Method for manufacturing a three-dimensional shaped object

Abstract

The present invention provides a three-dimensional shaped object manufacturing method capable of shaping a three-dimensional shaped object with high quality, including: a solidified layer forming step of repeatedly performing a material layer forming step and a solidification step of irradiating a laser or the like to an irradiation region of the material layer to form a solidified layer, thereby layering the solidified layer; a shaping condition setting step of setting an irradiation condition and a division width of the irradiation region; an irradiation region determining step of determining the irradiation region for each divided layer obtained by dividing a three-dimensional shape; a division step of dividing the irradiation region by the division width along a prescribed division direction to form a divided region; and a scan line setting step of setting a raster scan line within the divided region, in the solidification step, a laser or the like is scanned along a scan path including the raster scan line, and in the division step, a direction obtained by horizontally rotating the division direction of the irradiation region in the subject divided layer is set as the division direction in the divided layer directly above.

Description

Technical Field

[0001] This invention relates to a method for manufacturing three-dimensional objects. Background Technology

[0002] Various methods are known for layering techniques to create three-dimensional objects. For example, a layering apparatus that performs powder bed fusion bonding forms a material layer containing powder in the modeling area. The material layer is then sintered or melted by scanning a laser or electron beam and directed to a predetermined location, thus forming a solidified layer. Furthermore, by repeatedly forming material layers and solidified layers to create a solidified layer, the desired three-dimensional object can be manufactured.

[0003] Laser or electron beams scan along so-called grating scan lines, which are scanning patterns arranged in a straight line within the irradiation area of ​​the material layer. Here, the irradiation area is sometimes divided into segments with a predetermined width, and grating scanning is performed on each segment. When grating scanning is performed on each segment, the length of the grating scan lines in each segment is essentially the same according to the predetermined segment width, thus allowing the material layer to melt and solidify with uniform irradiation energy without changing the irradiation conditions. Therefore, the amount of sputtering scattering is reduced, and pinholes or voids are less likely to form. Furthermore, the reference length of the grating scan lines, depending on the predetermined segment width, is as short as a few centimeters, so even with high-speed scanning lasers or electron beams, adverse effects such as heat on the surrounding environment can be minimized. Therefore, the required pause time is shorter, and high-speed melting and solidification with small unevenness and stable quality can be achieved. Patent Document 1 discloses a lamination molding apparatus that uses a laser with a slender spot shape to uniformly heat the material layer by grating scanning each segment to improve molding quality.

[0004] [Existing Technical Documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent No. 6266040 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] When grating scanning is performed without segmenting the irradiation area, the long reference length of the grating scan lines that determine the irradiation conditions means that the difference in length of each grating scan line has a relatively small impact on the shape difference of the edge portion of the irradiation area. On the other hand, when grating scanning is performed for each segmented area, each grating scan line is set to be a straight line with a length substantially the same as the specified segment width. In this case, grating scan lines shorter than the segment width inevitably occur at the ends of the irradiation area. However, compared to the case where grating scanning is performed without segmenting the irradiation area, the reference length of the grating scan lines is significantly shorter. Since the reference length of the grating scan lines is set based on the irradiation conditions including the irradiation energy, the temperature of the melt pool formed by irradiation becomes relatively high at the irradiation sites based on grating scan lines shorter than the reference length. As the cured layers are stacked, the irradiation sites based on the short grating scan lines overlap in the vertical direction. Due to the deformation of each cured layer and the accumulation of multiple layers, the bulge gradually increases, eventually causing the blade of the material layer forming apparatus to collide with the material layer.

[0009] The material layer forming apparatus moves within the molding area and supplies material powder, while simultaneously using a blade to homogenize the powder and form a material layer. Therefore, if the blade of the material layer forming apparatus collides with a protrusion, the amount of material powder supplied changes, resulting in an uneven material layer and potentially reduced molding quality. Furthermore, depending on the size of the protrusion, the blade may be unable to move while colliding with it; unless the protrusion is removed, the molding process cannot continue.

[0010] The present invention was made in view of this situation, and its object is to provide a method for manufacturing three-dimensional objects that can create three-dimensional objects with high quality.

[0011] [Technical means to solve the problem]

[0012] The present invention provides the following invention.

[0013] [1] A method for manufacturing a three-dimensional model, comprising a curing layer forming process, wherein the curing layer forming process stacks curing layers by repeatedly performing a material layer forming process and a curing process, wherein the material layer forming process supplies material powder to the modeling area to form a material layer, and the curing process forms the curing layer by irradiating a predetermined irradiation area of ​​the material layer with a laser or an electron beam, the method for manufacturing the three-dimensional model comprising: a modeling condition setting process, setting the irradiation conditions of the laser or the electron beam and the segmentation width of the irradiation area; an irradiation area determination process, determining the irradiation area for each of the multiple segmented layers into which the desired three-dimensional shape is divided according to a predetermined height; and a segmentation process. The process involves dividing the irradiated area of ​​each of the irradiated layers along a predetermined dividing direction with a dividing width suitable for the irradiation conditions to form multiple dividing regions; and a scan line setting process, in which a grating scan line along a predetermined scanning direction is set within the dividing region; in the curing process, the laser or the electron beam scans along a scan path containing the grating scan line; and in the dividing process, the direction after which the dividing direction of the irradiated area in the object dividing layer is horizontally rotated by a rotation angle θ is set as the dividing direction of the irradiated area in the dividing layer directly above the object dividing layer, wherein the rotation angle θ satisfies 0° < θ < 180° or -180° < θ < 0° (where the symbol represents the rotation direction).

[0014] [2] In the manufacturing method of the three-dimensional model described in [1], the scanning direction is set to be parallel to the segmentation direction in the scanning line setting process.

[0015] [3] The manufacturing method of the three-dimensional model according to [1] or [2] further includes a length determination process, wherein the length determination process determines whether the scanning path on the object segmentation layer contains a grating scan line less than a specified value. In the segmentation process, when it is determined in the length determination process that the scanning path on the object segmentation layer contains a grating scan line less than the specified value, the direction after horizontally rotating the segmentation direction of the irradiation area in the object segmentation layer by the rotation angle θ is set as the segmentation direction of the irradiation area in the segmentation layer directly above the object segmentation layer.

[0016] [4] The method for manufacturing a three-dimensional model according to any one of [1] to [3] further includes a rotation angle setting step, wherein the rotation angle setting step sets the rotation angle θ based on processing conditions, wherein the processing conditions include at least one of the segmentation width, the material of the material powder, the conditions of the irradiation area, and the irradiation conditions.

[0017] [The effects of the invention]

[0018] In the method for manufacturing three-dimensional models of the present invention, the direction in which the irradiation area in any object material layer is horizontally rotated by a predetermined rotation angle θ (0° < θ < 180° or -180° < θ < 0°) is set as the irradiation area in the material layer directly above the object material layer. By rotating the irradiation direction, the overlap of irradiated areas based on short grating scan lines in the vertical direction is reduced, thereby suppressing the formation of bulges in the cured layer and reducing the quality of the model. Attached Figure Description

[0019] Figure 1 This is a schematic structural diagram of the stacking molding device 100 according to an embodiment of the present invention.

[0020] Figure 2 This is a three-dimensional view of the material layer forming device 3.

[0021] Figure 3 This is a three-dimensional view viewed from above the coating head 11.

[0022] Figure 4 This is a three-dimensional view taken from below the coating head 11.

[0023] Figure 5 This is a schematic structural diagram of the irradiation device 13.

[0024] Figure 6 This is a block diagram of the control system of the layered modeling device 100.

[0025] Figure 7A , Figure 7B This is an explanatory diagram of raster scanning. Figure 7A This indicates the use of a non-segmented raster scanning method. Figure 7B This indicates raster scanning using a region segmentation method.

[0026] Figure 8 This diagram illustrates a method for manufacturing a three-dimensional model using a layered modeling device 100.

[0027] Figure 9 This diagram illustrates a method for manufacturing a three-dimensional model using a layered modeling device 100.

[0028] Figure 10 L represents the k-th segmentation layer of an exemplary three-dimensional object. k The irradiated area S in k A diagram showing segmented regions and raster scan lines.

[0029] Figure 11 This represents the (k+1)th segmentation layer L of the exemplary three-dimensional model. k+1 The irradiated area S in k+1A diagram showing segmented regions and raster scan lines.

[0030] Figure 12 It is a three-dimensional model of a three-dimensional object that is horizontally divided into n layers.

[0031] [Explanation of Symbols]

[0032] 1: Chamber

[0033] 1a: Window

[0034] 3: Material layer forming device

[0035] 4: Base

[0036] 5: Styling Table

[0037] 6: CAM device

[0038] 7: Control device

[0039] 11: Coating head

[0040] 11a: Materials Storage Department

[0041] 11b: Material Supply Port

[0042] 11c: Material discharge outlet

[0043] 11fb: Blade

[0044] 11rb: Blade

[0045] 12: Coating head drive device

[0046] 13: Irradiation device

[0047] 17: Pollution prevention device

[0048] 17a: Frame

[0049] 17b: Opening

[0050] 17c: Diffusion component

[0051] 17d: Inert gas supply space

[0052] 17e: Fine pores

[0053] 17F: Cleaning Room

[0054] 31: Light source

[0055] 33: Collimator

[0056] 35: Focusing control unit

[0057] 37: Scanning device

[0058] 37a: First Flow Detector

[0059] 37b: Second Flow Detector

[0060] 51: Styling table drive device

[0061] 61: Storage device

[0062] 62: Computing device

[0063] 63: Memory

[0064] 71: Main control device

[0065] 72: Irradiation control device

[0066] 81: Base Plate

[0067] 82: Material layer

[0068] 83: Curing layer

[0069] 100: Layered Design Installation

[0070] B: Laser

[0071] R: Design Area Detailed Implementation

[0072] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The features shown in the embodiments described below can be combined with each other. Furthermore, the invention is independent of each feature.

[0073] 1. Layered modeling device 100

[0074] Figure 1 This is a schematic structural diagram of the layered modeling apparatus 100 according to this embodiment. The layered modeling apparatus 100 includes a chamber 1, a material layer forming apparatus 3, and an irradiation apparatus 13. In the modeling area R provided on the modeling stage 5 disposed in the chamber 1, a desired three-dimensional model can be formed by repeatedly forming a material layer 82 and a curing layer 83.

[0075] 1.1. Chamber 1

[0076] Chamber 1 covers the shaping area R, which serves as the region for forming the three-dimensional model. The interior of chamber 1 is filled with an inert gas of a predetermined concentration supplied by an inert gas supply device (not shown). In this specification, inert gas refers to a gas that does not substantially react with material layer 82 or curing layer 83, and is selected depending on the type of material; for example, nitrogen, argon, or helium can be used. The inert gas containing fumes generated during the formation of curing layer 83 is discharged from chamber 1, and after fumes are removed in a fume collector (not shown), it is supplied back to chamber 1 for reuse. The fume collector is, for example, an electrostatic precipitator or a filter.

[0077] On the upper surface of chamber 1, a window 1a is provided, serving as a transmission window for laser B. Window 1a is formed of a material that allows laser B to pass through. Specifically, the material of window 1a is selected from quartz glass, borosilicate glass, or crystals of germanium, silicon, zinc selenide, or potassium bromide, depending on the type of laser B. For example, in the case where laser B is a fiber laser or a yttrium aluminum garnet (YAG) laser, window 1a may comprise quartz glass.

[0078] Furthermore, a contamination prevention device 17 is provided on the upper surface of chamber 1, covering window 1a. The contamination prevention device 17 includes a cylindrical frame 17a and a cylindrical diffusion member 17c disposed within the frame 17a. An inert gas supply space 17d is provided between the frame 17a and the diffusion member 17c. Additionally, an opening 17b is provided on the bottom surface of the frame 17a, inside the diffusion member 17c. A plurality of fine holes 17e are provided on the diffusion member 17c, through which clean inert gas supplied to the inert gas supply space 17d fills the clean chamber 17f. Then, the clean inert gas filling the clean chamber 17f is ejected downwards through the opening 17b. This structure prevents smoke from adhering to window 1a, thereby removing smoke from the irradiation path of laser B.

[0079] 1.2. Material layer forming apparatus 3

[0080] like Figure 1 As shown, the material layer forming apparatus 3 is disposed inside the chamber 1. Figure 2 As shown, the material layer forming apparatus 3 includes a base 4 and a coating head 11 disposed on the base 4. The coating head 11 is configured to be able to move back and forth in a horizontal single-axis direction by a coating head drive device 12.

[0081] like Figure 3 and Figure 4 As shown, the coating head 11 includes a material receiving section 11a, a material supply port 11b, and a material discharge port 11c. The material supply port 11b is located on the upper surface of the material receiving section 11a and serves as a receiving port for material powder supplied from a material supply unit (not shown) to the material receiving section 11a. The material discharge port 11c is located on the bottom surface of the material receiving section 11a and discharges the material powder from the material receiving section 11a. The material discharge port 11c has a slit shape extending along the long side of the material receiving section 11a. Flat blades 11fb and 11rb are provided on both sides of the coating head 11. The blades 11fb and 11rb flatten the material powder discharged from the material discharge port 11c, thereby forming a material layer 82.

[0082] like Figure 1 and Figure 2 As shown, the modeling area R is located on the modeling platform 5, and a desired three-dimensional model is formed in the modeling area R. The modeling platform 5 can be driven by the modeling platform drive device 51 to move in the vertical direction. During modeling, a base plate 81 is arranged in the modeling area R, and material powder is supplied to the upper surface of the base plate 81 to form a material layer 82.

[0083] 1.3. Irradiation device 13

[0084] like Figure 1 As shown, the irradiation device 13 is positioned above the chamber 1. The irradiation device 13 irradiates the irradiation area of ​​the material layer 82 formed in the molding area R with laser B, causing the material powder to melt or sinter and solidify, thereby forming a solidified layer 83.

[0085] like Figure 5 As shown, the irradiation device 13 includes a light source 31, a collimator 33, a focusing control unit 35, and a scanning device 37, which is controlled by the irradiation control device 72 described later. The light source 31 generates laser B. Laser B can be used to sinter or melt material powder, such as a fiber laser, CO2 laser, or YAG laser. In this embodiment, a fiber laser is used as laser B.

[0086] Collimator 33 includes a collimating lens that converts the laser B output from light source 31 into parallel light. Focusing control unit 35 includes a focus control lens and a motor that moves the focus control lens back and forth along the optical axis. By adjusting the focus position of the laser B converted into parallel light by collimator 33, the beam diameter of the laser B on the surface of material layer 82 is adjusted.

[0087] The scanning device 37 is, for example, a galvano scanner, including a first galvanometer 37a and a second galvanometer 37b, and a first actuator and a second actuator (not shown) that rotate the first galvanometer 37a and the second galvanometer 37b to desired angles, respectively. The laser B, after passing through the focusing control unit 35, performs a two-dimensional scan on the upper surface of the material layer 82 within the shaping region R using the first galvanometer 37a and the second galvanometer 37b. Specifically, the laser B is reflected by the first galvanometer 37a in the X-axis direction, which is a horizontal single-axis direction within the shaping region R, and is reflected by the second galvanometer 37b in the Y-axis direction, which is another horizontal single-axis direction within the shaping region R and orthogonal to the X-axis direction.

[0088] Laser B, reflected by the first and second detectors 37a and 37b, passes through window 1a and irradiates the material layer 82 within the molding area R, thereby forming a cured layer 83. Furthermore, the irradiation device 13 is not limited to the aforementioned configuration. For example, an fθ lens can be used instead of the focusing control unit 35. Alternatively, the irradiation device 13 can be configured to irradiate the material layer 82 with an electron beam instead of laser B. Specifically, the irradiation device 13 can be configured to include a cathode electrode that emits electrons, an anode electrode that converges and accelerates electrons, a solenoid that forms a magnetic field and converges the electron beam in one direction, and a collector electrode that is electrically connected to the material layer 82, which is the irradiated object, and applies a voltage between the collector electrode and the cathode electrode.

[0089] 1.4. Control System

[0090] like Figure 6 As shown, the control system of the stacked modeling apparatus 100 includes a computer-aided manufacturing (CAM) device 6 and a control device 7. The CAM device 6 and the control device 7 are constructed by arbitrarily combining hardware such as a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), auxiliary storage devices, input / output interfaces, and software.

[0091] The CAM device 6 generates a project file that specifies instructions for the stacked modeling device 100 based on shape data (such as computer-aided design (CAD) data) determining the shape of a three-dimensional model, the material composition of the powder, and the irradiation conditions of laser B. The CAM device 6 includes a computing unit 62 for performing desired calculations, a storage unit 61 storing data required for the calculations, and a memory 63 for temporarily storing values ​​or data during the calculation process. Furthermore, the CAM device 6 is configured to transmit the project file to the control device 7 via a communication line or storage medium.

[0092] The control device 7 controls the material layer forming apparatus 3 and the irradiation device 13 according to the project file to perform layered modeling. The control device 7 includes a main control device 71 and an irradiation control device 72. The main control device 71 controls the coating head drive device 12 or the modeling table drive device 51 according to the project file created by the CAM device 6. In addition, the main control device 71 sends the modeling program containing instructions related to the irradiation of laser B in the project file to the irradiation control device 72. The irradiation control device 72 controls the irradiation device 13 according to the modeling program. Specifically, the irradiation control device 72 controls the first actuator and the second actuator to rotate the first detector 37a and the second detector 37b to the desired angle, irradiating laser B to the specified position. In addition, it controls the light source 31 to switch the output (laser power) or on / off of laser B, and controls the motor of the focusing control unit 35 to adjust the focal position of laser B.

[0093] 2. Raster scanning

[0094] Next, the grating scanning of laser B will be explained. Furthermore, the following explanation also applies when an electron beam is used instead of laser B.

[0095] Figure 7A and Figure 7B This is an explanatory diagram of raster scanning, specifically illustrating the scan path when performing raster scanning on an exemplary irradiation area S0. Laser B scans along the raster scan lines indicated by the arrows. Furthermore, laser B is irradiated at the arrow portions, and irradiation of laser B is temporarily stopped for a predetermined time (OFF time) at the dashed lines connecting adjacent arrows. The OFF time is the period from the end of irradiation of a predetermined raster scan line to the start of irradiation of the next raster scan line, during which irradiation of laser B is temporarily stopped. This OFF time is ensured to suppress the thermal effects of laser B irradiation on the surrounding environment.

[0096] When laser B is irradiated along the grating scan line, the temperature of the irradiated area rises sharply, and the material powder melts to form a molten pool. When the irradiation of the area ends, the temperature decreases due to heat dissipation, and a solidified layer 83 is formed.

[0097] exist Figure 7A In the grating scanning using a non-segmented region method shown, within the illumination region S0, grating scan lines are set for each spacing p along a predetermined scanning direction. The grating scan line is a straight line connecting two points on the outer edge of the illumination region S0 along the scanning direction, and scanning is performed in a direction orthogonal to the grating scan line.

[0098] exist Figure 7BIn the raster scanning using the region segmentation method shown, firstly, the illumination area S0 is divided into multiple segmented regions along the segmentation direction D0 with a segmentation width w. Figure 7B The dashed lines in the diagram represent the dividing lines of the irradiated area. Furthermore, within each divided area, a grating scan line is set for each spacing p along a predetermined scanning direction. Within the divided area, laser B is repeatedly applied along the grating scan line while simultaneously scanning in a direction orthogonal to the grating scan line. When the scanning within a divided area is completed, the same scanning process is used to irradiate other divided areas with laser B.

[0099] In the region segmentation method, since the grating scan lines essentially have the same reference length d corresponding to the segmentation width w, the material layer 82 can be melted and solidified under more uniform conditions without changing the irradiation conditions. Figure 7B In the example, since the scanning direction is set parallel to the segmentation direction D0, the reference length d is equal to the segmentation width w, and the length of most of the grating scan lines is equal to the reference length d. Furthermore, compared to the non-segmentation method, the grating scan lines are shorter, thus suppressing the thermal effects on the area surrounding the irradiated region.

[0100] On the other hand, at the ends of the segmented region, grating scan lines shorter than the reference length d may be generated. Figure 7B In the diagram, at the right end of each segmented region and in the lower segmented region, grating scan lines shorter than the reference length d are generated. At the irradiation sites based on these shorter grating scan lines, the temperature of the molten pool formed by the laser B becomes relatively high, making the solidified layer 83 prone to deformation. As the solidified layers 83 are stacked, when the irradiation sites based on these shorter grating scan lines overlap in the vertical direction, the bulges increase due to the accumulation of deformation in the solidified layers 83, making the blades 11fb and 11rb of the material layer forming apparatus 3 prone to collision.

[0101] This type of bulge is more pronounced in area segmentation methods with shorter raster scan lines, but is less of a problem in non-segmentation methods with longer raster scan lines. Furthermore, extending the disconnection time can suppress the rise in molten pool temperature, but this increases molding time and reduces manufacturing efficiency.

[0102] In this embodiment, in the region segmentation method, as described later, the grating scan line is set while rotating the segmentation direction of the irradiation region, thereby reducing the overlap of the irradiation portion in the vertical direction based on the grating scan line shorter than the reference length d, and suppressing the generation of bulges.

[0103] 3. Methods for manufacturing three-dimensional objects

[0104] Next, a method for manufacturing a three-dimensional model using the aforementioned layering modeling apparatus 100 will be described. The manufacturing method of this embodiment includes a curing layer forming step, in which a curing layer 83 is layered by repeatedly performing a material layer forming step and a curing step. The material layer forming step supplies material powder to a modeling region R to form a material layer 82, and the curing step forms a curing layer 83 by irradiating a predetermined irradiation area of ​​the material layer 82 with a laser B or an electron beam. Furthermore, the manufacturing method of this embodiment includes: a modeling condition setting step, an irradiation area determination step, a segmentation step, a scan line setting step, and a rotation angle setting step.

[0105] 3.1. Curing layer formation process

[0106] The curing layer formation process includes a material layer formation process and a curing process. In the material layer formation process of this embodiment, a material layer 82 containing material powder is formed in the molding area R. Furthermore, in the curing process of this embodiment, a curing layer 83 is formed by irradiating a predetermined irradiation area of ​​the material layer 82 with laser B. The material layer formation process and the curing process are repeatedly performed.

[0107] First, the first material layer formation process is performed. For example... Figure 8 As shown, with the base plate 81 placed on the molding table 5, the height of the molding table 5 is adjusted to an appropriate position. In this state, the coating head 11 is moved from... Figure 8 Move from the left to the right, such as Figure 9 As shown, a first material layer 82 is formed on the base plate 81.

[0108] Next, the first curing process will be carried out. For example... Figure 9 As shown, the first material layer 82 is cured by irradiating a predetermined irradiation area with laser B, thus obtaining a first cured layer 83. During the curing process, laser B scans along the scan path of the grating scan lines set in the scan line setting process, as described later.

[0109] Next, a second material layer formation process is performed. After the first cured layer 83 is formed, the height of the molding table 5 is lowered by an amount equivalent to one layer of material layer 82. In this state, the coating head 11 is moved from the molding area R... Figure 9 The material moves from right to left to form a second material layer 82, which covers the first cured layer 83. Then, a second curing process is performed. Using the same method as described above, the second material layer 82 is cured by irradiating a designated irradiation area with laser B or an electron beam to obtain the second cured layer 83.

[0110] The material layer formation and curing processes are repeated, and multiple cured layers 83 are stacked until the desired three-dimensional shape is obtained. Adjacent cured layers 83 are firmly fixed to each other.

[0111] 3.2. Modeling Condition Setting Process

[0112] In the modeling condition setting process, the irradiation conditions of laser B or electron beam and the segmentation width of the irradiation area are set as modeling conditions. Examples of irradiation conditions include the output (laser power) of laser B, the size of the spot diameter, the scanning speed, the laser B disconnection time, and the spacing p of the grating scan lines. The segmentation width of the irradiation area is set to a suitable value based on these irradiation conditions. In addition, the modeling conditions may include other conditions, such as the stacking thickness of the material layer 82 that is the object of irradiation by laser B (the thickness equivalent to one material layer). In this embodiment, a condition file recording the modeling conditions is created and read into the CAM device 6, thereby setting the irradiation conditions.

[0113] 3.3. Irradiation area determines process.

[0114] In the illumination area determination process, the illumination area is determined for each of the multiple segmented layers that divide the desired three-dimensional shape of the three-dimensional model at each specified height. In the illumination area determination process of this embodiment, multiple segmented layers are created by dividing the three-dimensional shape according to the stack thickness of each layer of material layer 82 set in the modeling condition setting process. The segmented layer is equivalent to the material layer 82 virtually formed by dividing the three-dimensional shape. Then, in each segmented layer, the area that roughly coincides with the area surrounded by the outline shape of the three-dimensional model is determined as the illumination area. In addition, in this embodiment, the CAM device 6 performs calculation processing using CAD data and condition files to create the segmented layers and determine the illumination area.

[0115] 3.4. Segmentation process

[0116] In the segmentation process, the irradiation area of ​​each segmentation layer is segmented along a specified segmentation direction with a specified segmentation width w suitable for the irradiation conditions to form multiple segmentation areas. Figure 10 As an example, the k-th segmentation layer L of a three-dimensional object is shown. k The irradiated area S in k And its segmented region. In this example, along the segmentation direction D k The irradiated area S is divided by a straight line with a width w. k It is divided into multiple segmented regions. Figure 10 The dashed line in the diagram represents the irradiation area S. k The dividing line. In this example, the dividing line is perpendicular to the dividing direction D. kOrthogonal straight lines. Furthermore, the starting point of the segmentation can be determined based on the irradiated area S. k The shape and other parameters can be appropriately set; for example, the irradiation area S can be... k The starting point can be configured on the outer edge, or it can be configured further inside the outer edge.

[0117] Furthermore, in the segmentation process, the segmentation direction of the irradiated area in the object segmentation layer is horizontally rotated by a rotation angle θ and set as the segmentation direction of the irradiated area in the segmentation layer directly above the object segmentation layer. Here, the rotation angle θ satisfies 0° < θ < 180° or -180° < θ < 0° (where the symbol represents the rotation direction). The method for setting the rotation angle θ will be described in detail below.

[0118] Figure 11 As an example, the k-th layer is divided into layers L. k When used as an object segmentation layer, the (k+1)th segmentation layer L is directly above it. k+1 The irradiated area S in k+1 And segmentation regions. In this example, the object segmentation layer L will be... k The irradiated area S in k The segmentation direction D k The direction after horizontal rotation by an angle θ = 67° is set as the segmentation layer L. k+1 The irradiated area S in k+1 The segmentation direction D k+1 Then, along the segmentation direction D k+1 The irradiation area S is divided by the width w. k+1 It is divided into multiple segmented regions. Figure 11 The dashed line in the diagram represents the irradiation area S. k+1 The dividing line.

[0119] In this embodiment, all segmentation layers are rotated in the segmentation direction. That is, if the three-dimensional shape is divided into n segmentation layers L1, L2, L3, ... L starting from the lower surface of the three-dimensional object... n The irradiation directions in each segmented layer are set as D1, D2, D3, ... D n For the segmentation layer L k (k = 1, 2, 3, ..., n-1) and the segmentation layer L directly above it. k+1 Segmentation direction D k+1 Relative to the segmentation direction D k It was rotated horizontally by an angle θ.

[0120] In addition, in this embodiment, the CAM device 6 forms a segmented region by performing calculations on the irradiation region determined in the irradiation region determination process and the rotation angle θ set in the rotation angle setting process described later.

[0121] 3.5. Scan line setting process

[0122] In the scan line setting process, grating scan lines are set along the specified scan direction within the segmented area. Figure 10 and Figure 11 In the image, as an example, an arrow is used to illustrate the segmentation layer L. k Segmentation layer L k+1 The grating scan lines are set within the segmented area. In this embodiment, the scanning direction is set to be parallel to the segmentation direction. Furthermore, the grating scan lines within the segmented area are arranged according to each spacing p set in the modeling condition setting process. That is, within the segmented area, grating scan lines parallel to the segmentation direction are arranged along the segmentation line at intervals of spacing p.

[0123] Furthermore, the scanning direction is not limited to this example and can also be set to be non-parallel to the segmentation direction (e.g., the direction after rotating the segmentation direction by ±45°). In addition, the relationship between the scanning direction and the segmentation direction (the angle between the scanning direction and the segmentation direction) in each segmentation layer can be the same in all segmentation layers or can be different depending on the segmentation layer.

[0124] Figure 10 and Figure 11 In the illustrated grating scan lines, the solid lines represent grating scan lines with a reference length d equal to the segmentation width w, and the dashed lines represent grating scan lines shorter than the reference length d. Generally, since the irradiation areas of adjacent segmented layers in the vertical direction have similar shapes, if the irradiation area is segmented along the same segmentation direction, the locations of grating scan lines shorter than the reference length d tend to overlap in the vertical direction. On the other hand, in this embodiment, for adjacent segmented layers L in the vertical direction... k Segmentation layer L k+1 By making the segmentation direction D k+1 Relative to the segmentation direction D k By rotating horizontally by an angle θ (in this example, θ = 67°), the location where the grating scan line shorter than the reference length d is positioned changes, and the overlap in the vertical direction decreases. By rotating all the segmented layers in the segmentation direction, the cured layer 83 can be laminated while suppressing the overlap of the designated locations of the short grating scan lines, thereby suppressing the generation of bulges caused by the deformation and accumulation of the cured layer 83.

[0125] In this embodiment, the CAM device 6 sets the raster scan lines by performing calculations on the segmented areas formed in the segmentation process using a condition file.

[0126] 3.6. Rotation Angle Setting Procedure

[0127] In the rotation angle setting process, the rotation angle θ is set based on the processing conditions. The processing conditions include at least one of the following: the segmentation width w, the material composition of the powder, the conditions of the irradiation area, the irradiation conditions of the laser B or electron beam, and the formation conditions of the material layer 82. The rotation angle θ is set based on the processing conditions such that the overlap in the vertical direction of the portions of the irradiation area of ​​each segmented layer where grating scan lines shorter than the reference length d are arranged is reduced.

[0128] If the segmentation direction is rotated sequentially, the segmentation direction of each layer for a predetermined number of segmented layers will be consistent. For example, when the rotation angle θ = ±90°, the segmentation direction will be consistent every two layers. From the perspective of reducing overlap in areas where grating scan lines shorter than the reference length d are arranged, it is preferable to have a large period (number of segmented layers) where the segmentation direction is consistent. From the viewpoint of increasing the period, the rotation angle θ is preferably not to include ±90° (i.e., 0° < θ < 90°, 90° < θ < 180°, -180° < θ < -90°, or -90° < θ < 0°). Furthermore, the rotation angle θ is preferably not to include values ​​where its absolute value |θ| is a divisor of 360°. Additionally, the rotation angle θ is preferably set to be as large as possible the least common multiple of its absolute value |θ| and 90°.

[0129] Furthermore, if the absolute value of the rotation angle θ, |θ|, is too small, or if the rotation angle θ is too close to ±180°, the positional change of the grating scan lines shorter than the reference length d between adjacent segmented layers will be small, which may not be sufficient to suppress the formation of bulges. From this perspective, it is preferable to have 40°≦|θ|≦140°, and more preferably 60°≦|θ|≦120°.

[0130] The processing conditions considered when setting the rotation angle θ are those that can influence the formation of bulges in the area segmentation method. For example, the smaller the segmentation width w and the smaller the reference length d of the grating scan line, the easier it is for bulges to form. The ease of bulge formation varies depending on the material powder, specifically, the specific heat capacity of the material. The ease of bulge formation also varies depending on the conditions of the irradiation area, specifically, the shape or size of the irradiation area. Furthermore, the ease of bulge formation varies depending on the irradiation conditions of the laser B or electron beam, specifically, the output of the laser B, the size of the spot diameter, the scanning speed, the laser B disconnection time, and the spacing p of the grating scan lines. By setting an appropriate rotation angle θ based on these processing conditions in the rotation angle setting process, the formation of bulges can be suppressed more effectively.

[0131] 4. Other implementation methods

[0132] The present invention can also be implemented in the following forms.

[0133] In the described embodiment, the segmentation direction is rotated for all segmentation layers during the segmentation process, but this structure is not limited to this. For example, the segmentation direction may be rotated for a portion of the segmentation layers depending on the shape of the irradiation area.

[0134] Alternatively, the manufacturing method for a three-dimensional object can be structured as follows: It includes a length determination process, which determines whether the scanning path on the object segmentation layer contains raster scan lines smaller than a predetermined value, and based on the determination result, rotates the segmentation direction in the segmentation process. In this case, in the segmentation process, when it is determined in the length determination process that the scanning path on the object segmentation layer contains raster scan lines smaller than a predetermined value, the direction after horizontally rotating the segmentation direction of the irradiated area in the object segmentation layer by a rotation angle θ is set as the segmentation direction of the irradiated area in the segmentation layer directly above the object segmentation layer.

[0135] The predetermined value used as the judgment criterion is, for example, the reference length d. If it is determined that the scan path on the object segmentation layer contains raster scan lines smaller than the reference length d, the segmentation direction can be rotated to determine the segmentation direction in the segmentation layer directly above the object segmentation layer. Furthermore, the predetermined value is not limited to this example; for example, a value shorter than the reference length d can also be set.

[0136] The foregoing has described various embodiments of the present invention, but these are merely examples and are not intended to limit the scope of the invention. The novel embodiments described can be implemented in various other ways, with various omissions, substitutions, and modifications made without departing from the spirit of the invention. These embodiments and their variations are included within the scope or spirit of the invention, and are also included within the scope of the invention as set forth in the claims and its equivalents.

Claims

1. A method for manufacturing a three-dimensional model, comprising a curing layer forming step, wherein the curing layer forming step stacks curing layers by repeatedly performing a material layer forming step and a curing step, wherein the material layer forming step supplies material powder to a modeling area to form a material layer, and the curing step forms the curing layer by irradiating a predetermined irradiation area of ​​the material layer with a laser or electron beam, the method for manufacturing the three-dimensional model comprising: The modeling condition setting process sets the irradiation conditions of the laser or the electron beam and the segmentation width of the irradiation area; The process of determining the irradiation area involves determining the irradiation area for each of the multiple segmented layers into which the desired three-dimensional shape is divided according to a specified height. The length determination process checks whether the scanning path on the object segmentation layer contains raster scan lines smaller than a specified value. The segmentation process involves dividing the irradiated area of ​​each segmentation layer along a predetermined segmentation direction with a segmentation width suitable for the irradiation conditions to form multiple segmented areas. as well as The scan line setting process involves setting the grating scan lines along a predetermined scan direction within the segmented area. In the curing process, the laser or the electron beam scans along the scanning path that includes the grating scan lines. In the segmentation process, when it is determined in the length determination process that the scanning path on the object segmentation layer contains a grating scan line smaller than the predetermined value, the segmentation direction of the irradiation area in the object segmentation layer is horizontally rotated by a rotation angle θ and then set as the segmentation direction of the irradiation area in the segmentation layer directly above the object segmentation layer. The rotation angle θ satisfies 0° < θ < 180° or -180° < θ < 0°, where the symbol represents the direction of rotation.

2. The method for manufacturing a three-dimensional object according to claim 1, wherein, In the scan line setting process, the scan direction is set to be parallel to the segmentation direction.

3. The method for manufacturing a three-dimensional object according to claim 1 or 2, wherein, Also includes: The rotation angle setting process involves setting the rotation angle θ based on the processing conditions. The processing conditions include at least one of the following: the segmentation width, the material composition of the powder, the conditions of the irradiation area, and the irradiation conditions.

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