Method for making stacking forming program, stacking forming method and stacking forming device

Abstract

A method for making a stacking forming program, a stacking forming method and a stacking forming device, which can reduce the support part without excessively increasing the forming time. The method for making a stacking forming program includes a reading process, a segmentation process, an overhang calculation process, a re-segmentation process, a maintenance process and an output process. In the reading process, a three-dimensional model is read. In the segmentation process, the three-dimensional model is segmented into a plurality of segmented layers. In the overhang calculation process, the overhang angle or overhang length of the segmented layer is calculated. In the re-segmentation process, at least a part of the segmented layer including the overhang part is re-segmented into two or more parts in the stacking direction. In the maintenance process, the segmented layer is not re-segmented, and a support part for supporting the segmented layer is not provided. The re-segmentation process and the maintenance process are selectively implemented based on the overhang angle or overhang length. In the output process, the stacking forming program that specifies the instructions related to the stacking forming is output.

Description

Technical Field

[0001] The present invention relates to a method for preparing a stacking forming program, a stacking forming method for performing stacking forming based on the stacking forming program prepared by the preparation method, and a stacking forming device for implementing the stacking forming method. Background Art

[0002] Generally speaking, a stacking molding device operates according to a stacking molding program created by a computer aided manufacturing (CAM) device to manufacture a desired three-dimensional object. In the stacking molding program, instructions related to the formation of a material layer and the formation of a solidified layer for each divided layer of the desired three-dimensional object divided at a specified stacking pitch are specified.

[0003] For example, a layered forming apparatus that performs powder bed fusion bonding forms a material layer in a region where a desired three-dimensional object is to be formed, i.e., a forming region, for each segmented layer, and irradiates the material layer with a laser or an electron beam to form a solidified layer. Then, the formation of the material layer and the solidified layer is repeated alternately to form a stack of multiple solidified layers, i.e., a three-dimensional object.

[0004] Sometimes, a three-dimensional object has a portion that extends further than the solidified layer directly below, namely an overhanging portion. Since the overhanging portion is easily deformed due to its own weight or thermal contraction, a support portion for supporting the overhanging portion may be provided as needed. US Patent Gazette US2020 / 0269509A1 discloses a CAM device that provides an appropriate support portion by considering mechanical quantities. Summary of the invention

[0005] [Problems to be solved by the invention]

[0006] The support part must be removed after the stacking and shaping, but the removal takes time and effort. In addition, in order to shape the support part, extra material is required, and the shaping time is extended by the amount corresponding to the time spent on shaping the support part. Therefore, it is ideal to reduce the support part within the range that does not hinder shaping.

[0007] Whether a support part is required for a given split layer directly depends on the horizontal length of the overhanging part in the split layer, i.e., the overhanging length. The overhanging length is determined by the inclination angle of the overhanging part, i.e., the overhanging angle, and the thickness of the split layer, i.e., the stacking pitch. By shortening the overhanging length, the possibility of forming without a support part increases.

[0008] If the stacking pitch is further reduced, the overhang length in each segmented layer can be shortened. On the other hand, if the stacking pitch is reduced, the number of segmented layers also increases, so the formation of the material layer and the solidified layer necessarily requires more time, thereby increasing the molding time.

[0009] The present invention is made in view of this situation, and its purpose is to provide a method for making a stacked forming program, which only re-divides at least a part of a specific split layer based on an overhang angle or an overhang length, thereby reducing the support portion without excessively increasing the forming time.

[0010] [Technical means to solve the problem]

[0011] According to the present invention, a method for making a stacked forming program is provided, comprising: a reading step of reading a three-dimensional model of a desired three-dimensional forming object; a segmentation step of segmenting the three-dimensional model into a plurality of segmented layers in a stacking direction at a normal stacking spacing of a specified size; an overhang calculation step of calculating an overhang angle or an overhang length for each of the plurality of segmented layers, wherein the overhang angle is an inclination angle of the overhanging portion, i.e., a portion protruding in the horizontal direction relative to the segmented layer directly below, and the overhang length is a length of the overhanging portion in the horizontal direction; and a re-segmentation step of calculating, when the overhang angle of the specified segmented layer is less than a first angle threshold, Or it is implemented when the overhanging length of the specified split layer is greater than a first length threshold, and the re-segmentation process is to re-divide at least a part of the split layer including the overhanging part into two or more in the stacking direction; a maintaining process is implemented when the overhanging angle of the specified split layer is greater than a first angle threshold, or when the overhanging length of the specified split layer is less than the first length threshold, and the maintaining process is not to re-divide the split layer and does not provide a supporting part to support the split layer; and an output process, based on the shape of each split layer, outputs a stacking formation program that specifies instructions related to stacking formation.

[0012] [Effects of the Invention]

[0013] In the method for making a stacked forming program of the present invention, a maintenance step without re-dividing or a re-dividing step of re-dividing is selectively performed based on the overhang angle or overhang length. Thus, only the split layers that need to be re-divided are re-divided, thereby reducing the support portion without excessively increasing the forming time. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structure of a stacking forming device.

[0015] Figure 2 It is a three-dimensional diagram of a coating machine head.

[0016] Figure 3 It is a three-dimensional diagram of a coating machine head.

[0017] Figure 4 It is an explanatory diagram of the material layer forming process.

[0018] Figure 5 It is an explanatory diagram of the material layer forming process.

[0019] Figure 6 It is an explanatory diagram of the material layer forming process.

[0020] Figure 7 This is a schematic diagram of the structure of the irradiation device.

[0021] Figure 8 This is a block diagram of a control device and a CAM device.

[0022] Fig. 9 This is a flowchart of a method for producing a layered modeling program.

[0023] Fig.10 An example of a three-dimensional model is shown.

[0024] Fig.11 This shows the three-dimensional model after the segmentation process.

[0025] Fig.12 This is an enlarged view of the fifth segmentation layer.

[0026] Fig.13 This is an enlarged view of the seventh segmentation layer.

[0027] Fig.14 This is an enlarged view of the seventh segmented layer after the overhanging portion setting process and the overlapping portion setting process.

[0028] Fig.15 This is an enlarged view of the seventh segmentation layer after the sub-segmentation process.

[0029] Fig.16 This is an enlarged view of the ninth segmentation layer.

[0030] Fig.17 This is an enlarged view of the ninth segmented layer after the overhanging portion setting process and the overlapping portion setting process.

[0031] Fig.18 This is an enlarged view of the ninth segmentation layer after the re-segmentation process.

[0032] Fig.19 The three-dimensional model after the maintaining step, the re-dividing step, or the supporting portion providing step is shown.

[0033] Fig. 20 This is an explanatory diagram of the irradiation sequence setting process.

[0034] Fig.21 It is an explanatory diagram after the redivision step, the overhanging portion setting step, and the overlapping portion setting step of the modified example.

[0035] Fig. 22 This is an example of a three-dimensional object formed by the layered forming procedure of this embodiment. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments of the present invention will be described using the drawings. Various modifications described below can be implemented in any combination.

[0037] First, the stacking forming device 1 is described. The stacking forming device 1 performs stacking forming according to the stacking forming program produced by the CAM device 5. Specifically, Figure 1 The stacking forming apparatus 1 of the present embodiment shown is an apparatus for performing powder bed fusion bonding, and alternately and repeatedly performs a material layer forming step of forming a material layer 73 and a solidified layer forming step of forming a solidified layer 75, thereby manufacturing a desired three-dimensional object. The stacking forming apparatus 1 includes a chamber 11, a material layer forming apparatus 2, an irradiation apparatus 3, and a control apparatus 4.

[0038] The chamber 11 is constructed in a substantially sealed manner, covering the area where the desired three-dimensional object is formed, namely the forming area R. During the forming process, an inert gas is supplied to the chamber 11 from an inert gas supply device not shown in the figure, and the chamber 11 is filled with an inert gas of a specified concentration. The inert gas supply device is, for example, an inert gas generating device that generates an inert gas from air or a gas cylinder that stores an inert gas. In addition, the inert gas including the fume generated when the solidified layer 75 is formed is discharged from the chamber 11. Ideally, the inert gas discharged from the chamber 11 is returned to the chamber 11 after the fume is removed by a fume collector not shown in the figure. The fume collector is, for example, an electric precipitator or a filter. The inert gas refers to a gas that does not substantially react with the material layer 73 or the solidified layer 75, and a suitable one is selected from nitrogen, argon, helium, etc. according to the type of material.

[0039] The material layer forming device 2 is disposed in the chamber 11 and forms a material layer 73 of a desired thickness on the forming region R. The material layer forming device 2 includes a base 21 , a forming platform 22 , a coating head 25 , a first scraper 27 , and a second scraper 28 .

[0040] The base 21 has a forming area R. A surplus material storage portion 213 is provided below the base 21, and a discharge opening 211 communicating with the surplus material storage portion 213 is formed on the base 21. When forming the material layer 73, the surplus material spread on the base 21 is pushed out by the first scraper 27 or the second scraper 28 as the coating head 25 moves, falls from the discharge opening 211, and is stored in the surplus material storage portion 213.

[0041] The forming platform 22 is arranged in the forming area R, and is configured to be movable in the vertical direction by a forming platform driving device 23 having an arbitrary actuator. The uncured material is held by the forming platform 22 and the groove wall 24 surrounding the forming platform 22. An opening communicating with the surplus material storage portion 213 may also be formed below the groove wall 24. After the forming is completed, the uncured material is discharged to the surplus material storage portion 213 by positioning the forming platform 22 at a position lower than the opening. During the forming, the base plate 71 may also be placed on the forming platform 22.

[0042] The coating head 25 is disposed on the base 21 and is configured to be reciprocally movable in the horizontal direction on the forming platform 22 by a coating head driving device 26 having an arbitrary actuator. A first scraper 27 and a second scraper 28 are mounted on both side surfaces of the coating head 25, respectively.

[0043] In this embodiment, the coating head 25 is configured to be movable while discharging the material stored inside. Figure 2 and Figure 3 As shown, the coating head 25 has a material storage section 251, a material supply port 253, and a material discharge port 255. The material storage section 251 stores powdered material. More specifically, as the material, metal powder or ceramic powder, etc. can be used. The material supply port 253 is provided on the upper surface of the material storage section 251, and serves as a receiving port for the material supplied from the material supply device 17 to the material storage section 251. The material discharge port 255 is provided on the bottom surface of the material storage section 251, and ejects the material in the material storage section 251. The material discharge port 255 is in the shape of a slit, and extends in a horizontal direction orthogonal to the moving direction of the coating head 25.

[0044] The material supply device 17 is a device for replenishing material to the coating head 25. The material supply device 17 of this embodiment includes: a material bottle 171 for storing material, a hopper 173 for receiving the material supplied from the material bottle 171, and a conduit 175 connected to the hopper 173 and guiding the material to the coating head 25. The material stored in the remaining material storage section 213 is transferred by a conveying device such as a vacuum conveyor, and is sent to the hopper 173 after the inclusions are removed by the classification device 177. The classification device 177 is, for example, a three-dimensional screen or an ultrasonic screen. The material supplied from the material bottle 171 and the material recovered from the remaining material storage section 213 are dropped into the coating head 25 via the hopper 173 and the conduit 175. The material supply device 17 is not limited to the above structure as long as it is configured to be able to replenish material to the coating head 25 at any time.

[0045] The coating head 25 moves between a first position and a second position which are set across the forming area R. Here, the side of the coating head 25 facing the second position is referred to as the first side, and the side of the coating head 25 facing the first position is referred to as the second side. The first scraper 27 is mounted on the first side of the coating head 25. The second scraper 28 is mounted on the second side of the coating head 25. The first scraper 27 and the second scraper 28 are, for example, flat plate-shaped components, but may also be in other shapes such as a brush shape. Here, the second scraper 28 is arranged so that the lower end of the second scraper 28 is higher than the lower end of the first scraper 27 and lower than the material discharge port 255.

[0046] If the height of the lower end of the first scraper 27 is the same as that of the lower end of the second scraper 28, the thickness of the material layer 73 should be theoretically the same whether the coating head 25 is moved from the first position to the second position or from the second position to the first position. However, due to the inevitable installation error, it is difficult to make the height of the lower end of the first scraper 27 and the lower end of the second scraper 28 completely the same. As described later, in this embodiment, there is a case where the thickness of the material layer 73 becomes relatively small, and the influence of the error in the thickness of the material layer 73 becomes relatively large. In the case where a scraper is provided only on one side of the coating head 25 configured to be able to eject the material stored inside, there is a possibility that the material leaks out unnecessarily from the side where the scraper is not provided. Therefore, in this embodiment, the material thicker than the desired thickness is flattened by the second scraper 28, and then the material is further flattened by the first scraper 27, thereby forming a material layer 73 with a desired thickness. The first scraper 27 plays a role in forming a material layer 73 of a desired thickness, and the second scraper 28 plays a role in limiting the amount of material ejected from the coating head 25.

[0047] Here, refer to Figures 4 to 6 , the operation of the material layer forming step when forming one material layer 73 is described. Figures 4 to 6 In the figure, the first side surface on which the first scraper 27 is installed is the left side surface of the coating head 25, and the second side surface on which the second scraper 28 is installed is the right side surface of the coating head 25. The first position is a position further to the right than the forming area R, and the second position is a position further to the left than the forming area R.

[0048] When the material layer 73 having a desired thickness is formed, the formation platform 22 is set to an appropriate height. When the material layer forming step is started, the coating head 25 is located at the first position.

[0049] First, the coating head 25 is moved from the first position to the second position. Figure 4 and Figure 52 shows the coating head 25 in the process of moving from the first position to the second position. At this time, the material ejected from the material outlet 255 of the coating head 25 is flattened by the second scraper 28. The thickness of the material layer flattened by the second scraper 28 is greater than the thickness of the material layer 73. By providing the second scraper 28, the amount of material ejected from the material outlet 255 is appropriately limited.

[0050] Next, the coating head 25 is moved from the second position to the first position. Figure 6 2 shows the coating head 25 in the process of moving from the second position to the first position. At this time, the material flattened by the second scraper 28 is further flattened by the first scraper 27. In this way, a material layer 73 of a desired thickness is formed.

[0051] The irradiation device 3 is disposed above the chamber 11. The irradiation device 3 irradiates the material layer 73 with laser light L to melt or sinter it, thereby forming a solidified layer 75. Figure 7 As shown, the irradiation device 3 of this embodiment includes a light source 31 , a collimator 33 , a focus control unit 35 and a scanning device 37 .

[0052] The light source 31 generates laser light L. Here, the type of laser light L is not limited as long as it can sinter or melt the material layer 73, and it can be, for example, a fiber laser, a CO2 laser, a yttrium aluminum garnet (YAG) laser, a green laser, or a blue laser. The collimator 33 converts the laser light L output from the light source 31 into parallel light. The focus control unit 35 has a focus lens 351, a lens actuator 353 that moves the focus lens 351 back and forth, and a focusing lens fixed at a predetermined position. The laser light L output from the light source 31 is adjusted to a desired spot diameter via the focus lens 351 and the focusing lens. The scanning device 37 is, for example, a galvano scanner. The scanning device 37 has an X-axis galvanometer mirror 371, an X-axis actuator 373 that rotates the X-axis galvanometer mirror 371, a Y-axis galvanometer mirror 375, and a Y-axis actuator 377 that rotates the Y-axis galvanometer mirror 375. The rotation angles of the X-axis galvano mirror 371 and the Y-axis galvano mirror 375 are controlled so that the laser light L output from the light source 31 performs two-dimensional scanning.

[0053] The laser light L that has passed through the X-axis galvanometer mirror 371 and the Y-axis galvanometer mirror 375 is transmitted through the window 13 provided on the upper surface of the chamber 11 and irradiated onto the material layer 73 formed in the formation region R. The window 13 is formed of a material that can transmit the laser light L. For example, when the laser light L is a fiber laser or a YAG laser, the window 13 may include quartz glass.

[0054] On the upper surface of the chamber 11, an anti-pollution device 15 is provided in a manner covering the window 13. The anti-pollution device 15 includes a cylindrical frame and a cylindrical diffusion member arranged in the frame. An inert gas supply space is provided between the frame and the diffusion member. In addition, an opening is provided on the bottom surface of the frame inside the diffusion member. A large number of fine holes are provided on the diffusion member, and the clean inert gas supplied to the inert gas supply space passes through the fine holes and fills the clean room. In addition, the clean inert gas filling the clean room passes through the opening and is ejected toward the bottom of the anti-pollution device 15. In this way, smoke is prevented from adhering to the window 13.

[0055] The irradiation device 3 of this embodiment is configured to irradiate the laser light L to form the solidified layer 75, but the irradiation device may also irradiate electron beams. For example, the irradiation device may also be configured to include: a cathode electrode that emits electrons, an anode electrode that gathers and accelerates the electrons, a solenoid that forms a magnetic field to gather the direction of the electron beam in one direction, and a collector that is electrically connected to the material layer 73 as the irradiated body and applies a voltage to the cathode electrode.

[0056] The stacking forming apparatus 1 may also include a cutting device for cutting the surface or useless portion of the solidified layer 75. The cutting device includes, for example, a processing head; a processing head driving device for moving the processing head to a desired position in the chamber 11; and a spindle provided at the processing head and holding a cutting tool to rotate the spindle.

[0057] The control device 4 controls each part of the stacking forming device 1 based on the stacking forming program created by the CAM device 5. Figure 8 As shown, the control device 4 includes a main control device 41 and an irradiation control device 43 .

[0058] The main control device 41 controls each part according to the stacking forming program created by the CAM device 5. Specifically, the main control device 41 drives the forming platform driving device 23 and the coating head driving device 26 to move the forming platform 22 and the coating head 25, thereby forming the material layer 73. More specifically, as described above, the main control device 41 controls so that when forming one material layer 73, the coating head 25 is moved from the right side of the forming area R to the left side of the forming area R, and then the coating head 25 is moved from the left side of the forming area R to the right side of the forming area R. In addition, when the stacking forming device 1 includes a cutting device, the main control device 41 controls the cutting device to cut the solidified layer 75. In addition, the main control device 41 sends the instructions related to the irradiation device 3 in the stacking forming program to the irradiation control device 43.

[0059] The irradiation control device 43 controls the irradiation device 3 according to the stacking formation program sent from the main control device 41. Specifically, the irradiation control device 43 drives the X-axis actuator 373 to control the rotation angle of the X-axis galvanometer mirror 371, and drives the Y-axis actuator 377 to control the rotation angle of the Y-axis galvanometer mirror 375. Thus, the irradiation position of the laser L is controlled. In addition, the irradiation control device 43 controls the light source 31 to switch the intensity and on / off of the laser L. In addition, the irradiation control device 43 drives the lens actuator 353 to control the position of the focus lens 351, thereby controlling the spot diameter of the laser L.

[0060] The control device 4 is not limited to the above-described embodiment as long as it is configured to control each unit based on the command of the stacking forming program created by the CAM device 5. The control device 4 can be configured by arbitrarily combining hardware and software.

[0061] Next, the CAM device 5 for producing the stacking molding program will be described. The CAM device 5 is a computer installed with computer-aided manufacturing software, and produces the stacking molding program to be used in the stacking molding device 1. Figure 8 As shown, the CAM device 5 has an input device 51, an output device 53, a computing device 55, and a storage device 57. The input device 51 is a device for the operator to input information required for various processes, such as a keyboard or a mouse. The output device 53 is a device for displaying various information to the operator, such as a monitor. The computing device 55 performs various operations based on the program of the computer-aided manufacturing software or the three-dimensional model 6 of the three-dimensional object, or the information input by the operator. The computing device 55 is, for example, a central processing unit (CPU). The storage device 57 stores the three-dimensional model 6 or the data required for the operation. The storage device 57 is, for example, a random access memory (RAM), a read only memory (ROM), an auxiliary storage device, or a combination thereof.

[0062] Here, the method of creating a layered forming program in the CAM device 5 is described. Fig. 9 As shown, the method for creating a stacked formation program of the present embodiment includes: a reading step, a segmentation step, an exception setting step, an overhang calculation step, a maintenance step, an overhang portion setting step, an overlap portion setting step, a re-segmentation step, a support portion providing step, an irradiation sequence setting step, an irradiation condition setting step, and an output step. In the following description, a portion that protrudes in the horizontal direction relative to the segmented layer directly below is referred to as an overhang portion 64. The inclination angle of the overhang portion 64 is referred to as an overhang angle θ. The length of the overhang portion 64 in the horizontal direction is referred to as an overhang length d.

[0063] In the reading process, a three-dimensional model 6 of a desired three-dimensional object produced by a computer aided design (CAD) device or the like is read. The so-called three-dimensional model 6 is design data that expresses the three-dimensional shape of the desired three-dimensional object. The read three-dimensional model 6 is arranged on a three-dimensional coordinate at an appropriate position and angle. Here, the horizontal axis of the three-dimensional coordinate is set as the X-axis, the horizontal axis orthogonal to the X-axis is set as the Y-axis, and the vertical axis is set as the Z-axis. The direction of the Z-axis is consistent with the direction of stacking the solidified layer 75, that is, the stacking direction. Fig.10 Here, for simplicity of description, a three-dimensional model 6 in which the overhanging portion 64 protrudes only in the X-axis direction is described as an example, but a stacking forming program can also be produced in the same process for a three-dimensional model including an overhanging portion 64 protruding in the Y-axis direction.

[0064] In the segmentation process, the three-dimensional model 6 is segmented into a plurality of segmentation layers in the stacking direction at a predetermined stacking pitch. That is, the segmentation layer is the so-called slice data of the three-dimensional model 6. Hereinafter, the stacking pitch in the segmentation process is particularly referred to as a normal stacking pitch p, and the segmentation layer obtained by segmentation at the normal stacking pitch p is particularly referred to as a normal segmentation layer 61. Fig.11 2 shows an example of the three-dimensional model 6 after the segmentation step. The normal segmentation layers 61 are numbered in order from bottom to top. N in the figure represents the number of the normal segmentation layer 61.

[0065] In the exception setting process, the operator arbitrarily sets the normal split layer 61 to be subjected to the support portion imparting process described later without considering the overhang angle θ or the overhang length d. Sometimes, the support portion 66 may be imparted for purposes other than supporting the overhanging portion 64. For example, the support portion 66 may be imparted in order to suppress the strain caused by the influence of the residual stress generated in the solidified layer 75 during the formation. In addition, the support portion 66 may be imparted in order to dissipate the heat generated in the material layer 73 and the solidified layer 75 during the formation to the forming platform 22, or to transfer the heat of the heated forming platform 22 to the material layer 73 and the solidified layer 75. Through the exception setting process of the embodiment, from the viewpoint of supporting the overhanging portion 64, even for the normal split layer 61 that does not require the support portion 66, the support portion 66 may be imparted as needed. In the three-dimensional model 6 of the present embodiment, the twelfth normal split layer 61 and the thirteenth normal split layer 61 are exceptionally set.

[0066] After the exception setting step, for example, any one of the overhang calculation step, the maintenance step, the re-division step, and the support portion providing step is sequentially performed starting from the first normal division layer 61. However, for the normal division layer 61 for which the exception setting is performed in the exception setting step, the overhang calculation step may be skipped and the support portion providing step may be performed directly.

[0067] In the overhang calculation step, the overhang angle θ is calculated for each normal split layer 61. The end surface of the normal split layer 61 sometimes includes a curved surface portion, or sometimes has multiple inclinations. Therefore, the overhang angle θ can also be calculated by using a straight line to supplement the upper surface end and the lower surface end of the normal split layer 61 that is the object of calculation of the overhang angle θ. In this embodiment, the overhang angle θ is calculated based on the size of the overhang length d and the size of the normal stacking pitch p and is given by the formula: θ = tan -1 When the overhang angle θ of the predetermined normal segmentation layer 61 is less than 90°, the normal segmentation layer 61 has an overhang portion 64. The overhang angle θ is calculated in the X-axis direction and the Y-axis direction.

[0068] Based on the overhang angle θ calculated in the overhang calculation process, one of the maintenance process, the re-division process and the support portion imparting process is selectively implemented. Specifically, the maintenance process is implemented for the normal segmentation layer 61 whose overhang angle θ is greater than the first angle threshold tm. The re-division process is implemented for the normal segmentation layer 61 whose overhang angle θ is less than the first angle threshold tm and greater than the second angle threshold ts. The support portion imparting process is implemented for the normal segmentation layer 61 whose overhang angle θ is less than the second angle threshold ts. Here, the first angle threshold tm is an arbitrary value less than 90°, and the second angle threshold ts is smaller than the first angle threshold tm. In the three-dimensional model 6 of the present embodiment, the maintenance process is performed on the first normal segmentation layer 61 to the sixth normal segmentation layer 61, the fourteenth normal segmentation layer 61 and the fifteenth normal segmentation layer 61. The re-division process is performed on the seventh normal segmentation layer 61 to the tenth normal segmentation layer 61. The support portion imparting process is performed on the eleventh normal segmentation layer 61.

[0069] The first angle threshold tm is a threshold value of an angle that is considered to be able to be formed directly using the normal split layer 61. The second angle threshold ts is a threshold value of an angle that is considered to require the support portion 66. The first angle threshold tm and the second angle threshold ts may be configured so that the operator can input any value. The first angle threshold tm is, for example, 45°. The second angle threshold ts is, for example, 15°.

[0070] In the maintaining step, the normal dividing layer 61 is not divided again, and the support portion 66 for supporting the normal dividing layer 61 is not provided. That is, the state of the normal dividing layer 61 generated by the dividing step is maintained. Even if it is a normal dividing layer 61 having an overhanging portion 64, as long as the overhanging angle θ is large, that is, the inclination is gentle, it can be directly formed using the normal stacking pitch p. Fig.122 shows the fifth normal division layer 61 to which the maintenance step is performed. When the overhanging portion 64 does not exist in the normal division layer 61, the overhanging angle θ is 90° or more, and therefore the maintenance step is selected except when an exceptional setting is performed.

[0071] In this embodiment, before the re-division process is performed, the overhanging portion setting process and the overlapping portion setting process are performed, and only the overhanging portion 64 and the overlapping portion 65 are the objects of re-division. However, in the re-division process, in the normal divided layer 61 that is the object, at least a part including the overhanging portion 64 is re-divided in the stacking direction. For example, the entire normal divided layer 61 that is the object may be re-divided in the stacking direction. In this case, the overhanging portion setting process and the overlapping portion setting process may not be performed. However, from the viewpoint of shortening the molding time, it is advantageous to re-divide only a part.

[0072] Here, with Fig.13 The seventh normal split layer 61 shown in the figure is used as an example to explain the overhanging portion setting process, the overlapping portion setting process and the re-splitting process. Fig.14 As shown, first, in the overhanging portion setting process, the area of ​​the overhanging portion 64 is set for the normal split layer 61 that becomes the object of the re-segmentation process. That is, the portion protruding in the X-axis direction and the portion protruding in the Y-axis direction are respectively set as the overhanging portion 64. Next, an area of ​​a predetermined width, namely, the overlapping portion 65, is set at a position adjacent to the overhanging portion 64. The width of the overlapping portion 65 can be arbitrarily set, for example, not less than 0.1 mm and not more than 10 mm. Hereinafter, in the normal split layer 61, the area other than the overlapping portion 65 and the overhanging portion 64 is referred to as the normal portion 63. Then, in the re-segmentation process, the overhanging portion 64 and the overlapping portion 65 are re-segmented into two or more in the stacking direction. Specifically, in the seventh normal split layer 61, the overhanging portion 64 and the overlapping portion 65 are re-segmented into two at a re-segmented stacking pitch p / 2 obtained by dividing the normal stacking pitch p by 2. Hereinafter, the split layer that has been subjected to the re-segmentation process is specifically referred to as the re-segmented split layer 62. As shown Fig.15 As shown, in this way, a re-divided dividing layer 62 can be obtained by further dividing at least a portion of the normal dividing layer 61.

[0073] The value of the stacking pitch p usually depends on the specifications of the irradiation device 3, but is generally about 20 μm to about 150 μm. The subdivided stacking pitch can be any value smaller than the normal stacking pitch p, but the lower limit is determined by the average particle size of the material. When the material layer 73 is melted or sintered to form the solidified layer 75, if the thickness of the layer is slightly reduced, then in theory, the lower limit of the subdivided stacking pitch is smaller than the average particle size of the material. For example, in the case of using a material with an average particle size of about 35 μm, the lower limit of the subdivided stacking pitch can also be set to about 10 μm.

[0074] When at least a portion of the normal split layer 61 is split again, it is not necessary to make the thickness of each split layer equal, but in terms of simple calculation and control, it is ideal to divide the normal stacking pitch p / m obtained by dividing the normal stacking pitch p by an integer m greater than 2 into two or more equal parts.

[0075] In addition, the number of divisions of the division layer in the re-division process may be different according to the size of the overhang angle θ or the overhang length d. That is, the size of the re-division stacking pitch may also be changed according to the size of the overhang angle θ or the overhang length d. In the present embodiment, the operator sets the appropriate re-division stacking pitch according to the value of the overhang angle θ. For example, when the overhang angle θ is greater than 30° and less than 45°, the re-division stacking pitch is set to p / 2, and when the overhang angle θ is greater than 15° and less than 30°, the re-division stacking pitch is set to p / 3. Alternatively, the operator may set the appropriate re-division stacking pitch according to the value of the overhang length d. Alternatively, the operator may set an allowable value as the overhang length d of the re-division division layer 62, and automatically calculate the re-division stacking pitch in a manner that the overhang length d of the re-division division layer 62 is less than a specified value. The re-division stacking pitch may also be determined by referring to a database of appropriate re-division stacking pitches corresponding to the overhang angle θ or the overhang length d pre-stored in the CAM device 5.

[0076] In addition, when there are a plurality of overhanging portions 64 in the normal dividing layer 61, and the overhanging angles θ associated with the respective overhanging portions 64 are different, the structure may be such that the smallest overhanging angle θ is regarded as the overhanging angle θ of the normal dividing layer 61. Specifically, there are cases where there are two or more overhanging portions 64 protruding in the X-axis direction, or there are two or more overhanging portions 64 protruding in the Y-axis direction, or there are one or more overhanging portions 64 protruding in the X-axis direction and one or more overhanging portions 64 protruding in the Y-axis direction, but in any case, the structure may be such that the smallest overhanging angle θ is regarded as the overhanging angle θ of the normal dividing layer 61.

[0077] exist Figures 16 to 18 , the overhanging portion setting process, the overlapping portion setting process, and the re-dividing process of the ninth normal divided layer 61 are shown. The ninth normal divided layer 61 has two overhanging portions 64, each with a different overhanging angle θ. In the ninth normal divided layer 61, based on the smaller overhanging angle θ of the two overhanging angles θ, the overhanging portion 64 and the overlapping portion 65 are divided into three again at a re-divided stacking pitch p / 3 obtained by dividing the normal stacking pitch p by 3.

[0078] In the support portion imparting step, the normal split layer 61 is not divided again, and the support portion 66 supporting the normal split layer 61 is imparted to the three-dimensional model 6. When the overhang angle θ is small, that is, the inclination is steep, if the overhang length d is reduced by re-division to a degree that the shaping can be performed without the support portion 66, the re-divided stacking spacing sometimes becomes very small. If the re-divided stacking spacing is too small, it is sometimes difficult to perform shaping, or there is a risk of consuming too much shaping time. Therefore, in this embodiment, for the normal split layer 61 with a small overhang angle θ, the support portion 66 is correspondingly imparted. In addition, as described above, the support portion 66 is also imparted to the normal split layer 61 that has been exceptionally set in the exceptional setting step. The shape of the support portion 66 can be any shape as long as it can serve the purpose of supporting the normal split layer 61. For example, the support portion 66 can be a simple columnar shape, or a shape with gaps such as a lattice shape. In addition, the support portion 66 is divided in the stacking direction at the normal stacking spacing p.

[0079] The above steps are repeated to selectively perform one of the maintenance step, the re-segmentation step, and the support portion imparting step on all the normal segmentation layers 61. That is, the selective step is performed on all the segmentation layers. Fig.19 Here, the irradiation order setting step and the irradiation condition setting step are performed on the divided layers that have been subjected to the maintaining step, the re-dividing step, or the supporting portion providing step.

[0080] In the irradiation sequence setting step, the irradiation sequence of each segmented layer is set. For example, the irradiation sequence is set in order from bottom to top, such as the first segmented layer and the support portion 66 at the same height, the second segmented layer and the support portion 66 at the same height, etc. In addition, for the segmented layer that has undergone the re-segmentation process, that is, the overhanging portion 64 and the overlapping portion 65 at the same height in the re-segmented segmented layer 62, the irradiation sequence is set so that the overlapping portion 65 is irradiated with the laser L or the electron beam before the overhanging portion 64.

[0081] Here, with Fig. 20The following description will be made by taking the subdivided split layer 62 shown in FIG. 1 as an example. In addition, the circled numbers in the figure indicate the irradiation order. In the following, when the overhanging portion 64 and the overlapping portion 65 are divided into m, the lowermost overhanging portion 64 and the overlapping portion 65 are taken as the first, and the uppermost overhanging portion 64 and the overlapping portion 65 are taken as the mth. First, the irradiation order is set in the order of the first overlapping portion 65 and the first overhanging portion 64. Similarly, the irradiation order is set in the order of the overlapping portion 65 and the overhanging portion 64 after the second. After the m-1th overhanging portion 64, the irradiation order is set in the order of the normal portion 63, the mth overlapping portion 65, and the mth overhanging portion 64. However, the irradiation order of the normal portion 63 may be after the mth overlapping portion 65 or the mth overhanging portion 64. In addition, when there is a support portion 66 at the same height as the subdivided split layer 62, the irradiation order of the support portion 66 can be set after the m-1th overhanging portion 64. The irradiation order of the subdivided division layer 62 is set in this way.

[0082] At least a portion of the solidified layer 75 associated with the overhanging portion 64 is formed so that there is no portion of the solidified layer 75 directly below. In contrast, since the solidified layer 75 associated with the overlapping portion 65 is formed on another solidified layer 75, the forming can be performed relatively stably. By forming the overlapping portion 65 and the overhanging portion 64 in this order at the same height, the solidified layer 75 associated with the overhanging portion 64 is fixed to the side of the solidified layer 75 associated with the overlapping portion 65, so the forming can be performed more stably.

[0083] In the irradiation condition setting step, the irradiation conditions of the laser light L or the electron beam for each segmented layer are set based on information input by the operator or pre-stored data, etc. For the normal segmented layer 61 and the normal portion 63, the same irradiation conditions as in the past may be set.

[0084] The thickness of the material layer 73 and the solidified layer 75 associated with the overhanging portion 64 and the overlapping portion 65 becomes relatively small. Therefore, for the overhanging portion 64 and the overlapping portion 65, it is desirable to set the irradiation conditions with lower energy density than the irradiation conditions for the normal segmentation layer 61 and the normal portion 63. Here, the energy density is expressed by the following formula: Energy density [J / mm 2 ]=intensity [W] / (spot diameter [mm]×irradiation speed [mm / s]). That is, the energy density can be reduced by reducing the intensity, increasing the spot diameter or increasing the irradiation speed. For example, when the number of divisions of the overhanging portion 64 and the overlapping portion 65 in the predetermined re-divided division layer 62 is set to m, the intensity under the irradiation condition for the normal division layer 61 and the normal portion 63 can be divided by m, and then the irradiation condition can be set as the irradiation condition for the overhanging portion 64 and the overlapping portion 65.

[0085] Since the support portion 66 is eventually removed, the required dimensional accuracy is relatively low. In addition, for the support portion 66 provided for the purpose of supporting the extension portion 64, the strength required of the support portion 66 itself is relatively low. Therefore, for the support portion 66 for the purpose of support, it is ideal to set irradiation conditions that emphasize the ease of removal and the molding speed of the support portion 66. For example, for the support portion 66 for the purpose of support, irradiation conditions that increase the strength, increase the spot diameter, and increase the irradiation speed within the range that can obtain a specified energy density can also be applied. On the other hand, for the support portion 66 provided for the purpose of suppressing the strain caused by the residual stress of the solidified layer 75, a certain degree of strength is required. Therefore, for the support portion 66 that requires a certain degree of strength for the purpose of strain suppression, etc., irradiation conditions that are the same as the irradiation conditions for the normal split layer 61 and the normal portion 63 can also be set.

[0086] Finally, based on the information such as the stacking spacing, shape, irradiation sequence, and irradiation conditions of each segmented layer, an output process is implemented, and the output process outputs a stacking forming program that specifies instructions related to stacking forming. The stacking forming program includes action instructions for the material layer forming device 2 and the irradiation device 3. In the case where the stacking forming device 1 includes a cutting device, the stacking forming program may also include action instructions for the cutting device such as a cutting path. The stacking forming program output from the CAM device 5 is sent to the control device 4 of the stacking forming device 1, for example, via a portable storage medium or through wired or wireless communication.

[0087] The method for preparing the stacking forming program described above is only an example and is not limited thereto. Within the scope of the technical concept of the present invention, some processes may be changed, omitted or added, the order of the processes may be changed, and some processes may be performed in parallel. In addition, at least part of each process may be performed by the control device 4 of the stacking forming device 1 instead of the CAM device 5.

[0088] For example, in the present embodiment, whether re-division is required and whether the support portion 66 is required is determined based on the overhang angle θ, but the determination may also be made based on the overhang length d. In the present variant, in the overhang calculation process, it is not necessary to calculate the overhang angle θ, but only the overhang length d needs to be calculated. Moreover, a maintenance process is performed on a normal split layer 61 whose overhang length d is less than the first length threshold um. A re-division process is performed on a normal split layer 61 whose overhang length d is greater than the first length threshold um and less than the second length threshold us. A support portion imparting process is performed on a normal split layer 61 whose overhang length d is greater than the second length threshold us. Among them, the first length threshold um is an arbitrary value exceeding 0μm, and the second length threshold us is greater than the first length threshold um.

[0089] In addition, in the present embodiment, when the re-division process is performed, the overhanging portion setting process and the overlapping portion setting process are performed first, but the overhanging portion setting process and the overlapping portion setting process may be performed after the re-division process. In the present variation, first, the re-division process is performed on the normal division layer 61, and the entire normal division layer 61 is divided at the re-division stacking pitch. Next, the overhanging portion setting process and the overlapping portion setting process are performed on each layer divided at the re-division stacking pitch, and the overhanging portion 64 and the overlapping portion 65 are set. The remaining portion that is not set as the overhanging portion 64 and the overlapping portion 65 is treated as the normal portion 63. Fig.21 , a re-divided split layer 62 is shown in which the re-dividing step, the overhanging portion setting step, and the overlapping portion setting step are performed according to the above process. In addition, in the re-divided split layer 62 of this modified example, the stacking pitch of the normal portion 63 is different depending on the position. Therefore, in the irradiation condition setting step, it is ideal to change the irradiation conditions according to the position of the normal portion 63. According to this modified example, since the size of the overhanging portion 64 can be reduced, the molding speed can be further increased.

[0090] According to the method for preparing the stacked forming program described above, it is possible to determine the normal split layer 61 that can be formed without the support portion 66 by re-splitting, based on the overhang angle θ or the overhang length d, and to perform the re-splitting process only on the normal split layer 61, thereby reducing the support portion 66 without increasing the forming time. In addition, it is also expected that the surface aspect of the solidified layer 75 related to the re-splitting split layer 62 will be improved.

[0091] According to the stacking forming program prepared according to the above process, stacking forming is performed in the stacking forming device 1. However, the stacking forming program can also be corrected by the control device 4 according to the correction data related to the laser coordinate system or the cutting coordinate system, or the state of the stacking forming device 1 or the surrounding environment. The stacking forming method of this embodiment alternately repeats the material layer forming step of forming a material layer 73 containing a powder material on the forming area R, and the solidified layer forming step of irradiating the material layer 73 with a laser L or an electron beam to form a solidified layer 75.

[0092] The base plate 71 is placed on the formation stage 22, and the chamber 11 is filled with an inert gas of a predetermined concentration. Then, the material layer forming step and the solidified layer forming step are sequentially performed starting from the lower separation layer.

[0093] The operation when forming the solidified layer 75 associated with the normal split layer 61 is described. First, the forming platform 22 is lowered by an amount corresponding to the normal stacking pitch p. However, when forming the initial material layer 73 and the solidified layer 75, the forming platform 22 is positioned so that the distance between the base plate 71 and the lower end of the first scraper 27 is the same as the normal stacking pitch p. Next, the coating head 25 reciprocates on the forming area R to flatten the material to form a material layer 73 of a desired thickness. Then, the irradiation device 3 irradiates the material layer 73 with a laser L or an electron beam, thereby forming a solidified layer 75 associated with the normal split layer 61. Here, when there is a support portion 66 at the same height, the support portion 66 is also formed.

[0094] The operation when forming the solidified layer 75 associated with the re-divided divided layer 62 is described. Hereinafter, the division number of the overhanging portion 64 and the overlapping portion 65 is set to m for description. First, the forming platform 22 is lowered by an amount corresponding to the re-divided layer stacking pitch p / m. However, when forming the initial material layer 73 and the solidified layer 75, the forming platform 22 is positioned so that the distance between the base plate 71 and the lower end of the first scraper 27 is the same as the re-divided layer stacking pitch p / m. Next, the coating head 25 reciprocates on the forming area R to flatten the material to form a material layer 73 of a desired thickness. Then, the irradiation device 3 irradiates the material layer 73 with a laser L or an electron beam according to the irradiation order determined by the irradiation order setting process, thereby forming the solidified layer 75 associated with the first overlapping portion 65 and the overhanging portion 64. The above process is repeated to form the solidified layer 75 associated with the overlapping portions 65 and the overhanging portions 64 up to m-1. Then, the forming stage 22 is lowered by an amount corresponding to the subdivided layer stacking pitch p / m, and the solidified layer 75 related to the normal portion 63, the mth overlapping portion 65, and the overhanging portion 64 is formed according to the irradiation sequence determined by the irradiation sequence setting step. Here, when the support portion 66 exists at the same height, the support portion 66 is also formed.

[0095] According to the above process, the formation of the solidified layer 75 related to the normal split layer 61 or the re-split split layer 62 is carried out in order from bottom to top, forming Fig. 22 Furthermore, when the layered forming apparatus 1 includes a cutting device, a cutting process may be performed to cut the inner or outer side surfaces of the solidified layer 75 each time a predetermined number of solidified layers 75 are formed.

[0096] Although some examples have been specifically shown, the present invention is not limited to the configurations of the embodiments shown in the drawings, and various modifications and applications are possible within the scope of the technical concept of the present invention.

Claims

1. A method for making a stacking shaping program, comprising: A reading process, reading a three-dimensional model of a desired three-dimensional object; A segmentation step of segmenting the three-dimensional model into a plurality of segmented layers in a stacking direction at a normal stacking pitch having a predetermined size; an overhang calculation step of calculating an overhang angle or an overhang length for each of the plurality of segmentation layers, wherein the overhang angle is an inclination angle of a portion of the segmentation layer protruding in the horizontal direction relative to a segmentation layer directly below, that is, an overhang portion, and the overhang length is a length of the overhang portion in the horizontal direction; The determining step is to select one of the steps from a group of steps including a re-segmenting step and a maintaining step according to the overhanging angle or the overhanging length of each of the plurality of segmented layers, wherein: The re-segmentation step is performed when the overhanging angle of the predetermined segmentation layer is less than a first angle threshold, or when the overhanging length of the predetermined segmentation layer is greater than or equal to a first length threshold, and the re-segmentation step is to divide at least a portion of the predetermined segmentation layer including the overhanging portion into two or more portions in the stacking direction; The maintaining step is performed when the protruding angle of the specified segmentation layer is greater than or equal to the first angle threshold, or when the protruding length of the specified segmentation layer is less than the first length threshold, and the maintaining step does not re-divide the specified segmentation layer and does not provide a support portion for supporting the specified segmentation layer; as well as The output step outputs a stacking formation program that defines instructions related to stacking formation based on the shapes of each divided layer.

2. The method for making a layered forming program according to claim 1, wherein: In the re-dividing step, the predetermined divided layer is divided again into two or more divided layers at a re-divided stacking pitch obtained by dividing the normal stacking pitch by an integer greater than or equal to 2.

3. The method for making a stacking forming program according to claim 1, wherein: In the subdivision step, the number of divisions of the predetermined division layer varies depending on the magnitude of the overhanging angle or the overhanging length.

4. The method for making a stacking forming program according to claim 1, further comprising an overhanging portion setting step, wherein the overhanging portion setting step is performed when the overhanging angle of the specified segment layer is less than the first angle threshold, or when the overhanging length of the specified segment layer is greater than the first length threshold, and the overhanging portion setting step is to set the overhanging portion area for the specified segment layer. In the re-dividing step, only a portion of the predetermined dividing layer including the overhanging portion is re-divided into two or more layers.

5. The method for making a stacked forming program according to claim 4, wherein: After the overhanging portion setting step, the method further includes an overlapping portion setting step of setting an overlapping portion, which is an area of ​​a predetermined width at a position adjacent to the overhanging portion. In the re-dividing step, only the overhanging portion and the overlapping portion of the predetermined dividing layer are re-divided into two or more dividing layers, and The method for producing the stacked forming program also includes an irradiation sequence setting process, in which the irradiation sequence is set for the protruding portion and the overlapping portion located at the same height in the split layer that has undergone the re-segmentation process, so that the overlapping portion is irradiated with laser or electron beam before the protruding portion.

6. A method for producing a stacking forming program according to claim 1, wherein the process group also includes a support portion assigning process, and the support portion assigning process is implemented instead of the re-segmentation process when the outward extension angle of the specified segmentation layer is less than a second angle threshold which is smaller than the first angle threshold, or when the outward extension length of the specified segmentation layer is greater than a second length threshold which is greater than the first length threshold, and in the support portion assigning process, the specified segmentation layer is not re-split, and a support portion for supporting the specified segmentation layer is assigned to the three-dimensional model.

7. The method for preparing a stacking formation program according to claim 6, further comprising an exception setting step of arbitrarily setting a division layer on which the support portion providing step is to be performed regardless of the overhang angle or the overhang length.

8. A stacking molding method, comprising: performing stacking molding according to the stacking molding program produced by the stacking molding program production method according to claim 1, wherein the stacking molding method repeatedly performs the following steps to produce the three-dimensional object: a material layer forming step of forming a material layer including a powder material on a region for manufacturing the three-dimensional object, namely, a forming region; and In the solidified layer forming step, the material layer is irradiated with laser light or electron beam to form a solidified layer.

9. A stacking forming device, for implementing the stacking forming method according to claim 8, the stacking forming device comprising: A material layer forming device, forming the material layer on the shaping area; an irradiation device for irradiating the material layer with the laser or the electron beam to form the solidified layer; as well as A control device controls the material layer forming device and the irradiation device based on the stacking forming program.

10. The stacking forming device according to claim 9, wherein: The material layer forming device comprises: A shaping platform is arranged in the shaping area and is configured to be movable in a vertical direction; A coating head is configured to be able to reciprocate in a horizontal direction on the forming platform and to move between a first position and a second position set across the forming area; A first scraper is installed on a first side surface of the coating head that faces the second position and flattens the material sprayed to the forming area; and The second scraper is mounted on the side of the coating head facing the first position, that is, the second side, and flattens the material sprayed to the forming area. The coating head has: A material storage unit for storing the material; a material supply port, provided on an upper surface of the material storage portion, serving as a receiving port for the material supplied to the material storage portion; and The material discharge port is arranged on the bottom surface of the material storage portion, and discharges the material in the material storage portion. The second scraper is arranged at a position where the lower end of the second scraper is higher than the lower end of the first scraper and lower than the material discharge port. The control device performs control so that, when forming one material layer, after moving the coating head from the first position to the second position, the coating head is moved from the second position to the first position.

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