3D additive manufacturing equipment

Abstract

To secure detecting accuracy of convexoconcave of a molding area in an apparatus for molding a three-dimensional laminate.SOLUTION: An apparatus for molding a three-dimensional laminate pertaining to at least one embodiment of the present disclosure is an apparatus for molding a three-dimensional laminate which molds a laminate by irradiating a powder bed laid on a molding surface area with beams including: a projecting part constituted so as to project a pattern having a distribution of luminance in a molding surface area, and varying the distribution of luminance with time; an imaging part constituted so as to image the pattern projected on the molding surface area; and a reflecting part constituted so as to reflect at least any one of a first light flux that the projecting part projects or a second light flux that the imaging part images. The projecting part and the imaging part are arranged outside of a chamber in which laminate molding is performed to the molding surface area, and the reflecting part is housed in the chamber. The first light flux and the second light flux are passable through one of a first window part arranged on the chamber.SELECTED DRAWING: Figure 4A

Description

[Technical Field]

[0001] The present disclosure relates to a three-dimensional additive manufacturing apparatus. [Background technology]

[0002] Three-dimensional additive manufacturing techniques are known for manufacturing three-dimensional objects by irradiating a layer of powder with a beam such as a light beam or an electron beam to perform additive manufacturing. Patent Document 1 discloses an example of this type of technology, describing that a powder layer formed from powder is irradiated with a light beam to form a sintered layer, and by repeating this process, multiple sintered layers are laminated together to manufacture a three-dimensional object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-1900 [Patent Document 2] Japanese Patent Application Publication No. 2019-173103 Summary of the Invention [Problem to be solved by the invention]

[0004] In the 3D additive manufacturing method described in Patent Document 1, a large 3D object is formed by repeatedly stacking sintered layers, which requires a long working time to complete. In particular, when using metal powders such as iron, copper, aluminum, or titanium, the working time can reach several tens of hours. Furthermore, because the manufacturing process performed with this type of 3D additive manufacturing method is a thermal process, abnormalities can occur on the powder-laying surface or the manufacturing surface during the manufacturing process. For example, if the manufacturing surface deforms so that it protrudes upward, the surface of the powder laid on the manufacturing surface will become uneven. Furthermore, if spatter occurs during the manufacturing process, the spatter may remain as foreign matter within the manufactured object. These abnormalities can occur while the manufacturing process is in progress.

[0005] Therefore, in order to detect these abnormalities while the modeling operation is in progress, a three-dimensional additive manufacturing device such as that described in Patent Document 2 detects unevenness in the modeling surface area based on image data obtained by photographing a fringe pattern, which is represented by a continuous sinusoidal illuminance distribution projected onto the modeling surface area. However, if the projection unit and image capture unit for detecting unevenness are housed inside the chamber of the 3D additive manufacturing device, there is a risk that they will disrupt the airflow introduced into the chamber to ensure modeling quality. Therefore, it is desirable to place the projection unit and image capture unit for detecting unevenness outside the chamber.

[0006] When the projection unit and the image capture unit are located outside the chamber, it is possible to locate them above the chamber, where it is relatively easy to secure the installation space. In this case, a window is provided in the ceiling of the chamber to allow the light beam emitted from the projection unit and the light beam from the printing surface area to be captured by the image capture unit to enter and exit. However, in recent 3D additive manufacturing (AM) devices, multiple beam irradiation devices are installed, and beams are irradiated from each irradiation device, for example, to shorten the manufacturing time. In such cases, the beam is irradiated through a different window for each irradiation device, making it difficult to provide separate windows for the projection unit and the imaging unit in the ceiling of the chamber due to space constraints. Therefore, it is desirable to have the irradiating light beam and the light beam from the manufacturing surface area to be captured by the imaging unit enter and exit through a single window. However, in this case, the angle between the optical axis of the light beam emitted from the projection unit and the optical axis of the light beam from the modeling surface area to be captured by the imaging unit becomes relatively small, making it difficult to ensure the accuracy of detecting unevenness by capturing the fringe pattern.

[0007] In view of the above circumstances, at least one embodiment of the present disclosure aims to ensure the detection accuracy of unevenness in a modeling area in a three-dimensional additive manufacturing device. [Means for solving the problem]

[0008] (1) A three-dimensional additive manufacturing apparatus according to at least one embodiment of the present disclosure, A three-dimensional additive manufacturing apparatus that performs additive manufacturing by irradiating a powder bed laid on a manufacturing surface area with a beam, a projection unit configured to project a pattern having a luminance distribution in the printing surface area, the luminance distribution changing over time; an imaging unit configured to capture an image of the pattern projected onto the build surface area; a reflecting unit configured to reflect at least one of a first light beam projected by the projection unit and a second light beam captured by the imaging unit; Equipped with the projection unit and the imaging unit are disposed outside a chamber in which additive manufacturing is performed on the manufacturing surface area; the reflector is housed within the chamber; The first light beam and the second light beam can pass through a first window portion provided in the chamber. [Effects of the Invention]

[0009] According to at least one embodiment of the present disclosure, it is possible to ensure the accuracy of detecting unevenness in a modeling area in a three-dimensional additive manufacturing device. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating an overall configuration of a three-dimensional additive manufacturing apparatus according to at least one embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram showing the internal configuration of the beam irradiation unit of FIG. [Figure 3] FIG. 2 is a schematic diagram illustrating the configuration of the shape measuring device of FIG. 1. [Figure 4A] 4 is a schematic side view showing an example of the configuration of the shape measuring device of FIG. 3. FIG. [Figure 4B] 4 is a schematic side view showing another example of the configuration of the shape measuring device of FIG. 3. FIG. [Figure 4C] 4 is a schematic side view showing still another example of the configuration of the shape measuring device of FIG. 3. FIG. [Figure 4D] 4 is a schematic side view showing still another example of the configuration of the shape measuring device of FIG. 3. FIG. [Figure 4E] 4 is a schematic side view showing still another example of the configuration of the shape measuring device of FIG. 3. FIG. [Figure 4F] 4 is a schematic side view showing still another example of the configuration of the shape measuring device of FIG. 3. FIG. [Figure 4G] 4 is a schematic side view showing still another example of the configuration of the shape measuring device of FIG. 3. FIG. [Figure 5] 10 is a flowchart illustrating the control process of a three-dimensional additive manufacturing apparatus according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions that exclude the presence of other elements.

[0012] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing the overall configuration of a three-dimensional additive manufacturing apparatus 1 according to at least one embodiment of the present disclosure.

[0013] The 3D additive manufacturing apparatus 1 is an apparatus for manufacturing a three-dimensional object by irradiating a beam onto powder laid in layers to perform additive manufacturing. The 3D additive manufacturing apparatus 1 includes a base plate 2 that serves as a base on which a three-dimensional object is manufactured. The base plate 2 is arranged so that it can be raised and lowered inside a substantially cylindrical cylinder 4 having a central axis along the vertical direction. A powder bed 8 is formed on the base plate 2 by laying powder on the upper layer as described below. During the manufacturing operation, a new powder bed 8 is formed by laying powder on the upper layer each time the base plate 2 descends in each cycle.

[0014] In addition, although the three-dimensional additive manufacturing device 1 of this embodiment shows a case where a light beam is irradiated as the beam B, the concept of the present disclosure can also be similarly applied when other forms of beam B, such as an electron beam, are used.

[0015] The 3D additive manufacturing apparatus 1 includes a powder laying unit 10 for laying powder on a base plate 2 to form a powder bed 8. The powder laying unit 10 supplies powder to the upper surface of the base plate 2 and flattens the surface, thereby forming a layered powder bed 8 having a substantially uniform thickness across the entire upper surface of the base plate 2. The powder bed 8 formed in each cycle is selectively solidified by irradiating it with a beam B from a beam irradiation unit 14 (described later). In the next cycle, the powder laying unit 10 lays powder again on the upper layer, forming a new powder bed. This process is repeated, and the powder is piled up in layers.

[0016] The powder supplied from the powder laying unit 10 is a powdered substance that serves as the raw material for a three-dimensional object, and a wide range of materials can be used, including metal materials such as iron, copper, aluminum, or titanium, and non-metallic materials such as ceramics.

[0017] The three-dimensional additive manufacturing apparatus 1 includes a beam irradiation unit 14, which is an irradiation section for irradiating the powder bed 8 with a beam B so as to selectively solidify the powder bed 8. Fig. 2 is a schematic diagram showing the internal configuration of the beam irradiation unit 14 of Fig. 1. The beam irradiation unit 14 includes a light source 18 that outputs laser light as the beam B, an optical fiber 22 that guides the beam B from the light source 18 to the focusing section 25, and the focusing section 25 that is made up of a plurality of optical devices.

[0018] In the focusing section 25, the beam B guided by the optical fiber 22 is incident on the collimator 24. The collimator 24 focuses the beam B into a parallel beam. The light emitted from the collimator 24 passes through an isolator 26 and a pinhole 28 and enters a beam expander 30. After the beam expander 30 expands the diameter of the beam B, it is deflected by a galvanometer mirror 32 that can swing in any direction, and is irradiated onto the powder bed 8 via an fθ lens 33. The beam irradiation from the galvanometer mirror 32 to the powder bed 8 may be performed without the fθ lens 33 .

[0019] The beam B emitted from the beam irradiation unit 14 is scanned two-dimensionally along the surface of the powder bed 8. Such two-dimensional scanning of the beam B is performed in a pattern corresponding to the three-dimensional shape to be formed, and specifically, is performed by driving and controlling the angle of the galvanometer mirror 32. The two-dimensional scanning of the beam B may be performed, for example, by moving the beam irradiation unit 14 parallel to the surface of the base plate 2 using a driving mechanism not shown, or may be performed in combination with the angle driving control of the galvanometer mirror 32 described above.

[0020] In the three-dimensional additive manufacturing apparatus 1 having such a configuration, in each cycle, powder is laid on the base plate 2 by the powder laying unit 10 based on a control signal from the control device 100 (for example, an arithmetic processing device such as a computer), which is a control unit, to form a powder bed 8, and the powder contained in the powder bed 8 is selectively solidified by two-dimensionally scanning the powder bed 8 while irradiating it with beam B from the beam irradiation unit 14. In the manufacturing process, this cycle is repeated, and solidified molding layers are stacked to manufacture the target three-dimensional object.

[0021] 1, the 3D additive manufacturing apparatus 1 is equipped with a shape measuring device 34 for monitoring the shape of the powder bed 8 or the manufacturing surface (the surface irradiated with the beam B) during the manufacturing operation. In this embodiment, an optical scanner based on the fringe projection method is used as an example of the shape measuring device 34.

[0022] Fig. 3 is a schematic diagram of the shape measuring device 34 of Fig. 1. Note that a reflecting unit 36, which will be described later, is not shown in Fig. 3. The shape measuring device 34 includes a projection unit 34a, which is a projector configured to project a fringe pattern (a striped pattern with a continuous sinusoidal intensity distribution) onto a build surface area (powder bed 8 or build surface) 50 on the base plate 2, an imaging unit 34b configured to capture an image of the fringe pattern projected onto the build surface area 50, and an unevenness detection unit 34c configured to detect unevenness in the build surface area 50 based on the image data acquired by the imaging unit 34b.

[0023] The pattern projected by the projection unit 34a is, for example, a fringe pattern as described above, which has a luminance distribution in the build surface area 50 and in which the luminance distribution changes over time. However, the pattern projected by the projection unit 34a may be a pattern other than a fringe pattern as long as it has a luminance distribution in the build surface area 50 and the luminance distribution, which is known as a function of the azimuth angle from the reference axis of the projector, changes over time in a known manner with respect to repeated image measurements. In other words, it is necessary that the azimuth angle from the reference axis of the projector can be calculated from the pattern of change over time for any point measured by the imaging device. Furthermore, although the imaging unit 34b for capturing an image of the fringe pattern is a single unit in this embodiment, a pair of imaging units may be provided to capture a stereo image. That is, in some embodiments, the shape measuring device 34 includes a projection unit 34a configured to project a pattern having a brightness distribution in the build surface area 50 and in which the brightness distribution changes over time, and an imaging unit 34b configured to image the pattern projected onto the build surface area 50. In the following description, the light beam of the pattern projected by the projection unit 34a will also be referred to as the first light beam 41, and the light beam from the projected pattern, i.e., the light beam emitted from the printing surface area 50 and imaged by the imaging unit 34b, will also be referred to as the second light beam 42.

[0024] The unevenness detection unit 34c is an image analysis device that can evaluate unevenness in the printing surface area 50 by analyzing the image acquired by the imaging unit 34b, and is configured by an arithmetic processing device such as a computer. The unevenness detection unit 34c converts the two-dimensional image acquired from the imaging unit 34b into an independent three-dimensional coordinate system for each pixel based on an optical conversion formula, thereby calculating the uneven shape in the printing surface area 50. The unevenness detector 34c may be configured as a part of the control device 100 shown in FIG. 1, or may be configured as a separate unit.

[0025] FIG. 4A is a schematic side view showing an example of the configuration of the shape measuring device 34 in FIG. FIG. 4B is a schematic side view showing another example of the configuration of the shape measuring device 34 in FIG. FIG. 4C is a schematic side view showing yet another example of the configuration of the shape measuring device 34 in FIG. FIG. 4D is a schematic side view showing yet another example of the configuration of the shape measuring device 34 in FIG. FIG. 4E is a schematic side view showing yet another example of the configuration of the shape measuring device 34 in FIG. FIG. 4F is a schematic side view showing yet another example of the configuration of the shape measuring device 34 in FIG. FIG. 4G is a schematic side view showing yet another example of the configuration of the shape measuring device 34 in FIG.

[0026] In the embodiment shown in Figures 4A to 4G, the shape measurement device 34 includes, in addition to the above-mentioned projection units 34a and 34b and unevenness detection unit 34c, a reflection unit 36 configured to reflect at least one of the first light beam 41 projected by the projection unit 34a or the second light beam 42 captured by the imaging unit 34b. 4A to 4G, the reflecting portion 36 has a reflecting surface 36a for reflecting the light beam. As will be described later, in some embodiments, the reflecting surface 36a is a flat or curved surface. That is, in the embodiment shown in FIGS. 4A to 4G, the reflecting portion 36 is a mirror.

[0027] In the embodiment shown in FIGS. 4A to 4G, the projection unit 34a and the imaging unit 34b of the shape measurement device 34 are disposed outside the chamber 60 where additive manufacturing of the manufacturing surface area 50 is performed. In the embodiment shown in FIGS. 4A to 4G, the reflector 36 is housed within a chamber 60 . 4A to 4G, the first light beam 41 and the second light beam 42 can pass through a single first window 71 provided in the chamber. Note that a protective glass or the like is provided in the first window 71 so that the first light beam 41 and the second light beam 42 can pass through while maintaining airtightness between the inside and outside of the chamber 60.

[0028] In the embodiment shown in FIGS. 4A to 4F, the first window portion 71 is provided in the upper portion of the chamber 60 (ceiling portion 62). In the embodiment shown in FIG. 4G, the first window portion 71 is provided in the side portion (side wall 61) of the chamber 60.

[0029] 4A to 4G, the beam B from the beam irradiation unit 14 is introduced into the chamber 60 through a second window 72 provided in the upper part (ceiling part 62) of the chamber 60 and directed to the printing surface area 50 provided in the bottom part of the chamber 60. Note that in the embodiment shown in FIG. 4F, two beam irradiation units 14 are provided. In the embodiment shown in FIG. 4F, the beam B from one beam irradiation unit 14 is introduced through the second window 72, and the beam B from the other beam irradiation unit 14 is introduced through a third window 73 provided in the upper part (ceiling part 62) of the chamber 60 and directed to the printing surface area 50 provided in the bottom part of the chamber 60. The beam B from the beam irradiation unit 14 is two-dimensionally scanned over the modeling surface area 50 according to the angle of the galvanometer mirror 32 . In addition, a protective glass or the like is arranged in the second window portion 72 so as to maintain airtightness between the inside and outside of the chamber 60 while allowing the beam B from the beam irradiation unit 14 to pass through.

[0030] In the embodiments shown in Figures 4A, 4C, 4E, 4F, and 4G, the reflecting portion 36 is configured to reflect the first light beam. In the embodiments shown in FIGS. 4A, 4C, 4F, and 4G, the reflecting portion 36 is configured to reflect the first light beam 41 but not the second light beam 42.

[0031] In the embodiments shown in Figures 4B, 4D, and 4E, the reflecting portion 36 is configured to reflect the second light beam. In the embodiment shown in FIGS. 4B and 4D, the reflecting portion 36 is configured not to reflect the first light beam 41 but to reflect the second light beam 42.

[0032] This figure corresponds to claim 1. In the embodiment shown in Fig. 4E, the reflecting portion 36 includes a first reflecting portion 361 configured to reflect the first light beam 41 and a second reflecting portion 362 configured to reflect the second light beam 42 and different from the first reflecting portion 361.

[0033] In the embodiments shown in Figures 4A, 4B, 4E, 4F, and 4G, the reflecting portion 36 includes a reflecting surface 36a that is flat, i.e., in the embodiments shown in Figures 4A, 4B, 4E, 4F, and 4G, the reflecting portion 36 is a flat mirror.

[0034] 4C and 4D, the reflecting portion 36 includes a reflective surface 36a that is a curved surface, that is, in the embodiment shown in Figures 4C and 4D, the reflecting portion 36 is a curved mirror. 4C, the reflecting surface 36a of the reflecting unit 36 may be a convex curved surface or a concave curved surface as long as the irradiation angle θ1 of the first light flux 41 from the projection unit 34a can be made smaller than when the reflecting surface 36a is a flat surface. Alternatively, the reflecting surface 36a may be a combination of an equivalent optical element with refractive power and a reflecting mirror. 4D, the reflecting surface 36a of the reflecting unit 36 may be a convex curved surface or a concave curved surface as long as the angle of view θ2 of the imaging unit 34b required to capture an image of the pattern projected onto the build surface area 50 can be made smaller than when the reflecting surface 36a is flat. Alternatively, the reflecting surface 36a may be a combination of a transmissive optical element with refractive power and a reflecting mirror.

[0035] 4A to 4F, the projection unit 34a and the imaging unit 34b are disposed above the chamber 60. In the embodiment shown in Figures 4A to 4F, the first light beam 41 and the second light beam 42 can pass through a first window 71 provided in the upper part (ceiling 62) of the chamber 60. In the embodiment shown in Figures 4A to 4F, the reflecting unit 36 is attached to the side part (side wall 61) of the chamber 60.

[0036] 4G, the projection unit 34a and the imaging unit 34b may be disposed on the side of the chamber 60. In the embodiment shown in FIG. 4G, the first light beam 41 and the second light beam 42 can pass through a first window 71 provided in the side (side wall 61) of the chamber 60. In the embodiment shown in FIG. 4G, the reflecting unit 36 is attached to the ceiling 62 of the chamber 60.

[0037] In the embodiments shown in FIGS. 4A to 4E and 4G, there is one beam irradiation unit (irradiation section) 14. The embodiment shown in Figure 4F includes a first beam irradiation unit (first irradiation section) 141, which is a beam irradiation unit capable of irradiating beam B and arranged outside chamber 60, and a second beam irradiation unit (second irradiation section) 142, which is a beam irradiation unit different from first beam irradiation unit 141, which is capable of irradiating beam B and arranged outside chamber 60. 4F , the beam B irradiated from the first beam irradiation unit 141 can pass through a second window 72 that is different from the first window 71 and that is installed in the chamber 60. The beam B irradiated from the second beam irradiation unit 142 can pass through a third window 73 that is installed in the chamber 60 and that is different from the first window 71 and the second window 72. In the embodiment shown in FIG. 4F, the second window portion 72 and the different third window portion 73 are provided in the upper portion (ceiling portion 62) of the chamber 60, as described above.

[0038] (Issues with conventional 3D additive manufacturing devices) When detecting unevenness in the printing surface area 50 based on image data acquired by the imaging unit 34b, if the angle θ3 between the optical axis 41xi (incident optical axis) of the first light beam 41 that enters the printing surface area 50 and the optical axis 42x (exiting optical axis) 42xe of the second light beam 42 that exits the printing surface area 50 is relatively small, the accuracy of detecting unevenness in the printing surface area 50 decreases. Therefore, it is preferable that the angle θ3 be relatively large. To achieve this, it is possible to provide separate windows for allowing the first light beam 41 to enter the chamber 60 and for allowing the second light beam 42 to exit the chamber 60, and to increase the distance between these two windows. Alternatively, it is possible to allow the first light beam 41 and the second light beam 42 to enter and exit through a single window with a relatively large opening area. However, in recent 3D additive manufacturing devices, as shown in FIG. 4F, for example, in order to shorten the manufacturing time, multiple beam irradiation units may be provided, and beam B may be irradiated from each beam irradiation unit. In such cases, a different window portion is provided in the ceiling portion 62 of the chamber 60 for each beam irradiation unit, and the beam from each beam irradiation unit is irradiated through the respective window portion. Therefore, due to space limitations, it is difficult to provide separate windows for the entrance of the first light beam 41 and the exit of the second light beam 42 in the ceiling portion 62 of the chamber 60, or to provide a single window portion with a relatively large opening area.

[0039] (Solving the issues with conventional 3D additive manufacturing equipment) (Regarding this disclosure in general) 4A to 4G, at least one of the first light beam 41 and the second light beam 42 is reflected by the reflecting unit 36, so the angle θ3 can be made larger than when the reflecting unit 36 is not provided. This ensures the accuracy of detecting irregularities in the printing surface area 50. Furthermore, according to the embodiment shown in Figures 4A to 4G, the angle θ3 can be increased, so that it is possible to ensure unevenness detection accuracy that is equal to or higher than that when a window for the entrance of the first light beam 41 and a window for the exit of the second light beam 42 are provided separately, or when a single window with a relatively large opening area is provided. According to the embodiment shown in Figures 4A to 4G, the only window portion required to pass the first light beam 41 and the second light beam 42 is the first window portion 71, so it is easy to secure a window portion even if there are space constraints. Furthermore, according to the embodiment shown in FIGS. 4A to 4G, the opening area of the first window portion 71 can be made relatively small, so that the first window portion 71 can be easily secured even if there are space restrictions.

[0040] The range through which the light beam can pass through the first window portion 71 is limited by the width and thickness of the first window portion 71. According to the embodiment shown in Figures 4A to 4G, the influence of these limitations can be alleviated. Furthermore, there are limitations on the placement position of the first window 71, and there are also limitations on the placement positions of the projection unit 34a and the image capture unit 34b. Therefore, there are limitations on the positional relationship between the first window 71 and the projection unit 34a and the image capture unit 34b. According to the embodiment shown in Figures 4A to 4G, the effects of such limitations on the positional relationship can be alleviated.

[0041] According to the embodiment shown in Figures 4A to 4G, the projection unit 34a and the imaging unit 34b are arranged outside the chamber 60, so that space within the chamber 60 can be secured and the flow of air such as an inert gas introduced into the chamber 60 to ensure the molding quality is less likely to be disturbed.

[0042] In the embodiments shown in Figures 4A, 4C, 4E, 4F, and 4G, the reflecting portion 36 is configured to reflect the first light beam. In the embodiments shown in FIGS. 4A, 4C, 4F, and 4G, the reflecting portion 36 is configured to reflect the first light beam 41 but not the second light beam 42. In this way, if the reflector 36 is configured to reflect the first light beam 41, the optical path of the first light beam 41 can be made longer than when the first light beam 41 from the projection unit 34a is directly irradiated onto the printing surface area 50, and the irradiation angle θ1 of the first light beam 41 from the projection unit 34a can be made smaller. This makes it possible to suppress distortion of the periphery of the pattern projected onto the printing surface area 50. This improves the accuracy of detecting irregularities in the region of the printing surface area 50 that corresponds to the periphery of the pattern. Furthermore, because the irradiation angle θ1 of the first light beam 41 from the projection unit 34a can be made smaller, the size (opening area) of the first window 71 can be made smaller.

[0043] In the embodiments shown in Figures 4B, 4D, and 4E, the reflecting portion 36 is configured to reflect the second light beam. In the embodiment shown in FIGS. 4B and 4D, the reflecting portion 36 is configured not to reflect the first light beam 41 but to reflect the second light beam 42. In this way, if the reflector 36 is configured to reflect the second light beam 42, the optical path of the second light beam 42 can be made longer than when the second light beam 42 emitted from the print surface area 50 is directly incident on the image capture unit 34b, and the angle of view θ2 of the image capture unit 34b required to capture the pattern projected on the print surface area 50 can be made smaller. This reduces distortion of the peripheral image of the pattern captured by the image capture unit 34b. This improves the accuracy of detecting irregularities in the region of the print surface area 50 that corresponds to the peripheral portion of the pattern. Furthermore, because the angle of view θ2 of the image capture unit 34b required to capture the pattern projected on the print surface area 50 can be made smaller, the size (opening area) of the first window 71 can be made smaller.

[0044] In the embodiment shown in FIG. 4E, the reflecting portion 36 includes a first reflecting portion 361 configured to reflect the first light beam 41 and a second reflecting portion 362 different from the first reflecting portion 361 configured to reflect the second light beam 42. As a result, by reflecting the first light beam 41 by the first reflecting portion 361, it is possible to improve the accuracy of detecting unevenness in the region of the printing surface area 50 that corresponds to the periphery of the pattern, as described above. Furthermore, by reflecting the second light beam 42 by the second reflecting portion 362, it is possible to improve the accuracy of detecting unevenness in the region of the printing surface area 50 that corresponds to the periphery of the pattern, as described above. That is, in the embodiment shown in FIG. 4E, it is possible to further improve the accuracy of detecting unevenness in the region that corresponds to the periphery of the pattern.

[0045] In the embodiments shown in Figures 4A, 4B, 4E, 4F, and 4G, the reflecting portion 36 includes a reflecting surface 36a that is flat, i.e., in the embodiments shown in Figures 4A, 4B, 4E, 4F, and 4G, the reflecting portion 36 is a flat mirror. As a result, when performing calculations to detect unevenness in the build surface area 50 based on image data acquired by the imaging unit 34b, the presence of the reflecting unit 36 makes the corrections required relatively simple compared to when the reflecting surface 36a is not flat. Furthermore, in the embodiments shown in FIGS. 4A, 4B, 4E, 4F, and 4G, the cost of the reflecting section 36 can be reduced compared to when the reflecting surface 36a is not flat.

[0046] 4C and 4D, the reflecting portion 36 includes a reflective surface 36a that is a curved surface, that is, in the embodiment shown in Figures 4C and 4D, the reflecting portion 36 is a curved mirror. 4C, if the reflecting unit 36 is configured to reflect the first light beam 41, the irradiation angle θ1 of the first light beam 41 from the projection unit 34a can be made smaller than when the reflecting surface 36a is flat. This makes it possible to project a pattern over a relatively wide range on the printing surface area 50, even if the size of the first window 71 is small. The same effect as that of a curved mirror can also be achieved by combining a transmissive optical element with refractive power and one or more reflecting mirrors. 4D , when the reflecting unit 36 is configured to reflect the second light beam 42, the same effect as when the aperture diameter of the optical system in the image capturing unit 34b is increased can be achieved compared to when the reflecting surface 36a is flat. This can prevent deterioration of the optical resolution due to the diffraction limit in the optical system. Furthermore, when the reflecting unit 36 is configured to reflect the second light beam 42, as in the embodiment shown in FIG. 4D , the angle of view θ2 of the image capturing unit 34b required to capture an image of the pattern projected on the build surface area 50 can be reduced compared to when the reflecting surface 36a is flat, making it easier to reduce the size of the first window 71.

[0047] 4A to 4F, the projection unit 34a and the imaging unit 34b are disposed above the chamber 60. In the embodiment shown in Figures 4A to 4F, the first light beam 41 and the second light beam 42 can pass through a first window 71 provided in the upper part (ceiling 62) of the chamber 60. In the embodiment shown in Figures 4A to 4F, the reflecting unit 36 is attached to the side part (side wall 61) of the chamber 60. This means that there are relatively few restrictions on the placement of the projection unit 34a, the image capture unit 34b, and the reflection unit 36, making it possible to place them relatively easily.

[0048] 4G, the projection unit 34a and the imaging unit 34b are disposed on the sides of the chamber 60. In the embodiment shown in FIG. 4G, the first light beam 41 and the second light beam 42 may be able to pass through a first window 71 provided in the side (side wall 61) of the chamber 60. In the embodiment shown in FIG. 4G, the reflecting unit 36 is attached to the ceiling 62 of the chamber 60. As a result, even if it is difficult to arrange the projection unit 34a and the image capture unit 34b above the chamber 60, the projection unit 34a and the image capture unit 34b can be arranged on the side of the chamber 60. In this case, by attaching the reflecting unit 36 to the ceiling portion 62 of the chamber 60, the angle θ3 formed between the optical axis (incident optical axis) 41xi of the first light beam 41 incident on the printing surface area 50 and the optical axis (exiting optical axis) 42xe of the second light beam 42 exiting from the printing surface area 50 can be made relatively large.

[0049] 4F , the beam B irradiated from the first beam irradiation unit 141 can pass through a second window 72 that is different from the first window 71 and that is installed in the chamber 60. The beam B irradiated from the second beam irradiation unit 142 can pass through a third window 73 that is installed in the chamber 60 and that is different from the first window 71 and the second window 72. 4F , in a three-dimensional additive manufacturing apparatus 1 configured to reduce the modeling time by irradiating beam B from multiple beam irradiation units 14, the number of windows provided in the chamber 60 increases as the number of beam irradiation units 14 increases. This further restricts the size and installation position of the first window 71. 4F , even if the size and installation position of the first window portion 71 are further restricted, it is possible to increase the angle θ3 between the optical axis (incident optical axis) 41xi of the first light beam 41 incident on the printing surface area 50 and the optical axis (exiting optical axis) 42xe of the second light beam 42 exiting from the printing surface area 50. This ensures the accuracy of detecting unevenness in the printing surface area 50.

[0050] Next, a description will be given of an example of control of the three-dimensional additive manufacturing apparatus 1 having the above-described configurations. Fig. 5 is a flowchart showing the control content of the three-dimensional additive manufacturing apparatus 1 according to some embodiments of the present disclosure for each step.

[0051] First, the 3D additive manufacturing apparatus 1, more specifically the CPU (not shown) of the control device 100, starts the additive manufacturing operation (step S1). The additive manufacturing operation progresses by repeatedly performing a step of forming a powder bed 8 by laying powder on the base plate 2 and a step of irradiating the powder bed 8 with a beam.

[0052] During the additive manufacturing operation, the three-dimensional additive manufacturing apparatus 1 measures the surface shape of the manufacturing surface area 50 by acquiring measurement results from the shape measuring device 34 (step S2). At this time, the shape measuring device 34 measures the surface shape of the manufacturing surface area 50 as a three-dimensional structure by measurement based on the fringe projection method as described above.

[0053] Next, the 3D additive manufacturing apparatus 1 determines whether or not there are irregularities on the manufacturing surface area 50 based on the measurement results of step S2 (step S3). In this embodiment, if the detected irregularities are outside the tolerance range, it is determined that there are irregularities. This tolerance range is set based on whether or not the irregularities are abnormal to an unacceptable degree for product quality as the manufacturing cycle progresses.

[0054] If it is determined that unevenness exists in the build surface area 50 (step S3: YES), the 3D additive manufacturing apparatus 1 implements various measures to improve product quality (step S4). The measures implemented here may be repair work such as redoing the laying work of the powder bed 8 by the powder laying unit 10 (recoater), or re-irradiating the build surface area 50 with a beam, or may notify the operator that unevenness exists in the build surface area 50. Such surface shape-based unevenness monitoring is continued until the additive manufacturing work is completed (step S5).

[0055] The shape measuring device 34 may monitor the build surface area 50 with respect to the powder bed 8 before the beam irradiation, or may monitor the build surface after the powder bed 8 has been irradiated with the beam.

[0056] As described above, according to the above-described three-dimensional additive manufacturing apparatus 1, irregularities on the manufacturing surface area 50 that may be abnormalities or symptoms of abnormalities are monitored by the shape measuring device 34. If the shape measuring device 34 detects irregularities that are outside the allowable range, appropriate corrective measures are implemented, thereby preventing fatal abnormalities at an early stage as the manufacturing operation progresses.

[0057] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications. For example, in the embodiment shown in Fig. 4E, at least one of the first reflecting portion 361 and the second reflecting portion 362 may include a curved reflecting surface 36a. That is, in the embodiment shown in Fig. 4E, at least one of the first reflecting portion 361 and the second reflecting portion 362 may be a curved mirror.

[0058] The embodiment shown in Fig. 4F has a similar configuration to the embodiment shown in Fig. 4A, except that one beam irradiation unit 14 is added. However, the embodiment shown in Fig. 4F may have a similar configuration to the embodiment shown in Fig. 4A, except that two or more beam irradiation units 14 are added. Additionally, one or more beam projection units 14 may be added to the embodiments shown in Figures 4B to 4E and 4G.

[0059] In the embodiment shown in FIG. 4G, the reflecting portion 36 is configured to reflect the first light beam 41, but the reflecting portion 36 may be configured to reflect the second light beam 42. In the embodiment shown in Fig. 4G, the reflecting portion 36 may include a reflecting surface 36a that is a curved surface. That is, in the embodiment shown in Fig. 4G, the reflecting portion 36 may be a curved mirror.

[0060] The contents described in each of the above embodiments can be understood, for example, as follows. (1) A three-dimensional additive manufacturing apparatus 1 according to at least one embodiment of the present disclosure is a three-dimensional additive manufacturing apparatus 1 that performs additive manufacturing by irradiating a beam B onto a powder bed 8 laid on a manufacturing surface area 50. The additive manufacturing apparatus 1 includes a projection unit 34a configured to project a pattern having a brightness distribution on the manufacturing surface area 50, where the brightness distribution changes over time; an imaging unit 34b configured to capture an image of the pattern projected on the manufacturing surface area 50; and a reflector 36 configured to reflect at least one of a first light beam 41 projected by the projection unit 34a or a second light beam 42 captured by the imaging unit 34b. The projection unit 34a and the imaging unit 34b are disposed outside a chamber in which additive manufacturing of the manufacturing surface area is performed. The reflector is housed within a chamber 60. The first light beam 41 and the second light beam 42 can pass through a first window 71 installed in the chamber 60.

[0061] According to the configuration (1) above, compared to a case where the reflecting unit 36 is not provided, the angle θ3 formed between the optical axis 41xi (incident optical axis) of the optical axis 41x of the first light beam 41 that is incident on the printing surface area 50 and the optical axis 42xe (outgoing optical axis) of the optical axis 42x of the second light beam 42 that is emitted from the printing surface area 50 can be made larger. This ensures the accuracy of detecting unevenness on the printing surface area 50. Furthermore, according to the configuration (1) above, the angle θ3 can be increased, so that the detection accuracy of unevenness can be ensured to be equal to or higher than when a window for the entrance of the first light beam 41 and a window for the exit of the second light beam 42 are provided separately, or when a single window portion with a relatively large opening area is provided. According to the configuration (1) above, the first window 71 is the only window that is required to allow the first light beam 41 and the second light beam 42 to pass through, so it is easy to secure a window even if there are space restrictions. Furthermore, according to the configuration (1) above, the size of the first window portion 71 can be made relatively small, so that the first window portion 71 can be easily secured even if there are space restrictions.

[0062] The range through which the light beam can pass through the first window portion 71 is limited by the width and thickness of the first window portion 71. The above configuration (1) can mitigate the influence of these limitations. Furthermore, there are limitations on the position where the first window 71 can be disposed, and there are also limitations on the positions where the projection unit 34a and the imaging unit 34b can be disposed. Therefore, there are limitations on the positional relationship between the first window 71 and the projection unit 34a and the imaging unit 34b. The configuration (1) above can alleviate the effects of such limitations on the positional relationship.

[0063] According to the configuration (1) above, the projection unit 34a and the imaging unit 34b are arranged outside the chamber 60, so that space within the chamber 60 can be secured and the flow of air such as an inert gas introduced into the chamber to ensure the molding quality is less likely to be disturbed.

[0064] According to the configuration (1) above, if the reflector 36 is configured to reflect the first light beam 41, the optical path of the first light beam 41 can be made longer than when the first light beam 41 from the projection unit 34a is directly irradiated onto the printing surface area 50, and the irradiation angle θ1 of the first light beam 41 from the projection unit 34a can be made smaller. This makes it possible to suppress distortion of the periphery of the pattern projected onto the printing surface area 50. This improves the accuracy of detecting irregularities in the region of the printing surface area 50 that corresponds to the periphery of the pattern. Furthermore, because the irradiation angle θ1 of the first light beam 41 from the projection unit 34a can be made smaller, the size of the first window 71 can be made smaller.

[0065] According to the configuration (1) above, if the reflector 36 is configured to reflect the second light beam 42, the optical path of the second light beam 42 can be lengthened compared to when the second light beam 42 emitted from the print surface area 50 is directly incident on the image capture unit 34b, thereby reducing the angle of view θ2 of the image capture unit 34b required to capture the pattern projected on the print surface area 50. This reduces distortion of the peripheral image of the pattern captured by the image capture unit 34b. This improves the accuracy of detecting irregularities in the region of the print surface area 50 that corresponds to the peripheral portion of the pattern. Furthermore, because the angle of view θ2 of the image capture unit 34b required to capture the pattern projected on the print surface area 50 can be reduced, the size of the first window 71 can be easily reduced.

[0066] (2) In some embodiments, in the configuration of (1) above, the reflecting section 36 may be configured to reflect the second light beam 42 without reflecting the first light beam 41.

[0067] According to the configuration (2) above, by reflecting the second light beam 42 at the reflecting section 36, as described above, the accuracy of detecting unevenness in the region of the printing surface area 50 corresponding to the periphery of the pattern can be improved.

[0068] (3) In some embodiments, in the configuration of (1) above, the reflecting section 36 may be configured to reflect the first light beam 41 without reflecting the second light beam 42.

[0069] According to the configuration (3) above, by reflecting the first light beam 41 at the reflecting section 36, as described above, it is possible to improve the accuracy of detecting unevenness in the region of the printing surface area that corresponds to the periphery of the pattern.

[0070] (4) In some embodiments, in the configuration of (1) above, the reflecting portion 36 may include a first reflecting portion 361 configured to reflect the first light beam 41 and a second reflecting portion 362 different from the first reflecting portion 361 configured to reflect the second light beam 42.

[0071] According to the above configuration (4), by reflecting the first light beam 41 by the first reflecting portion 361, it is possible to improve the accuracy of detecting unevenness in the region of the printing surface area 50 that corresponds to the periphery of the pattern, as described above. Furthermore, according to the above configuration (4), by reflecting the second light beam 42 by the second reflecting portion 362, it is possible to improve the accuracy of detecting unevenness in the region of the printing surface area 50 that corresponds to the periphery of the pattern, as described above. Therefore, according to the above configuration (4), it is possible to further improve the accuracy of detecting unevenness in the region that corresponds to the periphery of the pattern.

[0072] (5) In some embodiments, in any of the configurations (1) to (4) above, the reflecting portion 36 may include a reflecting surface 36a that is a flat surface.

[0073] According to the configuration (5) above, when performing calculations to detect unevenness in the printing surface area based on image data acquired by the imaging unit 34b, the presence of the reflecting unit 36 makes the correction required relatively simple compared to when the reflecting surface 36a is not flat. Furthermore, according to the configuration (5) above, the cost of the reflecting section 36 can be reduced compared to when the reflecting surface 36a is not flat.

[0074] (6) In some embodiments, in any of the configurations (1) to (4) above, the reflecting portion 36 may include a reflecting surface 36a that is a curved surface.

[0075] According to the above configuration (6), if the reflecting unit 36 is configured to reflect the first light beam 41, the irradiation angle θ1 of the first light beam 41 from the projection unit 34a can be made smaller than when the reflecting surface 36a is flat. This makes it possible to project a pattern over a relatively wide range on the printing surface area 50, even if the size of the first window 71 is small. Furthermore, according to the configuration (6) above, if the reflecting unit 36 is configured to reflect the second light beam 42, the same effect as increasing the aperture diameter of the optical system in the image capturing unit 34b can be obtained compared to when the reflecting surface 36a is flat. This makes it possible to suppress deterioration of the optical resolution due to the diffraction limit in the optical system. Furthermore, according to the configuration (6) above, if the reflecting unit 36 is configured to reflect the second light beam 42, the angle of view θ2 of the image capturing unit 34b required to capture an image of the pattern projected on the printing surface area 50 can be made smaller compared to when the reflecting surface 36a is flat, making it easier to reduce the size of the first window 71.

[0076] (7) In some embodiments, in any of the configurations (1) to (6) above, the projection unit 34a and the image capture unit 34b may be disposed above the chamber 60. The first light beam 41 and the second light beam 42 may be able to pass through a first window 71 provided at the top of the chamber 60. The reflector 36 may be attached to a side wall of the chamber 60.

[0077] According to the configuration (7) above, there are relatively few restrictions on the placement of the projection unit 34a, the image capture unit 34b, and the reflection unit 36, so they can be placed relatively easily.

[0078] (8) In some embodiments, in any of the configurations (1) to (6) above, the projection unit 34a and the imaging unit 34b may be disposed on the side of the chamber 60. The first light beam 41 and the second light beam 42 may be able to pass through a first window 71 provided on the side of the chamber 60. The reflecting unit 36 may be attached to the ceiling 62 of the chamber 60.

[0079] According to the configuration (8) above, even if it is difficult to arrange the projection unit 34a and the image capture unit 34b above the chamber 60, the projection unit 34a and the image capture unit 34b can be arranged on the side of the chamber 60. In this case, by attaching the reflecting unit 36 to the ceiling 62 of the chamber 60, the angle θ3 formed between the optical axis (incident optical axis) 41xi of the first light beam 41 incident on the printing surface area 50 and the optical axis (exiting optical axis) 42xe of the second light beam 42 exiting from the printing surface area 50 can be made relatively large.

[0080] (9) In some embodiments, in any of the configurations (1) to (8) above, a first irradiation unit (first beam irradiation unit 141) capable of irradiating beam B and disposed outside the chamber 60, and a second irradiation unit (second beam irradiation unit 142) capable of irradiating beam B and disposed outside the chamber 60 and different from the first irradiation unit (first beam irradiation unit 141) may be provided. The beam B irradiated from the first irradiation unit (first beam irradiation unit 141) may be able to pass through a second window 72 disposed in the chamber 60 and different from the first window 71, and the beam B irradiated from the second irradiation unit (second beam irradiation unit 142) may be able to pass through a third window 73 disposed in the chamber 60 and different from the first window 71 and the second window 72.

[0081] In the three-dimensional additive manufacturing apparatus 1 configured to reduce the modeling time by irradiating the beam B from multiple irradiation parts (beam irradiation units 14) as in the configuration (9) above, the number of windows provided in the chamber 60 increases as the number of irradiation parts (beam irradiation units 14) increases. Therefore, the size and installation position of the first window part 71 are further restricted. According to the configuration (9) above, even if the size and installation position of the first window portion 71 are further restricted, it is possible to increase the angle formed between the optical axis (incident optical axis) 41xi of the first light beam 41 incident on the printing surface area 50 and the optical axis (exiting optical axis) 42xe of the second light beam 42 exiting from the printing surface area 50. This ensures the accuracy of detecting unevenness in the printing surface area 50. [Explanation of symbols]

[0082] 1. 3D additive manufacturing equipment 8 Powder Bed 14 Beam irradiation unit (irradiation unit) 34 Shape measuring device 34a Projection section 34b Imaging unit 34c Unevenness detection unit 36 Reflector 361 1st reflection section 362 2nd reflection section 60 Chambers 61 Side wall (side) 62 Ceiling (upper part) 71 First window 72 Second window section 73 Third window section 100 control device 141 First beam irradiation unit (first irradiation unit) 142 Second beam irradiation unit (second irradiation unit)

Claims

1. A three-dimensional additive manufacturing apparatus that performs additive manufacturing by irradiating a powder bed laid on a manufacturing surface area with a beam, a projection unit configured to project a pattern having a luminance distribution in the printing surface area, the luminance distribution changing over time; an imaging unit configured to capture an image of the pattern projected onto the build surface area; a reflecting unit configured to reflect at least one of a first light flux projected by the projection unit and a second light flux captured by the image capturing unit; Equipped with the projection unit and the imaging unit are disposed outside a chamber in which additive manufacturing is performed on the manufacturing surface area; the reflector is housed within the chamber; the first light beam and the second light beam can pass through a first window portion provided in the chamber; The reflecting portion includes a reflecting surface that is a curved surface. 3D additive manufacturing equipment.

2. A three-dimensional additive manufacturing device that performs additive manufacturing by irradiating a powder bed laid in a manufacturing surface area with a beam, comprising: a projection unit configured to project a pattern having a luminance distribution in the printing surface area, the luminance distribution changing over time; an imaging unit configured to capture an image of the pattern projected onto the build surface area; a reflecting unit configured to reflect at least one of a first light flux projected by the projection unit and a second light flux captured by the image capturing unit; Equipped with the projection unit and the imaging unit are disposed outside a chamber in which additive manufacturing is performed on the manufacturing surface area; the reflector is housed within the chamber; the first light beam and the second light beam can pass through a first window portion provided in the chamber; the projection unit and the imaging unit are disposed above the chamber, the first light beam and the second light beam can pass through the first window portion provided in the upper portion of the chamber; The reflector is attached to the side wall of the chamber. 3D additive manufacturing equipment.

3. A three-dimensional additive manufacturing device that performs additive manufacturing by irradiating a beam onto a powder bed laid in a manufacturing surface area, a projection unit configured to project a pattern having a luminance distribution in the printing surface area, the luminance distribution changing over time; an imaging unit configured to capture an image of the pattern projected onto the build surface area; a reflecting unit configured to reflect at least one of a first light flux projected by the projection unit and a second light flux captured by the image capturing unit; Equipped with the projection unit and the imaging unit are disposed outside a chamber in which additive manufacturing is performed on the manufacturing surface area; the reflector is housed within the chamber; the first light beam and the second light beam can pass through a first window portion provided in the chamber; the projection unit and the imaging unit are disposed on the sides of the chamber, the first light beam and the second light beam can pass through the first window portion provided on a side portion of the chamber; The reflector is attached to the ceiling of the chamber. 3D additive manufacturing equipment.

4. The reflecting portion is configured not to reflect the first light beam but to reflect the second light beam. The three-dimensional additive manufacturing apparatus according to any one of claims 1 to 3.

5. The reflecting portion is configured to reflect the first light beam without reflecting the second light beam. The three-dimensional additive manufacturing apparatus according to any one of claims 1 to 3.

6. The reflecting portion is a first reflecting portion configured to reflect the first light flux; a second reflecting section different from the first reflecting section, configured to reflect the second light flux; Including, The three-dimensional additive manufacturing apparatus according to any one of claims 1 to 3.

7. The reflecting portion includes a flat reflecting surface. The three-dimensional additive manufacturing apparatus according to any one of claims 1 to 6.

8. a first irradiation unit capable of irradiating the beam and disposed outside the chamber; a second irradiation unit that is capable of irradiating the beam and is disposed outside the chamber and is different from the first irradiation unit; Equipped with the beam irradiated from the first irradiation unit can pass through a second window unit that is installed in the chamber and is different from the first window unit, the beam irradiated from the second irradiation unit can pass through a third window unit that is installed in the chamber and is different from the first window unit and the second window unit; The three-dimensional additive manufacturing apparatus according to any one of claims 1 to 7.

Images