Additive manufacturing process monitoring

Abstract

The invention relates to an add-on kit for an additive manufacturing machine, the add-on kit being configured to scan a build beam over a region of interest and thereby add material to a workpiece at a moving build point located in the region of interest, the add-on kit comprising: a base plate configured for mounting to the additive manufacturing machine; an optical assembly mounted to the base plate, the optical assembly comprising a housing and a beam splitter located within the housing, wherein the housing comprises a plurality of exit apertures, the beam splitter being configured to split electromagnetic radiation entering the optical assembly into a plurality of beams, the optical assembly being configured to direct each of the plurality of beams to a respective one of the plurality of exit apertures; a moveable reflector configured to reflect electromagnetic radiation from a field of view to the optical assembly such that each beam comprises electromagnetic radiation from the field of view; and a controller configured to move the moveable reflector to maintain a predetermined relationship between the moving build point and the field of view. The invention also relates to a system and method for monitoring an additive manufacturing process.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to additive manufacturing, and more particularly but not exclusively to systems and methods for monitoring additive manufacturing processes. BACKGROUND

[0002] Metal additive manufacturing (AM) now constitutes a multi-billion dollar market size. Notably, AM has been used to produce high-value aerospace, defense, and medical components. However, there remains an issue with the reproducible production of high-quality, defect-free components. To this end, in-situ sensing has been proposed as a means to measure process physics and related build quality.

[0003] Unfortunately, there remain significant obstacles in the development of in-situ process monitoring and metrics for characterizing AM component quality. Monitoring process physics can require in-situ sensing at inter-layer, intra-layer, and melt pool scale / level / height throughout the build process. Achieving fidelity at these three scales requires high resolution, large field of view (FOV), and high data rates. These specifications are largely unattainable by off-the-shelf in-situ sensors. Single-point detectors such as photodiodes or pyrometers can record high-resolution data quickly, but their FOV is limited. Large FOVs can be achieved by visible or infrared camera systems, however, the sheer amount of data limits the speed at which data can be recorded. Therefore, a solution to monitor the entire build process is either to use multiple sensors working at different resolutions and frame rates or to use a high-fidelity, high-speed sensor.

[0004] While high-fidelity, laboratory-scale sensors such as high-speed visible (VIS), infrared (IR), or X-ray imaging have recently been adapted to elucidate AM process physics, their high cost, limited field of view, and extremely high data rates inhibit their use with commercially available hardware and software systems and limit their use in simplified experiments in a laboratory setting. For example, while synchrotron X-ray imaging has been widely used to capture process dynamics of AM processes, experiments are limited to idealized environments (e.g., measuring a single powder layer between two glass carbon windows). High-speed VIS and IR imaging, which can be used to assess melt pool surface geometry and map complex process interactions, are also limited to small fields of view of the melt pool due to limitations associated with commercially available resolution, capture rates, and data transfer requirements. In short, these methods are difficult to apply to the simplest experiments (e.g., single-tracks) and are neither scalable nor suitable for validating the quality of AM components.

[0005] However, monitoring the AM process with multiple sensors brings its own set of complexities. That is, the introduction of multiple sensors implies variations in the inter-sensor perspective and FOV. These variations often require careful calibration of each sensor and add complexity to cross-register, correlate, and validate the data collected by simultaneous in-situ sensing as the signals being measured are often joint functions of the sensing location on the build plane and its perspective.

[0006] Similar limitations apply to characterizing the AM process physics. Even with the algorithms and boundary conditions, the physical modeling of inter-layer, intra-layer, and melt pool behavior are fundamentally different from each other. Furthermore, powder re-coating is a statistical process, the physics of laser-material interaction is complex, and high temperature thermophysical data can lack fidelity. As a result, many methods that simulate the AM process physics use multi-scale, multi-physics approaches that include a series of solutions at each time step.

[0007] Finally, calibrating sensor data with process physics to characterize AM part quality can require multi-scale approaches. Thus, a fundamental problem is the mismatch in spatial resolution, temporal resolution, and fidelity. As a result, there is a need for integration and application of methods to facilitate repeatable calibration between multi-scale in-situ process monitoring sensors and AM part quality. For these reasons, among others, there remains a need for further improvement in this field of technology. SUMMARY

[0008] An exemplary method generally includes reflecting electromagnetic radiation from a field of view in a region of interest in an additive manufacturing machine to an optical assembly by a movable reflector; splitting the electromagnetic radiation into a plurality of beams by a beam splitter of the optical assembly; directing the plurality of beams to a plurality of optical sensors such that each of the plurality of optical sensors receives a respective corresponding beam of the plurality of beams; generating a plurality of outputs by the plurality of optical sensors, each output including information related to the respective corresponding beam; and controlling the movable reflector by a controller to move the field of view to maintain a predetermined relationship between the field of view and a moving build point within the region of interest. Further embodiments, forms, features, and aspects of the application will become apparent from the description and drawings provided herein. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a schematic diagram of an additive manufacturing system including a monitoring assembly in accordance with certain embodiments.

[0010] Figure 2 is a perspective view of the monitoring assembly.

[0011] Figure 3 is a schematic diagram of the monitoring assembly.

[0012] Figure 4 is a schematic block diagram of the monitoring assembly.

[0013] Figure 5 To construct a simplified map of a path, a build bundle can travel along the path during a workpiece manufacturing process.

[0014] Figures 6-9 A schematic flow diagram of a method / process in accordance with certain embodiments.

[0015] Figure 10 A schematic block diagram of a computing device that can be used in connection with certain embodiments. DETAILED DESCRIPTION

[0016] While the concepts of the present disclosure can be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the intention is not to limit the concepts of the present disclosure to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure and the appended claims.

[0017] Reference is made in the description to "one embodiment", "an embodiment", "an illustrative embodiment", etc. As such terminology is used herein to describe a particular feature, structure, or characteristic, it is within the knowledge of those skilled in the art to appreciate that each

[0018] Furthermore, it should be understood that items included in a list in the form of "at least one of A, B, and C" can refer to (A); (B); (C); (A and B); (B and C); (A and C); or (A, B, and C). Similarly, items listed in the form of "at least one of A, B, or C" can refer to (A); (B); (C); (A and B); (B and C); (A and C); or (A, B, and C). Items listed in the form of "A, B, and / or C" can also refer to (A); (B); (C); (A and B); (B and C); (A and C); or (A, B, and C). Furthermore, unless specifically stated to the contrary, the use of words and phrases such as “a,” “one,” “at least one,” and / or “at least a portion” with respect to the claims should not be construed as limiting to only one such element, and the use of phrases such as “at least a portion” and / or “a portion” should be construed as covering embodiments that include only a portion of such an element and embodiments that include the entirety of such an element, unless specifically stated to the contrary.

[0019] In the accompanying drawings, certain structural or methodological features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. Rather, in some embodiments, these features may be arranged in a different manner and / or order than shown in the illustrative drawings, unless otherwise indicated. Furthermore, the inclusion of structural or methodological features in a particular drawing does not imply that such features are necessary in all embodiments, and in some embodiments, these structural or methodological features may be omitted or may be combined with other features.

[0020] In some cases, the disclosed embodiments may be implemented by hardware, firmware, software, or a combination thereof. The disclosed embodiments may also be implemented as instructions carried or stored thereon on one or more temporary or non-temporary machine-readable (e.g., computer-readable) storage media, which may be read and executed by one or more processors. Machine-readable storage media may be implemented as any storage device, mechanism, or other physical structure (e.g., volatile or non-volatile memory, media disk, or other media device) for storing or transmitting information in a machine-readable form.

[0021] refer to Figure 1 The diagram illustrates an additive manufacturing system 90 according to certain embodiments. According to some embodiments, system 90 generally includes a conventional additive manufacturing (AM) machine 100 and a modular additional monitoring assembly 200. As described herein, AM machine 100 is configured to manufacture workpiece 80 in a layer-by-layer manner by scanning an energy beam 151 over a build plane 104 comprising one or more layers of powder material 102, and monitoring assembly 200 is configured to monitor the scan via two or more optical sensors 260.

[0022] Generally, the AM machine 100 includes a housing 110, a build table 120 located in the housing 110, a powder distributor 130 operable to distribute powder 102 over the build table 120 to define a build plane 104, a reservoir 140 to provide powder 102 to the powder distributor 130, an energy beam generator 150 operable to generate an energy beam 151, a mirror galvanometer 160 operable to redirect the energy beam 151 onto the build plane 104 to create an irradiation spot, and a control system 170 to control operation of the AM machine 100.

[0023] The housing 110 defines a chamber 111 in which the build table 120 is located, and which includes a first window 112 and a second window 115. The build plane 104 is visible via the first window 112, and as described herein, a portion of the monitoring assembly 200 is located proximate the first window 112 such that electromagnetic (EM) radiation (e.g., visible light, IR rays, ultraviolet light, and / or X-rays) can enter the monitoring assembly 200 via the first window 112. The build plane 104 is also visible through the second window 115, and the mirror galvanometer 160 directs the energy beam 151 onto the build plane 104 to create an irradiation spot 159.

[0024] The build table 120 supports the workpiece 80 and the surrounding powder 102, and is operably coupled with an actuator 122 operable to move the build table 120 vertically. The actuator 122 can move the build table 120 under control of the control system 170, and can for example include a motor or a hydraulic cylinder. As described herein, the build table 120 lowers the thickness of each layer of powder 102 after that particular layer of powder 102 has been scanned by the energy beam 151 to accommodate a subsequent layer to be distributed by the powder distributor 130.

[0025] The powder distributor 130 is configured to distribute the powder 102 to the top layer after the build table 120 has been lowered by an appropriate vertical displacement. The powder distributor 130 receives the powder 102 from the reservoir 140 and moves along the build plane 104 to distribute the powder 102, creating a new layer of powder. The powder distributor 130 can for example be under control of the control system 170. In certain embodiments, the powder distributor 130 can include one or more levelers 132, such as blades or rollers, which can help ensure that the powder 102 is evenly distributed over the build plane 104.

[0026] The reservoir 140 holds the powder 102 to be distributed by the powder distributor 130, and fills the powder distributor 130 as appropriate. In the illustrated embodiment, the powder 102 includes a metal powder. Additionally or alternatively, the powder 102 can include another form of powder, such as a ceramic powder.

[0027] The energy beam generator 150 is configured to generate the energy beam 151 with sufficient power to melt the powder 102 at the irradiation point 159 and its surroundings, thereby forming a melt pool 106 which subsequently hardens to form a portion of the workpiece 80. The irradiation point 159 can therefore alternatively be referred to as a build point 159. In the illustrated form, the energy beam generator 150 is provided in the form of a laser generator, and the energy beam 151 is provided in the form of a laser beam. It is also envisaged that the beam 151 can be provided as another form of energy beam (e.g. an electron beam), and the energy beam generator 150 can be configured to generate such other form of energy beam.

[0028] The galvanometer mirror 160 includes a mirror 162 and is configured to move the mirror 162 under the control of the control system 170 to direct the energy beam 151 onto the build plane 104. More particularly, the control system 170 controls the galvanometer mirror 160 to direct the energy beam 151 based on a model of the workpiece 80 to build the workpiece 80 in accordance with the model.

[0029] The control system 170 controls various aspects of the workpiece 80 build, such as the movement of the build table 120, the dispensing of the powder 102 by the powder dispenser 130, and the directing of the energy beam 151 by the galvanometer mirror 160. Reference is made below to Figure 10 Certain example features are provided which can be associated with the control system 170.

[0030] In the illustrated form, the AM machine 100 is provided in the form of a laser powder bed fusion additive manufacturing machine. However, it will be appreciated that the monitoring assembly 200 described herein can be used in conjunction with other forms of additive manufacturing machine, including but not limited to a stereolithography AM machine, a material jetting AM machine, a binder jetting AM machine, a directed energy deposition AM machine, and a wire-fed AM machine.

[0031] As one example, the AM machine 100 can be provided in the form of a stereolithography AM machine, in which layers of the workpiece 80 are repeatedly generated by scanning an energy beam (e.g. an ultraviolet beam) over a photo-curable resin. In this form, the beam 151 can be an ultraviolet beam, and the build point 159 can be a point at which the ultraviolet beam impinges on the photo-curable resin.

[0032] As another example, the AM machine 100 can alternatively be provided in the form of a material jetting AM machine, in which layers of the workpiece are repeatedly generated by jetting a beam or jet of build material at a region of interest for building the workpiece. In this form, the jet of build material can be considered to serve to provide the build beam 151, and the build point 159 can be the point at which the build beam 151 intersects the region of interest for building the workpiece 80. Similarly, the AM machine can be provided in the form of a binder jetting AM machine, in which layers of the workpiece are repeatedly generated by scanning a beam or jet of binder across the build plane to bind previously deposited material, thereby building the workpiece. In this form, the jet of binder can be considered to serve to provide the build beam 151, and the build point 159 can be the point at which the jet of binder strikes the deposited material to build the workpiece 80.

[0033] As will be apparent from the foregoing, the build beam 151 can be provided in a variety of different forms, including but not limited to the form of an energy beam (e.g., a laser beam, an electron beam, or an ultraviolet beam) or a jet of build material or binder. Accordingly, embodiments of the moving build point 159 are not limited to an irradiation point, but can also include a point at which build material or binder is deposited on the workpiece 80. Moreover, embodiments of the region of interest are not limited to the build plane 104, but can also encompass a three-dimensional region of interest (e.g., in embodiments in which the AM machine is provided in the form of a material deposition AM machine).

[0034] With additional reference to Figure 2 and Figure 3 , the monitoring assembly 200 is mounted to the housing 110 proximate the first window 112, and generally includes a backplane 210, a plurality of lens mounts 220 mounted to the backplane 210, an optical assembly 230 mounted to the backplane 210, a movable reflector 240 configured to reflect electromagnetic radiation within a field of view (FOV) 202 to the optical assembly 230, a controller 250 configured to move the movable reflector 240 to maintain a predetermined relationship between the irradiation point 159 and the FOV 202, and a plurality of optical sensors 260, each of which can be coupled to a corresponding one of the lens mounts 220. As described herein, the optical assembly 230 includes a beamsplitter 232 that splits electromagnetic (EM) radiation 204 received from the movable reflector 240 into a plurality of beams 206, each of which is directed along a corresponding one of the lens mounts 220 to a corresponding one of the optical sensors 260.

[0035] In certain forms, one or more components of the monitoring assembly 200 can be provided with the AM machine 100 at the time of sale of the AM machine 100. In such forms, the controller 250 can not necessarily be included, and its functionality can be performed by the control system 170. In certain embodiments, one or more components of the monitoring assembly 200 can be provided in an add-on kit 200' for an existing AM machine 100. Further details regarding each of these forms are provided herein.

[0036] The base plate 210 is configured to be mounted to the housing 110 of the AM machine 100 at a location proximate the first window 112, and can include features to facilitate such mounting. For example, the base plate 210 can include one or more apertures 211 that align with corresponding mounting features formed in the housing 110 to facilitate mounting of the base plate 210 to the housing 110, e.g., via one or more threaded fasteners. In certain embodiments, such as those in which the monitoring assembly 200 is provided on the AM machine 100 at the time of manufacture of the machine 100, the base plate 210 can constitute a portion of the housing 110. In the illustrated form, the base plate 210 is also configured to facilitate the removable mounting of one or more other components of the monitoring assembly 200 to the base plate 210. For example, the apertures 211 can provide mounting locations for the lens holder 220 and / or the sensor 260.

[0037] The plurality of lens holders 220 includes at least a first lens holder 220a and a second lens holder 220b. Each lens holder 220 is configured to direct a respective beam 206 from the optical assembly 230 to a respective optical sensor 260, and can also be configured to adjust the beam 206 in one or more ways. For example, one or more of the lens holders 220 can include one or more lenses 222 operable to focus the respective beam 206, and / or one or more filters 224 to remove or reduce electromagnetic radiation of one or more frequencies from the respective beam 206. In certain embodiments, one or more of the lens holders 220 can have an opaque layer that shields the interior of the lens holder 220 from external light.

[0038] Each lens seat 220 has a proximal end 228 adjacent the optical assembly 230 and an opposing distal end 229 adjacent a respective optical sensor 260. In the illustrated form, each proximal end 228 is detachably coupled with a housing 231 of the optical assembly 230, and each distal end 229 is detachably coupled with a housing 261 of the respective optical sensor 260. In certain embodiments, the proximal end 228 and / or the distal end 229 can include features that facilitate detachable coupling of the lens seat 220 with the respective component. In the illustrated form, the proximal end 228 and the optical assembly housing 231 cooperate to define a proximal mating structure 208, and the distal end 229 and the optical sensor housing 261 cooperate to define a distal mating structure 209. For example, each of the proximal end 228 and the distal end 229 can be threaded to facilitate threaded coupling with the housings 231, 261. It is also contemplated that one or both of the ends 228, 229 can not necessarily include coupling features, or can include another form of quick coupling features (e.g., a bayonet coupling feature, a press-fit coupling feature, or other coupling features).

[0039] The optical assembly 230 includes a beam splitter 232, and in the illustrated form, also includes a housing 231 and a pair of mirrors 234. The housing 231 is mounted on the substrate 210 and protects the internal components of the optical assembly 230 from external light. The housing 231 includes an entrance aperture 233 through which the electromagnetic radiation 204 enters the optical assembly 230, and the housing 231 also includes a plurality of exit apertures 237 through which the beams 206 exit the housing 231. In certain embodiments, the entrance aperture 233 and / or one or more of the exit apertures 237 can be provided with a lens. In the illustrated form, each exit aperture 237 is connected with a respective lens seat 220 by the quick connection mating structure 208 as described above.

[0040] The beam splitter 232 is configured to split the electromagnetic radiation 204 reflected by the movable reflector 240 such that the electromagnetic radiation 204 emitted from the FOV 202 is split into a plurality of beams 206, including at least a first beam 206a and a second beam 206b. The partial optical assembly 230 (e.g., the beam splitter 232) can be configured to collimate the electromagnetic radiation such that the plurality of beams 206 are collimated beams. In certain embodiments, the beam splitter 232 can be in the form of a double-prism beam splitter or a half-silvered mirror, for example. In certain embodiments, the beam splitter 232 can include a coating through which electromagnetic radiation is selectively reflected based on the wavelength of the electromagnetic radiation. For example, the beam splitter 232 can reflect radiation above a certain wavelength to form the first beam 206a, while allowing radiation below the certain wavelength to pass through the beam splitter 232 to form the second beam 206b.

[0041] In certain forms, the beam splitter 232 can be configured to split the electromagnetic radiation 204 into multiple beams 206 without regard to the frequency / wavelength of the split electromagnetic radiation 204, such that each beam 206 is substantially the same. However, in the illustrated form, the beam splitter 232 is configured to split the electromagnetic radiation 204 based on the frequency / wavelength of the electromagnetic radiation 204, such that the first beam 206a and the second beam 206b include different wavelengths / frequencies of electromagnetic radiation. More particularly, the illustrated beam splitter 232 is configured to split the electromagnetic radiation 204 into a first beam 206a that primarily includes electromagnetic radiation in the infrared spectrum (IR) having wavelengths in the range of 0.75 microns to 15 microns and a second beam 206b that primarily includes electromagnetic radiation in the visible spectrum (VIS) having wavelengths in the range of 380 nm to 750 nm.

[0042] In certain embodiments, the IR beam 206a can primarily include near infrared (NIR) having wavelengths in the range of 0.75 pm to 1.4 pm. In certain embodiments, the IR beam 206a can primarily include short wave infrared (SWIR) having wavelengths in the range of 1.4 pm to 3 pm. In certain embodiments, the IR beam 206a can primarily include mid wave infrared (MWIR) having wavelengths in the range of 3 pm to 8 pm. In certain embodiments, the IR beam 206a can primarily include long wave infrared (LWIR) having wavelengths in the range of 8 pm to 15 pm. In certain embodiments, the IR beam 206a can include a combination including one or more of NIR radiation, SWIR radiation, MWIR radiation, and / or LWIR radiation.

[0043] While the illustrated beam splitter 232 is configured to split the electromagnetic radiation 204 into an infrared beam 206a and a visible beam 206b, it should be appreciated that the beam splitter 232 can alternatively be configured to split the electromagnetic radiation 204 into a different beam combination. For example, the beam splitter 232 can be configured to split the electromagnetic radiation 204 into two or more beams, where one or more of the beams 206 primarily includes ultraviolet radiation, VIS radiation, NIR radiation, SWIR radiation, MWIR radiation, and / or LWIR radiation, and another one of these beams primarily includes electromagnetic radiation having a different frequency range than the first beam. Additionally or alternatively, the optical assembly 230 and / or one or more lens mounts can include optical devices (e.g., filters) that cause the one or more beams 206 to primarily include ultraviolet radiation, VIS radiation, NIR radiation, SWIR radiation, MWIR radiation, and / or LWIR radiation as the one or more beams enter the respective optical sensor 260.

[0044] As noted above, the illustrated optical assembly 230 includes a plurality of mirrors 234 that facilitate directing the beams 206 along the respective lens holders 220. While the illustrated optical assembly 230 includes two mirrors 234, it should be appreciated that the optical assembly 230 can include more or fewer mirrors 234. In certain embodiments, the optical assembly 230 is devoid of mirrors 234, and the beams 206 propagate directly from the beam splitter 232 to the respective lens holders 220. In certain embodiments, the optical assembly 230 can include additional or alternative devices, such as lenses and / or filters, that assist in conditioning the electromagnetic radiation passing therethrough. In certain embodiments, such as those in which one or more of the lens holders 220 include one or more lenses 222 and / or one or more filters 224, such lens holders 220 can be considered to include a portion of the optical assembly 230.

[0045] Generally, the movable reflector 240 includes a mirror 242 and an actuator 244, such as a scanning motor, configured to move the mirror 242 under the control of a controller 250. The mirror 242 reflects electromagnetic radiation 204 from the FOV 202 to the entrance of the optical assembly 230, where the electromagnetic radiation 204 is split into a plurality of beams 206. As noted above, each beam 206 propagates along a respective lens holder 220 to a respective optical detector 260. As a result, each optical detector 260 is provided with electromagnetic radiation from the same FOV 202. While other forms are contemplated, in the illustrated embodiment, the movable reflector 240 is provided in the form of a galvanometer mirror.

[0046] With additional reference to Figure 4 The controller 250 is in communication with the movable reflector 240 and the controller 250 is operable to control the movable reflector 240 so as to maintain the moving illumination spot 159 in a predetermined relationship with the FOV 202 with respect to the optical detectors 260. In certain embodiments, the controller 250 can also be in communication with one or more of the optical detectors 260, such that the controller 250 receives information generated by the optical detectors 260 in communication with the controller 250. Further details regarding the control of the controller 250 over the movable reflector 240 are provided below with reference to Figure 8 Further details regarding the control of the controller 250 over the movable reflector 240 are provided below with reference to

[0047] The optical sensors 260 are disposed at the distal end 229 of the lens seats 220 such that each optical sensor 260 is positioned to receive the beam 206 directed along the respective lens seat 220. In the form shown, the plurality of optical sensors 260 includes a first optical sensor 260a positioned at the distal end 229 of the first lens seat 220a and operable to receive the first beam 206a, and a second optical sensor 260b positioned at the distal end 229 of the second lens seat 220b and operable to receive the second beam 206b. In the form shown, each optical sensor 260 includes a housing 261 and a sensing region 262 mounted within the housing 261. Each housing 261 is configured for coupling with the respective lens seat 220, either directly or through one or more adapters. For example, the housing 261 of the first optical sensor 260a can include a threaded region through which the housing 261 can be threadably coupled with the distal end 229 of the first lens seat 220a. The housing 261 of the second optical sensor 260b likewise can include a threaded region through which the housing 261 can be threadably coupled with the distal end 229 of the second lens seat 220b.

[0048] The sensing region 262 is configured to receive the respective beam 206, each optical sensor 260 being configured to generate information based on one or more characteristics of the beam 206 impinging the sensing region 262. In certain embodiments, the sensing region 262 can be a multi-pixel sensing region, such as in embodiments in which the optical sensor 260 is provided in the form of a camera. In such a form, the optical sensor 260 can generate a digital image of the FOV 202 in response to the beam 206 impinging the sensing region 262. In certain embodiments, the sensing region 262 need not necessarily be pixelated, such as in embodiments in which the optical sensor 260 is provided in the form of a pyrometer. In such a form, the optical sensor 260 can generate value information (e.g., estimated temperature information) in response to the beam 206 impinging the sensing region 262.

[0049] In some embodiments, such as those where beams 206a and 206b are provided to optical sensor 260 at different wavelength bands, optical sensor 260 may be specifically configured to generate information associated with such wavelength bands. For example, in an embodiment where the first beam 206a primarily comprises VIS radiation when received by the first sensor 260a, the first sensor 260a may be provided in the form of a visible light camera. As another example, in an embodiment where the second beam 206b primarily comprises MWIR radiation when received by the second sensor 260b, the second sensor 260b may be provided in the form of an MWIR camera. In some forms, one or more optical sensors 260 may be selected from the group consisting of camera 291, pyrometer 292, photodiode 293, phototransistor 294, and photoresistor 295. In some embodiments, one or more optical sensors 260 may have high spatial resolution. For example, camera 291 may have a resolution of 1 megapixel or higher, or 10 megapixels or higher.

[0050] Understandably, the area of ​​the FOV 202 sensed by the optical sensor 260 depends on a variety of factors, such as the size of the reflector 242, the magnification provided by the optical assembly 230 (including any lenses 222 disposed in the lens mount 220), and other factors. To provide a high spatial resolution FOV 202, it may be advantageous to provide the FOV 202 with a relatively small FOV 202, as sensed by the optical sensor 260. For example, the FOV 202 could have a size of 200 mm. 2 Or a smaller area. In some embodiments, the FOV 202 may be provided in a square shape of approximately 12 mm on each side (e.g., 12 mm + / - 10%). However, it should be understood that other areas and geometries of the FOV 202 are also conceivable.

[0051] For further reference Figure 5 The figure shows a simplified example of build path 190, along which build point 159 travels during the first time period when building artifact 80. Figure 5 The diagram also shows a coordinate system including the Y-axis and X-axis.

[0052] The illustrated build path 190 includes a plurality of trajectories along which the build point 159 travels, including longitudinal or X-direction trajectories 192 and transverse or Y-direction trajectories 194. The transverse or Y-direction trajectories 194 include Y+ trajectories 196 extending in the positive Y-direction and Y- trajectories 198 extending in the negative Y-direction. The illustrated build path 190 is a generally rectangular raster scan build path in which each pair of adjacent transverse trajectories 194 are connected by a respective longitudinal trajectory 192. As the build point 159 travels along the build path 190, it travels along a first Y+ trajectory 196 to a first longitudinal trajectory 192, then along a first Y- trajectory to a second longitudinal trajectory 192. This process can be repeated for a first period of time until the build path 190 has been completed.

[0053] Although the illustrated build path 190 is provided as a simplified raster scan for purposes of illustration, it will be appreciated that the AM machine can utilize more complex build paths. For example, the trajectories can not necessarily be aligned with the axes (e.g., can be tilted with respect to the axes), and / or can include curved portions, for example where the AM machine 100 uses a vector / vector scan build plan for at least a portion of the build.

[0054] To ensure that the build point 159 maintains the predetermined relationship with the FOV 202, the controller 250 can control the movable reflector 240 to move the FOV 202 at a FOV velocity v202 for at least a portion of the first period of time. In certain forms, the FOV velocity v202 is selected based on the average build point velocity v159. Those skilled in the art will readily recognize that the Y-direction velocities of the transverse trajectories substantially cancel each other out during the first period of time, such that the average velocity v159 of the build point 159 is the longitudinal or X-direction velocity. Accordingly, in the illustrated form, the controller 250 can control the movable reflector 240 to move the FOV 202 at a longitudinal FOV velocity v202.

[0055] As noted above, the controller 250 can be configured to control the movable reflector 240 to move the FOV 202 at a FOV velocity v202 to maintain a predetermined relationship between the FOV 202 and the build point 159. In certain embodiments, maintaining the predetermined relationship between the FOV 202 and the build point 159 includes maintaining the build point 159 within the FOV 202. In certain embodiments, maintaining the relationship between the FOV 202 and the build point 159 includes maintaining the build point within or near the FOV 202. In certain embodiments, maintaining the relationship between the FOV 202 and the build point 159 includes maintaining the build point outside of the FOV 202, such as focusing the FOV 202 on a trajectory that the build point 159 most recently passed. In certain embodiments, selecting the FOV velocity v202 based on the average build point velocity v159 includes selecting the FOV velocity v202 to be a predetermined percentage of the average build point velocity v159. In certain embodiments, the predetermined percentage is 100%, such that the FOV velocity v202 is selected to be the average build point velocity v159.

[0056] To maintain the predetermined relationship between the FOV 202 and the build point 159, it can be necessary or desirable for the controller 250 to track the build point 159. Several methods of tracking the build point 159 can be contemplated herein. In certain embodiments, the controller 250 can be provided with a build plan for the workpiece 80, and can control the movable reflector 240 based on the build plan. Such a build plan can associate particular time periods with particular average velocities of the build point 159. For example, the build plan can indicate that the build point 159 is to move from a first identified location to a second identified location at a first average build point velocity v159 during a first time period. In this form, the controller 250 can control the movable reflector 240 to move the FOV 202 at a first FOV velocity v202 selected based on the first average build point velocity v159 during at least a portion of the first time period to maintain the predetermined relationship between the FOV 202 and the build point 159.

[0057] In certain embodiments, the controller 250 can receive information from one or more optical detectors 260, and can control the movable reflector 240 based on the information received from the optical detectors 260. For example, the optical detectors 260 can be provided in the form of a camera, and the controller 250 can process information generated by the camera and control the movable reflector 240 based on the processed information in a manner that causes the build point 159 to maintain a predetermined relationship with the FOV 202.

[0058] In certain embodiments, the controller 250 can be provided with a model of the AM machine manufactured workpiece 80 (e.g., a computer aided design or CAD model) and can control the movable reflector 240 based on the model. For example, the model can indicate to the controller 250 that the build point 159 will be in a particular location at a particular time, and the controller 250 can control the movable reflector 240 to ensure that the predetermined relationship exists between the FOV 202 and the build point 159 at that particular time. Additionally or alternatively, the controller 250 can receive information generated by the optical sensor 260 and record the information into the model. For example, the controller 250 can associate information generated by the optical sensor 260 with the model such that one or more points on the model are known to correspond to particular information generated by the optical sensor 260.

[0059] As an example, a point (X, Y, Z) on the model can be associated with information generated by the optical sensor 260 at time t, and a point (X', Y', Z') on the model can be associated with time t'. If a defect is later found at the point (X, Y, Z) in the workpiece 80, the information generated by the optical sensor at and / or near time t can be evaluated to determine the source of the defect. Such information can be used, for example, to prevent and / or detect future defects. As one example, if the information generated at and / or near time t exhibits an abnormal characteristic (e.g., a spike in temperature, an increase or decrease in electromagnetic radiation in one or more wavebands, etc.), such abnormal characteristic can be indicative of a manufacturing anomaly that caused the defect. Thus, if the abnormal characteristic is again noted at time t', the presence of such abnormal characteristic can be indicative of a defect at the point (X', Y', Z') in the workpiece 80. It will be appreciated that such information is useful not only in evaluating whether a defect exists in a particular workpiece 80, but also in detecting or predicting defects in other workpieces and / or in studying the process physics of the AM process.

[0060] With additional reference Figure 6 to FIG. 3, an example method 300 that can be performed using the AM machine 100 and the monitoring system 200 is shown. Unless explicitly stated otherwise, these blocks shown in the method in this application are understood to be examples only and the blocks can be combined or divided, added or removed, and reordered in whole or in part. Moreover, while the blocks are shown in a relatively serial fashion, it will be appreciated that two or more of the blocks can be performed simultaneously or in parallel with each other. Furthermore, while the method 300 is described herein with specific reference to the AM machine 100, the monitoring system 200, and the related kit 200' shown in FIG. 1, it will be appreciated that the method 300 can be performed with AM machines, monitoring systems, and / or kits having additional or alternative features. Figures 1-4

[0061] ​The illustrated method 300 can begin with block 310, which generally involves installing a monitoring assembly onto an AM machine. For example, block 310 can include installing the add-on kit 200' for the monitoring assembly 200 onto the AM machine 100. Reference is made below to Figure 7 Further details are provided regarding an example method 400 for performing block 310.

[0062] The illustrated method 300 includes block 320, which generally involves monitoring a build of a workpiece by the monitoring assembly installed on the AM machine. For example, block 320 can include monitoring a build of the workpiece 80 by the monitoring assembly 200 installed on the AM machine 100. Reference is made below to Figure 8 Further details are provided regarding an example method 500 for performing block 320.

[0063] The method 300 can further include block 330, which generally involves modifying the monitoring assembly. For example, block 330 can include modifying the monitoring assembly 200 by replacing one or more interchangeable components of the monitoring assembly 200. Reference is made below to Figure 9 Further details are provided regarding an example method 600 for performing block 330.

[0064] Reference is additionally made to Figure 7 , which illustrates an example installation method 400 that can be performed using the illustrated add-on kit 200'. Unless explicitly stated to the contrary, these blocks shown in the methods in this application are understood to be examples and the blocks can be combined or divided, added or removed, and reordered in whole or part. Further, while the blocks are shown in relatively serial fashion, it is to be understood that two or more of the blocks can be performed simultaneously or in parallel with each other. Further, while the method 300 is described herein with specific reference to the AM machine 100, monitoring system 200, and related kit 200' shown in Figures 1-4 , it is to be understood that the method 300 can be performed with AM machines, monitoring systems, and / or kits having additional or alternative features.

[0065] In certain embodiments, the method 400 can be performed in conjunction with the method 300 described above to complete the installation of block 310. In certain embodiments, the method 400 can be performed to install the sensor assembly 200 onto the AM machine 100 prior to the sale of the AM machine 100, thereby providing the system 90 as an original configuration. It is also contemplated that the method 400 can include purchasing the add-on kit 200' for an existing AM machine 100 and installing the kit 200' in situ to the machine to form the system 90 as a retrofit system.

[0066] In certain embodiments, the method 400 can include block 410, which generally involves mounting the substrate 210 to the housing 110 of the AM machine 100 in the vicinity of the first window 112. In certain forms, block 410 can involve releasably mounting the substrate 210 to the housing 110, such as by one or more threaded fasteners. In certain forms, block 410 can involve permanently mounting the substrate 210 to the housing 110, such as by welding. In certain embodiments, such as those in which the system 90 is provided as an original (non- retrofit) system, block 410 can be omitted.

[0067] The illustrated method 400 includes block 420, which generally involves mounting the lens holder 220. For example, block 420 can involve securing the proximal end 228 of the lens holder 220 to the optical assembly housing 231. As noted above, the optical assembly housing 231 and / or the proximal end 228 of the lens holder 220 can include one or more quick-connect fitting structures 208 that facilitate detachable coupling of the lens holder 220 to the optical assembly housing 231. It is also contemplated that the lens holder 220 can be permanently secured to the optical assembly housing 231. However, as described herein, in certain embodiments, the lens holder 220 can preferably be readily detachable / removable, such as to facilitate modification / retrofitting of an installed monitoring assembly 200.

[0068] The illustrated method 400 includes block 430, which generally involves mounting the optical assembly 230. For example, block 430 can involve mounting the optical assembly 230 to the housing 110 via the substrate 210, either before or after the substrate 210 is mounted to the housing 110. It is also contemplated that block 430 can involve mounting the optical assembly 230 directly to the housing 110 in the vicinity of the first window 112. The optical assembly 230 mounted in accordance with block 430 generally includes the beamsplitter 232 and can also include one or more mirrors 234, one or more filters, and / or an optical assembly housing 231 that houses at least a portion of the optical assembly 230.

[0069] The illustrated method 400 includes block 440, which generally involves mounting the movable reflector 240. For example, block 440 can involve mounting the movable reflector 240 to the optical assembly housing 231 such that the movable reflector 240 is located in the vicinity of the entrance aperture 233 of the optical assembly housing 231. When the monitoring assembly 200 is fully mounted to the AM machine 100, the movable reflector 240 is also in the vicinity of the first window 112, such that the mirror 242 is operable to reflect electromagnetic radiation 204 from the FOV 202 in a region of interest (e.g., on the build plane 104) to the entrance aperture 233 for splitting by the beamsplitter 232.

[0070] The illustrated method 400 includes block 450, which generally involves installing the controller 250. Installing the controller 250 generally involves placing the controller 250 in communication with the actuator 244, such that the controller 250 is operable to control the movable reflector 240 to adjust the FOV 202 seen by the optical assembly 230 (and thus by the optical sensor 260). In certain embodiments, block 450 can also include placing the controller 250 in communication with one or more optical sensors 260, such that the controller 250 is operable to receive information generated by the optical sensor 260. In certain embodiments, such as those in which the system 90 is provided as a factory configuration, the monitoring assembly 200 can not necessarily have a dedicated controller 250, but can instead be controlled by the control system 170 of the AM machine 100. Alternatively, the dedicated controller 250 can be considered to comprise a portion of the AM machine control system 170.

[0071] The illustrated method 400 includes block 460, which generally includes installing the optical sensors 260. In the illustrated form, block 460 includes threadably engaging the threaded portion of each optical sensor housing 261 with the threaded distal end 229 of the corresponding lens mount 220. Block 460 can also include releasably securing the optical sensor housing 261 to the AM machine housing 110, such as by the base plate 210. Those skilled in the art will readily recognize that optical sensors configured for use in a laboratory environment typically include housings having quick coupling features (e.g., threaded features) to facilitate quick coupling of the housing 261 with a lens tube. In providing the distal end 229 of the lens mount 220 with corresponding threaded features, the systems and methods described herein can facilitate installation of the optical sensors. However, it will be appreciated that in certain embodiments, one or more of the optical sensor housings 261 can be permanently secured together with the corresponding lens mount 220.

[0072] Upon completion of the method 400, a system 90 is provided that includes the AM machine 100 and the sensor assembly 200. As noted above, the system 90 can be a factory configuration that includes the AM machine 100 and the sensor assembly 200 at the time of sale, or the system 90 can be a retrofit system in which an existing AM machine 100 has been retrofitted with the additional kit 200' to provide the AM machine 100 with the sensor assembly 200. Further, while the installation method 400 can be used to perform block 310 of the method 300 described above, it is also contemplated that the installation method 400 can be performed in conjunction with other processes / methods, or can be performed as a standalone process / method.

[0073] Reference is additionally made to Figure 8FIG. 5 shows an exemplary monitoring method 500 that can be performed using the system 90 and / or the monitoring assembly 200. As described above, unless explicitly stated to the contrary, these blocks shown in the methods in this application are to be understood to be merely examples, and the blocks can be combined or divided, added or removed, and reordered in whole or in part. Further, while the blocks are shown in a relatively serial fashion, it is to be understood that two or more of the blocks can be performed simultaneously or in parallel with each other. Further, while the method 500 is described herein with specific reference to the system 90 and the monitoring assembly 200 shown in FIGS. 1-2, it is to be understood that the method 500 can be performed with systems and / or monitoring assemblies having additional or alternative features. Figures 1-5

[0074] As described herein, the method 500 generally involves monitoring one or more parameters related to a moving FOV 202 within a region of interest in an AM machine, such as the AM machine 100. The method 500 can be performed, for example, as the AM machine 100 manufactures a workpiece 80 in a layer-by-layer fashion. For example, the AM machine 100 can scan a build beam 151 (e.g., an energy beam, a build material jet, or a binder jet) over a region of interest (e.g., a build plane or a build area) to add material to the workpiece 80 at a moving build point 159. As will be apparent from the description herein, the method 500 can be used to monitor one or more process parameters related to the build of the workpiece 80.

[0075] The method 500 includes a block 510, which generally involves reflecting electromagnetic radiation from a field of view in a region of interest of an additive manufacturing machine to an optical assembly. The block 510 can be performed, for example, by a movable reflector, such as the movable reflector 240. In the illustrated form, the block 510 involves reflecting electromagnetic radiation 204 from the FOV 202 on the build plane 104 of the AM machine 100 to the optical assembly 230.

[0076] The method 500 also includes a block 520, which generally involves splitting the electromagnetic radiation into a plurality of beams, with each beam having a respective corresponding wavelength range. The block 520 can be performed by a beam splitter of the optical assembly, such as the beam splitter 232 of the illustrated optical assembly 230. For example, the block 520 can include the beam splitter 232 splitting the electromagnetic radiation 204 reflected by the movable reflector 240 into a plurality of beams 206. In certain embodiments, two or more of the beams 206 can have the same wavelength range after being split by the beam splitter 232. In certain embodiments, two or more of the beams 206 can have different wavelength ranges after being split by the beam splitter 232.

[0077] ​The method 500 also includes block 530, which generally involves directing each of the plurality of beams toward a respective corresponding optical sensor of a plurality of optical sensors. For example, block 530 can be performed at least in part by the optical assembly 230 and / or at least in part by the lens holders 220. For example, the mirrors 234 of the optical assembly 230 can direct each beam 206 through the proximal end 228 of a corresponding lens holder 220, such that each lens holder 220 directs the corresponding beam 206 to a corresponding optical sensor 260. In the process of directing the beams 206 to the optical sensors 260, one or more lens holders 220 can condition the corresponding beam 206 to a state more suitable for use with the corresponding optical sensor 260. In this form, the lens holders 220 can be considered to comprise a portion of the optical assembly 230. As one example, one or more lens holders 220 can include one or more lenses 222 that help to focus the corresponding beam 206 on the sensing region 262 of the corresponding optical sensor 260. As another example, one or more lens holders 220 can include one or more optical filters 224 that filter one or more frequencies of electromagnetic radiation from the corresponding beam 206 before the beam 206 impinges on the sensing region 262 of the corresponding optical sensor 260.

[0078] The method 500 also includes block 540, which generally involves generating a plurality of outputs, each output corresponding to a respective corresponding beam. Block 540 can be performed at least in part by the plurality of optical sensors 260. For example, the first optical sensor 260a can produce output information related to the first beam 206a, and the second optical sensor 260b can produce output information related to the second beam 206b. While other forms are contemplated, in the illustrated embodiment, the plurality of optical sensors 260 simultaneously produce the plurality of outputs. Since each optical sensor 260 is receiving electromagnetic radiation from the same FOV 202, the simultaneous generation of output information enables the outputs to be registered with one another, which can facilitate comparison of the information output by the optical sensors 260.

[0079] In certain embodiments, each output is provided in the form of an information stream. In certain embodiments, for example in embodiments in which one or more optical sensors 260 have a high sampling rate, one or more information streams can have a corresponding high refresh rate or temporal resolution. For example, some pyrometers 292 have a sampling rate of 100,000 samples per second or higher. In certain embodiments, for example in those in which one or more optical sensors 260 have a relatively low sampling rate, one or more information streams can have a relatively low refresh rate or temporal resolution. For example, currently available high-speed cameras 291 typically have a sampling rate of 250 frames per second to 10,000 frames per second. Even lower sampling rates are also contemplated as being associated with information streams, for example in embodiments in which sampling rate or temporal resolution is sacrificed for image quality or spatial resolution.

[0080] In certain embodiments, two or more beams 206 can be substantially the same when received by optical sensors 260. For example, each of first beam 206a and second beam 206b can have been subjected to the same conditioning (e.g., focusing and / or filtering) such that each beam 206a, 206b includes or primarily includes EM radiation within the same range of wavelengths. In certain embodiments, two or more beams 206 can be significantly different (e.g., of different wavebands) when received by optical sensors 260. For example, first beam 206a and second beam 206b can have been split based on wavelength and / or subjected to different forms of conditioning (e.g., focusing and / or filtering) such that first beam 206a and second beam 206b include or primarily include EM radiation within different ranges of wavelengths.

[0081] Method 500 also includes block 550, which generally involves controlling the movable reflector to move the field of view to maintain a predetermined relationship between the field of view and a moving build point within the region of interest. Block 550 may, for example, include the control system 170 and / or controller 250 operating the actuator 244 of the movable reflector 240 to move the mirror 242. For example, block 550 can involve the control system 170 and / or controller 250 controlling the movable reflector 240 to move the FOV 202 to maintain a predetermined relationship between the FOV 202 and a moving build point 159 within the region of interest (e.g., the build plane 104). In various embodiments, maintaining a predetermined relationship between the FOV 202 and the moving build point 159 can include one or more of: maintaining the moving build point 159 within the FOV 202; maintaining the moving build point 159 within or near the FOV 202; maintaining the moving build point 159 adjacent to the FOV 202; maintaining the moving build point 159 outside of the FOV 202. The above references to maintaining a predetermined relationship between the FOV 202 and the moving build point 159 are also applicable to block 550. Figure 5Further details are provided regarding example methods by which a predetermined relationship between the FOV 202 and the build point 159 can be maintained.

[0082] In certain embodiments, the method 500 can include a block 560, which generally involves registering at least one data point of at least one of the plurality of outputs to a model of the workpiece built by the mobile build point. Block 560 can be performed, for example, by the control system 170 and / or the controller 250. For example, the control system 170 and / or the controller 250 can be provided with (or can access) a model by which the workpiece 80 is built, and can correlate the outputs generated by one or more of the optical sensors 260 to a location on the model that corresponds to the location at which the build point 159 was at when the output was generated. Reference is made above to FIG. 3 for further details regarding such registration. Figure 5 Further details are provided regarding such registration and its potential benefits.

[0083] In certain embodiments, the method 500 can include a block 570, which generally involves calibrating at least one of the plurality of optical sensors based on a comparison of the output generated by the at least one optical sensor to the output generated by at least one other of the plurality of optical sensors. Block 570 can be performed, for example, at least in part by the control system 170 and / or the controller 250. For example, if it is suspected that a first optical sensor 260a is generating biased or incorrect information, the first optical sensor 260a can be calibrated based on a comparison of the output of the first optical sensor 260a to the output of a second optical sensor 260b. As described above, the beams 206a, 206b can be substantially identical when received at the optical sensors 260 (e.g., in embodiments in which the EM radiation 204 is split and the beams 206 are subjected to identical conditioning, without regard to wavelength). Thus, in embodiments in which the beams 206a, 206b are substantially identical and the optical sensors 260a, 260b are substantially identical, the outputs of the optical sensors 260a, 260b should be substantially identical. A bias in the output can indicate incorrect calibration of one or both of the optical sensors 260a, 260b, which can be corrected by calibrating the erroneous optical sensor 260 using the other, correct optical sensor 260.

[0084] As described above, the monitoring method 500 can be used, for example, to perform block 320 of the method 300. It is also contemplated that the method 500 can be used in conjunction with other processes / methods (e.g., those by which the monitoring assembly 200 is installed according to methods other than the installation method 400), or can be performed as a standalone process / method.

[0085] Reference is also made to FIG. 4 for further details. Figure 9FIG. 6 illustrates an exemplary retrofit / modification method 600 that can be performed using the monitoring assembly 200. As described above, unless explicitly stated to the contrary, the blocks illustrated for the methods in this application are to be understood to be merely examples, and the blocks can be combined or divided, added or removed, and reordered in whole or in part. Further, while the blocks are illustrated in a relatively serial fashion, it is to be understood that two or more of the blocks can be performed simultaneously or in parallel with each other. Further, while the method 600 is described herein with specific reference to the monitoring assembly 200 shown in FIGS. 1-4, it is to be understood that the method 600 can be performed with a monitoring assembly having additional or alternative features. Figures 1-4

[0086] In some cases, it can be desirable to interchange one or more of the lens seats 220 with another lens seat (e.g., a differently configured lens seat). In this form, the method 600 can include a block 610 that generally involves replacing an existing lens seat 220 with a replacement lens seat. In some embodiments, the replacement lens seat can have at least one feature that is different from the existing lens seat 220, such as the length, presence, and / or configuration of the lens 222, and / or the presence and / or configuration of the filter 224.

[0087] In cases where the lens seat 220 to be replaced is releasably secured to the optical assembly housing 231, the block 610 can include manipulating the proximal end fitting 208 in a decoupled manner to remove the lens seat 220 from the housing 231. For example, in embodiments where the proximal end fitting 208 includes an engagement thread, the block 610 can include rotating the lens seat 220 to unscrew the lens seat 220 from the optical assembly housing 231. As the existing lens seat 220 is removed, the proximal end 228 of the replacement lens seat 220 can be coupled to the optical assembly housing 231 by manipulating the proximal end fitting 208 in a coupled manner.

[0088] In cases where the lens seat 220 to be replaced is releasably secured to the corresponding optical sensor housing 261, the block 610 can include manipulating the distal end fitting 209 in a decoupled manner to remove the lens seat 220 from the optical sensor housing 261. For example, in embodiments where the distal end fitting 209 includes an engagement thread, the block 610 can include causing relative rotation of the lens seat 220 and the optical sensor 260 to unscrew the lens seat 220 from the optical sensor housing 261. As the existing lens seat 220 is removed from the optical sensor 260, the distal end 229 of the replacement lens seat 220 can be coupled to the optical sensor housing 261 by manipulating the distal end fitting 209 in a coupled manner. It is also contemplated that the replacement lens seat 220 can be coupled to a replacement optical sensor 260, such as in embodiments where the method 600 includes a block 620. ​

[0089] In some cases, it can be desirable to swap one or more optical sensors 260 with another optical sensor, e.g., a differently configured optical sensor. In such forms, the process 600 can include a block 620 that generally involves replacing an existing optical sensor 260 with a replacement optical sensor 260. In certain embodiments, the replacement optical sensor 260 can have at least one characteristic that is different from the existing lens mount 220, e.g., the type of optical sensor 260 (e.g., camera 291, pyrometer 292, photodiode 293, phototransistor 294, photoresistor 295), the waveband configured to be sensed by the optical sensor 260, the sampling rate of the optical sensor 260, and / or other characteristics.

[0090] In cases where the optical sensor 260 to be replaced is releasably secured to the corresponding lens mount 220, the block 620 can include manipulating the mating structure 209 of the distal end in a decoupled manner to remove the optical sensor 260 from the lens mount 220. For example, in embodiments where the mating structure 209 includes an engagement thread, the block 620 can include causing relative rotation of the lens mount 220 and the optical sensor 260 to unscrew the lens mount 220 from the optical sensor housing 261. As the existing lens mount 220 is removed, the distal end 229 of the existing lens mount 220 (or a replacement lens mount 220) can be coupled with the housing 261 of the replacement optical sensor 260 by manipulating the mating structure 209 of the distal end in a coupled manner.

[0091] From the foregoing, it will be appreciated that certain embodiments of the systems and methods described herein provide a non-limiting sensor interface 201 through which modular components of a monitoring assembly 200 can be replaced as needed. Such modularity and ease of modification can provide one or more advantages to a user. For example, the systems and methods described herein can provide greater flexibility than traditional monitoring assemblies. By way of example, certain high-end cameras can cost upwards of $100,000, but are often available for lease for a limited time at a fraction of that price. Accordingly, a resource-limited team can find it advantageous to lease a camera for a limited experiment. Upon providing the camera and a suitably configured lens mount, the team will be able to easily install and remove the leased camera for the duration of the experiment.

[0092] In view of the costs associated with certain forms of optical sensors 260 described above, an additional kit 200' according to certain embodiments can not necessarily include a sensor 260. In certain forms, the kit 200' can be provided as a modular unit including the base plate 210, the optical assembly 230, the movable reflector 240, and the controller 250. Such a modular unit can be installed to an AM machine 100, and an optical sensor 260 and / or lens mount 220 can be leased for use with the installed unit.

[0093] It will be appreciated that the systems and methods described herein can provide repeatable calibration between in-situ process monitoring sensors and physics-based models. This objective can be achieved, at least in part, by the non-limiting sensor interface (NRSI) 201 described above, which is an off-axis optical design that can integrate commercially available optical in-situ process monitoring sensors. The NRSI 201 can allow two or more interchangeable sensors 260 to view a region of interest at the same FOV 202. The NRSI 201 scanner system tracks the build point 159 to maintain a predetermined relationship between the FOV 202 and the build point 159. One result that can be provided is a system that synchronizes a pair of arbitrary optical sensors 260 so that they view a single FOV 202 around the build point 159 using a common perspective. The NRSI 201 system is universal / unobtrusive / non-intrusive and can not require modifications to the existing hardware of the AM machine 100. Furthermore, unlike sensors placed in-line with the build beam 151, the NRSI 201 system can avoid impacting the build beam 151 (e.g., by thermal lensing) and / or avoid many of the complexities associated with using lossy mirrors.

[0094] Note that since the size of the imaging FOV 202 can be about 10 4 times the size of the build point 159, the speed and agility required of the movable reflector 240 is much lower than the speed and agility required of the galvanometer 160 of the energy beam 151. As a result, in-situ data can be collected all around the build point 159, which simplifies the registration of in-situ data to the build plane trajectory vector.

[0095] As described above, the reflected electromagnetic radiation 204 will pass through the beam splitter 232, which will produce multiple beams 206 of electromagnetic radiation (e.g., light). In certain embodiments, the beam splitter 232 can produce two orthogonal beams 206, one for imaging in the 0.4 pm to 2 pm waveband (VIS and SWIR) and the other for imaging in the 2 pm to 5 pm waveband (MWIR). Both beams 206 can pass through optics that result in an Airy disk radius of 60 pm, 40 pm, and 12 pm in the MWIR, SWIR, and VIS wavebands, respectively, for imaging on the build plane. The folding mirror 234 can bend one beam 206 and make it parallel to the other beam 206. These optical elements include aft optics, which can be fixed within the enclosure or housing 231. The exit of each beam can be a lens mount 220 to which a sensor 260 is coupled.

[0096] Each lens holder 220 can be configured as a standard two-inch diameter light pipe that can block stray light and can provide a mounting location into which additional lenses can be inserted to focus the beam 206 as required by the particular optical sensor 260 being used. The lens holder 220 can be bolted to the optical housing 231 at the proximal end 228 and threaded onto the sensor housing 261 at the distal end 229.

[0097] As described above, the movable reflector 240 can include a scanning motor 244 with an optical mirror 242 mounted on the shaft of the scanning motor 244 and a detector 246 that provides feedback to the controller 250. In certain embodiments, the controller 250 can use a function generator with a square or sinusoidal wave output to simulate an input signal to enable the movable reflector 240 to traverse its range. A programmable voltage source can be used to simulate the movement of the galvanometer 160 to track the sequence of build plane trajectory vectors.

[0098] It will be appreciated that the NRSI 201, including the movable reflector 240 and the optical assembly 231, provides a reusable system for off-axis in-situ sensing. Off-the-shelf sensors 260 can be coupled to the system using the lens holders 220, and one or more sensors 260 can be updated or replaced as needed. Embodiments and modifications of the NRSI 201 can be used with many forms of existing AM machines 100, and thus can be beneficial to multiple parties.

[0099] Referring now to Figure 10 , a simplified block diagram of at least one embodiment of a computing device 700 is shown. The example computing device 700 depicts at least one embodiment of a control system or controller that can be used in conjunction with the control system 170 and / or the controller 250 shown in Figures 1-4 .

[0100] According to particular embodiments, the computing device 700 can be embodied as a server, a desktop computer, a laptop computer, a tablet computer, a notebook, a netbook, an Ultrabook TM , a mobile computing device, a cellular telephone, a smartphone, a wearable computing device, a personal digital assistant, an Internet of Things (IoT) device, a control panel, a processing system, a router, a gateway, and / or any other computing, processing, and / or communication device capable of carrying out the functions described herein.

[0101] The computing device 700 includes a processing device 702 that executes algorithms and / or processes data according to operational logic 708, an input / output device 704 that enables communication between the computing device 700 and one or more external devices 710, and a memory 706 that stores data received from the external devices 710, for example, through the input / output device 704.

[0102] The input / output device 704 allows the computing device 700 to communicate with external devices 710. For example, the input / output device 704 can include a transceiver, a network adapter, a network card, an interface, one or more communication ports (e.g., USB ports, serial ports, parallel ports, analog ports, digital ports, VGA, DVI, HDMI, FireWire, CAT 5, or any other type of communication port or interface), and / or other communication circuitry. The communication circuitry can be configured to use any one or more communication technologies (e.g., wireless or wired communication) and related protocols (e.g., Ethernet, Wi-Fi, Bluetooth®, Bluetooth Low Energy (BLE), WiMAX, etc.) to facilitate such communication in accordance with the particular computing device 700 implementation. The input / output device 704 can include hardware, software, and / or firmware suitable for performing the techniques described herein. Bluetooth Low Energy (BLE), WiMAX, etc.) to facilitate such communication in accordance with the particular computing device 700 implementation. The input / output device 704 can include hardware, software, and / or firmware suitable for performing the techniques described herein.

[0103] The external devices 710 can be any type of device that allows data to be input to or output from the computing device 700. For example, in various embodiments, the external devices 710 can be implemented as the build table 120, the powder dispenser 130, the reservoir 140, the beam generator 150, the mirror galvanometer 160, the movable reflector 240, and / or the optical sensor 260. Further, in some embodiments, the external devices 710 can be implemented as another computing device, a switch, a diagnostic tool, a controller, a printer, a display, an alarm, a peripheral device (e.g., a keyboard, a mouse, a touch screen display, etc.), and / or any other computing, processing, and / or communication device capable of performing the functions described herein. Further, in some embodiments, it should be understood that the external devices 710 can be integrated into the computing device 700.

[0104] The processing device 702 can be implemented as any type of processor capable of executing the functions described herein. In particular, the processing device 702 can be implemented as one or more single core or multicore processors, microcontrollers, or other processors or processing / control circuits. For example, in some embodiments, the processing device 702 can include or be implemented as an arithmetic logic unit (ALU), a central processing unit (CPU), a digital signal processor (DSP), and / or other suitable processor. The processing device 702 can be of a programmable type, a dedicated hardwired state machine, or a combination thereof. In various embodiments, the processing device 702 having multiple processing units can utilize distributed, pipelined, and / or parallel processing. Moreover, the processing device 702 can be dedicated to performing only the operations described herein, or can be used in one or more additional applications. In the illustrative embodiment, the processing device 702 is of a programmable type that executes algorithms and / or processes data according to operational logic 708 defined by programmed instructions (e.g., software or firmware) stored in the memory 706. Additionally or alternatively, the operational logic 708 of the processing device 702 can be defined at least in part by hardwired logic or other hardware. Furthermore, the processing device 702 can include any type of component or components suitable for processing signals received from the input / output device 704 or from other components or devices and providing desired output signals. These components can include digital circuitry, analog circuitry, or a combination thereof.

[0105] The memory 706 can be one or more types of non-transitory computer- readable media, such as solid state memory, electromagnetic memory, optical memory, or a combination thereof. Moreover, the memory 706 can be volatile and / or non-volatile, and in some embodiments, some or all of the memory 706 can be portable, such as a disk, tape, memory stick, cartridge, and / or other suitable portable memory. In operation, the memory 706 can store various data and software used during operation of the computing device 700, such as operating systems, applications, programs, libraries, and drivers. It should be understood that the memory 706 can store data manipulated by the operational logic 708 of the processing device 702, such as, for example, data representative of signals received from and / or transmitted to the input / output device 704 in addition to or in lieu of storing programmed instructions defining the operational logic 708. As shown, the memory 706 can be included in and / or coupled to the processing device 702, according to particular embodiments. For example, in some embodiments, the processing device 702, the memory 706, and / or other components of the computing device 700 can form part of a system on a chip (SoC) and be incorporated on a single integrated circuit chip.

[0106] In some embodiments, the various components of computing device 700 (e.g., processing device 702 and memory 706) can be communicatively coupled by an input / output subsystem, which can be implemented as circuitry and / or components that facilitate input / output operations with processing device 702, memory 706, and other components of computing device 700. For example, the input / output subsystem can be implemented as or can include a memory controller hub, an input / output controller hub, firmware devices, communication links (i.e., point-to-point links, bus links, wires, cables, light guides, printed circuit board traces, etc.), and / or other components and subsystems that facilitate input / output operations.

[0107] In other embodiments, computing device 700 can include other or additional components, such as those commonly found in a typical computing device (e.g., various input / output devices and / or other components). It should be understood that the computing device 700 described herein can be a general- purpose computing device, such as a personal computer, laptop computer, or netbook computer. In other embodiments, the computing device 700 can be a mobile computing device, such as a smartphone or tablet computer. In yet other embodiments, the computing device 700 can be a computer system in a server or other networked environment. Figure 10 In other embodiments, computing device 700 can include other or additional components, such as those commonly found in a typical computing device (e.g., various input / output devices and / or other components). It should be understood that the computing device 700 described herein can be a general- purpose computing device, such as a personal computer, laptop computer, or netbook computer. In other embodiments, the computing device 700 can be a mobile computing device, such as a smartphone or tablet computer. In yet other embodiments, the computing device 700 can be a computer system in a server or other networked environment.

[0108] While the present application has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the application are desired to be protected.

[0109] It should be understood that the words "preferred," "preferably," "preferred" and "more preferred" and "most preferred" and the like in the description above indicate that the feature so described can be more desirable, but is not required, and that not having the feature so described can be considered to be a matter of preference, and that embodiments can be considered to be within the scope of the application irrespective of having the particular feature so described. Unless otherwise specified specifically in the claims, the intention is that where a word or the like is used in the description or claims, that word or the like is intended to include one of, but not limited to, that item, and that the word or the like can be considered to be a matter of preference. Unless specifically set forth in the claims, the mere use of the word "or" is not intended to be limiting.

Claims

1. An add-on kit for an additive manufacturing machine configured to scan a build bundle over a region of interest and thereby add material to a workpiece at a moving build point located within the region of interest, the add-on kit comprising: A substrate configured for mounting to the additive manufacturing machine; An optical assembly mounted to the substrate includes a housing and a beam splitter located within the housing, wherein the housing includes a plurality of exit holes, wherein the beam splitter is configured to split electromagnetic radiation entering the optical assembly into a plurality of beams, and wherein the optical assembly is configured to guide each of the plurality of beams to a corresponding exit hole among the plurality of exit holes. A movable reflector configured to reflect electromagnetic radiation from within the field of view to the optical assembly, such that each beam includes electromagnetic radiation from the field of view; and A controller configured to move the movable reflector to maintain a predetermined relationship between the moving construction point and the field of view; Wherein, the build bundle travels along the build bundle path from the build bundle source to the build point; and Neither the movable reflector nor the beam splitter is located in the beam-building path.

2. The additional kit of claim 1, further comprising a plurality of lens mounts, wherein each lens mount includes a proximal end and an opposing distal end; in, The proximal end of each lens mount is connected to the housing near the corresponding outlet hole in the plurality of outlet holes, such that each lens mount is operable to receive a corresponding beam in the plurality of beams; and Each lens mount is configured to guide the corresponding beam to the distal end of the lens mount.

3. The add-on kit according to claim 2, wherein, At least one of the plurality of lens mounts is removably attached to the housing.

4. The add-on kit according to claim 2, further comprising a plurality of optical sensors; in, Each optical sensor is connected to the distal end of the corresponding lens mount in the plurality of lens mounts; Each optical sensor is configured to generate information related to the beam guided along its respective lens mount.

5. The add-on kit according to claim 4, wherein, The plurality of optical sensors are configured to simultaneously generate information related to the beam guided along the respective lens mounts.

6. The add-on kit according to claim 4, wherein, At least one of the optical sensors includes a camera.

7. The add-on kit according to claim 2, wherein, The first of the plurality of beams mainly comprises electromagnetic radiation within a first wavelength range in the distal end portion of the first lens mount in the plurality of lens mounts. The second of the plurality of beams primarily comprises electromagnetic radiation within a second wavelength range, which is different from the first wavelength range, in the distal end portion of the second lens mount among the plurality of lens mounts.

8. The add-on kit according to claim 7, further comprising: A first optical sensor is configured to generate information related to electromagnetic radiation within the first wavelength range, wherein the first beam is guided to the first optical sensor by the first lens mount. and A second optical sensor is configured to generate information related to electromagnetic radiation in the second wavelength range, wherein the second beam is guided to the second optical sensor by the second lens mount.

9. The add-on kit according to claim 7, wherein, The first wavelength range includes visible light; wherein the second wavelength range includes infrared radiation.

10. The add-on kit according to claim 2, wherein, Each of the plurality of lens mounts includes at least one threaded end portion.

11. The add-on kit according to claim 2, wherein, At least one of the plurality of lens mounts includes a portion of the optical assembly.

12. The add-on kit of claim 2, further comprising an optical sensor, the optical sensor including a housing and a sensing area located within the housing of the optical sensor; in, The housing of the optical sensor is threadedly engaged with the distal end of the first lens mount among the plurality of lens mounts.

13. The add-on kit according to claim 1, wherein, The area of ​​the field of view is 200 mm. 2 Or smaller.

14. The add-on kit according to claim 1, wherein, Maintaining a predetermined relationship between the moving build point and the field of view includes keeping the moving build point within the field of view.

15. A system comprising: An additive manufacturing machine configured to selectively scan a build bundle in a region of interest and thereby add material to a workpiece at a moving build point located in the region of interest; and A first optical sensor is configured to generate information related to electromagnetic radiation within a first wavelength range; A second optical sensor is configured to generate information related to electromagnetic radiation in a second wavelength range; An optical component, the optical component including a beam splitter configured to split electromagnetic radiation entering the optical component into a first beam and a second beam, to direct the first beam to a first optical sensor, and to direct the second beam to a second optical sensor, wherein the first beam includes electromagnetic radiation within a first wavelength range when it reaches the first optical sensor, and wherein the second beam includes electromagnetic radiation within a second wavelength range when it reaches the second optical sensor. A movable reflector configured to reflect electromagnetic radiation from the region of interest to the optical assembly, such that each of the first optical sensor and the second optical sensor has a field of view in the region of interest; and A controller configured to move the movable reflector to maintain a predetermined relationship between the moving construction point and the field of view; Wherein, the build bundle travels along the build bundle path from the build bundle source to the build point; and Neither the movable reflector nor the beam splitter is located in the beam-building path.

16. The system according to claim 15, wherein, The first wavelength range is different from the second wavelength range.

17. The system according to claim 15, wherein, Each of the first wavelength range and the second wavelength range includes at least one of X-rays, ultraviolet light, visible light, and infrared light.

18. The system according to claim 15, wherein, The first optical sensor includes an infrared camera; The second optical sensor includes a visible light camera.

19. The system of claim 15, further comprising: A housing, wherein the optical components are at least partially located within the housing; A first lens mount having a first proximal end and a first distal end, wherein the first proximal end is removably coupled to the housing, and wherein the first distal end is removably coupled to the first optical sensor; and A second lens mount having a second proximal end and a second distal end, wherein the second proximal end is removably coupled to the housing, and wherein the second distal end is removably coupled to the second optical sensor.

20. A method for monitoring a region of interest (ROI) of an additive manufacturing machine, the additive manufacturing machine selectively scanning a build bundle in the ROI and thereby adding material to a workpiece at a moving build point located in the ROI, the method comprising: Electromagnetic radiation from the field of view in the region of interest is reflected to the optical components via a movable reflector; The electromagnetic radiation is split into multiple beams by the beam splitter of the optical component; The plurality of beams are directed to a plurality of optical sensors such that each of the plurality of optical sensors receives its respective beam from the plurality of beams; Multiple outputs are generated by the plurality of optical sensors, each output including information related to its respective beam; and The movable reflector is controlled by a controller to move the field of view, thereby maintaining a predetermined relationship between the field of view and the moving construct point within the region of interest; Wherein, the build bundle travels along the build bundle path from the build bundle source to the build point; and Neither the movable reflector nor the beam splitter is located in the beam-building path.

21. The method according to claim 20, wherein, The moving build point has an average build point speed during the first time period; The method further includes selecting the field of view velocity based on the average construction point velocity; Controlling the movable reflector includes moving the field of view at the field of view speed for at least a portion of the first time period.

22. The method according to claim 21, wherein, Selecting the field of view velocity based on the average build point velocity includes selecting the field of view velocity as equal to the average build point velocity.

23. The method of claim 20, wherein, At least a portion of the optical components is located within the housing; The first optical sensor among the plurality of optical sensors is connected to the housing via a first lens mount; The method further includes replacing the first optical sensor with a second optical sensor; Replacing the first optical sensor with the second optical sensor includes: Remove the first optical sensor by unscrewing it from the distal end of the first lens mount; and The second optical sensor is screwed onto the distal end of the first lens mount.

24. The method of claim 20, wherein, Each of the multiple outputs includes its own corresponding information stream.

25. The method according to claim 20, wherein, The multiple outputs include: A first image information stream generated by a first optical sensor among the plurality of optical sensors, the first image information stream including a first image generated based on a first wavelength range; and A second image information stream generated by a second optical sensor among the plurality of optical sensors, the second image information stream including a second image generated based on a second wavelength range different from the first wavelength range.

26. The method of claim 20, wherein, The first of the plurality of beams is received by the first optical sensor among the plurality of optical sensors, and the first beam, when received by the first optical sensor, mainly includes electromagnetic radiation within a first wavelength range; The second of the plurality of beams is received by the second optical sensor among the plurality of optical sensors, and the second beam, when received by the second optical sensor, mainly comprises electromagnetic radiation within a second wavelength range; and The first wavelength range is different from the second wavelength range.

27. The method of claim 20, wherein, The multiple outputs are generated simultaneously.

28. The method according to claim 20, wherein, Maintaining a predetermined relationship between the field of view and the moving build point includes keeping the moving build point within the field of view.

29. The method of claim 20, further comprising registering at least one data point of at least one of the plurality of outputs to a model of the workpiece constructed by the moving build point.

30. The method according to claim 29, wherein, The registration includes associating the at least one data point with a location on the model that corresponds to the location of the construction point when the at least one data point was generated.

31. The method of claim 20, further comprising calibrating the at least one optical sensor based on a comparison of the output generated by at least one of the plurality of optical sensors with the output generated by at least one other of the plurality of optical sensors.

32. The method according to claim 20, wherein, The control is performed based on a model of the workpiece being constructed by the moving build point.

Images