Method and apparatus for manufacturing three-dimensional object

Abstract

To provide a method for manufacturing high-precision three-dimensional objects in a short time.SOLUTION: A method for manufacturing a three-dimensional object by curing a stereolithography material 9 using a light irradiation device 1 includes: a material forming step of forming a layer of the stereolithography material 9, comprising a light-curable resin and solid filler, on the surface of a build table 4; and an exposure step of irradiating a portion to be cured within the stereolithography material 9 formed at the material forming step with light, the portion to be cured including a contour portion and a non-contour portion other than the contour portion. The exposure step provides a greater light energy per unit area to the contour portion than to the non-contour portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method and an apparatus for manufacturing a three-dimensional object. [Background technology]

[0002] Patent Document 1 (Japanese Patent No. 5024001) describes a method for manufacturing a three-dimensional object in which light corresponding to cross-sectional shape data of a three-dimensional model is irradiated onto the surface of a photocurable resin to form a hardened layer, and the hardened layers are stacked to form a three-dimensional model. This method uses a batch exposure means that irradiates the photocurable resin with light all at once, and a scanning exposure means that scans a light beam over the surface of the photocurable resin. Specifically, the scanning exposure means is used to scan the photocurable resin along the contour line with a light beam, and the batch exposure means is used to expose the other parts of the surface of the photocurable resin all at once. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5024001 Summary of the Invention [Problem to be solved by the invention]

[0004] The stereolithography material used for stereolithography of a three-dimensional object is generally composed of a photocurable resin as described in Patent Document 1. However, a stereolithography material containing a photocurable resin and a solid filler such as ceramic particles may also be used. In this case, the stereolithography material is irradiated with light to harden the photocurable resin, thereby obtaining a three-dimensional object containing the solid filler. The obtained three-dimensional object is then fired to obtain a three-dimensional product composed of ceramic.

[0005] Furthermore, if the solid filler is contained in a high concentration in the stereolithography material, there are problems such as reduced toughness and adhesive strength of the three-dimensional object after irradiation with light, and problems such as cracking, warping, and collapse due to stress caused by curing shrinkage. Furthermore, if the curing characteristics of the photocurable resin itself are softened, the three-dimensional object becomes more likely to deform after irradiation with light, making it unsuitable for obtaining fine structures. On the other hand, if the solid filler is contained in a low concentration in the stereolithography material, there are problems such as reduced strength of the three-dimensional object after irradiation with light, making it more likely to deform, and more likely to collapse after degreasing and reduce performance.

[0006] Furthermore, when a photo-lithography material containing a photo-curable resin and a solid filler such as ceramic particles is used, the problem of the irradiated light being scattered by the solid filler easily occurs. When irradiating a target portion to be cured with light, if the target portion to be cured is divided into a contoured portion and a non-contoured portion other than the contoured portion (i.e., the internal portion surrounded by the contoured portion), the strength of the portion that is originally desired to be cured decreases, particularly around the contoured portion, and the portion that is not desired to be cured (i.e., the portion that is given light energy by light scattering despite not being irradiated with light) will harden.

[0007] In the method for manufacturing a three-dimensional object described in Patent Document 1, a scanning exposure means is used to scan a light beam onto a photocurable resin in the contour portion, but there is a problem in that the finer the contour shape, the longer it takes to scan with the light beam.

[0008] The present disclosure has been made in view of the above-mentioned problems, and relates to a manufacturing method and a manufacturing apparatus for a three-dimensional object that can manufacture a highly accurate three-dimensional object in a short time. [Means for solving the problem]

[0009] To achieve the above object, the present disclosure provides a method for manufacturing a three-dimensional object, which uses a light irradiation device that collectively irradiates light onto at least a portion of a predetermined exposable range that extends over a surface of a modeling table, to irradiate light onto a surface of a layer of a photo-lithography material formed on the surface of the modeling table, thereby hardening the photo-lithography material, a material forming step of forming a layer of the optical shaping material containing a photocurable resin and a solid filler on the surface of the shaping table; an exposure step of irradiating light onto a curing target portion of the optical shaping material formed by the material formation step, the portion being desired to be cured; the portion to be hardened includes a contour portion and a non-contour portion other than the contour portion, In the exposure step, the light energy per unit area given to the contour portion is set to be greater than the light energy per unit area given to the non-contour portion. Here, the solid filler may include a ceramic. The concentration of the solid filler contained in the optical shaping material may be 35% by volume or more and 75% by volume or less.

[0010] According to the above configuration, in the exposure process, the curing target portion, including the contour portion that forms the contour of the curing target portion and the non-contour portion other than the contour portion, is irradiated with light using a light irradiation device that irradiates light simultaneously on at least a portion of the exposable range. In other words, even if the contour portion has a fine or complex shape, the light irradiation performed on the stereolithography material by the light irradiation device can be completed in a short time. Furthermore, by increasing the light energy per unit area applied to the contour portion compared to the non-contour portion, the strength of the photocurable resin in the contour portion of the three-dimensional object after light irradiation can be ensured. In particular, when manufacturing a three-dimensional object with a fine structure, the finer the structure, the more contour portions there are, so the strength of those fine portions is naturally ensured. Therefore, it is possible to provide a method for manufacturing a three-dimensional object that can manufacture a high-precision three-dimensional object in a short time.

[0011] In another configuration of the method for manufacturing a three-dimensional object according to the present disclosure, in the exposure step, the intensity of light irradiated onto the contour portion is set to be stronger than the intensity of light irradiated onto the non-contour portion, and light is irradiated onto the contour portion and the non-contour portion simultaneously.

[0012] According to the above configuration, since the light is irradiated simultaneously onto the contour portion and the non-contour portion in the exposure step, there is an advantage that the time required for the exposure step is shortened.

[0013] In another configuration of the method for manufacturing a three-dimensional object according to the present disclosure, in the exposure step, light is irradiated onto at least one of the contour portion and the non-contour portion multiple times so that the cumulative time of light irradiation onto the contour portion is longer than the cumulative time of light irradiation onto the non-contour portion.

[0014] According to the above configuration, even when the light intensity of the light irradiation device cannot be distributed, for example, by irradiating light multiple times, the total light energy per unit area applied to the contour portion can be made greater than the total light energy per unit area applied to the non-contour portion. Furthermore, according to the above configuration, the light intensity can be reduced to reduce light scattering, while the cumulative time of light irradiation can be extended by irradiating multiple times, thereby increasing the light energy applied to the contour portion. Furthermore, according to the above configuration, the light intensity can be kept constant to simplify control, and the light energy applied to the contour portion and non-contour portion can be controlled by the number of irradiations.

[0015] The configuration of the three-dimensional object manufacturing device according to the present disclosure is configured to execute the above-described three-dimensional object manufacturing method.

[0016] According to the above configuration, it is possible to provide a three-dimensional object manufacturing device that can manufacture a three-dimensional object with high accuracy in a short time. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a manufacturing apparatus for a three-dimensional object. [Figure 2] FIG. 10 is a diagram illustrating shape data. [Figure 3] 10A and 10B are diagrams illustrating a cured state of a stereolithography material when irradiated with light. [Figure 4] 10A and 10B are diagrams illustrating a cured state of a stereolithography material when irradiated with light. [Figure 5] 10A and 10B are diagrams illustrating a cured state of a stereolithography material when irradiated with light. [Figure 6] FIG. 2 is a diagram showing the shape of a portion to be hardened. [Figure 7] 10A and 10B are diagrams illustrating a cured state of a stereolithography material when irradiated with light. [Figure 8] FIG. 2 is a diagram showing the shape of a portion to be hardened. [Figure 9] FIG. 2 is a diagram showing the shape of a portion to be hardened. [Figure 10] 10A and 10B are diagrams illustrating a cured state of a stereolithography material when irradiated with light. [Figure 11] 10A and 10B are diagrams illustrating a cured state of a stereolithography material when irradiated with light. DETAILED DESCRIPTION OF THE INVENTION

[0018] A method and an apparatus for manufacturing a three-dimensional object will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a three-dimensional object manufacturing apparatus. The three-dimensional object manufacturing apparatus includes a light irradiation device 1, a table unit 3, a supply unit 2, a recoater 6, a cleaning unit 7, and a control unit 10. The light irradiation device 1 irradiates a layer of the photo-lithography material 9 supplied by the supply unit 2 and spread by the recoater 6 with light, thereby hardening the photo-lithography material 9 into a desired shape. This supply and hardening of the photo-lithography material 9 is repeated multiple times while stacking the photo-lithography material 9 in the height direction, thereby obtaining a model with a desired three-dimensional shape. For example, if the photo-lithography material 9 contains a solid filler containing ceramic, a three-dimensional product made of ceramic can be obtained by firing the resulting three-dimensional model. In this embodiment, mutually perpendicular directions in a horizontal plane are sometimes referred to as the X direction and the Y direction, and the vertical direction is sometimes referred to as the Z direction.

[0019] <Light irradiation device 1> The light irradiation device 1 irradiates the photo-lithography material 9 with light to harden it into a desired shape. For example, if the photo-lithography material 9 contains a photo-curable resin that hardens when exposed to ultraviolet light, the light irradiation device 1 irradiates ultraviolet light of an appropriate wavelength for that purpose. For this purpose, the light irradiation device 1 can collectively (i.e., simultaneously) irradiate a predetermined exposable range that extends two-dimensionally in the XY plane of the modeling table 4 with light. The light irradiation device 1 is disposed above the modeling table 4. For example, the light irradiation device 1 can be realized using a device that irradiates the exposable range with light from a single light source, or a device that irradiates the exposable range with light from multiple light sources. The light irradiation device 1 may include an optical element between the light source and the modeling table 4 that can adjust the light traveling direction, light intensity, etc.

[0020] For example, the light irradiation device 1 can be realized using an LCD (Liquid Crystal Display) that includes a light source unit and two-dimensionally arranged liquid crystal elements as optical elements. Alternatively, the light irradiation device 1 can be realized using a light source unit in which light-emitting elements (light source units) such as μLEDs (Light Emitting Diodes) or EL elements (Electro Luminescence elements) are two-dimensionally arranged. Alternatively, the light irradiation device 1 may be a device that includes a light source unit and a digital micromirror device as an optical element. In either case, the light irradiation device 1 can adjust the intensity of light irradiated to one region within the exposable range by controlling the operation of the light source unit and the optical elements, such as increasing the intensity of light irradiated to another region and decreasing the intensity of light irradiated to another region (or reducing the light intensity to zero). The operation of the light irradiation device 1 is controlled by a control unit 10 .

[0021] The table unit 3 includes a modeling table 4 on whose surface a three-dimensional object is modeled, and an elevating mechanism 5 that raises and lowers the modeling table 4 in the Z direction. In the example shown in Fig. 1, for example, a flat substrate 8 is placed on the modeling table 4, and a layer of a photo-lithography material 9 is formed on the substrate 8. The table unit 3 may also include a suction mechanism that adsorbs the substrate 8 onto the surface of the modeling table 4. The operation of the table unit 3 is controlled by a control unit 10 .

[0022] The modeling table 4 is a flat table on the XY plane on which modeling is performed. The lifting mechanism 5 includes, for example, an electric motor. The relative positions of the modeling table 4, the light irradiation device 1, the supply unit 2, and the recoater 6 are adjusted by operating the lifting mechanism 5. Then, with the modeling table 4 in an appropriate position, the supply of the photo-lithography material 9, the spreading of the photo-lithography material 9 by the recoater 6, and the light irradiation (i.e., exposure) by the light irradiation device 1 are performed.

[0023] When a suction mechanism is provided, it is used to fix the substrate 8 placed on the surface of the modeling table 4 during modeling. When the suction mechanism operates with the substrate 8 placed thereon, the substrate 8 is adsorbed to the surface of the modeling table 4.

[0024] <Supply section 2> The supply unit 2 supplies the stereolithography material 9 to the surface of the substrate 8. The supply unit 2 includes a tank for storing the stereolithography material and a discharge device equipped with a discharge pump for discharging the stereolithography material 9 stored in the tank through a discharge port. The stereolithography material 9 contains a photocurable resin and a solid filler and has fluidity. Examples of the photocurable resin include acrylic resin and epoxy resin. The solid filler includes ceramic particles such as alumina, zirconia, yttria, silicon oxide, calcium carbonate, calcium phosphate, zeolite, cordierite, aluminum nitride, silicon nitride, and barium titanate, which have high light scattering properties, and silicon carbide, graphite, and composites thereof, which have low light scattering properties. Alternatively, the solid filler may include metal or organic particles. The concentration of the solid filler in the stereolithography material 9 is preferably 35% by volume or more and 75% by volume or less. Alternatively, the concentration of the solid filler contained in the stereolithography material 9 is preferably 40% by volume or more and 65% by volume or less.

[0025] <Recoating unit> The recoat unit includes a recoater 6 that spreads the flowable stereolithography material 9 dispensed onto the modeling table 4 to form a film, a movement mechanism (not shown) equipped with an electric motor that moves the recoater 6, and a cleaning unit 7 that cleans the recoater 6. The recoater 6 is made up of, for example, a plate-shaped member. The cleaning unit 7 may be equipped with a spatula, a brush, or the like, or may have other configurations. After the recoater 6 is used, the cleaning unit 7 moves while in contact with the recoater 6, thereby removing (i.e., cleaning) the stereolithography material 9 adhering (remaining) to the recoater 6. The operation of the recoating unit is controlled by a control unit 10 .

[0026] Although not shown, the three-dimensional object manufacturing apparatus also includes a removal mechanism for removing unnecessary uncured stereolithography material 9. The removal mechanism includes, for example, a cleaning tank in which a cleaning liquid is stored and a mechanism for submerging the three-dimensional object in the cleaning liquid. The control unit 10 may control the operation of the removal mechanism.

[0027] <Control unit 10> The control unit 10 controls the operation of the light irradiation device 1, the table unit 3, the supply unit 2, and the recoat unit (recoater 6, cleaning unit 7), thereby controlling the operation of the three-dimensional object manufacturing apparatus. The control unit 10 includes an arithmetic processing unit 11, a memory unit 13, a display unit 12, and an operation input unit 14. The arithmetic processing unit 11 is realized, for example, by a CPU (Central Processing Unit) and controls various components of the three-dimensional object manufacturing apparatus and processes data. The memory unit 13 includes, for example, a semiconductor memory or a hard disk, and stores shape data indicating the three-dimensional shape of the object to be manufactured and a control program. As will be described later, the shape data stored in the memory unit 13 includes contour data 18 that indicates the horizontal cross-sectional shape of the object using contour lines and interior fill data 19 that indicates the area surrounded by the contour lines. The display unit 12 displays information to an operator of the three-dimensional object manufacturing apparatus. The operation input unit 14 accepts inputs, such as operation instructions for the three-dimensional object manufacturing apparatus, from the operator.

[0028] <Shape data> 2 is a diagram illustrating shape data. The shape data is composed of 3D data 15, which is the shape of a 3D model digitized, mesh data 16, which is the 3D data 15 meshed, slice data 17, which is the mesh data 16 sliced ​​at a predetermined thickness, contour data 18, which indicates the contour of the object based on the slice data 17, and interior fill data 19, which indicates the interior of the object based on the slice data 17. The control unit 10 uses the contour data 18 and the interior fill data 19 to manufacture a three-dimensional object.

[0029] Next, a method for manufacturing a three-dimensional object performed by the three-dimensional object manufacturing apparatus will be described. In the method for manufacturing a three-dimensional object, a light irradiation device 1 is used to irradiate a predetermined exposable area extending over the surface of the modeling table 4 with light all at once, and the surface of a layer of the photo-lithography material 9 formed on the surface of the modeling table 4 is irradiated with light to harden the photo-lithography material 9. In this disclosure, the expression "on the surface" includes cases where the layer is in contact with the surface and cases where the layer is located above the surface (for example, when the layer of the photo-lithography material 9 is located on the substrate 8 or another layer of the photo-lithography material 9).

[0030] The method for manufacturing a three-dimensional object according to this embodiment includes a material formation step of forming a layer of a photo-lithography material 9 containing a photo-curable resin and a solid filler on the surface of the modeling table 4, and an exposure step of irradiating light onto the curing target portion 20 of the photo-lithography material 9 formed in the material formation step. This exposure step cures the photo-curable resin in the curing target portion 20 of the photo-lithography material 9, resulting in a model layer of a desired shape. Another material formation step is then performed on the created model layer to form a layer of the photo-lithography material 9, which is then subjected to another exposure step, thereby creating another model layer. By stacking the model layers in this manner, a model of a desired three-dimensional shape is finally obtained.

[0031] Next, the curing state when a layer of a photo-fabrication material 9 containing a photo-curable resin and a solid filler is irradiated with light will be described with reference to Figures 3 to 5. Figure 3 shows an example where low-intensity light irradiation is performed once. Figure 4 shows an example where low-intensity light irradiation (i.e., light irradiation with the same light intensity) is performed twice. Figure 5 shows an example where high-intensity light irradiation is performed once.

[0032] 3 to 5, light irradiated from the light irradiation device 1 onto the portion 20 to be cured of the optically shaped material 9 is scattered by the solid filler contained in the optically shaped material 9. As a result, the light also reaches the optically shaped material 9 in the adjacent portion 21 adjacent to the portion to be cured 20, which is part of the non-to-be-cured portion 24 that is not the portion to be cured 20. Then, not only does the optically shaped material 9 present in the portion to be cured 20 harden, but the optically shaped material 9 present in the adjacent portion 21 (non-to-be-cured portion 24) also hardens.

[0033] The size of adjacent portion 21 depicted in the figure differs from the size of the region that is actually hardened by light scattering. As will be described later, the width of adjacent portion 21 in the XY plane in the figure increases as the intensity of the irradiated light increases, so it cannot be generalized, but adjacent portion 21 that has hardened by light scattering will occur with a width of, for example, several tens of μm to several hundreds of μm.

[0034] 3 and 4, the shape of the portion to be cured 20 is the same, and the intensity of the irradiated light is also the same, so the size of the adjacent portion 21 is also the same. However, the light energy per unit area imparted to the adjacent portion 21 due to light scattering is greater in the case shown in Fig. 4 (two irradiations), so the hardness of the adjacent portion 21 shown in Fig. 4 is higher than the hardness of the adjacent portion 21 shown in Fig. 3.

[0035] In the case shown in Figure 5, the shape of the portion to be cured 20 is the same as in Figures 3 and 4, but the light intensity in one light irradiation is set to be greater than in Figures 3 and 4. Therefore, the scattered light spreads over a wider range than in Figures 3 and 4, and as a result, the curing of the optical shaping material 9 occurs over a wider range. Note that, of the adjacent portion 21, the portion 21a that is closer to the portion to be cured 20 has a higher hardness than the portion 21b that is farther from the portion to be cured 20. However, the portions 21a and 21b are shown only to explain the change in hardness, and in reality, the hardness of the optical shaping material 9 does not change in two stages, but rather the hardness of the optical shaping material 9 changes gradually.

[0036] As described above, there are two methods for adjusting the light energy per unit area given to the curing target portion 20: adjusting the light intensity and adjusting the time for light irradiation (the number of irradiations in the above example). When using the method for adjusting the time for light irradiation or the number of irradiations, the intensity of curing can be adjusted while narrowing the range affected by light scattering.

[0037] 6 is a diagram showing the shape of the portion to be cured 20 that is desired to be cured by light irradiation. Light irradiation by the light irradiation device 1 of the apparatus for manufacturing a three-dimensional object produces a model layer that has a predetermined thickness in the Z direction and a two-dimensional shape that corresponds to the portion to be cured 20 in the XY plane.

[0038] FIG. 7 is a diagram showing an example of a case where a layer of the optical shaping material 9 prepared on the shaping table 4 is irradiated with light from the Z direction. Specifically, this is an example where light is irradiated once to an area corresponding to the portion to be cured 20 shown in FIG. 6. Note that the same light energy per unit area is applied to the optical shaping material 9 in the entire area where light is irradiated. Also, in FIG. 7, the portion of the optical shaping material 9 other than the portion to be cured 20 is shown as a portion not to be cured 24.

[0039] 7, the light irradiated onto the stereolithography material 9 is scattered by the solid filler contained in the stereolithography material 9. As a result, the light also reaches the stereolithography material 9 in the adjacent portion 21 adjacent to the curing target portion 20, which is part of the non-curing target portion 24. Then, not only does the stereolithography material 9 present in the curing target portion 20 cure, but the stereolithography material 9 present in the adjacent portion 21 (non-curing target portion 24) also cures.

[0040] As shown in the figure, the corner portion 21c of the adjacent portion 21, which corresponds to the corner portion 20a of the portion to be cured 20, has a smoother shape, i.e., a shape with a larger radius of curvature, compared to the shape of the corner portion 20a of the portion to be cured 20. In other words, because light also reaches the stereolithography material 9 of the adjacent portion 21 adjacent to the portion to be cured 20, the shape of the corner portion 20a of the portion to be cured 20 is not accurately reflected in the corner portion 21c of the adjacent portion 21, resulting in a shape error.

[0041] The method for manufacturing a three-dimensional object of this embodiment takes measures to alleviate the above-mentioned problem caused by light scattering allowing light to reach the stereolithography material 9 in the adjacent portion 21 adjacent to the portion to be cured 20. Specifically, the portion to be cured 20 includes a contour portion 22 adjacent to a non-to-be-cured portion 24 that is not the portion to be cured 20, and a non-contour portion 23 other than the contour portion 22. In the method for manufacturing a three-dimensional object of this embodiment, the light energy per unit area applied to the contour portion 22 is greater than the light energy per unit area applied to the non-contour portion 23 in the exposure step.

[0042] FIG. 8 is a diagram showing the shape of a contour portion 22 of the curing target portion 20 that is adjacent to a non-curing target portion 24. FIG. 9 is a diagram showing the shape of a non-contour portion 23 of the curing target portion 20 other than the contour portion 22. The calculation processing unit 11 of the control unit 10 uses the contour data 18 and the interior fill data 19 described above to create data indicating the shape of the contour portion 22 as shown in FIG. 8 and data indicating the shape of the non-contour portion 23 as shown in FIG. 9, and stores these in the storage unit 13. For example, within the region determined by the interior fill data 19 (i.e., the region of the curing target portion 20), the control unit 10 determines the region that is a predetermined width inside the contour line determined by the contour data 18 as the contour portion 22, and the remaining region as the non-contour portion 23. Note that the control unit 10 may determine the curing target portion 20 to be an area smaller than the contour shape determined by the contour data 18, taking into account that the curing of the optical shaping material 9 occurs over a wider range due to light scattering. The thickness of the contour portion 22 (the distance between the boundary line between the contour portion 22 and the non-hardening target portion 24 and the boundary line between the contour portion 22 and the non-contour portion 23) is not particularly limited and can be determined based on, for example, the light intensity, the number of light irradiations, the required accuracy, etc.

[0043] Then, the control unit 10 performs the exposure step using data indicating the shape of the contour portion 22 and data indicating the shape of the non-contour portion 23, which are stored in the storage unit 13. For example, the control unit 10 can perform the exposure step by irradiating light once, or by irradiating light multiple times. An example of the exposure process will be described below.

[0044] [Example 1 of exposure process] The control unit 10 can perform the exposure step by irradiating the entire curing target portion 20 with light once from the light irradiation device 1. In this case, the control unit 10 sets the intensity of light irradiated from the light irradiation device 1 onto the contour portion 22 shown in Fig. 8 of the curing target portion 20 shown in Fig. 6 to be greater than the intensity of light irradiated from the light irradiation device 1 onto the non-contour portion 23 shown in Fig. 9. As a result, in the exposure step, the light energy per unit area applied to the contour portion 22 is greater than the light energy per unit area applied to the non-contour portion 23.

[0045] [Example 2 of exposure process] The control unit 10 can perform the exposure step by two light irradiations, namely, by separately irradiating the entire curing target portion 20 shown in FIG. 6 with light from the light irradiation device 1 at a uniform light intensity and irradiating the contour portion 22 shown in FIG. 8 with light from the light irradiation device 1 at a uniform light intensity. That is, in the exposure step, the contour portion 22 of the curing target portion 20 is irradiated with light two times, and the non-contour portion 23 is irradiated with light once. For example, the light intensity and duration of each light irradiation are set to be the same. As a result, in the exposure step, the light energy per unit area applied to the contour portion 22 is greater than the light energy per unit area applied to the non-contour portion 23.

[0046] If it takes time for the optical shaping material 9 to harden after light irradiation, the control unit 10 preferably performs the second light irradiation after a predetermined curing time required for the optical shaping material 9 to harden has elapsed following the first light irradiation. For example, although this depends on the characteristics of the photocurable resin contained in the optical shaping material 9 and cannot be generalized, it is preferable to perform the second light irradiation after a curing time of, for example, 0.5 to 10 seconds has elapsed. The order of irradiating the entire curing target portion 20 shown in FIG. 6 with light from the light irradiation device 1 with a uniform light intensity and irradiating the outline portion 22 shown in FIG. 8 with light from the light irradiation device 1 with a uniform light intensity can be set as appropriate. Irradiating the outline portion 22 with light in two separate steps, as in this example, can ensure the strength of the outer periphery of the shaping portion while suppressing light scattering and preventing peeling of the cured film.

[0047] [Example 3 of exposure process] The control unit 10 can perform the exposure step by two light irradiations, namely, by separately irradiating the contour portion 22 shown in Fig. 8 with light from the light irradiation device 1 with uniform light intensity and irradiating the non-contour portion 23 shown in Fig. 9 with light from the light irradiation device 1 with uniform light intensity. That is, in the exposure step, of the portion to be cured 20, the contour portion 22 is irradiated with light once, and the non-contour portion 23 is irradiated with light once. For example, in the exposure step, at least one of the light intensity and irradiation time of light irradiation on the contour portion 22 is set to be greater and longer than the light intensity of light irradiation on the non-contour portion 23 so that the light energy per unit area applied to the contour portion 22 is greater than the light energy per unit area applied to the non-contour portion 23.

[0048] In this example, too, the control unit 10 preferably performs the second light irradiation after a predetermined curing time required for the curing of the stereolithography material 9 has elapsed following the first light irradiation. The order of the light irradiation with uniform light intensity from the light irradiation device 1 on the contour portion 22 shown in FIG. 8 and the light irradiation with uniform light intensity from the light irradiation device 1 on the non-contour portion 23 shown in FIG. 9 can be appropriately set. For example, if the light irradiation on the contour portion 22 is performed first, the contour portion 22, which is cured and formed first by the light irradiation, corrects the shape deformation of the subsequent modeling layer. This suppresses deformation during the formation of the cured film on the non-contour portion 23, which is cured by the subsequent light irradiation. Furthermore, if the light irradiation on the contour portion 22 is performed later, the contour shape of the cured film obtained by the light irradiation on the non-contour portion 23 can be corrected. Furthermore, by strengthening the contour portion 22, the strength of the periphery of the modeling part can be ensured, and peeling of the cured film can be suppressed.

[0049] An example of the results when the exposure step of Example 3 is carried out will be described below with reference to FIGS.

[0050] FIG. 10 is a diagram showing the shape of the photo-lithography material 9 that hardens when the region corresponding to the non-outlined portion 23 shown in FIG. 9 is irradiated with light a first time. The dashed line shows the shape of the region that is ultimately desired to be hardened (i.e., the shape shown in FIG. 6). The same light energy per unit area is applied to the photo-lithography material 9 in all regions that are irradiated with light. As shown in the figure, the photo-lithography material 9 hardens in the same shape as the non-outlined portion 23. Furthermore, hardening of the photo-lithography material 9 also occurs in non-hardening target portions 24 that correspond to portions of the photo-lithography material 9 other than the non-outlined portion 23 that are desired to be hardened by this light irradiation.

[0051] Next, a second light irradiation is performed on the region of the optical shaping material 9 shown in Fig. 10 that corresponds to the contour portion 22 shown in Fig. 8. Fig. 11 is a diagram showing the shape of the region that will be hardened by this second light irradiation. In other words, the region that will be hardened by these two light irradiations is the region that combines the hardening target portion 20 shown in Figs. 10 and 11 and the adjacent portion 21 shown in Figs. 10 and 11.

[0052] In order to make the light energy per unit area imparted to the optical shaping material 9 by the light irradiation of the outline portion 22 here greater than the light energy per unit area imparted to the non-outline portion 23 shown in Fig. 10, at least one of the light intensity and irradiation time of the light irradiation of the outline portion 22 is set greater and longer than the light intensity of the light irradiation of the non-outline portion 23. Note that the light energy per unit area imparted to the optical shaping material 9 is the same in the entire region where this second light irradiation is performed.

[0053] 11, the photo-lithography material 9 is hardened in the same shape as the contour portion 22. Furthermore, the photo-lithography material 9 is also hardened in the non-hardening target portion 24 corresponding to the portion of the photo-lithography material 9 other than the contour portion 22 that is desired to be hardened by this light irradiation. Furthermore, in the second light irradiation, the photo-lithography material 9 that has been hardened by the first light irradiation is further irradiated with light, so that the hardening of the photo-lithography material 9 occurs overlappingly with each light irradiation.

[0054] As shown in the figure, the shape of the contour portion 22 shown in Fig. 11 is narrower than the shape of the non-contour portion 23 shown in Fig. 10. Therefore, the width in the XY plane of the adjacent portion 21 generated as a result of light irradiation of the contour portion 22 shown in Fig. 11 is narrower than the width in the XY plane of the adjacent portion 21 generated as a result of light irradiation of the non-contour portion 23 shown in Fig. 10. Specifically, even if the light energy applied to the stereolithography material 9 by light irradiation is the same, the amount of energy leaking to the periphery is relatively reduced by irradiating a narrow shape such as the contour portion 22 with light. As a result, the excess cured width such as the adjacent portion 21 becomes smaller, and the radius of curvature of the corner portion 21c also becomes smaller.

[0055] 11, the corner portion 21c of the adjacent portion 21 corresponding to the corner portion 20a of the portion to be cured 20 has a smoother shape, i.e., a larger radius of curvature, than the shape of the corner portion 20a of the portion to be cured 20, but the radius of curvature is smaller than in the case shown in FIG. 7. In this example, the shape of the corner portion 21c with the smaller radius of curvature becomes the shape of the corner portion of the region that will be cured by two light irradiations. In other words, by increasing the light energy per unit area applied to the contour portion 22 in the exposure step compared to the light energy per unit area applied to the non-contour portion 23, shape errors in the contour portion can be improved compared to the case shown in FIG. 7.

[0056] As described above, the manufacturing method and manufacturing apparatus for a three-dimensional object according to this embodiment uses the light irradiation device 1 that irradiates light all at once onto at least a portion of a predetermined exposable area extending over the surface of the modeling table 4. This allows the light irradiation of the optical shaping material 9 by the light irradiation device 1 to be completed in a short time, even if the contour portion 22 of the portion to be cured 20 has a fine or complex shape. Furthermore, by increasing the light energy per unit area applied to the contour portion 22 compared to the light energy per unit area applied to the non-contour portion 23, the strength of the photocurable resin in the contour portion 22 of the three-dimensional object after light irradiation can be ensured. In particular, when manufacturing a three-dimensional object with a finer structure, the finer the structure, the more contour portions 22 there are, and therefore the strength of the finer portions is naturally ensured.

[0057] The larger the area of ​​the non-contoured portion 23, the greater the effects of curing shrinkage and other factors, resulting in greater deformation and deformation stress of the cured film's outer shape. Furthermore, three-dimensional stacking also accumulates deformation stress in each layer, leading to significant three-dimensional deformation of the object due to warping and other factors. By strengthening the outer shape of each three-dimensionally stacked cured film while correcting it with the contoured portion 22, the stacking of the contoured portion 22 alone can form a certain degree of Z-direction outer shell of the three-dimensional object. Therefore, by combining changes in the curing strength of the XY-direction surfaces of the upper and lower layers of the three-dimensional object, it is possible to strengthen the curing strength of only the outer shell of the three-dimensional object. Because the outer shell maintains the three-dimensional shape of the three-dimensional object, adjusting the amount of light energy in the non-contoured portion 23 to control the internal stress, which accounts for a large volume, can suppress significant deformation. Since the contoured portion 22 ensures the outer shape accuracy of each layer, it is not affected by fluctuations in light energy in the non-contoured portion 23.

[0058] <Another embodiment> In the above embodiment, the configuration of the three-dimensional object manufacturing apparatus has been described using a specific example, but the configuration can be changed as appropriate.

[0059] In the above embodiment, an example has been described in which there is one (i.e., single) contour portion 22, but the contour portion 22 may have a multiple configuration. For example, the contour portion 22 may be composed of an outermost contour portion that directly faces the non-target portion 24, and an inner contour portion that does not directly face the non-target portion 24 but directly faces the outermost contour portion. The number of outermost contour portions and inner contour portions that make up the contour portion 22 can be set as appropriate, and is, for example, a number between 2 and 10. In this case, the light energy per unit area applied to the outermost contour portion and the inner contour portion may be the same or different.

[0060] Furthermore, in the "Example 2 of the exposure step," the outline portion 22 may be irradiated with light at the same light intensity two or more times. In this case, too, the order of irradiating the outline portion 22 with light and irradiating the entire portion to be cured 20 with light can be set as appropriate. For example, the outline portion 22 may be irradiated with light, followed by irradiating the entire portion to be cured 20 with light, and then irradiating the outline portion 22 with light. In the "Example 2 of the exposure step," the light intensity of irradiating the non-outline portion 23 with light and the light intensity of irradiating the outline portion 22 with light may be set to the same, and the non-outline portion 23 may be irradiated with light two or more times. In this case, too, the order of irradiating the outline portion 22 with light and irradiating the non-outline portion 23 of the portion to be cured 20 with light can be set as appropriate. For example, the outline portion 22 may be irradiated with light, followed by irradiating the non-outline portion 23 with light, and then irradiating the outline portion 22 with light.

[0061] In the above embodiment, several numerical examples are given, but these numerical values ​​are given for illustrative purposes only and can be changed as appropriate.

[0062] The configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradictions arise. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present disclosure are not limited to these and can be modified as appropriate within the scope of not departing from the purpose of the present disclosure. [Industrial Applicability]

[0063] The present disclosure can be used for a method and an apparatus for manufacturing a three-dimensional object that can manufacture a highly accurate three-dimensional object in a short time. [Explanation of symbols]

[0064] 1:Light irradiation device 4: Modeling table 9: Materials for stereolithography 20: Part to be cured 21a :part 21b :part 22: Contour area (curing target area 20) 23: Non-rimmed portion (hardened counterpart portion 20) 24: Non-hardened target area

Claims

1. A method for manufacturing a three-dimensional object, comprising: using a light irradiation device that collectively irradiates light onto at least a portion of a predetermined exposable range that extends over a surface of a modeling table, irradiating a surface of a layer of a photo-lithography material formed on the surface of the modeling table with light, thereby hardening the photo-lithography material; a material forming step of forming a layer of the optical shaping material containing a photocurable resin and a solid filler on the surface of the shaping table; an exposure step of irradiating light onto a curing target portion of the optical shaping material formed by the material formation step, the portion being desired to be cured; the portion to be hardened includes a contour portion and a non-contour portion other than the contour portion, In the exposure step, the light energy per unit area applied to the contour portion is set to be greater than the light energy per unit area applied to the non-contour portion.

2. 2. The method for manufacturing a three-dimensional object according to claim 1, wherein in the exposure step, the intensity of light irradiated onto the contour portion is set to be stronger than the intensity of light irradiated onto the non-contour portion, and light is irradiated onto the contour portion and the non-contour portion simultaneously.

3. 2. The method for manufacturing a three-dimensional object according to claim 1, wherein in the exposure step, light is irradiated onto at least one of the contour portion and the non-contour portion multiple times so that a cumulative time of light irradiation onto the contour portion is longer than a cumulative time of light irradiation onto the non-contour portion.

4. The method for producing a three-dimensional object according to claim 1 , wherein the solid filler includes a ceramic.

5. 4. The method for producing a three-dimensional object according to claim 1, wherein the concentration of the solid filler contained in the optical shaping material is 35% by volume or more and 75% by volume or less.

6. A three-dimensional object manufacturing apparatus configured to execute the three-dimensional object manufacturing method according to any one of claims 1 to 3.

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