Three-dimensional lamination molding evaluation system and three-dimensional lamination molding evaluation method

Abstract

To provide a three-dimensional lamination molding evaluation system which can evaluate the quality of a molten pool accurately, and to provide a three-dimensional lamination molding evaluation method.SOLUTION: A three-dimensional lamination molding evaluation system includes: a radiation device configured to emit a beam for melting a powder layer installed; a scanning device for reflecting the beam from the radiation device toward the powder layer and changing a reflection angle of the beam to move a beam radiation position in the powder layer; a light measurement device for measuring an intensity of light emission from a molten pool formed in the radiation position of the powder layer; a reflection device disposed between the scanning device and the radiation device and configured to reflect the light emission reflected by the scanning device toward the light measurement device; and a first light condensing position change device including a first lens disposed between the reflection device and the light measurement device and configured to move the first lens in a first optical axis direction which is an optical axis direction of the first lens.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a three-dimensional additive manufacturing evaluation system and a three-dimensional additive manufacturing evaluation method. [Background technology]

[0002] Conventionally, there is known a three-dimensional printing apparatus that forms a model by irradiating a beam onto a laid powder layer. For example, a three-dimensional printing apparatus disclosed in Patent Document 1 includes a laser for irradiating a powder-laying surface (build surface) with a laser beam. The irradiated laser beam passes through a focusing system and is projected onto the powder-laying surface. Light energy resulting from light emitted by a molten pool formed on the powder-laying surface passes through the focusing system and a partially reflecting mirror and enters an axial optical sensor. Data generated by the axial optical sensor is used to determine the thermal energy density during the printing process. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2023-531178 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned three-dimensional modeling device, when the projection position on the powder-laying surface moves, the optical path length from the molten pool to the axial optical sensor changes. In this case, the light emitted from the molten pool is not collected by the axial optical sensor, and the thermal energy density in the molten pool may not be measured accurately. Therefore, the quality of the molten pool may not be evaluated accurately. To give a more specific example, in the above-mentioned three-dimensional modeling device, the light from the metal plume directly above the molten pool is focused by the axial optical sensor, which may make it difficult to accurately evaluate whether there is an abnormality in the molten pool.

[0005] An object of the present disclosure is to provide a three-dimensional additive manufacturing evaluation system and a three-dimensional additive manufacturing evaluation method that can accurately evaluate the quality of a molten pool. [Means for solving the problem]

[0006] A three-dimensional additive manufacturing evaluation system according to at least one embodiment of the present disclosure includes: an irradiation device configured to irradiate a beam for melting the laid powder layer; a scanning device for reflecting the beam from the irradiation device toward the powder layer and changing a reflection angle of the beam to move an irradiation position of the beam on the powder layer; an optical measuring device for measuring an intensity of light emitted from a molten pool formed at the irradiation position of the powder layer; a reflecting device disposed between the scanning device and the illumination device and configured to reflect the emitted light reflected by the scanning device towards the optical measurement device; a first focusing position changing device including a first lens disposed between the reflecting device and the light measuring device, the first lens being configured to move in a first optical axis direction that is an optical axis direction of the first lens; Equipped with.

[0007] A three-dimensional additive manufacturing evaluation method according to at least one embodiment of the present disclosure includes: a measuring step of measuring, by an optical measuring device, an intensity of light emitted from a molten pool formed at a position where the powder layer is irradiated with the beam; a first lens moving step of moving a first lens disposed between a reflecting device that reflects the emitted light toward the optical measuring device and the optical measuring device in a first optical axis direction that is an optical axis direction of the first lens according to the irradiation position on the powder layer during the execution of the measurement step; Equipped with. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a three-dimensional additive manufacturing evaluation system and a three-dimensional additive manufacturing evaluation method that can accurately evaluate the quality of a molten pool. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a three-dimensional additive manufacturing apparatus according to an embodiment. [Diagram 2] FIG. 1 is a schematic diagram of a three-dimensional additive manufacturing evaluation system according to an embodiment. [Diagram 3] FIG. 1 is a schematic diagram illustrating a beam irradiation position on a powder layer according to one embodiment. [Figure 4] FIG. 2 is a schematic diagram of a controller according to one embodiment. [Diagram 5] 1 is a flowchart of a three-dimensional additive manufacturing evaluation method according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, some 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 the 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 configuration, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such a configuration, 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 indicating that things are in an equal state, such as "identical," "equal," and "homogeneous," 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 describing shapes such as a rectangular shape or a cylindrical shape do not only refer to rectangular shapes, cylindrical shapes, etc. in the strict geometric sense, but also refer to shapes that include uneven portions, chamfered portions, etc., to the extent that the same effect is obtained. On the other hand, the expressions "comprise", "include", or "have" a certain element are not exclusive expressions excluding the presence of other elements. In addition, the same components are denoted by the same reference numerals and the description thereof may be omitted.

[0011] <Basic configuration of 3D additive manufacturing device 1> 1 is a schematic diagram of a three-dimensional additive manufacturing apparatus 1 according to an embodiment of the present disclosure. The three-dimensional additive manufacturing apparatus 1 includes a powder supplying device 3 for laying down powder that is a raw material for a three-dimensional object, an irradiation device 4 for irradiating a beam that melts the powder, a scanning device 30 for reflecting the beam irradiated from the irradiation device 4 toward a powder layer 6 made of the laid down powder, and a base plate 9 that can be raised and lowered.

[0012] The powder supplying device 3 is configured to move horizontally. The irradiation device 4 is fixed above a base plate 9. The scanning device 30 includes at least one mirror for reflecting the beam, an actuator for rotating the mirror, and a control driver for sending a drive command to the actuator. The actuator rotates the mirror according to the drive command sent from the control driver, and the scanning device 30 changes the reflection angle of the beam.

[0013] As a more detailed example, the scanning device 30 is a galvanometer scanner. The mirror has an X mirror configured to rotate around the X axis, and a Y mirror configured to rotate around the Y axis. Both the X axis and the Y axis are horizontal axes. The actuator has an X motor and a Y motor for applying rotational power to the X mirror and the Y mirror, respectively. The galvanometer scanner changes the reflection angle of the beam by driving the X motor and the Y motor according to a drive command sent from a control driver serving as a motor driver.

[0014] The operation of the three-dimensional additive manufacturing apparatus 1 to form a model is as follows. The powder supplying device 3 forms the first powder layer 6 by laying powder on the base plate 9 while moving horizontally. The irradiation device 4 then irradiates a beam toward the scanning device 30, which reflects the beam toward the powder layer 6. The powder layer 6 irradiated with the beam melts. The scanning device 30 changes the reflection angle of the beam, so that the area (spot) irradiated with the beam moves across the entire area of ​​the first powder layer 6. The parts of the powder layer 6 that have been irradiated with the beam solidify sequentially, forming the first modeling layer 7. The irradiation device 4 stops irradiating the beam, and the base plate 9 moves down a distance equivalent to the thickness of the modeling layer 7.

[0015] Thereafter, the powder supplying device 3 forms a second powder layer 6 by laying powder on the first modeling layer 7, and the scanning device 30 reflects the beam irradiated from the irradiation device 4 toward the second powder layer 6. After the second modeling layer 7 is formed, the base plate 9 descends again. The powder supplying device 3, the irradiation device 4, the scanning device 30, and the base plate 9 repeat the above operations, forming a model as stacked modeling layers 7. In the schematic diagram of FIG. 1, a third powder layer 6 is laid on the second modeling layer 7.

[0016] The powder supplied by the powder supplying device 3 may be a metal material such as iron, copper, aluminum, or titanium, or a non-metal material such as ceramic. The beam irradiated by the irradiation device 4 may be either a laser beam or an electron beam.

[0017] <Basic configuration of 3D additive manufacturing evaluation system 5> 2 is a schematic diagram showing a three-dimensional additive manufacturing evaluation system 5 according to an embodiment of the present disclosure. At an irradiation position P of the powder layer 6 where a beam from the irradiation device 4 hits, a molten pool 8 of the powder layer 6 is formed, and the molten pool 8 solidifies to form a modeling layer 7. The three-dimensional additive manufacturing evaluation system 5 is configured to evaluate the quality of the molten pool 8, and both the irradiation device 4 and the scanning device 30 described above are components of the three-dimensional additive manufacturing evaluation system 5. Note that the molten pool 8 may include a molten portion of the modeling layer 7 located directly below the powder layer 6.

[0018] The three-dimensional additive manufacturing evaluation system 5 includes an optical measurement device 80 for measuring the intensity of the light emitted from the molten pool 8 (hereinafter, the light emitted from the molten pool 8 may be simply referred to as "light emission"). The scattered light emission is indicated by an arrow S in FIG. 2. The optical measurement device 80 includes a light receiving unit configured to receive at least a portion of the light emission reaching the scanning device 30, and an analysis unit configured to analyze the intensity of the light emission received by the light receiving unit. As a more specific example, the light receiving unit is a photodiode, and is fixed at a predetermined position. The analysis unit is a calculation device configured to calculate the intensity of the light emission based on an electrical signal output from the photodiode.

[0019] The three-dimensional additive manufacturing evaluation system 5 further includes a reflecting device 40 disposed on the beam path between the scanning device 30 and the irradiation device 4. The reflecting device 40 includes a half mirror which may be a dichroic mirror or the like. The half mirror is configured to allow the passage of the beam from the irradiation device 4 toward the scanning device 30, and is configured to reflect the emitted light reflected by the scanning device 30 toward the optical measurement device 80. A part of the emitted light from the molten pool 8 formed in the powder layer 6 by the irradiation of the beam reaches the scanning device 30, and the emitted light passing through the mirror of the scanning device 30 and the half mirror of the reflecting device 40 in this order reaches the light receiving section of the optical measurement device 80.

[0020] The intensity of the emitted light needs to be measured accurately in order to accurately evaluate the quality of the molten pool 8. For this purpose, it is preferable that the emitted light that passes through the scanning device 30 and the reflecting device 40 in this order is collected at the light receiving portion of the optical measuring device 80.

[0021] 3, when the irradiation position P moves horizontally (arrow H) by changing the beam reflection angle using the scanning device 30, the optical path length (dimension L) of the emitted light between the irradiation position P and the optical measurement device 80 changes. Conventionally, when the dimension L increases, the emitted light scattered at the irradiation position P becomes concentrated in front of the light receiving part of the optical measurement device 80. Instead, the light emitted by the plume formed directly above the molten pool 8 (arrow Q) becomes concentrated at the light receiving part. This makes it difficult to accurately measure the intensity of the emitted light.

[0022] 2, the three-dimensional additive manufacturing evaluation system 5 according to this embodiment further includes a first light-collection-position varying device 10 including a first lens 11 disposed between the reflecting device 40 and the optical measuring device 80. The first light-collection-position varying device 10 is configured to move the first lens 11 along the optical axis direction (first optical axis direction) of the first lens 11. As a more specific example, the first light-collection-position varying device 10 further includes a first motor 101 for moving the first lens 11. The first optical axis direction is the vertical direction.

[0023] The three-dimensional additive manufacturing evaluation system 5 according to an embodiment of the present disclosure further includes a first condenser lens 13 fixed between the first lens 11 and the reflecting device 40. The first lens 11 also includes a first diffusing lens 11a. The focal length of the first condenser lens 13 changes as the first motor 101 moves the first diffusing lens 11a in the first optical axis direction.

[0024] According to the above configuration, when the irradiation position P moves horizontally, the first focusing position changing device 10 can move the first lens 11 in the first optical axis direction. Since the focal length of the first focusing lens 13 changes, even if the optical path length (dimension L in FIG. 3) between the irradiation position P and the optical measurement device 80 changes, the state in which the light emitted from the molten pool 8 is focused at the light receiving unit of the optical measurement device 80 is maintained. More specifically, even if the dimension L shown in FIG. 3 increases, the light emitted by the plume is less likely to be focused at the light receiving unit of the optical measurement device 80, and the state in which the light emitted is focused at the light receiving unit is maintained. Thus, a three-dimensional additive manufacturing evaluation system 5 capable of accurately evaluating the quality of the molten pool 8 is realized.

[0025] The first light-collecting-position-changing device 10 according to an embodiment of the present disclosure may be a 3D scanner, and the first lens 11 may have a plurality of first diffusing lenses 11a. The first light-collecting-position-changing device 10 may further include an objective lens 15 fixed between the first lens 11 and the first condensing lens 13.

[0026] The optical path of the light emitted from the molten pool 8 between the scanning device 30 and the irradiation device 4 is also the path of the beam irradiated by the irradiation device 4. That is, the dimension L shown in FIG. 3 corresponds to the beam path length between the scanning device 30 and the irradiation device 4.

[0027] <Details of the optical system of the 3D additive manufacturing evaluation system 5> A configuration that may be additionally provided in the three-dimensional additive manufacturing evaluation system 5 will be described with reference to FIG. The three-dimensional additive manufacturing evaluation system 5 further includes a second focusing position changing device 20 including a second lens 22 arranged on a beam path between the reflecting device 40 and the irradiation device 4. The second focusing position changing device 20 is configured to move the second lens 22 along the optical axis direction (second optical axis direction) of the second lens 22. As a more specific example, the second focusing position changing device 20 further includes a second motor 102 for moving the second lens 22. Note that the second optical axis direction is perpendicular to the first optical axis direction.

[0028] The three-dimensional additive manufacturing evaluation system 5 according to an embodiment of the present disclosure further includes a second condenser lens 23 fixed between the second lens 22 and the reflecting device 40. The second lens 22 also has a second diffusing lens 22a. The focal length of the second condenser lens 23 changes as the second motor 102 moves the second diffusing lens 22a in the second optical axis direction.

[0029] According to the above configuration, when the irradiation position P of the beam on the powder layer 6 moves horizontally due to a change in the reflection angle of the beam in the scanning device 30, the second lens 22 moves in the second optical axis direction, and the focal length of the second condenser lens 23 changes. Therefore, even if the irradiation position P moves horizontally and the beam path length (dimension L in FIG. 3) from the irradiation device 4 to the irradiation position P changes, the state in which the beam is condensed on the powder layer 6 is maintained. Therefore, the thermal energy for melting can be concentrated on the powder layer 6.

[0030] The second focusing position changing device 20 according to an embodiment of the present disclosure may be a 3D scanner, and the second lens 22 may have a plurality of second diffusing lenses 22a. The second focusing position changing device 20 may further include an objective lens 25 fixed between the second lens 22 and the second focusing lens 23.

[0031] <Control system of 3D additive manufacturing evaluation system 5> 2 and 4, the three-dimensional additive manufacturing evaluation system 5 includes a controller 90. The controller 90 includes a first light collection control unit 91 for controlling the first light collection position changing device 10. More specifically, the first light collection control unit 91 is configured to control a first motor 101 so that the first diffusing lens 11a moves in the first optical axis direction in response to a change in the beam reflection angle by the scanning device 30.

[0032] More specifically, when the optical path length (dimension L in FIG. 3) of the emitted light between the scanning device 30 and the irradiation position P increases due to a change in the reflection angle by the scanning device 30, the first light collection control unit 91 controls the first motor 101 to move the first diffusing lens 11a in a direction away from the first condensing lens 13. Conversely, when the optical path length between the scanning device 30 and the irradiation position P decreases, the first light collection control unit 91 controls the first motor 101 to move the first diffusing lens 11a toward the first condensing lens 13.

[0033] According to a configuration in which the controller 90 includes the first light collection control unit 91, the first lens 11 of the first light collection position changing device 10 can be automatically moved in response to a change in the optical path length between the scanning device 30 and the irradiation position P. As a result, even if the optical path length between the irradiation position P and the optical measurement device 80 changes, the state in which the light emitted from the molten pool 8 is collected on the light receiving part of the optical measurement device 80 can be automatically maintained.

[0034] Furthermore, according to the configuration in which the first focusing control unit 91 controls the first motor 101 as described above, even if the optical path length between the scanning device 30 and the irradiation position P increases, the distance between the first diffusing lens 11a and the first condensing lens 13 increases, and the focal length of the first condensing lens 13 increases. Even if the optical path length decreases, the distance between the first diffusing lens 11a and the first condensing lens 13 decreases, and the focal length of the first condensing lens 13 decreases. Therefore, even if the irradiation position P of the beam on the powder layer 6 moves horizontally, the light emitted from the molten pool 8 can be properly focused by the light receiving unit of the optical measurement device 80.

[0035] 4, the controller 90 further includes a second focus control unit 92 for controlling the second focus position changing device 20. More specifically, the second focus control unit 92 is configured to control the second motor 102 so that the second diffusing lens 22a moves in the second optical axis direction in response to a change in the beam reflection angle by the scanning device 30.

[0036] More specifically, when the beam path length (dimension L in FIG. 3) between the scanning device 30 and the irradiation position P increases due to a change in the reflection angle by the scanning device 30, the second condenser control unit 92 controls the second motor 102 to move the second diffusing lens 22a in a direction away from the second condenser lens 23. Conversely, when the beam path length between the scanning device 30 and the irradiation position P decreases, the second condenser control unit 92 controls the second motor 102 to move the second diffusing lens 22a toward the second condenser lens 23.

[0037] According to a configuration in which the controller 90 includes the second focus control unit 92, the second lens 22 of the second focus position changing device 20 can be automatically moved even if the beam path length (dimension L in FIG. 3) between the scanning device 30 and the irradiation position P changes. This makes it possible to automatically maintain the state in which the beam from the irradiation device 4 is focused on the powder layer 6.

[0038] Furthermore, according to the configuration in which the second focusing control unit 92 controls the second motor 102 as described above, even if the beam path length between the scanning device 30 and the irradiation position P increases, the distance between the second diffusing lens 22a and the second condensing lens 23 increases, and the focal length of the second condensing lens 23 increases. Even if the beam path length decreases, the distance between the second diffusing lens 22a and the second condensing lens 23 decreases, and the focal length of the second condensing lens 23 decreases. Therefore, even if the irradiation position P of the beam on the powder layer 6 moves horizontally, the beam can be properly focused on the powder layer 6.

[0039] The motor control of each of the first light collection control unit 91 and the second light collection control unit 92 is synchronized with the control of changing the reflection angle of the beam by the scanning device 30. A specific implementation method is as follows. The second light collection control unit 92 is configured to monitor the reflection control of the beam by the scanning device 30. For example, data indicating the rotation amount and rotation direction of each of the X motor and the Y motor is sent from the motor driver of the scanning device 30 to the second light collection control unit 92. The second light collection control unit 92 controls the second motor 102 according to the above data acquired from the motor driver. Furthermore, the control data of the second motor 102 by the second light collection control unit 92 is sent to the first light collection control unit 91. The control data indicates the rotation amount and rotation direction of the second motor 102. The first light collection control unit 91 controls the first motor 101 according to the control data acquired from the second light collection control unit 92. As a result, the first motor 101 and the second motor 102 are driven in synchronization with the control of changing the reflection angle of the beam in the scanning device 30.

[0040] 4, the controller 90 further includes a measurement control unit 94 and an abnormality determination unit 95. The measurement control unit 94 is configured to send a command to the optical measurement device 80 to measure the intensity of the light emitted from the molten pool 8, and is configured to acquire the measurement result from the optical measurement device 80. The measurement result acquired by the measurement control unit 94 is output to the abnormality determination unit 95.

[0041] The abnormality determination unit 95 is configured to determine that there is an abnormality in the molten pool 8 when the intensity of the light emission measured by the optical measurement device 80 does not fall within an allowable range. The allowable range is defined by an upper threshold and a lower threshold. An event in which the intensity of the light emission falls below the lower threshold is caused by the temperature of the molten pool 8 being too low. An event in which the intensity of the light emission exceeds the upper threshold is caused by the temperature of the molten pool 8 being too high. Either of these events indicates that the quality of the molten pool 8 is insufficient. When it is determined that there is an abnormality in the molten pool 8, the additive manufacturing operation of the three-dimensional additive manufacturing device 1 is interrupted, for example, by the operation of the operator or by the control of the controller 90. This allows the three-dimensional additive manufacturing device 1 to take appropriate measures.

[0042] In this example, the allowable range referred to by the abnormality determination unit 95 is the same regardless of the irradiation position P in the powder layer 6. Since the light emitted from the molten pool 8 is focused on the light receiving unit of the optical measurement device 80 regardless of the position of the molten pool 8, even if only a single allowable range is referred to, the abnormality determination unit 95 can properly determine the presence or absence of an abnormality in the molten pool 8. Therefore, the determination process of the abnormality determination unit 95 can be simplified compared to the case where multiple types of allowable ranges are prepared according to the position where the molten pool 8 is formed.

[0043] <3D additive manufacturing evaluation method> 5 is a flowchart of a 3D additive manufacturing evaluation method according to an embodiment of the present disclosure. The evaluation method is a control process executed by the processor of the controller 90 each time a powder layer 6 is laid. Through execution of the evaluation method, the quality of the molten pool 8 is evaluated and the powder layer 6 is transformed into a modeling layer 7. In the following description, "step" may be abbreviated as "S".

[0044] First, a beam irradiation step (S11) is performed in which a beam is irradiated toward the powder layer 6. The processor controls the irradiation device 4 and the scanning device 30, so that the beam is irradiated onto the powder layer 6, and a molten pool 8 is formed at the irradiation position P.

[0045] Next, a measurement step (S13) is executed to measure the intensity of the light emitted from the molten pool 8. The processor sends a measurement command to the analysis unit of the optical measurement device 80, and obtains the measurement result of the light emission intensity from the analysis unit. The processor that executes S13 is an example of the measurement control unit 94. Next, the processor determines whether the light emission intensity is within an allowable range (S15). The processor that executes S15 is an example of the abnormality determination unit 95.

[0046] If it is determined that the measured intensity falls within the allowable range (S15: YES), the processor controls the scanning device 30 so that the irradiation position P moves horizontally (S17). More specifically, the processor sends a predetermined command to a control driver of the scanning device 30, thereby moving the irradiation position P of the powder layer 6 horizontally. The molten pool 8 that is no longer irradiated with the beam gradually solidifies, and the modeling layer 7 begins to be formed.

[0047] Next, the processor executes a second lens moving step (S19) of moving the second lens 22 (more specifically, the second diffusing lens 22a) of the second focusing position changing device 20 in the second optical axis direction in response to the irradiation position P, and a first lens moving step (S21) of moving the first lens 11 (more specifically, the first diffusing lens 11a) of the first focusing position changing device 10 in the first optical axis direction in response to the movement of the second lens 22. By executing S19 and S21, even if the irradiation position P moves in the horizontal direction, the beam is focused at the irradiation position P, and the light emitted from the molten pool 8 is focused by the light receiving unit of the optical measurement device 80. The processor that executes S19 is an example of the second focusing control unit 92, and the processor that executes S21 is an example of the first focusing control unit 91. Note that S19 and S21 may be executed simultaneously.

[0048] Next, the processor determines whether to continue the 3D additive manufacturing evaluation method (S23). If there are any remaining portions of the powder layer 6 that have not been irradiated with the laser, the processor determines to continue (S23: YES), and the process returns to S11. By repeating S11 to S23, the entire powder layer 6 is irradiated with the beam, and the modeling layer 7 is completed. If the processor determines to end the 3D additive manufacturing evaluation method (S23: NO), the control process ends. After the 3D additive manufacturing device 1 further lays a new powder layer 6, the processor starts the control process again.

[0049] Furthermore, if it is determined that the intensity of the light emitted from the molten pool 8 is outside the acceptable range (S15: NO), the processor executes an abnormality notification step (S17) that displays information indicating an abnormality on a monitor (not shown) of the 3D additive manufacturing device 1, etc., and terminates this 3D additive manufacturing evaluation method.

[0050] <Other> The three-dimensional additive manufacturing evaluation system 5 does not need to include the second focusing position changing device 20. For example, if there is a device that raises and lowers at least one of the three-dimensional additive manufacturing evaluation system 5 or the base plate 9 according to the irradiation position P, it is possible to focus the laser at the irradiation position P regardless of the irradiation position P. Alternatively, when the beam irradiated by the irradiation device 4 is a laser beam, an Fθ lens may be mounted on the three-dimensional additive manufacturing evaluation system 5 instead of the second focusing position changing device 20. The Fθ lens is disposed between the scanning device 30 and the powder layer 6.

[0051] The controller 90 described above includes a processor and a memory (storage medium). The processor may be a CPU, a GPU, an MPU, a DSP, or a combination thereof. The processor according to another embodiment may be realized by an integrated circuit such as a PLD, an ASIC, an FPGA, or an MCU. The memory is configured to store various data temporarily or non-temporarily, and may be realized by at least one of a RAM, a ROM, or a flash memory, for example. The processor executes various control processes according to instructions of a program loaded into the memory. The controller 90 may be realized by one or more arithmetic units, one or more control drivers, or a combination thereof.

[0052] <Summary> The contents described in the above-mentioned embodiments can be understood, for example, as follows.

[0053] 1) A three-dimensional additive manufacturing evaluation system (5) according to at least one embodiment of the present disclosure, an irradiation device (4) configured to irradiate a beam for melting the laid powder layer (6); a scanning device (30) for reflecting the beam from the irradiation device toward the powder layer and for moving an irradiation position (P) of the beam on the powder layer by changing a reflection angle of the beam; an optical measuring device (80) for measuring an intensity of light emitted from a molten pool formed at the irradiation position of the powder layer; a reflecting device (40) disposed between the scanning device and the illumination device and configured to reflect the emitted light reflected by the scanning device towards the optical measurement device; a first focusing position changing device (10) including a first lens (11) disposed between the reflecting device and the light measuring device, and configured to move the first lens in a first optical axis direction that is an optical axis direction of the first lens; Equipped with.

[0054] According to the above configuration 1), when the irradiation position of the beam on the powder layer moves horizontally, the first focusing position changing device can move the first lens in the first optical axis direction. That is, even if the optical path length between the irradiation position and the optical measurement device changes, the state in which the light emitted from the molten pool is focused by the optical measurement device is maintained. Thus, a 3D additive manufacturing evaluation system that can accurately evaluate the quality of the molten pool is realized.

[0055] 2) In some embodiments, the three-dimensional additive manufacturing evaluation system described in 1) above, The optical system further includes a first focus control unit (91) for controlling the first focus position changing device so that the first lens moves in the first optical axis direction in response to a change in the reflection angle by the scanning device.

[0056] According to the above configuration 2), the first lens can be automatically moved in response to a change in the optical path length between the scanning device and the irradiation position, so that the emitted light from the molten pool can be automatically kept focused on the optical measurement device even if the optical path length between the irradiation position and the optical measurement device changes.

[0057] 3) In some embodiments, the three-dimensional additive manufacturing evaluation system described in 2) above, The optical system further includes a first focusing lens (13) fixed between the first focusing position changing device and the reflecting device, The first lens includes a first diffusing lens (11a), The first focusing control unit is configured to control the first focusing position changing device to move the first diffusing lens in a direction away from the first focusing lens when the change in the reflection angle by the scanning device increases the beam path length between the scanning device and the irradiation position.

[0058] According to the above configuration 3), even if the optical path length from the molten pool to the optical measurement device increases with an increase in the beam path length between the scanning device and the irradiation position, the distance between the first diffusing lens and the first condensing lens becomes longer, and the focal length of the first condensing lens becomes longer. Therefore, even if the beam irradiation position changes in the horizontal direction, the light emitted from the molten pool can be properly condensed by the optical measurement device.

[0059] 4) In some embodiments, the three-dimensional additive manufacturing evaluation system according to any one of 1) to 3) above, The apparatus further includes an abnormality determination unit (95) for determining that an abnormality exists in the molten pool when the intensity of the light emission measured by the optical measurement device is not within an allowable range.

[0060] According to the above configuration 4), if the abnormality determination unit determines that there is an abnormality in the molten area, measures such as interrupting additive manufacturing can be taken by an operator or by processor control.

[0061] 5) In some embodiments, the three-dimensional additive manufacturing evaluation system according to 4) above, The allowable range referred to by the abnormality determination unit is the same regardless of the irradiation position in the powder layer.

[0062] According to the above configuration 5), the light emitted from the molten pool is collected by the optical measurement device regardless of the position of the molten pool, so even if only one tolerance range is referenced, the abnormality determination unit can properly determine whether or not there is an abnormality in the molten pool. Therefore, the determination process of the abnormality determination unit can be simplified compared to the case where multiple types of tolerance ranges are prepared according to the position where the molten pool is formed.

[0063] 6) In some embodiments, the three-dimensional additive manufacturing evaluation system according to any one of 1) to 5) above, The optical system further includes a second focusing position changing device (20) including a second lens (22) arranged between the reflecting device and the irradiating device and configured to move the second lens in a second optical axis direction which is the optical axis direction of the second lens.

[0064] According to the above configuration 6), when the irradiation position of the beam on the powder layer moves horizontally, the second lens moves in the second optical axis direction. Even if the beam path length from the irradiation device to the irradiation position changes, the state in which the beam is focused on the powder layer is maintained. Therefore, the thermal energy for melting can be concentrated on the powder layer.

[0065] 7) In some embodiments, the three-dimensional additive manufacturing evaluation system described in 6) above, The optical system further includes a second focus control unit (92) for controlling the second focus position changing device so that the second lens moves in the second optical axis direction in response to a change in the reflection angle by the scanning device.

[0066] According to the above configuration 7), even if the beam path length between the reflecting device and the irradiation position changes, the state in which the beam is focused on the powder layer can be automatically maintained.

[0067] 8) In some embodiments, the three-dimensional additive manufacturing evaluation system described in 7) above, Further comprising a second focusing lens (23) disposed between the second focusing position changing device and the reflecting device, The second lens includes a second diffusing lens (22a), The second focusing control unit is configured to control the second focusing position changing device to move the second diffusing lens in a direction away from the second focusing lens when the change in the reflection angle by the scanning device increases the beam path length between the scanning device and the irradiation position.

[0068] According to the configuration of 8) above, even if the beam path length between the scanning device and the irradiation position increases, the distance between the second diverging lens and the second condenser lens becomes longer, and the second focal length of the second condenser lens becomes longer. Therefore, even if the irradiation position of the beam changes in the horizontal direction, the beam can be properly condensed on the powder layer.

[0069] 9) A three-dimensional additive manufacturing evaluation method according to at least one embodiment of the present disclosure, a measuring step (S13) of measuring the intensity of light emitted from a molten pool (8) formed at a beam irradiation position (P) of the powder layer (6) using an optical measuring device (80); a first lens moving step (S19) of moving a first lens (11) disposed between a reflecting device (40) that reflects the emitted light toward the optical measuring device and the optical measuring device in a first optical axis direction that is an optical axis direction of the first lens in accordance with the irradiation position on the powder layer during execution of the measurement step; Equipped with.

[0070] According to the above configuration 9), the same technical advantages as those of the above configuration 1) can be obtained. [Explanation of symbols]

[0071] 1: 3D additive manufacturing equipment 3: Powder feeding device 4: Irradiation device 5: 3D additive manufacturing evaluation system 6: Powder layer 7: Modeling layer 8: Molten pool 9: Base plate 10: First focusing position changing device 11: First lens 11a: First diffusing lens 13: First focusing lens 15: Objective lens 20: Second focusing position changing device 22: Second lens 22a: Second diffusing lens 23: Second focusing lens 25: Objective lens 30: Scanning device 40:Reflector 80: Optical measuring device 90: Controller 91: First light collection control unit 92: Second light collection control unit 94: Measurement control section 95: Abnormality determination section 101: First motor 102: Second motor H,L: Arrow P: Irradiation position Q, S: Arrow

Claims

1. an irradiation device configured to irradiate a beam for melting the laid powder layer; a scanning device for reflecting the beam from the irradiation device toward the powder layer and changing a reflection angle of the beam to move an irradiation position of the beam on the powder layer; an optical measuring device for measuring an intensity of light emitted from a molten pool formed at the irradiation position of the powder layer; a reflecting device disposed between the scanning device and the illumination device and configured to reflect the emitted light reflected by the scanning device towards the optical measurement device; a first focusing position changing device including a first lens disposed between the reflecting device and the light measuring device, the first lens being configured to move in a first optical axis direction that is an optical axis direction of the first lens; A three-dimensional additive manufacturing evaluation system comprising:

2. a first focusing control unit for controlling the first focusing position changing device so that the first lens moves in the first optical axis direction in response to a change in the reflection angle by the scanning device; The three-dimensional additive manufacturing evaluation system according to claim 1 .

3. a first focusing lens fixed between the first focusing position changing device and the reflecting device; The first lens comprises a first diffusing lens; The first focusing control unit is configured to control the first focusing position changing device so that the first diverging lens moves in a direction away from the first focusing lens when a beam path length between the scanning device and the irradiation position increases due to a change in the reflection angle by the scanning device. The three-dimensional additive manufacturing evaluation system according to claim 2 .

4. The apparatus further includes an abnormality determination unit for determining that an abnormality exists in the molten pool when the intensity of the emitted light measured by the optical measurement device is not within an allowable range. The three-dimensional additive manufacturing evaluation system according to any one of claims 1 to 3.

5. The tolerance range referred to by the abnormality determination unit is the same regardless of the irradiation position in the powder layer. The three-dimensional additive manufacturing evaluation system according to claim 4 .

6. The optical system further includes a second lens disposed between the reflecting device and the irradiating device, and a second focusing position changing device configured to move the second lens in a second optical axis direction that is an optical axis direction of the second lens. The three-dimensional additive manufacturing evaluation system according to claim 1 or 2.

7. a second light-focusing control unit for controlling the second light-focusing position changing device so that the second lens moves in the second optical axis direction in response to a change in the reflection angle by the scanning device; The three-dimensional additive manufacturing evaluation system according to claim 6.

8. Further comprising a second focusing lens disposed between the second focusing position changing device and the reflecting device; the second lens comprises a second diffusing lens; The second focusing control unit is configured to control the second focusing position changing device so that the second diverging lens moves in a direction away from the second focusing lens when a beam path length between the scanning device and the irradiation position increases due to a change in the reflection angle by the scanning device. The three-dimensional additive manufacturing evaluation system according to claim 7.

9. a measuring step of measuring, by an optical measuring device, an intensity of light emitted from a molten pool formed at a position where the powder layer is irradiated with the beam; a first lens moving step of moving a first lens disposed between a reflecting device that reflects the emitted light toward the optical measuring device and the optical measuring device in a first optical axis direction that is an optical axis direction of the first lens according to the irradiation position on the powder layer during the execution of the measurement step; A three-dimensional additive manufacturing evaluation method comprising:

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