Stereolithographic article for vehicle and method for producing same

Abstract

In order to make the film thickness of a coating film (15) uniform, a stereolithographic article (1) has: a body having a plurality of step-like recesses (12) formed in the shaping lamination direction by stereolithography; groove parts (13) or wall parts (14) discretely formed in the step-like recesses (12); and the coating film (15), which is applied to the surface of the body including the step-like recesses (12).

Description

Stereolithography for vehicles and its manufacturing method

[0001] The present invention relates to a stereolithographic product for a vehicle and a method for manufacturing the same.

[0002] In principle, stereolithography produces objects with stepped recesses that are hardened by scanning light, and the surface is smoothed by applying a photocurable resin with a high viscosity that can fill the stepped recesses due to surface tension (Patent Document 1).

[0003] Japanese Patent Application Publication No. 5-337951

[0004] When the stereolithography object is small and the extension length of the stepped recesses is short as in the above-mentioned conventional technology, a high-viscosity paint can be filled into the recesses, resulting in a smooth surface of the stepped recesses. However, when the stereolithography object is large and the extension length of the stepped recesses is long, such as in the case of vehicle parts, the paint applied to the stepped recesses shrinks and aggregates due to surface tension, resulting in a problem of uneven film thickness in the stepped recesses.

[0005] The problem to be solved by the present invention is to provide a stereolithography product for a vehicle in which the film thickness of the stepped recess is uniform.

[0006] The present invention solves the above problem by discretely forming grooves or wall portions in multiple stepped recesses formed in the modeling stacking direction using a photopolymerization method, and applying paint to the surface of the main body including these stepped recesses.

[0007] According to the present invention, the film thickness of the stepped recessed portion becomes uniform.

[0008] FIG. 1 is a perspective view showing an embodiment of a stereolithography product according to the present invention. FIG. 2 is a diagram showing the configuration of an example of a stereolithography device for manufacturing a stereolithography product according to the present invention. FIG. 3 is an enlarged perspective view showing an enlarged view of part III of FIG. 1. FIG. 3A is a cross-sectional view taken along line IIIB-IIIB of FIG. 3A. FIG. 3B is a cross-sectional view showing an example of a coating film formed on the stepped recess of FIG. 3B. FIG. 4A is a perspective view showing an embodiment of a groove according to the present invention. FIG. 4B is a perspective view for explaining the operation of an embodiment of a groove according to the present invention. FIG. 4A is a cross-sectional view taken along line IVD-IVD of FIG. 4C. FIG. 4A is a perspective view showing an embodiment of a groove according to the present invention. FIG. 4C is a perspective view showing another embodiment of a groove according to the present invention. FIG. 6A is a perspective view for explaining the operation of an embodiment of a wall according to the present invention. FIG. 6A is a cross-sectional view taken along line VID-VIC of FIG. 6C. FIG. 6B is a perspective view showing an embodiment of a wall according to the present invention. FIG. 6C is a cross-sectional view taken along line VID-VIC of FIG. 6C. FIG. 6C is a perspective view showing an embodiment of a wall according to the present invention. FIG. 6B is a perspective view showing another embodiment of a wall according to the present invention.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The stereolithography product 1 of this embodiment is an article used, for example, as an automobile part, and is not particularly limited as long as it is made of a photocurable resin, and includes all automobile parts. Below, the present invention will be described using the stereolithography product 1 as an example, although it is not a specific automobile part. FIG. 1 is a perspective view showing one embodiment of the stereolithography product 1 according to the present invention. The stereolithography product 1 of this embodiment has a shape obtained by cutting a rectangular parallelepiped along a diagonal slope, and has a slope 11. A stereolithography product 1 with such a shape can be manufactured, for example, as follows.

[0010] 2 is a diagram showing an example of a stereolithography apparatus 2 for producing the stereolithography product 1 of this embodiment. The stereolithography apparatus 2 of this example is a laser scanning type stereolithography apparatus 2, and includes a liquid vat 21 containing an ultraviolet-curable resin 28 as a photocurable resin, a table 22 that moves up and down within the liquid vat 21 by an elevator 23, a scanner 24 that irradiates ultraviolet laser light in a desired scanning pattern near the liquid surface of the liquid vat 21, an ultraviolet laser light irradiator 25 that generates the ultraviolet laser light, and a controller 26 that controls the elevator 23, the scanner 24, and the ultraviolet laser light irradiator 25.

[0011] The controller 26 stores three-dimensional shape data of the target stereolithographic product 1. This three-dimensional shape data is decomposed (sliced) in the layering direction at a predetermined layer pitch, and the data decomposed for each layer pitch is output to the scanner 24 and the elevator 23. When the scanner 24 receives the data for each layer pitch from the controller 26, it scans the ultraviolet laser light from the ultraviolet laser light irradiator 25 in accordance with the data for each layer pitch, irradiating the ultraviolet laser light onto the uncured ultraviolet-curable resin 28 on the upper surface of the table 22. This forms a layer corresponding to one layer pitch. Then, when the formation of one layer is completed, the elevator 23 lowers the table 22 by the layer pitch for one layer, and the next layer is formed. By repeating this process, a stereolithographic product 1 with a desired three-dimensional shape is manufactured.

[0012] The stereolithography product 1 of this embodiment can be manufactured by a stereolithography method using a surface exposure method as well as the laser scanning method. In either method, a stepped recess 12 corresponding to the build layer pitch is formed on the slope 11. Fig. 3A is an enlarged perspective view showing an enlarged view of part III in Fig. 1, and Fig. 3B is a cross-sectional view taken along line IIIB-IIIB in Fig. 3A. In these drawings, the direction in which the stepped recess 12 extends is referred to as the X-axis direction, and the direction in which the slope 11 extends and is perpendicular to the X-axis direction is referred to as the Y-axis direction.

[0013] As shown in FIG. 3B , the stepped recess 12 formed on the slope 11 of the stereolithography product 1 is composed of steps 121 with a depth D1 and vertical walls 122 with a height H1, and the height H1 of the vertical walls 122 corresponds to the build layer pitch. If the depth D1 of the steps 121 or the height H1 of the vertical walls 122 are large, the appearance of the slope 11 of the stereolithography product 1 as a finished product will be reduced. Reducing the build layer pitch reduces the height H1 of the vertical walls of the stepped recess 12, thereby preventing the appearance of the slope 11 from being reduced. However, reducing the build layer pitch increases the manufacturing time and reduces productivity. In particular, since the number of automotive parts manufactured is large, measures that result in reduced productivity are not practical.

[0014] Therefore, in the stereolithographic product 1 of this embodiment, instead of reducing the build layer pitch, paint is applied to the stepped recesses 12, and the stepped recesses 12 are filled with a coating film 15 as shown in FIG. 3C to smooth the surface of the slope 11. The build layer pitch of the stereolithographic product 1 of this embodiment is not particularly limited, but is preferably 35 to 350 μm. A build layer pitch of less than 35 μm is undesirable because it increases the manufacturing time for the stereolithographic product 1 and reduces productivity. Furthermore, a build layer pitch of more than 350 μm is undesirable because the step dimensions of the stepped recesses 12 become too large, making it difficult to smooth them by filling them with a coating film 15.

[0015] As a method for applying paint to the stepped recess 12, painting methods such as brush painting, spatula painting, roller brush painting, spray painting, and curtain flow coater painting can be used, but a dipping painting method in which the photopolymerized product 1 is immersed in a paint tank containing paint is more preferred.

[0016] The paint to be applied to the stereolithographic product 1 of this embodiment is not particularly limited, and a bake-curable paint or an ultraviolet-curable resin paint can be used. The ultraviolet-curable paint that can be used in this embodiment may be a paint obtained by blending a known ultraviolet-curable resin composition with, as needed, a colorant and known paint additives (for example, an antifoaming agent such as silicone oil, a fluorine-based surfactant, a silicone-based surfactant, a leveling agent such as an acrylic copolymer, a thickener, a viscosity reducer, etc.). Ultraviolet-curable resin compositions are broadly classified into ultraviolet-radical-curable resin compositions and cation-curable resin compositions, and either type of ultraviolet-curable resin composition can be used in this embodiment.

[0017] When the stereolithography product 1 is immersed in paint to apply the paint to the stepped recesses 12, the paint applied to the stepped recesses 12 shrinks due to surface tension and partially aggregates, resulting in a problem of uneven film thickness in the stepped recesses 12. Therefore, in the stereolithography product 1 of this embodiment, grooves 13 or wall portions 14 are discretely formed in the stepped recesses 12 to prevent the paint applied to the stepped recesses 12 from shrinking due to surface tension. FIGS. 4A to 5B show an embodiment of the present invention in which grooves 13 are formed, and FIGS. 6A to 7B show an embodiment of the present invention in which wall portions 14 are formed. While the grooves 13 and wall portions 14 are not shown in FIGS. 1 and 3A to 3C, the grooves 13 or wall portions 14 shown in FIGS. 4A to 7B are formed.

[0018] Fig. 4A is a perspective view showing one embodiment of the groove portion 13 according to the present invention, Fig. 4B is a perspective view for explaining the operation of the embodiment of the groove portion 13 according to the present invention, Fig. 4C is a view (plan view) taken along arrow IVC in Fig. 4A, and Fig. 4D is a cross-sectional view taken along line IVD-IVD in Fig. 4C. The groove portions 13 of this embodiment are formed discretely in the extension direction (X-axis direction) of each of the plurality of stepped recesses 12 formed on the slope 11.

[0019] The grooves 13 of this embodiment are formed on at least one of the steps 121 and the vertical walls 122 of the stepped recess 12, and more preferably on both the steps 121 and the vertical walls 122 of the stepped recess 12. Fig. 4A shows an example in which the grooves 13 are formed on both the steps 121 and the vertical walls 122 of the stepped recess 12.

[0020] The groove width W1 and groove depth D2 of each groove portion 13 are not particularly limited. For example, the groove width W1 of the groove portion 13 is greater than 5 μm and less than 100 μm, preferably 5 to 80 μm, and more preferably 10 to 60 μm. This is because a groove width W1 of the groove portion 13 exceeding 100 μm would affect the surface smoothness of the coating film 15. Furthermore, the groove depth D2 of the groove portion 13 is preferably 50% or more of the building layer pitch (height H1 of the vertical wall 122), i.e., 17.5 to 175 μm. This is because if the groove depth D2 of the groove portion 13 is less than 50% of the building layer pitch, shrinkage of the uncured paint 151 applied to the stepped recess 12 cannot be sufficiently suppressed.

[0021] The distance P1 between two adjacent grooves 13 formed in one stepped recess 12 is not particularly limited, but is, for example, greater than 5 μm and less than or equal to 500 μm, preferably 100 to 400 μm, and more preferably 200 to 300 μm. If the distance P1 between two adjacent grooves 13 exceeds 500 μm, shrinkage of the uncured paint 151 applied to the stepped recess 12 cannot be sufficiently suppressed.

[0022] FIG. 5A is a perspective view showing one embodiment of a groove portion 13 according to the present invention, and FIG. 5B is a perspective view showing another embodiment of a groove portion 13 according to the present invention. As shown in FIG. 5A , the groove portion 13 according to the present invention may be formed at the same position in the X-axis direction as the plurality of stepped recesses 12, 12 ... formed on the slope 11 along the Y-axis direction. Alternatively, as shown in FIG. 5B , the groove portion 13 according to the present invention may be formed at a position offset in the X-axis direction for each step or for each plurality of steps of the stepped recesses 12, 12 ... formed on the slope 11 along the Y-axis direction. By forming the groove portion 13 at a position offset in the X-axis direction for each step or for each plurality of steps of the stepped recesses 12, the effect of the groove portion 13 is uniform across the entire slope 11.

[0023] As described above, when grooves 13 are formed discretely in stepped recesses 12, as shown in Fig. 4B, uncured paint 151 applied to said stepped recesses 12 tends to shrink due to its own surface tension, but a force γL, which is the product of the capillary force γ of said groove and the circumferential length L of the groove, is generated in grooves 13, thereby suppressing the shrinkage of uncured paint 151. As a result, uncured paint 151 applied to stepped recesses 12 is fixed in place, thereby making the thickness of coating film 15 uniform.

[0024] Fig. 6A is a perspective view showing one embodiment of the wall portion 14 according to the present invention, Fig. 6B is a perspective view for explaining the operation of the embodiment of the wall portion 14 according to the present invention, Fig. 6C is a view (plan view) taken along arrow VIC in Fig. 6A, and Fig. 6D is a cross-sectional view taken along line VID-VID in Fig. 6C. The wall portions 14 of this embodiment are formed discretely in the extension direction (X-axis direction) of each of the plurality of stepped recesses 12 formed on the slope 11.

[0025] The wall portion 14 in this embodiment is formed on the step 121 of the stepped recess 12, but may also be formed in contact with the vertical wall 122 of the stepped recess 12. Fig. 4A shows an example of the wall portion 14 formed on the step 121 of the stepped recess 12 and in contact with the vertical wall 122.

[0026] The wall thickness W2, wall height H2, and step-direction length D3 of each wall portion 14 are not particularly limited. For example, the wall thickness W2 of the wall portion 14 is greater than 5 μm and less than 100 μm, preferably 5 to 80 μm, and more preferably 10 to 60 μm. This is because a wall width W2 of the wall portion 14 exceeding 100 μm would affect the surface smoothness of the coating film 15. Furthermore, the wall height H2 of the wall portion 14 is preferably 50% or more of the build layer pitch (the height H1 of the vertical wall 122), i.e., 17.5 to 175 μm. This is because if the wall height H2 of the wall portion 14 is less than 50% of the build layer pitch, shrinkage of the uncured paint 151 applied to the stepped recess 12 cannot be sufficiently suppressed. Furthermore, the step-direction length D3 of the wall portion 14 is preferably 50% or more of the step depth D1 of the step 121. If the length D3 of the wall portion 14 in the step direction is less than 50% of the depth D1 of the step 121, the shrinkage of the uncured paint 151 applied to the stepped recess 12 cannot be sufficiently suppressed.

[0027] The distance P2 between two adjacent wall portions 14 formed in one stepped recess 12 is not particularly limited, but is, for example, greater than 5 μm and equal to or less than 500 μm, preferably 100 to 400 μm, and more preferably 200 to 300 μm. If the distance P2 between two adjacent wall portions 14 exceeds 500 μm, shrinkage of the paint applied to the stepped recess 12 cannot be sufficiently suppressed.

[0028] FIG. 7A is a perspective view showing one embodiment of a wall portion 14 according to the present invention, and FIG. 7B is a perspective view showing another embodiment of the wall portion 14 according to the present invention. As shown in FIG. 7A , the wall portion 14 according to the present invention may be formed at the same position in the X-axis direction as the plurality of stepped recesses 12, 12 ... formed on the slope 11 along the Y-axis direction. Alternatively, as shown in FIG. 7B , the wall portion 14 according to the present invention may be formed at a position offset in the X-axis direction for each step or for each plurality of steps of the stepped recesses 12, 12 ... formed on the slope 11 along the Y-axis direction. By forming the wall portion 14 at a position offset in the X-axis direction for each step or for each plurality of steps of the stepped recesses 12, the influence of the wall portion 14 is uniform across the entire slope 11.

[0029] As described above, when the wall portions 14 are formed discretely in the stepped recess 12, the uncured paint 151 applied to the stepped recess 12 tends to shrink due to its own surface tension as shown in Fig. 6B, but a force nA, which is the product of the solid-liquid adhesion force n per unit area of ​​the wall and the surface area A of the wall, is generated in the wall portion 14, thereby suppressing the shrinkage of the uncured paint 151. As a result, the uncured paint 151 applied to the stepped recess 12 is fixed in place, thereby making the thickness of the coating film 15 uniform.

[0030] As described above, the stereolithographic product 1 of this embodiment includes a main body having a plurality of stepped recesses 12 formed in the modeling stacking direction by stereolithography, grooves 13 or wall portions 14 formed discretely in the stepped recesses 12, and a coating film 15 applied to the surface of the main body including the stepped recesses 12. Therefore, even if the uncured paint 151 tries to shrink due to its own surface tension, this can be suppressed by the grooves 13 or wall portions 14. As a result, the uncured paint 151 applied to the stepped recesses 12 is fixed in place, thereby making the thickness of the coating film 15 uniform.

[0031] Furthermore, according to the photopolymerization product of this embodiment, the groove portions 13 or the wall portions 14 are formed at positions offset from the extension direction X of the stepped recesses 12 for each step or for each plurality of steps of the plurality of stepped recesses 12, so that the influence of the groove portions 13 or the wall portions 14 is uniform across the entire slope 11.

[0032] Furthermore, according to the photopolymerized product of this embodiment, the groove width W1 of the groove portion 13 or the wall thickness W2 of the wall portion 14 is 100 μm or less, so the film thickness of the coating film 15 can be made uniform without affecting the smoothness of the surface of the coating film 15.

[0033] Furthermore, according to the stereolithography product of this embodiment, the grooves 13 or the walls 14 are formed discretely at intervals of 500 μm or less, which makes it possible to make the thickness of the coating film 15 even more uniform.

[0034] Furthermore, in the stereolithography product of this embodiment, the layer pitch of the staircase recess 12 is 35 to 350 μm, so that the film thickness of the coating film 15 can be made uniform while maintaining productivity.

[0035] Furthermore, according to the photopolymerization product of this embodiment, the groove depth D2 of the groove portion 13 is 50% or more of the molding layer pitch, so that the film thickness of the coating film 15 can be made uniform without affecting the smoothness of the surface of the coating film 15.

[0036] Furthermore, according to the photopolymerization product of this embodiment, the wall height H2 of the wall portion 14 is 50% or more of the molding layer pitch, and the length D3 of the wall of the wall portion 14 in the step direction is 50% or more of the depth D1 of the stepped recess 12, so that the film thickness of the coating film 15 can be made uniform without affecting the smoothness of the surface of the coating film 15.

[0037] Furthermore, the method for manufacturing a stereolithography product of this embodiment includes the steps of forming a main body having a plurality of stepped recesses 12 in the modeling stacking direction by stereolithography, forming grooves 13 or wall portions 14 discretely in the stepped recesses 12, and applying paint to the surface of the main body including the stepped recesses 12. Therefore, even if uncured paint 151 tries to shrink due to its own surface tension, this can be suppressed by the grooves 13 or wall portions 14. As a result, the uncured paint 151 applied to the stepped recesses 12 is fixed in place, thereby making the film thickness of the coating film 15 uniform.

[0038] In addition, in the manufacturing method of the photopolymerized product of this embodiment, the groove portion 13 or the wall portion 14 may be formed on the main body simultaneously in the process of forming the main body, or may be formed on the main body after the main body is formed.

[0039] The present invention will be described below with reference to examples and comparative examples that further embody the stereolithography product for vehicles according to the present invention. However, the specific values ​​below are examples and comparative examples for understanding the present invention and are not intended to limit the present invention.

[0040] First, the stereolithography product 1 shown in FIG. 1 was created using a stereolithography device 2 having the basic configuration shown in FIG. 2. The specific dimensions of the stereolithography product 1 shown in FIG. 1 were M1 = 50 mm, M2 = 28.9 mm, and M3 = 20 mm. Furthermore, as shown in Table 1, the layer build pitch and pixel builds used to create the stereolithography product 1 were set to 140 μm and 70 μm for Examples 1 to 3 and Comparative Example 1, respectively, and 70 μm and 35 μm for Example 4. Groove portions 13 were formed in Examples 1 and 2, wall portions 14 were formed in Examples 3 and 4, and neither groove portions 13 nor wall portions 14 were formed in Comparative Example 1.

[0041] The groove portions 13 in Examples 1 and 2 had a groove width W1 of 100 μm, a groove depth D2 of 100 μm, and a spacing P1 of 500 μm between adjacent groove portions 13. As shown in Fig. 5A , the groove portions 13 in Example 1 were formed at the same position in the X-axis direction with respect to the plurality of stepped recesses 12, 12..., while the groove portions 13 in Example 2 were formed at positions offset by 250 μm in the X-axis direction with respect to the plurality of stepped recesses 12, 12..., for every 10 steps of the stepped recesses 12, 12..., as shown in Fig. 5B .

[0042] The wall portions 14 of Example 3 had a wall thickness W2 of 100 μm, a wall height H2 of 100 μm, and a spacing P2 between adjacent wall portions 14 of 500 μm. In contrast, the wall portions 14 of Example 4 had a wall thickness W2 of 50 μm, a wall height H2 of 50 μm, and a spacing P2 between adjacent wall portions 14 of 200 μm. The wall portions 14 of Example 3 were formed at the same position in the X-axis direction relative to the plurality of stepped recesses 12, 12... as shown in FIG. 7A, while the wall portions 14 of Example 4 were formed at positions offset by 100 μm in the X-axis direction for each step of the plurality of stepped recesses 12, 12... as shown in FIG. 7B. The above conditions are shown in Table 1.

[0043]

[0044] The stereolithography products 1 of Examples 1 to 4 and Comparative Example 1 formed as described above were immersed in the same paint and cured under the same conditions to form a coating film 15 on the slope 11. The paint used was an ultraviolet-curable paint (Preveil manufactured by Nidek Co., Ltd.) with a viscosity of 30 cP, a paint solids content of 50 wt %, and a surface tension of 23 mN / m.

[0045] For the coating films 15 of the stereolithographic products 1 of Examples 1 to 4 and Comparative Example 1, in which the coating films 15 were formed as described above, the film thickness at the center and both end portions of each stepped recess 12 in the X-axis direction was measured, and the surface roughness at the center and both end portions of each stepped recess 12 in the X-axis direction was also measured. To measure the film thickness, the measurement location was cut using a grindstone cutter (Pcut special model, manufactured by Nippon Cutting Machine Manufacturing Co., Ltd.), and the rough cross section was observed and measured using a microscope (VHX-7000, manufactured by Keyence Corporation). The film thickness t was defined as the thickness t from the plane connecting the apexes of the stepped recesses 12 shown in Figure 3C. If the film protruded outward from this plane, it was designated +t, and if the film recessed inward, it was designated -t. The surface roughness Ra was measured as the arithmetic mean roughness Ra using a surface roughness meter (Talysurf, manufactured by Taylor Bobson). The results are shown in Table 2.

[0046]

[0047] <<Discussion>> From the results shown in Table 2, it was confirmed that the quality of film thickness and surface roughness was satisfactory for all of the stereolithography products 1 of Examples 1 to 4. In contrast, it was confirmed that the stereolithography product 1 of Comparative Example 1 experienced shrinkage of the uncured paint 151 at both ends of the stepped recess 12, resulting in a film thickness difference of 18 μm between the center and both ends, and the surface roughness at both ends was greater.

[0048] Furthermore, when Examples 1 to 4 were compared, no difference was observed in terms of surface roughness, but in terms of film thickness uniformity, Example 1 was the best, followed by Examples 2 and 4. However, Example 2 had a larger molding layer pitch than Example 4, and therefore was better in terms of productivity.

[0049] DESCRIPTION OF SYMBOLS 1...Stereolithography product 11...Slope 12...Stair-like recess 121...Step D1...Step depth 122...Vertical wall H1...Height of vertical wall (=modeling layer pitch) 13...Groove W1...Groove width D2...Groove depth P1...Groove spacing 14...Wall W2...Wall thickness H2...Wall height D3...Length of wall in step direction P2...Spacing of wall 15...Coating film 151...Uncured paint 2...Stereolithography device 21...Liquid tank 22...Table 23...Elevator 24...Scanner 25...Ultraviolet laser light irradiator 26...Controller 27...Ultraviolet laser light 28...Ultraviolet curing resin

Claims

1. a main body having a plurality of stepped recesses formed in a modeling stacking direction by a stereolithography method; grooves or walls formed discretely in the stepped recess; a coating film applied to the surface of the main body including the stepped recess.

2. The optically fabricated product for a vehicle according to claim 1 , wherein the groove portion or the wall portion is formed at a position offset from the extending direction of the stepped recesses for each step or for each plurality of steps of the stepped recesses.

3. 3. The stereolithographic product for a vehicle according to claim 1, wherein the groove width of the groove portion or the wall thickness of the wall portion is 100 [mu]m or less.

4. 3. The optically fabricated product for a vehicle according to claim 1, wherein the grooves or the walls are formed discretely at intervals of 500 μm or less.

5. 3. The optically fabricated product for a vehicle according to claim 1, wherein the layer pitch of the stepped recess is 35 to 350 μm.

6. The optically fabricated product for a vehicle according to claim 5 , wherein the depth of the groove portion is 50% or more of the layer pitch for fabrication.

7. The wall height of the wall portion is 50% or more of the building layer pitch, 6. The optically fabricated product for a vehicle according to claim 5, wherein the length of the wall of the wall portion in the step direction is 50% or more of the depth of the stepped recess.

8. forming a main body having a plurality of stepped recesses in a modeling stacking direction by a stereolithography method; forming grooves or walls discretely in the stepped recess; and applying paint to the surface of the main body including the stepped recess.

9. The method for manufacturing a stereolithography product for a vehicle according to claim 8 , wherein the groove or the wall is simultaneously formed in the main body in the process of forming the main body.

10. The method for manufacturing a stereolithography product for a vehicle according to claim 8 , wherein the groove or the wall is formed on the main body after the main body is formed.