Three-dimensional molding device

Abstract

To form moldings with high precision.SOLUTION: The three-dimensional modeling device 1 is equipped with a material holding unit 3, an optical head 2, and a control unit 5. The control by the control unit 5 can switch between a first drawing mode and a second drawing mode. In the first drawing mode, the optical beam is scanned only once for each position in the drawing area instructed to be drawn by design data in a layer to be drawn 92. In the second drawing mode, the light beam is scanned multiple times for each position of the drawing area with the light intensity given to each position of the drawing area in one scan of the light beam being smaller than that in the first drawing mode. This allows the modeling object to be formed with high precision.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a three-dimensional modeling apparatus. [Background technology]

[0002] In recent years, selective laser sintering (SLS) type 3D modeling devices have been used, which irradiate modeling materials such as resin powder or metal powder with modulated laser light to melt the material and then solidify it to create 3D shapes.

[0003] For example, in a powder bed type three-dimensional modeling apparatus, resin powder is spread in a thin layer on a build platform, and a laser beam is scanned over the layer of resin powder with a galvanometer mirror or the like to melt the powdered resin in the area irradiated with the laser beam. This operation is then repeated to stack and solidify the molten resin powder, thereby creating a model. In a powder bed type three-dimensional modeling apparatus, the resin powder on the build platform is generally heated to a predetermined preheat temperature that is several degrees Celsius to several tens of degrees Celsius lower than the melting point of the resin powder, and the resin powder maintained at the preheat temperature is irradiated with a laser beam (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2021-509094 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in the layer of resin powder on the build platform, the temperature of the region irradiated with the laser light (i.e., the imaging region) rises, and thermal diffusion occurs to the non-imaging region surrounding the imaging region. In addition, the amount of laser light gradually changes near the boundary between the imaging region and the non-imaging region, so the amount of light at the edge of the non-imaging region is not zero. For this reason, in a thin non-imaging region sandwiched between two imaging regions, the thermal diffusion from the imaging region and the amount of light at the edge of the imaging region may cause unintended melting of the resin powder, which may reduce the dimensional accuracy of the model.

[0006] In addition, in the build platform, when new resin powder is supplied onto a layer of resin powder on which a pattern has been drawn (hereinafter also referred to as the "drawn layer"), the temperature directly above the drawn area and the surrounding area of ​​the drawn layer in the new resin powder layer may become higher than the predetermined preheat temperature. Therefore, when a laser beam is irradiated directly above the drawn area in the new resin powder layer, there is a risk of unintended melting of the resin powder around the area irradiated with the laser beam. In particular, as described above, there is a high possibility of unintended melting of the resin powder in the narrow non-drawn area sandwiched between two drawn areas.

[0007] The present invention has been made in consideration of the above-mentioned problems, and has an object to form a shaped object with high accuracy. [Means for solving the problem]

[0008] A first aspect of the present invention is a three-dimensional modeling apparatus, comprising: a stage for holding a powdered modeling material; a material holding unit having a material supply unit for supplying the modeling material onto the stage; an optical head for scanning the modeling material held on the stage while modulating a light beam; and a control unit for controlling the material holding unit and the optical head based on design data of a model, thereby repeatedly supplying the modeling material onto the stage, scanning the light beam on a drawing target layer, which is a surface layer of the supplied modeling material, to melt the modeling material in an area irradiated with the light and draw a pattern. The control by the control unit is switchable between a first drawing mode in which the light beam is scanned only once for each position of a drawing area instructed to be drawn by the design data on the drawing target layer, and a second drawing mode in which the light beam is scanned multiple times for each position of the drawing area while the amount of light applied to each position of the drawing area in one scan of the light beam is smaller than that in the first drawing mode.

[0009] A second aspect of the present invention is a 3D printing device of the first aspect, wherein when a non-drawing area where drawing is not instructed in the design data includes a narrow non-drawing area having a width equal to or less than a predetermined threshold, the second drawing mode is selected by the control unit.

[0010] A third aspect of the present invention is the three-dimensional modeling apparatus of the first or second aspect, wherein a light intensity of the light beam in the second drawing mode is the same as a light intensity of the light beam in the first drawing mode, and a scanning speed of the light beam in the second drawing mode is higher than a scanning speed of the light beam in the first drawing mode.

[0011] A fourth aspect of the present invention is the three-dimensional modeling apparatus of the third aspect, wherein the number of scans of the light beam for each position in the drawing area in the second drawing mode is two, and the scanning speed of the light beam in the second drawing mode is twice the scanning speed of the light beam in the first drawing mode.

[0012] A fifth aspect of the present invention is the three-dimensional modeling apparatus of the first or second aspect, wherein a scanning speed of the light beam in the second drawing mode is the same as a scanning speed of the light beam in the first drawing mode, and a light intensity of the light beam in the second drawing mode is smaller than a light intensity of the light beam in the first drawing mode.

[0013] A sixth aspect of the present invention is the 3D printing apparatus of the first or second aspect (which may be any one of the first to fifth aspects), wherein the number of scans of the light beam with respect to each position of the drawing area in the second drawing mode is two, and the amount of light imparted to each position of the drawing area in the first scan of the light beam in the second drawing mode is the same as the amount of light imparted to each position of the drawing area in the second scan of the light beam in the second drawing mode.

[0014] A seventh aspect of the present invention is the 3D printing apparatus of the first or second aspect (which may be any one of the first to fifth aspects), wherein the number of scans of the light beam with respect to each position of the drawing area in the second drawing mode is two. The amount of light imparted to each position of the drawing area in the first scan of the light beam in the second drawing mode is greater than the amount of light imparted to each position of the drawing area in the second scan of the light beam in the second drawing mode.

[0015] Aspect 8 of the present invention is the 3D modeling apparatus of aspect 1 or 2 (or any one of aspects 1 to 7), in which the light beam is a multi-spot beam composed of a plurality of light spots linearly arranged in a predetermined arrangement direction. The multi-spot beam is scanned in a predetermined scanning direction inclined with respect to the arrangement direction.

[0016] A ninth aspect of the present invention is the 3D printing apparatus of the first or second aspect (which may be any one of the first to eighth aspects), further comprising a temperature measuring unit that measures a temperature distribution on an upper surface of the modeling material on the stage. The control unit adjusts the light intensity or the scanning speed of the light beam in the second drawing mode based on the temperature distribution measured by the temperature measuring unit.

[0017] A tenth aspect of the present invention is the three-dimensional modeling apparatus according to the first or second aspect (which may be any one of the first to ninth aspects), in which the modeling material is a resin material. Effect of the Invention

[0018] According to the present invention, a shaped object can be formed with high precision. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a 3-D printing apparatus according to one embodiment. [Diagram 2] FIG. 2 is a diagram illustrating a configuration of a control unit. [Diagram 3] FIG. 4 is a block diagram showing the functions of a control unit. [Figure 4] 1A to 1C are diagrams illustrating a flow of forming a shaped object. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] 11A to 11C are diagrams showing a light amount profile and the like when a pattern is drawn in a first drawing mode. [Figure 9] 1A to 1C are diagrams illustrating a flow of forming a shaped object. [Figure 10] 13A to 13C are diagrams showing a light amount profile and the like when a pattern is drawn in the second drawing mode. [Figure 11] 13A to 13C are diagrams showing a light amount profile and the like when a pattern is drawn in the second drawing mode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Fig. 1 is a diagram showing the configuration of a three-dimensional modeling apparatus 1 according to an embodiment of the present invention. The three-dimensional modeling apparatus 1 shown in Fig. 1 is an SLS (Selective Laser Sintering) type three-dimensional modeling apparatus that irradiates a powdered modeling material with modulated laser light to melt the modeling material and then solidifies it to perform three-dimensional modeling.

[0021] The above-mentioned modeling material is, for example, resin, metal, engineering plastic, ceramics, etc. The modeling material may contain multiple types of materials. In the present embodiment, the modeling material is a powdered resin material. The resin material is a modeling material containing resin as a main material, and may contain materials other than resin. The materials other than resin are, for example, materials (carbon particles, etc.) that have a relatively high absorptivity for the wavelength of the above-mentioned laser light.

[0022] The three-dimensional modeling device 1 includes an optical head 2, a material holding unit 3, a temperature measuring unit 4, and a control unit 5. The material holding unit 3 is disposed below the optical head 2 and holds a powdered modeling material 91. In FIG. 1, the material holding unit 3 is shown in vertical section, and the modeling material 91 is marked with parallel diagonal lines. The optical head 2 scans the modeling material 91 held by the material holding unit 3 with a modulated laser beam (i.e., a light beam). The light irradiated from the optical head 2 to the modeling material 91 is, for example, a multi-spot beam (i.e., a multi-spot line beam) composed of a plurality of light spots linearly arranged in a predetermined arrangement direction. The temperature measuring unit 4 measures the temperature of the modeling material 91 held by the material holding unit 3. The control unit 5 controls the optical head 2, the material holding unit 3, and the temperature measuring unit 4.

[0023] The material holding unit 3 includes a modeling unit 31 and a material supply unit 32. The modeling unit 31 includes a first cylinder 33 and a first piston 34. The first cylinder 33 is a cylindrical member extending in the vertical direction. The shape of the internal space of the first cylinder 33 in a plan view is, for example, substantially rectangular. The first piston 34 is a member accommodated in the internal space of the first cylinder 33. The first piston 34 is movable in the vertical direction in the internal space of the first cylinder 33. The first piston 34 includes a substantially flat stage 341 that is substantially perpendicular to the vertical direction, and a support 342 that supports the stage 341 from below. The shape of the stage 341 in a plan view is substantially the same as the shape of the internal space of the first cylinder 33 in a plan view.

[0024] In the modeling unit 31, a three-dimensional space surrounded by the inner surface of the first cylinder 33 and the upper surface of the stage 341 becomes a modeling space 30 where 3D modeling is performed. In the modeling space 30, a powdered modeling material 91 is held on the stage 341. That is, the 3D modeling device 1 is a powder bed type 3D modeling device.

[0025] The modeling unit 31 includes a heater 38 that heats the modeling material 91 on the stage 341. The heater 38 applies energy substantially uniformly to the modeling material 91 on the stage 341 to raise the temperature of the modeling material 91 to a temperature below the melting point and maintain the temperature. In the example shown in FIG. 1, the heater 38 includes a first heater 381 and a second heater 382. The first heater 381 is a substantially flat electric heater provided on the upper part of the stage 341. The first heater 381 is, for example, built into the stage 341 and provided over substantially the entire surface of the stage 341 in a plan view. The second heater 382 is a halogen lamp that is disposed above the stage 341 at a distance and irradiates light toward the stage 341. The configuration, arrangement, etc. of the heater 38 are not limited to those described above and may be changed in various ways.

[0026] The material supply unit 32 includes a second cylinder 35, a second piston 36, and a squeegee 37. The second cylinder 35 is a cylindrical member extending in the vertical direction, and is disposed adjacent to the side of the first cylinder 33. The shape of the internal space of the second cylinder 35 in a plan view is, for example, substantially rectangular. The second piston 36 is a member housed in the internal space of the second cylinder 35. The second piston 36 is movable in the vertical direction in the internal space of the second cylinder 35. The shape of the second piston 36 in a plan view is substantially the same as that of the internal space of the second cylinder 35.

[0027] In the material supply unit 32, a three-dimensional space surrounded by the inner surface of the second cylinder 35 and the upper surface of the second piston 36 becomes a storage space in which the modeling material 91 to be supplied to the modeling unit 31 is stored. The squeegee 37 is a rod-shaped (e.g., substantially cylindrical) or plate-shaped member that extends horizontally across the upper opening of the second cylinder 35. The squeegee 37 is movable horizontally along the upper end surface of the second cylinder 35.

[0028] In the material holding unit 3, when the modeling material 91 is supplied onto the stage 341, the first piston 34 of the modeling unit 31 descends a predetermined distance. As a result, the upper surface of the modeling material 91 on the stage 341 is located below the upper end surface of the first cylinder 33. Meanwhile, in the material supply unit 32, the second piston 36 rises a predetermined distance, and the modeling material 91 in the second cylinder 35 is lifted upward. Then, the squeegee 37 moves from above the second cylinder 35 to above the first cylinder 33, so that the modeling material 91 protruding above the upper end surface of the second cylinder 35 is supplied into the modeling space 30 of the modeling unit 31. The upper surface of the modeling material 91 held in the modeling space 30 is located at approximately the same height as the upper end surface of the first cylinder 33.

[0029] The optical head 2 includes a laser light source 21, an illumination optical system 221, an optical modulator 222, a first projection optical system 223, a scanning unit 23, and a second projection optical system 224. The laser light source 21 emits laser light. The laser light source 21 is, for example, a fiber laser light source. The type of the laser light source 21 may be changed in various ways. The wavelength of the laser light emitted from the laser light source 21 is appropriately set according to the type of the modeling material 91, etc.

[0030] The illumination optical system 221, the optical modulator 222, and the first projection optical system 223 modulate the laser light emitted from the laser light source 21 into a modulated beam and guide the modulated beam to the scanning unit 23. The second projection optical system 224 guides the multi-spot beam from the scanning unit 23 to the modeling material 91 on the stage 341. The illumination optical system 221, the first projection optical system 223, and the second projection optical system 224 each include a plurality of optical elements such as lenses.

[0031] The illumination optical system 221 shapes, for example, the laser light from the laser light source 21 into a substantially rectangular shaped beam that is long in one direction (hereinafter referred to as the "long axis direction") and guides it to the optical modulator 222. In other words, the cross-sectional shape of the shaped beam is a substantially rectangular shape that is long in the long axis direction and short in the short axis direction perpendicular to the long axis direction. The long axis direction and the short axis direction are directions perpendicular to the traveling direction of the shaped beam (i.e., the optical axis direction). The cross-sectional shape of the shaped beam is the shape of the shaped beam on a plane perpendicular to the traveling direction of the shaped beam. The cross-sectional shape of the shaped beam can also be regarded as a substantially straight line extending in the long axis direction.

[0032] The optical modulator 222 modulates the shaped beam from the illumination optical system 221 into a modulated beam and guides it to the first projection optical system 223. For example, an LPLV (Linear Planar Light Valve), which is a type of PLV (Planar Light Valve), is used as the optical modulator 222. The modulated beam is a multi-spot beam composed of a plurality of light spots linearly arranged in the long axis direction. Each light spot of the multi-spot beam can have its gradation adjusted (i.e., the light intensity of the emitted light can be adjusted).

[0033] The optical modulator 222 does not necessarily have to be an LPLV, and may have another structure. The light irradiated from the optical head 2 to the modeling material 91 is not limited to the multi-spot line beam described above, and may be variously changed. For example, the optical head 2 may irradiate the modeling material 91 with a light beam composed of a single light spot.

[0034] The scanning unit 23 reflects the modulated beam (i.e., the multi-spot beam) from the first projection optical system 223, and scans the modulated beam on the modeling material 91 in the modeling space 30 of the material holding unit 3 through the second projection optical system 224. The scanning unit 23 includes, for example, a relay lens 231 and a galvanometer scanner 232. The galvanometer scanner 232 is a scanning mechanism including a galvanometer mirror 233 and a galvanometer motor (not shown). In the scanning unit 23, the galvanometer mirror 233 is rotated by the galvanometer motor, so that the traveling direction of the multi-spot beam reflected by the galvanometer mirror 233 is changed. As a result, the multi-spot beam irradiated onto the modeling material 91 is scanned in a scanning direction inclined with respect to the long axis direction of the multi-spot beam (i.e., the arrangement direction of the multiple light spots). The scanning direction is, for example, a direction perpendicular to the long axis direction on the upper surface of the modeling material 91.

[0035] In the example shown in Fig. 1, the left-right direction in the figure is the above-mentioned scanning direction parallel to the stage 341. Moreover, the direction perpendicular to the paper surface of Fig. 1 is the width direction (i.e., the arrangement direction of multiple light spots in the multi-spot beam) perpendicular to the scanning direction and parallel to the stage 341. Note that the scanning unit 23 does not necessarily need to include a galvano scanner, and may have another structure.

[0036] The temperature measurement unit 4 measures the temperature distribution on the top surface of the modeling material 91 on the stage 341. The temperature measurement unit 4 is, for example, an infrared thermography camera capable of capturing an image of substantially the entire top surface of the modeling material 91 on the stage 341. The measurement result (for example, a captured image) by the temperature measurement unit 4 is sent to the control unit 5.

[0037] 2 is a diagram showing the configuration of the control unit 5. The control unit 5 has a configuration of a general computer system including a CPU 51, a ROM 52, a RAM 53, a fixed disk 54, a display 55, an input unit 56, a reading device 57, a communication unit 58, and a bus 50. The CPU 51 performs various arithmetic processing. The ROM 52 stores basic programs. The RAM 53 stores various information. The fixed disk 54 stores information. The display 55 is a display unit that displays various information such as images. The input unit 56 includes a keyboard 56a and a mouse 56b that receive input from an operator.

[0038] The reading device 57 reads information from a computer-readable recording medium 511 such as an optical disk, a magnetic disk, a magneto-optical disk, or a memory card. The display 55, the keyboard 56a, the mouse 56b, and the reading device 57 are connected to the bus 50 via an interface I / F. The communication unit 58 transmits and receives signals between the components of the 3D printing apparatus 1 other than the control unit 5 and external devices. The bus 50 is a signal circuit that connects the CPU 51, the ROM 52, the RAM 53, the fixed disk 54, the display 55, the input unit 56, the reading device 57, and the communication unit 58.

[0039] In control unit 5, program 512 is read in advance from recording medium 511 via reader 57 and stored in fixed disk 54. Program 512 may be stored in fixed disk 54 via a network. CPU 51 functions as a calculation unit that executes calculation processing while using RAM 53 and fixed disk 54 in accordance with program 512. Other components functioning as a calculation unit other than CPU 51 may be employed.

[0040] FIG. 3 is a diagram showing a functional configuration realized by the control unit 5 executing arithmetic processing and the like according to the program 512. These functional configurations include a storage unit 501, a scan control unit 502, an intensity control unit 503, and a mode switching unit 504. All or part of these functions may be realized by a dedicated electric circuit. Also, these functions may be realized by a plurality of computers. Among the functional configurations shown in FIG. 3, the scan control unit 502, the intensity control unit 503, and the mode switching unit 504 are realized by the CPU 51, the ROM 52, the RAM 53, the fixed disk 54, and their peripheral configurations. Also, the storage unit 501 is mainly realized by the RAM 53 and the fixed disk 54.

[0041] The memory unit 501 stores various information such as design data of a three-dimensional object to be formed by the 3D printing apparatus 1. The scan control unit 502 adjusts the scanning speed of the multi-spot beam on the printing material 91 by controlling the galvano scanner 232 of the scanning unit 23 and the like. The intensity control unit 503 adjusts the light intensity of the multi-spot beam irradiated onto the printing material 91 by controlling the laser light source 21 and the like. The light intensity means the light energy irradiated per unit area on the printing material 91 in unit time. The mode switching unit 504 switches the drawing mode of the 3D printing apparatus 1.

[0042] Next, an example of a flow of forming a model in the 3D printing apparatus 1 will be described with reference to FIG. 4. In the 3D printing apparatus 1, first, design data of a 3D model to be formed is stored in the memory unit 501 of the control unit 5 (step S11). The design data is a collection of data (hereinafter also referred to as "cross-sectional data") showing cross sections obtained by slicing the model at predetermined thicknesses in the vertical direction. The cross-sectional data is data showing the shape of a portion corresponding to one layer when the model is divided into multiple layers stacked in the vertical direction. The control unit 5 may perform a predetermined correction to the design data.

[0043] Next, the control unit 5 controls the material holding unit 3 to supply the powdered modeling material 91 onto the stage 341 (step S12). The modeling material 91 on the stage 341 is preheated by the heater 38 to increase in temperature, and is maintained at a temperature lower than the melting point of the modeling material 91 and higher than the crystallization point (i.e., crystallization temperature) of the modeling material 91. For example, when a resin powder with a melting point of 185°C and a crystallization point of 150°C is used as the modeling material 91, the temperature of the modeling material 91 on the stage 341 is maintained at a temperature higher than 150°C and lower than 185°C (for example, about 173°C). As a result, the modeling material 91 on the stage 341 is maintained in a powdered state without melting. In addition, the modeling material 91 melted on the stage 341 is maintained in a molten state without solidifying.

[0044] Then, the optical head 2 is controlled by the control unit 5, so that the multi-spot beam is scanned in the scanning direction while being modulated using the design data (i.e., drawing data) on the surface layer (hereinafter, also referred to as the "drawing target layer 92") of the modeling material 91 supplied onto the stage 341. As a result, the temperature of the modeling material 91 in the region irradiated with the light in the modeling target layer 92 rises to a modeling temperature (e.g., about 220°C) equal to or higher than the melting point, and the modeling material 91 in that region melts, so that a pattern (i.e., a pattern formed by the molten modeling material 91) is drawn on the modeling target layer 92 (step S13).

[0045] The pattern drawing in step S13 is performed by, for example, multi-pass drawing in which scanning of the multi-spot beam in the scanning direction and step movement in the width direction (i.e., the sub-scanning direction) are repeated to complete drawing on the entirety of the drawing target layer 92. Note that the pattern drawing may also be performed by single-pass drawing in which drawing on the entirety of the drawing target layer 92 is completed by scanning the multi-spot beam once in the scanning direction.

[0046] In the imaging target layer 92, heat is diffused from the molten modeling material 91 in the region irradiated with light to the modeling material 91 surrounding the region. As a result, the temperature of the modeling material 91 in the region irradiated with light drops, but since the temperature of the modeling material 91 in the imaging target layer 92 is maintained at a temperature higher than the crystallization point by the heater 38, the modeling material 91 in the region is maintained in a molten state.

[0047] When the drawing of the pattern on the drawing target layer 92 is completed, it is confirmed whether the formation of the modeled object is completed or not (step S14). If the formation of the modeled object is not completed, the process returns to step S12, and a new modeling material 91 is supplied onto the layer of the modeling material 91 on which the pattern is drawn on the stage 341, to form a new modeling target layer 92 (step S12). Then, the multi-spot beam is scanned onto the new modeling target layer 92, and a pattern is drawn with the molten modeling material 91 (step S13).

[0048] As described above, in the pattern drawn in step S13, the modeling material 91 is maintained in a molten state, and in the pattern drawn in the previous step S13, the modeling material 91 is also maintained in a molten state. In this manner, in the 3D modeling apparatus 1, the molten modeling material 91 is layered, and therefore, when solidified, a model having a high bonding strength in the layering direction (i.e., the vertical direction) is formed.

[0049] In the 3D modeling apparatus 1, steps S12 to S13 are repeated until the formation of the model is completed. While steps S12 to S13 are being repeated, the heater 38 continues to heat the modeling material 91, and when the repetition of steps S12 to S13 is completed, the heater 38 also stops heating the modeling material 91. As a result, the modeling material 91, which has been maintained in a molten state in the above-mentioned pattern, drops in temperature to below its crystallization point and solidifies, and a 3D model composed of the solidified modeling material 91 is formed.

[0050] Next, switching of the drawing mode in the 3D printing apparatus 1 will be described. In the 3D printing apparatus 1, the drawing mode of the pattern drawing (i.e., scanning) performed in the above-mentioned step S13 can be switched between the first drawing mode and the second drawing mode by the mode switching unit 504 of the control unit 5. The first drawing mode is a so-called normal drawing mode, and the drawing operation of the 3D printing apparatus 1 in step S13 can be simplified compared to the second drawing mode. On the other hand, the second drawing mode is a so-called high-precision drawing mode. In the second drawing mode, the drawing operation of the 3D printing apparatus 1 becomes more complicated compared to the first drawing mode, but the precision of the formed object can be improved. In the following, first, the first drawing mode will be described, and then the second drawing mode will be described.

[0051] In drawing a pattern in the first drawing mode, as described above, the multi-spot beam irradiated onto the modeling material 91 at a predetermined light intensity (hereinafter also referred to as "first light intensity") is scanned over the modeling material 91 at a predetermined scanning speed (hereinafter also referred to as "first scanning speed"). At this time, on the upper surface of the modeling material 91, the irradiated area of ​​the multi-spot beam passes through each position on the upper surface only once, thereby completing drawing of the pattern. In other words, the light from the optical head 2 is not irradiated again onto the area of ​​the modeling target layer 92 of the modeling material 91 that has been irradiated with light and melted.

[0052] 5 is a perspective view showing a model 81 to be modeled by the 3D modeling apparatus 1. The model 81 has a substantially rectangular parallelepiped shape, and a first groove 811 and a second groove 812 are provided on the upper surface of the model 81. The first groove 811 and the second groove 812 are substantially linear grooves extending parallel to the above-mentioned scanning direction, and are provided over the entire length of the model 81 in the scanning direction. The first groove 811 and the second groove 812 have the same depth, which is smaller than the height of the model 81. The size of the first groove 811 in the width direction is smaller than the size of the second groove 812 in the width direction.

[0053] Fig. 6 is a diagram showing a cross section 813 of the object 81 taken at a position VI-VI in Fig. 5. Fig. 7 is a diagram showing a cross section 814 of the object 81 taken at a position VII-VII in Fig. 5. The cross-sectional data corresponding to the cross sections 813 and 814 are included in the design data described above. In the cross section 813, the entire rectangular area corresponding to the object 81 is a drawing area 815 that is instructed to be drawn in the design data. In Fig. 6, the drawing area 815 is indicated by parallel diagonal lines.

[0054] In cross section 814, among the rectangular regions directly above drawing region 815 in cross section 813, rectangular band-shaped regions corresponding to first groove 811 and second groove 812, respectively, are non-drawing regions 816 and 817 for which drawing is not instructed in the design data. In addition, the rectangular region to the left of non-drawing region 816, the rectangular region between non-drawing region 816 and non-drawing region 817, and the rectangular region to the right of non-drawing region 817 are drawing regions 815a, 815b, and 815c for which drawing is instructed in the design data, respectively. In Fig. 7, drawing regions 815a, 815b, and 815c are indicated by parallel diagonal lines.

[0055] In the example shown in FIG. 7, the size in the width direction (i.e., the left-right direction in the figure) of the non-drawing region 816 corresponding to the first groove 811 is equal to or smaller than a predetermined threshold value (hereinafter also referred to as the "narrow threshold value"). Moreover, the size in the width direction of the non-drawing region 817 corresponding to the second groove 812 is larger than the narrow threshold value. In the following description, the non-drawing region 816 is also referred to as the "narrow non-drawing region 816." That is, in the example shown in FIG. 7, the non-drawing regions 816, 817 include the narrow non-drawing region 816.

[0056] FIG. 8 is a diagram showing a light amount profile and the like when drawing a pattern corresponding to the cross section 814 in the first drawing mode. The diagram marked with (a) in FIG. 8 (hereinafter also referred to as FIG. 8(a)) is a diagram showing a pattern on the design data in the cross section 814 (i.e., a design pattern). FIG. 8(b) is a graph showing a light amount profile of the multi-spot beam irradiated onto the drawing target layer 92. The horizontal axis in FIG. 8(b) indicates the width direction, and the vertical axis indicates the light amount. The light amount means the total amount of light energy irradiated to one position on the modeling material 91 in one scan of the optical head 2.

[0057] Fig. 8(c) is a diagram showing the temperature distribution in the drawing target layer 92 irradiated with the multi-spot beam with the light amount profile shown in Fig. 8(b). The horizontal axis in Fig. 8(c) indicates the width direction, and the vertical axis indicates the temperature of the modeling material 91 in the drawing target layer 92. Fig. 8(d) is a diagram showing the actually drawn pattern (i.e., the drawing pattern) in the cross section 814.

[0058] In Fig. 8(b), the regions marked with the reference symbols 711a, 711b, and 711c are ON regions in which the spots of the multi-spot beam are turned on. Moreover, the regions marked with the reference symbols 712 and 713 are OFF regions in which the spots of the multi-spot beam are turned off. In the ON regions 711a, 711b, and 711c, the multi-spot beam is scanned, and thereby the temperature of the modeling material 91 in the drawing target layer 92 rises to a modeling temperature (e.g., 220°C) that is higher than the melting point of the modeling material 91 (e.g., 185°C), as shown by the solid line in Fig. 8(c).

[0059] As shown in Fig. 8(b), the light amount distribution in the ON region 711a is a substantially rectangular distribution. Also, outside the end of the width direction of the ON region 711a, the light amount does not suddenly become 0, but gradually decreases as it moves away from the ON region 711a. In the following description, the light amount generated outside the end of the width direction of the ON region 711a due to the light in the light spot of the ON region 711a is also referred to as "end light amount". The same is true for the ON regions 711b and 711c.

[0060] In the OFF region 713 corresponding to the non-drawing region 817, which is relatively large in the width direction, the light amount at both ends in the width direction is slightly increased by the light amount at the ends of the ON regions 711b and 711c adjacent to both sides. In addition, thermal diffusion from the ON regions 711b and 711c also occurs in the OFF region 713. Therefore, as shown by the solid line in FIG. 8(c), the temperature of the modeling material 91 in the OFF region 713 is slightly higher than the preheat temperature (e.g., 173°C).

[0061] On the other hand, in the OFF region 712 corresponding to the narrow non-drawing region 816 having a small size in the width direction, as shown in Fig. 8(b), the light amount at the ends of the adjacent ON regions 711a and 711b on both sides is accumulated, so that the light amount is greater than that of the OFF region 713 corresponding to the non-drawing region 817. Also, in the OFF region 712, the heat diffused from the ON regions 711a and 711b also overlaps. Therefore, as shown by the solid line in Fig. 8(c), the temperature of the modeling material 91 in the OFF region 712 is higher than the temperature of the modeling material 91 in the OFF region 713.

[0062] Thereafter, due to thermal diffusion from the ON regions 711a, 711b, and 711c over time, the temperature of the modeling material 91 in the ON regions 711a, 711b, and 711c decreases, and the temperature of the modeling material 91 in the OFF regions 712 and 713 increases, as shown by the two-dot chain line in Fig. 8(c). The state shown by the two-dot chain line in Fig. 8(c) is the temperature about 0.3 to 0.5 seconds after the end of the irradiation of the multi-spot beam to the ON regions 711a, 711b, and 711c. As a result, the temperature of the modeling material 91 in the OFF region 712 becomes higher than the melting point (e.g., 185°C), and there is a possibility that the modeling material 91 in the OFF region 712 will melt unintentionally.

[0063] When the modeling material 91 melts in the OFF region 712, as shown in Fig. 8(d), in the actual drawing pattern, the narrow non-drawing region 816 disappears between the drawing region 815a and the drawing region 815b, or the width of the narrow non-drawing region 816 becomes smaller than the design value. Note that, since the temperature of the modeling material 91 in the OFF region 713 does not rise to the melting point, the modeling material 91 does not melt in the OFF region 713. Therefore, the non-drawing region 817 exists between the drawing region 815b and the drawing region 815c.

[0064] Thus, in drawing in the first drawing mode, if a pattern includes a narrow non-drawing region 816, there is a possibility that the drawing accuracy of the narrow non-drawing region 816 will decrease. The possibility of the decrease in drawing accuracy is the same whether the width of the non-drawing region is small in the scanning direction or in the vertical direction.

[0065] Therefore, in the three-dimensional modeling apparatus 1, when the pattern includes the narrow non-drawing region 816, the pattern is drawn in the second drawing mode instead of the first drawing mode. As described above, in the first drawing mode, the multi-spot beam is scanned only once for each position of the drawing regions 815a to 815c. On the other hand, in the second drawing mode, the multi-spot beam is scanned multiple times for each position of the drawing regions 815a to 815c. In the second drawing mode, the amount of light provided to each position of the drawing regions 815a to 815c in one scan of the multi-spot beam is smaller than the amount of light provided to each position of the drawing regions 815a to 815c in the first drawing mode.

[0066] For example, in the second drawing mode, the amount of light applied to each position of the drawing regions 815a-815c in one scan of the multi-spot beam (hereinafter also referred to as "amount of light per scan") is approximately half that in the first drawing mode, and the multi-spot beam scans each position of the drawing regions 815a-815c twice. Specifically, in the second drawing mode, the light intensity of the light beam irradiated to the drawing regions 815a-815c is set to the same as that in the first drawing mode, and the scanning speed of the multi-spot beam is set to approximately twice that of the first drawing mode, so that the amount of light per scan is approximately half that of the first drawing mode.

[0067] The drawing of patterns in the first drawing mode and the second drawing mode in the 3D modeling apparatus 1 will be described below with reference to FIG. 9 and the like. In the 3D modeling apparatus 1, the mode switching unit 504 checks (step S21) whether or not there is a narrow non-drawing region in the design data stored in the storage unit 501 in step S11 (see FIG. 4). Specifically, each non-drawing region is extracted from the design data, and the minimum width of each non-drawing region in the scanning direction, width direction, and vertical direction is compared with the narrow threshold value described above, and the presence or absence of a non-drawing region having a width equal to or smaller than the narrow threshold value (i.e., a narrow non-drawing region) is confirmed. Note that the narrow threshold values ​​in the scanning direction, width direction, and vertical direction may be the same or different.

[0068] If the design data does not include a narrow non-drawing region, the mode switching unit 504 selects the first drawing mode as the drawing mode (step S22), and the model 81 is formed (FIG. 4: steps S12 to S14). In step S13 in the first drawing mode, as described above, scanning of the multi-spot beam of the first light intensity is performed only once at the first scanning speed for each position in the drawing region.

[0069] On the other hand, if the design data includes a narrow non-drawing region, the mode switching unit 504 selects the second drawing mode as the drawing mode (step S23), and the model 81 is formed (FIG. 4: steps S12 to S14). In step S13 in the second drawing mode, as described above, scanning of the multi-spot beam is performed twice for each position in the drawing region. The light intensity of the multi-spot beam irradiated onto the modeling material 91 in the second drawing mode (hereinafter also referred to as the "second light intensity") is the same as the first light intensity. Moreover, the scanning speed of the multi-spot beam in the second drawing mode (hereinafter also referred to as the "second scanning speed") is approximately twice the first scanning speed.

[0070] FIG. 10 is a diagram showing a light amount profile and the like when a pattern corresponding to the cross section 814 is drawn in the second drawing mode. FIGS. 10(a) to 10(d) correspond to FIGS. 8(a) to 8(d) for the first drawing mode, respectively. FIG. 10(a) is a diagram showing a design pattern in the cross section 814. FIG. 10(b) is a graph showing a light amount profile of the multi-spot beam irradiated onto the drawing target layer 92 in the first scan of two scans of the multi-spot beam in the second drawing mode. As described above, the second light intensity is the same as the first light intensity, and the second scanning speed is about twice the first scanning speed, so that the light amount provided to each position of the ON regions 711a, 711b, and 711c in FIG. 10(b) is about half of the light amount provided to each position of the ON regions 711a, 711b, and 711c in FIG. 8(b).

[0071] Fig. 10(c) is a diagram showing a temperature distribution in the drawing target layer 92 scanned once with the multi-spot beam with the light amount profile shown in Fig. 10(b). In the ON regions 711a, 711b, and 711c, the temperature of the modeling material 91 in the drawing target layer 92 rises to a modeling temperature (e.g., 200°C) higher than the melting point (e.g., 185°C) of the modeling material 91 as shown by the solid line in Fig. 10(c) by scanning once with the multi-spot beam. The modeling temperature (e.g., 200°C) in the second drawing mode is lower than the above-mentioned modeling temperature (e.g., 220°C) in the first drawing mode.

[0072] In the OFF regions 712 and 713, substantially similar to the case of the first drawing mode, the temperature of the modeling material 91 rises above the preheat temperature (e.g., 173° C.) as shown by the solid line in Fig. 10(c) due to the influence of the end light amount of the adjacent ON regions 711a, 711b, and 711c and thermal diffusion from the ON regions 711a, 711b, and 711c. Also, in the OFF region 712 corresponding to the narrow non-drawing region 816 having a small size in the width direction, the temperature of the modeling material 91 becomes higher than that of the OFF region 713 corresponding to the non-drawing region 817 having a relatively large size in the width direction.

[0073] Thereafter, due to thermal diffusion from the ON regions 711a, 711b, and 711c over time, the temperature of the modeling material 91 in the ON regions 711a, 711b, and 711c decreases, and the temperature of the modeling material 91 in the OFF regions 712 and 713 increases, as shown by the two-dot chain line in Fig. 10(c). The state shown by the two-dot chain line in Fig. 10(c) is the temperature approximately 0.3 to 0.5 seconds after the end of irradiation of the multi-spot beam to the ON regions 711a, 711b, and 711c.

[0074] In the second drawing mode, as described above, the amount of light applied to each position of the ON regions 711a, 711b, and 711c is approximately half that of the first drawing mode, and the modeling temperature of the ON regions 711a, 711b, and 711c (e.g., 200°C) is lower than the modeling temperature of the first drawing mode (e.g., 220°C). For this reason, in the second drawing mode, the amount of temperature rise of the modeling material 91 in the OFF regions 712 and 713 (i.e., the difference between the solid line and the two-dot chain line in FIG. 10(c)) is also smaller than that in the first drawing mode. As a result, even in the OFF region 712 corresponding to the narrow non-drawing region 816, the temperature of the modeling material 91 becomes lower than the melting point (e.g., 185°C), and unintended melting of the modeling material 91 in the OFF region 712 is prevented.

[0075] In the second drawing mode, when the first scanning of the multi-spot beam on the entire drawing target layer 92 of the modeling material 91 is completed, the second scanning of the multi-spot beam is performed. The time from the start of the first scanning of the multi-spot beam to the end of the scanning is, for example, several tens of seconds. Therefore, when the second scanning of the multi-spot beam is started, the temperature of the drawing target layer 92 is generally lower than that shown in FIG. 10(c) and is close to the above-mentioned preheating temperature (for example, 173°C). In addition, in the second scanning of the multi-spot beam, the second light intensity and the second scanning speed are the same as those in the first scanning. Therefore, the amount of light provided to each position of the drawing regions 815a to 815c in the second scanning is the same as the amount of light provided to each position of the drawing regions 815a to 815c in the first scanning (see FIG. 10(b)). As a result, the temperature distribution of the drawing target layer 92 after the second scanning of the multi-spot beam is approximately the same as that shown in FIG. 10(c).

[0076] Therefore, in the second scan, in substantially the same manner as in the first scan, the temperature of the modeling material 91 is below the melting point (e.g., 185°C) in both the OFF region 712 corresponding to the narrow non-drawing region 816 and the OFF region 713 corresponding to the non-drawing region 817, and unintended melting of the modeling material 91 is prevented. Therefore, as shown in Fig. 10(d), the narrow non-drawing region 816 exists between the drawing region 815a and the drawing region 815b, and the non-drawing region 817 exists between the drawing region 815b and the drawing region 815c. That is, in the second drawing mode, the modeled object 81 can be formed with high accuracy.

[0077] In the second drawing mode, the time required for the multi-spot beam to traverse the drawing target layer 92 once in the scanning direction is approximately half that of the first drawing mode, and the number of scans is twice that of the first drawing mode. In addition, the interval between the above-mentioned one traverse (hereinafter also referred to as "one pass movement") and the next one pass movement is very short. Therefore, the time required for pattern drawing on one drawing target layer 92 in the second drawing mode is approximately the same as the time required for pattern drawing on one drawing target layer 92 in the first drawing mode.

[0078] It has been confirmed by experiments that the strength of the model 81 formed in the second drawing mode is equal to or higher than that in the first drawing mode. As described above, in the drawing regions 815a to 815c of the drawing target layer 92, the modeling material 91 irradiated with the multi-spot beam melts and the fluidity increases, and the voids existing between the particles of the modeling material 91 are filled with the molten modeling material 91. However, the fluidity of the modeling material 91 is high in a range equal to or higher than a predetermined temperature (e.g., melting point), but is not very high in a range below the predetermined temperature, even if the molten state is maintained. In addition, the temperature of the modeling material 91 melted by irradiation with the multi-spot beam drops relatively quickly as described above. Therefore, the removal of the voids proceeds remarkably in a short time (e.g., 0.5 to 1 second) after irradiation with the multi-spot beam, and does not proceed much thereafter. In the second drawing mode, when drawing a pattern on the drawing target layer 92, there are two time periods during which the removal of the voids progresses significantly, and it is therefore believed that the strength of the object 81 is greater than in the first drawing mode, in which such time period exists only once.

[0079] In the second drawing mode, other control different from the above example may be performed. For example, in the above example, the second light intensity and the second scanning speed are the same in the first and second scanning of the multi-spot beam in the second drawing mode, and the amount of light provided to each position in the drawing regions 815a to 815c is also the same, but this is not limited thereto.

[0080] In a first example of the other control, the amount of light applied to each position of the drawing regions 815a-815c in the first scan is controlled to be greater than the amount of light applied to each position of the drawing regions 815a-815c in the second scan. Specifically, for example, the second scanning speed in the first scan and the second scanning speed in the second scan are set to be the same, and the second light intensity in the first scan is set to be greater than the second light intensity in the second scan. For example, the second light intensity in the first scan is set to be 1.2 times the first light intensity in the first drawing mode, and the second light intensity in the second scan is set to be 0.8 times the first light intensity. Also, the second scanning speed in the first and second scans is about twice the first scanning speed in the first drawing mode, as described above.

[0081] In this case, the amount of light imparted to each position of the drawing regions 815a-815c in the first scan in the second drawing mode is about 0.6 times the amount of light imparted to each position of the drawing regions 815a-815c in the first drawing mode. Also, the amount of light imparted to each position of the drawing regions 815a-815c in the second scan in the second drawing mode is about 0.4 times the amount of light imparted to each position of the drawing regions 815a-815c in the first drawing mode. In the first example of this other control, the total amount of light imparted to each position of the drawing regions 815a-815c in the second drawing mode (i.e., the total amount of light imparted in two scans) is approximately the same as the amount of light imparted to each position of the drawing regions 815a-815c in the first drawing mode, but may be different.

[0082] In the second drawing mode, even if the light amount applied to each position of the drawing regions 815a to 815c is different between the first and second scans, the model 81 can be formed with high accuracy in substantially the same manner as when the light amount is the same between the first and second scans. Furthermore, as described above, by making the light amount in the second scan smaller than that in the first scan, the temperature rise of the modeling material 91 caused by the second scan of the multi-spot beam is smaller than that caused by the first scan. Therefore, even if the second scan is performed in a state in which the temperature of the drawing target layer 92 is not sufficiently lowered after the first scan, it is possible to suitably suppress melting of the modeling material 91 in the narrow non-drawing region 816 in the second scan.

[0083] In a second example of the other control, the second scanning speed in the first and second scans in the second drawing mode is set to be the same as the first scanning speed in the first drawing mode, and the second light intensity in the first and second scans in the second drawing mode is set to be approximately half of the first light intensity in the first drawing mode. In this case, the multi-spot beam is scanned twice on the drawing target layer 92 with a light amount profile approximately similar to the example shown in Fig. 10(b). As a result, unintended melting of the modeling material 91 is prevented even in the OFF region 712 corresponding to the narrow non-drawing region 816, approximately similar to the example shown in Fig. 10(d).

[0084] In the second example of the other control, the multi-spot beam is scanned twice on each position of the drawing regions 815a-815c at a second scanning speed that is the same as the first scanning speed. Therefore, the total irradiation time of the light beam on each position of the drawing regions 815a-815c in the second drawing mode (i.e., the total irradiation time of the light beam in two scans) is approximately twice as long as the irradiation time of the light beam on each position of the drawing regions 815a-815c in the first drawing mode. Therefore, in the second drawing mode, the time during which the fluidity of the modeling material 91 is maintained high is longer than in the first drawing mode, and as a result, the strength of the modeled object 81 is higher than in the first drawing mode.

[0085] In a second example of this other control, the total amount of light applied to each position of the drawing areas 815a-815c in the second drawing mode (i.e., the sum of the amount of light applied in two scans) is approximately the same as the amount of light applied to each position of the drawing areas 815a-815c in the first drawing mode, but may be different.

[0086] In the second drawing mode illustrated in FIG. 10, the second light intensity and / or the second scanning speed of the multi-spot beam may be adjusted based on the temperature distribution on the upper surface of the modeling material 91 (i.e., the temperature distribution of the modeling target layer 92) measured by the temperature measurement unit 4. For example, when the temperature distribution is measured before the first scan in the second drawing mode and the temperature of the modeling material 91 is higher than a predetermined temperature, the intensity control unit 503 controls the laser light source 21 and the like to adjust the second light intensity in the first scan to be slightly smaller. In this case, instead of or in addition to adjusting the second light intensity, the scan control unit 502 may control the scan unit 23 and the like to adjust the second scanning speed in the first scan to be slightly larger. Also, when the temperature of the modeling material 91 is lower than a predetermined temperature, the second light intensity in the first scan is adjusted to be slightly larger and / or the second scanning speed in the first scan is adjusted to be slightly smaller. The same applies to the second scan in the second drawing mode. The same applies to drawing in the first drawing mode, and further to the first and second examples of other control described above.

[0087] In the second drawing mode, the shape of the OFF region 712 of the light amount profile shown in FIG. 10(b) may be corrected to the OFF region 718 shown in FIG. 11(b). In the example shown in FIG. 11(b), the boundaries between the ON regions 717a and 717b corresponding to the drawing regions 815a and 815b and the OFF region 718 are tapered on both sides in the width direction of the OFF region 718 corresponding to the narrow non-drawing region 816. Specifically, the light amount at the end of the ON region 717a on the OFF region 718 side gradually decreases as it approaches the OFF region 718. Also, the light amount at the end of the ON region 717b on the OFF region 718 side gradually decreases as it approaches the OFF region 718. The width of the OFF region 718 (i.e., the width of the region in FIG. 11(b) where the light amount does not vary greatly near 0) is approximately the same as the width of the OFF region 712 shown in FIG. 10(b) (i.e., the width of the narrow non-drawing region 816 in the design pattern). The width of the OFF region 718 may be larger or smaller than the width of the OFF region 712 .

[0088] This suppresses irradiation of the light beam to a region of the drawing regions 815a, 815b adjacent to the narrow non-drawing region 816 (hereinafter also referred to as the "narrow-portion adjacent region"). In other words, the amount of light per unit area provided to the narrow-portion adjacent region is reduced compared to the amount of light per unit area provided to a region of the drawing regions 815a, 815b excluding the narrow-portion adjacent region. As a result, in the OFF region 718 corresponding to the narrow non-drawing region 816, accumulation of the end light amounts of the ON regions 717a, 717b adjacent to both sides in the width direction is suppressed. Also, overlapping of heat diffused from the ON regions 717a, 717b in the OFF region 718 is suppressed.

[0089] Therefore, the temperature of the modeling material 91 in the OFF region 718 rises to a certain degree above the preheating temperature (e.g., 173°C) as shown by the solid line in Fig. 11(c), but does not rise to the melting point of the modeling material 91 (e.g., 185°C) as shown by the two-dot chain line even after thermal diffusion from the ON regions 717a and 717b occurs over time. In addition, the temperature of the modeling material 91 in the OFF region 718 shown by the two-dot chain line in Fig. 11(c) is lower than the temperature of the modeling material 91 in the OFF region 712 shown by the two-dot chain line in Fig. 10(c). Therefore, unintended melting of the modeling material 91 in the OFF region 718 is preferably prevented.

[0090] The correction of the light intensity profile shown in Figure 11(b) is achieved, for example, by making the light intensity of the light spots corresponding to the narrow portion adjacent regions of the drawing regions 815a, 815b, among the multiple light spots of the multi-spot beam, smaller than the light intensity of the light spots corresponding to regions other than the narrow portion adjacent regions of the drawing regions 815a, 815b.

[0091] In the three-dimensional modeling apparatus 1, the number of scans of the multi-spot beam on each position of the drawing regions 815a-815c in the second drawing mode may be more than one, and is not limited to two. Even if the number of scans is three or more, the second scanning speed of the second drawing mode is controlled to be higher than the first scanning speed of the first drawing mode when the second light intensity of the second drawing mode is the same as the first light intensity of the first drawing mode, in substantially the same manner as the above example in which the number of scans is two. Furthermore, when the second scanning speed of the second drawing mode is the same as the first scanning speed of the first drawing mode, the second light intensity of the second drawing mode is controlled to be lower than the first light intensity of the first drawing mode.

[0092] As described above, the three-dimensional modeling apparatus 1 includes the material holding unit 3, the optical head 2, and the control unit 5. The material holding unit 3 includes the stage 341 that holds the powdered modeling material 91, and the material supply unit 32 that supplies the modeling material 91 onto the stage 341. The optical head 2 modulates and scans the modeling material 91 held on the stage 341. The control unit 5 controls the material holding unit 3 and the optical head 2 based on the design data of the modeled object 81, thereby supplying the modeling material 91 onto the stage 341, scanning the light beam on the drawing target layer 92, which is the surface layer of the supplied modeling material 91, and melting the modeling material 91 in the area irradiated with the light to draw a pattern, repeatedly.

[0093] The control by the control unit 5 can be switched between a first drawing mode and a second drawing mode. In the first drawing mode, the light beam is scanned only once on each position of the drawing regions 815a-815c on the drawing target layer 92 for which drawing is instructed by the design data. In the second drawing mode, the light beam is scanned multiple times on each position of the drawing regions 815a-815c in a state in which the amount of light provided to each position of the drawing regions 815a-815c in one scan of the light beam is smaller than that in the first drawing mode.

[0094] In the three-dimensional printing device 1, as described above, by performing pattern drawing in the second drawing mode, it is possible to prevent unintended melting of the printing material 91 in the non-drawing regions 816, 817 where drawing is not instructed in the design data. As a result, the model 81 can be formed with high accuracy. In addition, the strength of the model 81 can be increased. On the other hand, by performing pattern drawing in the first drawing mode, it is possible to simplify the drawing operation of the three-dimensional printing device 1.

[0095] As described above, in the 3D printing apparatus 1, when the non-drawing regions 816, 817 for which drawing is not instructed in the design data include a narrow non-drawing region 816 having a width equal to or smaller than a predetermined threshold (i.e., a narrow threshold), it is preferable that the second drawing mode be selected by the control unit 5. In this way, when the design data includes the narrow non-drawing region 816, the second drawing mode is automatically selected, and the model 81 can be formed with high accuracy.

[0096] As described above, it is preferable that the light intensity of the light beam in the second drawing mode (i.e., the second light intensity) is the same as the light intensity of the light beam in the first drawing mode (i.e., the first light intensity), and the scanning speed of the light beam in the second drawing mode (i.e., the second scanning speed) is higher than the scanning speed of the light beam in the first drawing mode (i.e., the first scanning speed). This makes it possible to accurately form the modeled object 81 in the second drawing mode, while making the time required for pattern drawing on one drawing target layer 92 (hereinafter also referred to as the "layer drawing time") approximately the same as the layer drawing time in the first drawing mode. Furthermore, even if the layer drawing time in the second drawing mode is longer than the layer drawing time in the first drawing mode, the amount of increase can be suppressed. That is, the modeled object 81 can be accurately and quickly formed in the second drawing mode.

[0097] More preferably, the number of times that the light beam scans each position in the drawing regions 815a-815c in the second drawing mode is two, and the scanning speed of the light beam in the second drawing mode (i.e., the second scanning speed) is twice as fast as the scanning speed of the light beam in the first drawing mode (i.e., the first scanning speed). This makes it possible to easily realize the second drawing mode with a realistic device configuration without requiring excessive performance from the scanning unit 23, etc.

[0098] As described above, it is also preferable that the scanning speed of the light beam in the second drawing mode (i.e., the second scanning speed) is the same as the scanning speed of the light beam in the first drawing mode (the first scanning speed), and the light intensity of the light beam in the second drawing mode (i.e., the second light intensity) is smaller than the light intensity of the light beam in the first drawing mode (i.e., the first light intensity). This makes it possible to form the model 81 with high accuracy in the second drawing mode, while further increasing the strength of the model 81.

[0099] As described above, the number of scans of the light beam on each position of the drawing regions 815a-815c in the second drawing mode is two, and it is preferable that the amount of light provided to each position of the drawing regions 815a-815c in the first scan of the light beam in the second drawing mode is the same as the amount of light provided to each position of the drawing regions 815a-815c in the second scan of the light beam in the second drawing mode. This can improve the uniformity of the temperature change of the modeling material 91 in the first and second scans of the light beam in the second drawing mode. In addition, by making the second light intensity and the second scanning speed the same in the first and second scans of the light beam in the second drawing mode, the control of the optical head 2 in the second drawing mode can be simplified.

[0100] As described above, the number of scans of the light beam on each position of the drawing regions 815a-815c in the second drawing mode is two, and it is also preferable that the amount of light provided to each position of the drawing regions 815a-815c by the first scan of the light beam in the second drawing mode is greater than the amount of light provided to each position of the drawing regions 815a-815c by the second scan of the light beam in the second drawing mode. This makes it possible to reduce the amount of light provided to the narrow non-drawing region 816, whose temperature has been increased by the first scan, in the second scan compared to the first scan. As a result, unintended melting of the modeling material in the narrow non-drawing region 816 can be further suppressed.

[0101] As described above, the light beam is a multi-spot beam composed of a plurality of light spots linearly arranged in a predetermined arrangement direction, and the multi-spot beam is preferably scanned in a predetermined scanning direction inclined with respect to the arrangement direction. This makes it possible to reduce the time required to draw a pattern on the drawing target layer 92. Furthermore, as described above, the three-dimensional printing apparatus 1 can form the model 81 with high accuracy even when the design data includes a narrow non-drawing region. Therefore, the three-dimensional printing apparatus 1 is particularly suitable for drawing with a multi-spot line beam in which the light beam may be irradiated simultaneously to drawing regions on both sides of a narrow non-drawing region.

[0102] As described above, it is preferable that the three-dimensional modeling apparatus 1 further includes a temperature measuring unit 4 that measures the temperature distribution on the upper surface of the modeling material 91 on the stage 341. It is also preferable that the control unit 5 adjusts the light intensity or scanning speed of the light beam in the second drawing mode (i.e., the second light intensity or the second scanning speed) based on the temperature distribution measured by the temperature measuring unit 4. This makes it possible to form the model 81 with even greater accuracy, as described above.

[0103] As described above, the modeling material 91 is preferably a resin material. As described above, the 3D modeling apparatus 1 can accurately form the modeling material 91 even when the heat in the drawing area does not dissipate immediately and the temperature of the non-drawing area is relatively likely to rise. Therefore, the 3D modeling apparatus 1 is particularly suitable for 3D modeling using a resin material that has a lower heat dissipation property than a metal material.

[0104] The above-described 3D printing apparatus 1 can be modified in various ways.

[0105] For example, it is not necessary to adjust the second light intensity and the second scanning speed based on the temperature distribution of the drawing target layer 92 measured by the temperature measurement unit 4. In this case, the temperature measurement unit 4 may be omitted.

[0106] In each multi-spot beam scan in the second drawing mode, both the second light intensity and the second scanning speed may be changed from the first light intensity and the first scanning speed in the first drawing mode. Also, in the second drawing mode, both the second light intensity and the second scanning speed in one of the multiple multi-spot beam scans may be different from the second light intensity and the second scanning speed in the other scans.

[0107] The switching between the first drawing mode and the second drawing mode does not necessarily have to be performed automatically by the control unit 5, and the first drawing mode or the second drawing mode may be selected by the operator making a specified input via the input unit 56, etc.

[0108] The configurations in the above-described embodiment and each of the modified examples may be combined as appropriate as long as they are not mutually inconsistent. [Explanation of symbols]

[0109] 1 3D printing equipment 2 Optical Head 3 Material holding part 4 Temperature measurement part 5. Control section 32 Material supply section 81 Sculptures 91 Modeling materials 92 Drawing target layer 341 Stage 815,815a,815b,815c drawing area 816 (Narrow) Non-drawing area 817 Non-drawing area

Claims

1. A three-dimensional printing apparatus, comprising: a material holding unit having a stage for holding a powdered modeling material and a material supply unit for supplying the modeling material onto the stage; an optical head that modulates and scans a light beam on the modeling material held on the stage; a control unit that controls the material holding unit and the optical head based on design data of a model, thereby repeatedly supplying the modeling material onto the stage, scanning the light beam on a drawing target layer, which is a surface layer of the supplied modeling material, to melt the modeling material in the area irradiated with light and draw a pattern; and Equipped with The control by the control unit is a first drawing mode in which scanning of the light beam is performed only once on each position of a drawing area instructed to be drawn in the design data on the drawing target layer; a second drawing mode in which the light beam is scanned a plurality of times with respect to each position in the drawing area while the amount of light applied to each position in the drawing area in one scan of the light beam is smaller than that in the first drawing mode; A three-dimensional printing device that can be switched between the above and the above.

2. The three-dimensional modeling apparatus according to claim 1 , A three-dimensional printing device in which the control unit selects the second drawing mode when a non-drawing area for which drawing is not instructed in the design data includes a narrow non-drawing area having a width equal to or smaller than a predetermined threshold.

3. The three-dimensional modeling apparatus according to claim 1 or 2, a light intensity of the light beam in the second drawing mode is the same as a light intensity of the light beam in the first drawing mode; A three-dimensional modeling apparatus, wherein a scanning speed of the light beam in the second drawing mode is faster than a scanning speed of the light beam in the first drawing mode.

4. The three-dimensional modeling apparatus according to claim 3, the number of scans of the light beam with respect to each position of the drawing area in the second drawing mode is two; A three-dimensional modeling apparatus, wherein a scanning speed of the light beam in the second drawing mode is twice as fast as a scanning speed of the light beam in the first drawing mode.

5. The three-dimensional modeling apparatus according to claim 1 or 2, a scanning speed of the light beam in the second drawing mode is the same as a scanning speed of the light beam in the first drawing mode; A three-dimensional modeling apparatus, wherein the light intensity of the light beam in the second drawing mode is smaller than the light intensity of the light beam in the first drawing mode.

6. The three-dimensional modeling apparatus according to claim 1 or 2, the number of scans of the light beam with respect to each position of the drawing area in the second drawing mode is two; A three-dimensional printing device, wherein the amount of light applied to each position of the drawing area by a first scan of the light beam in the second drawing mode is the same as the amount of light applied to each position of the drawing area by a second scan of the light beam in the second drawing mode.

7. The three-dimensional modeling apparatus according to claim 1 or 2, the number of scans of the light beam with respect to each position of the drawing area in the second drawing mode is two; A three-dimensional printing device in which the amount of light applied to each position of the drawing area by a first scan of the light beam in the second drawing mode is greater than the amount of light applied to each position of the drawing area by a second scan of the light beam in the second drawing mode.

8. The three-dimensional modeling apparatus according to claim 1 or 2, the light beam is a multi-spot beam composed of a plurality of light spots linearly arranged in a predetermined arrangement direction, A three-dimensional modeling apparatus in which the multi-spot beam is scanned in a predetermined scanning direction that is inclined with respect to the arrangement direction.

9. The three-dimensional modeling apparatus according to claim 1 or 2, a temperature measuring unit for measuring a temperature distribution on an upper surface of the modeling material on the stage, The control unit adjusts the light intensity or the scanning speed of the light beam in the second drawing mode based on the temperature distribution measured by the temperature measurement unit.

10. The three-dimensional modeling apparatus according to claim 1 or 2, The modeling material is a resin material.

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