compared with the expected relative positions of the first set of reference irradiations and the second set of reference irradiations relative to each other. and Based on the comparison, it is determined whether the first laser and the second laser are misaligned relative to each other.

20. The system according to claim 19, characterized in that, The alignment device is further configured to: Receive a build file associated with the part, the build file indicating a first plurality of laser irradiations to be performed by the first laser and a second plurality of laser irradiations to be performed by the second laser; and Based on the constructed file, the first set of reference irradiations is determined from the first plurality of laser irradiations and the second set of reference irradiations is determined from the second plurality of laser irradiations.

Images