Method for manufacturing shaped article

Abstract

Provided is a method for manufacturing a shaped article, the manufacturing method comprising: a step for preparing a base material; a step for forming a powder layer by disposing a metal powder in a layered shape on an upper surface of the base material; and a step for forming a solidified layer in which the metal powder is bonded by radiating a laser beam onto a prescribed portion of the powder layer, wherein the step for forming the powder layer and the step for forming the solidified layer are repeated to form a shaped article, in which the solidified layer is laminated on the base material, and a support body parallel to the shaped article. The shaped article has at least one protrusion protruding in a direction parallel to the upper surface of the base material, and an inner angle of the protrusion(s) is less than 90°. The support body contacts a side surface of the protrusion, and a position where the support body contacts the side surface of the protrusion is within 10 mm from the tip of the protrusion.

Description

Manufacturing method of the shaped object

[0001] The present disclosure relates to a method for manufacturing a shaped body. This application claims priority based on Japanese Patent Application No. 2023-108315 filed on June 30, 2023, and incorporates by reference all of the contents of said Japanese application.

[0002] Patent Documents 1 and 2 disclose a method of forming a powder layer by spreading metal powder on a base material, and then irradiating the powder layer with laser light to form a solidified layer in which the metal powder is bonded, and by repeating this process, stacking the solidified layers to form a shape.

[0003] International Publication No. WO 2018 / 230421 International Publication No. WO 2022 / 190376

[0004] The method for manufacturing a shaped body according to the present disclosure includes the steps of preparing a substrate, arranging metal powder in layers on the upper surface of the substrate to form a powder layer, and irradiating a predetermined portion of the powder layer with laser light to form a solidified layer in which the metal powder is bonded. By repeating the steps of forming the powder layer and forming the solidified layer, a shaped body in which the solidified layers are stacked on the substrate and a support body arranged in parallel with the shaped body are formed. The shaped body has at least one protrusion protruding in a direction parallel to the upper surface of the substrate. The interior angle of the protrusion is less than 90°. The support body is in contact with a side surface of the protrusion. The position at which the support body contacts the side surface of the protrusion is within 10 mm of the tip of the protrusion.

[0005] FIG. 1 is a schematic perspective view showing an example of a shaped body manufactured by a shaped body manufacturing method according to an embodiment. FIG. 2 is a schematic front view of the shaped body of FIG. 1. FIG. 3 is a schematic bottom view showing the bottom surface of the shaped body of FIG. 1. FIG. 4 is a schematic plan view of the support body of FIG. 1. FIG. 5 is a schematic perspective view of the support body of FIG. 1. FIG. 6 is a schematic perspective view showing a modified example of the support body of FIG. 1. FIG. 7 is a schematic top view of another example of the support body. FIG. 8 is a schematic top view of another example of the support body. FIG. 9 is a schematic top view of another example of the support body. FIG. 10 is a diagram showing the thermal stress distribution at the corner of the shaped body for Sample No. 10. FIG. 11 is a graph showing the relationship between the distance from the tip of the corner of the shaped body and stress for Sample No. 10. FIG. 12 is a graph showing the relationship between the distance from the tip of the corner of the shaped body and stress for Sample No. 1. FIG. 13 is a graph showing the relationship between the distance from the tip of the corner of the shaped body and stress for Sample No. 2.

[0006] [Problem to be Solved by the Present Disclosure] When a shaped object having protrusions such as corners or localized projections is formed, cracks may occur in the protrusions or the protrusions may peel off from the base material. It is desirable to reduce the occurrence of such cracks.

[0007] An object of the present disclosure is to provide a method for manufacturing a shaped body that can reduce the occurrence of cracks and the like on protruding portions of the shaped body.

[0008] Effect of the Present Disclosure The method for manufacturing a shaped body according to the present disclosure can reduce the occurrence of cracks and the like in the protruding portions of the shaped body.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) A method for manufacturing a shaped body according to the present disclosure includes the steps of preparing a substrate, arranging metal powder in layers on the upper surface of the substrate to form a powder layer, and irradiating a predetermined portion of the powder layer with laser light to form a solidified layer in which the metal powder is bonded. By repeating the steps of forming the powder layer and forming the solidified layer, a shaped body in which the solidified layers are stacked on the substrate and a support body arranged in parallel with the shaped body are formed. The shaped body has at least one protrusion that protrudes in a direction parallel to the upper surface of the substrate. The interior angle of the protrusion is less than 90°. The support body is in contact with a side surface of the protrusion. The position at which the support body contacts the side surface of the protrusion is within 10 mm from the tip of the protrusion.

[0011] The method for manufacturing a shaped body according to the present disclosure can reduce the occurrence of cracks and the like in the protruding portions of the shaped body. The reason why the occurrence of cracks and the like in the protruding portions can be reduced is that, as will be described in detail below, a support body is formed in contact with the side surface of the protruding portion simultaneously with the formation of the shaped body. One reason why cracks and the like in the protruding portions occur is that, during shaping, the portion closest to the tip of the protruding portion is cooled first, which generates thermal stress in the protruding portion due to temperature differences. Differences in the amount of shrinkage occur in the protruding portion, resulting in uneven thermal stress. By simultaneously forming the support body, the temperature difference in the protruding portion is reduced, and the difference in the amount of shrinkage is also reduced. The method for manufacturing a shaped body according to the present disclosure can reduce the occurrence of cracks and the like in the protruding portion because the support body relieves thermal stress in the protruding portion.

[0012] (2) In the method for manufacturing a shaped body according to (1), the volume of the support body is 10 mm ３ It may be more than that.

[0013] According to the manufacturing method (2) above, the difference in the amount of shrinkage and the temperature difference in the protrusions are likely to be small. Therefore, the effect of alleviating thermal stress in the protrusions is likely to be obtained. The manufacturing method (2) above is likely to reduce the occurrence of cracks and the like in the protrusions.

[0014] (3) In the method for manufacturing a shaped body according to (1) or (2) above, the width of the support body in contact with the side surface of the protrusion may be 0.5 mm or more and 2.5 mm or less.

[0015] According to the manufacturing method (3) above, the contact area between the support body and the protrusion is increased, so heat is easily transferred from the support body to the protrusion. The protrusion is less likely to cool, so the temperature difference is likely to be small. The effect of alleviating thermal stress in the protrusion is easily achieved. The manufacturing method (3) above is likely to reduce the occurrence of cracks and the like in the protrusion.

[0016] (4) In the method for manufacturing a shaped body according to any one of (1) to (3) above, the height of the support body may be 3 mm or more and equal to or less than the height of the shaped body.

[0017] According to the manufacturing method (4) above, the contact area between the support body and the protrusion is increased, so heat is easily transferred from the support body to the protrusion. The protrusion is less likely to cool, so the temperature difference is likely to be small. The effect of alleviating thermal stress in the protrusion is easily achieved. The manufacturing method (4) above is likely to reduce the occurrence of cracks and the like in the protrusion.

[0018] (5) In the method for manufacturing a shaped body according to any one of (1) to (4) above, the area of ​​a cross section of the support body parallel to an upper surface of the base material may increase toward the base material.

[0019] According to the manufacturing method (5) above, the volume of the support body is increased. Also, the bonding area between the support body and the upper surface of the base material is increased. The manufacturing method (5) above is likely to reduce the occurrence of cracks and the like in the protruding portion.

[0020] (6) In the method for manufacturing a shaped body according to any one of (1) to (5) above, the metal powder may be made of high-speed steel.

[0021] According to the manufacturing method (6) above, a shaped body made of high-speed steel can be manufactured.

[0022] [Details of the Embodiments of the Present Disclosure] Specific examples of methods for manufacturing shaped bodies according to embodiments of the present disclosure will now be described with reference to the drawings. The same reference numerals in the drawings indicate the same or equivalent parts. In the drawings, some components may be exaggerated or simplified for ease of explanation. The dimensional ratios of the various parts in the drawings may also differ from the actual ratios. Note that the present invention is not limited to these examples, but is defined by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

[0023] [Embodiment 1] <Method for Manufacturing a Shaped Body> An overview of a method for manufacturing a shaped body according to an embodiment will be described. In the method for manufacturing a shaped body according to an embodiment, a shaped body 2 is formed on a substrate 1 by repeating a step of forming a powder layer and a step of forming a solidified layer, as shown in FIGS. 1 and 2 . FIG. 1 is a perspective view of the shaped body 2 as seen from diagonally above. FIG. 2 is a front view as seen from the direction of arrow A in FIG. 1 . The shaped body 2 can be manufactured using a powder bed type metal 3D printer. One of the features of the method for manufacturing a shaped body according to an embodiment is that a support body 3 is formed simultaneously with the formation of the shaped body 2. As described below, the support body 3 serves to reduce the occurrence of cracks in the protruding portions 21 during the manufacturing of the shaped body 2. The support body 3 reduces the occurrence of cracks by alleviating thermal stress in the protruding portions 21. Each step will be described in detail below.

[0024] (Step of forming a powder layer) In the step of forming a powder layer, metal powder is arranged in a layer on the upper surface 10 of the substrate 1 to form a powder layer. The metal powder may be any material that can be used in a metal 3D printer. Examples of the material of the metal powder include iron, iron alloy, aluminum, aluminum alloy, copper, copper alloy, titanium, and titanium alloy. Specific examples of iron alloys include steels such as carbon steel, tool steel, high-speed steel, and stainless steel.

[0025] The average particle diameter of the metal powder is, for example, 10 μm or more and 100 μm or less. Metal powders with such an average particle diameter are easy to mold. The average particle diameter of the metal powder may further be 20 μm or more and 60 μm or less. The "average particle diameter" here refers to the particle diameter at which the cumulative volume in the volume particle size distribution measured by a laser diffraction particle size distribution analyzer is 50%.

[0026] <Substrate> The substrate 1 is a member that serves as the base of the shaped body 2 when the shaped body 2 is formed. The substrate 1 is, for example, a plate that is placed on the table of a metal 3D printer. The substrate 1 may also be a part of a metal part.

[0027] The material of the substrate 1 is a metal such as iron, iron alloy, aluminum, aluminum alloy, copper, copper alloy, titanium, or titanium alloy. The material of the substrate 1 may be the same as or different from the material of the metal powder.

[0028] The shape of the substrate 1 may be any shape such as a plate or a column, etc. The shape of the substrate 1 shown in Fig. 1 is a cylinder.

[0029] (Step of forming a solidified layer) In the step of forming a solidified layer, a laser beam is irradiated onto a predetermined portion of the powder layer to form the solidified layer. The laser beam is irradiated onto the portion to be shaped. The laser beam melts and solidifies the metal powder, forming a solidified layer in which the metal powder is bonded together.

[0030] The laser light is, for example, a solid-state laser or a gas laser. The solid-state laser is, for example, a fiber laser or a YAG (yttrium aluminum garnet) laser. The fiber laser is, for example, a Yb (ytterbium) fiber laser. The gas laser is, for example, a CO ２ It's a laser.

[0031] (Process for forming a shaped body) In the process for forming the shaped body 2, the process for forming a powder layer and the process for forming a solidified layer are repeated to form the shaped body 2 and the support body 3, in which solidified layers are stacked on the substrate 1. In this process, the support body 3 is formed in parallel with the shaped body 2 at the same time as the shaped body 2. The shaped body 2 and the support body 3 are directly bonded to the upper surface 10 of the substrate 1. The shaped body 2 and the support body 3 are made of the same metal as the metal powder.

[0032] <Shaped body> The shaped body 2 has a three-dimensional shape with at least one protrusion 21. The shape of the shaped body 2 is, for example, a prismatic or gear-like shape. The protrusion 21 is a portion that protrudes in a direction parallel to the upper surface 10 of the substrate 1. The "protrusion 21" here refers to a portion that protrudes outward from the inscribed circle of the bottom surface 22 (see FIG. 3). The protrusion 21 includes a corner 21c of a prismatic column. The protrusion 21 may also be a portion that locally protrudes outward like a gear tooth. In this example, the shape of a cross section of the shaped body 2 parallel to the upper surface 10 of the substrate 1 is constant in a direction perpendicular to the upper surface 10.

[0033] The shape of the shaped body 2 may be a prismatic shape such as a triangular prism, a quadrangular prism, or a hexagonal prism. The shape of the shaped body 2 shown in Fig. 1 is a regular triangular prism. As shown in Fig. 3, the bottom surface 22 of the shaped body 2 is an equilateral triangle. The shaped body 2 in this example has three corners 21c.

[0034] In this example, the protrusion 21 is a corner 21c. The protrusion 21, i.e., the corner 21c, is composed of three surfaces: a bottom surface 22 and two adjacent side surfaces 23. The bottom surface 22 contacts the upper surface 10 of the substrate 1, as shown in FIG. 2. The side surfaces 23 intersect with the bottom surface 22. In this example, the bottom surface 22 and the side surfaces 23 intersect perpendicularly. The tip of the protrusion 21, i.e., the tip of the corner 21c, is the intersection point where the adjacent side surfaces 23 intersect, as shown in FIG. 3. The tip of the protrusion 21 is not limited to a corner formed by two flat surfaces, but may also be a curved surface such as an arc. The tip of the protrusion 21 may also be chamfered. This chamfering may be a C-chamfer or an R-chamfer.

[0035] The interior angle of the protrusion 21 is less than 90°, i.e., an acute angle. The interior angle of the protrusion 21 is the angle at which adjacent side surfaces 23 intersect. The interior angle of the protrusion 21 may further be 80° or less, or 70° or less. The lower limit of the interior angle of the protrusion 21 is, for example, 10°. The interior angle of the protrusion 21 may be 10° or more and less than 90°, or even 20° or more and 80° or less, or 30° or more and 70° or less. In this example, the interior angle of the protrusion 21, i.e., the interior angle of the corner 21c, is 60°. When the protrusion 21 is a curved surface, the angle formed by the tangents of the side surfaces that make up the curved surface is considered to be the interior angle.

[0036] The height of the shaped body 2 is, for example, 10 mm or more. Here, "height" refers to the dimension in the Z direction. The "Z direction" is the direction perpendicular to the upper surface 10 of the substrate 1 and away from the upper surface 10. The height of the shaped body 2 may further be 20 mm or more. The upper limit of the height of the shaped body 2 is, for example, 300 mm. The height of the shaped body 2 may be 10 mm or more and 300 mm or less, or even 20 mm or more and 200 mm or less. In this example, the height of the shaped body 2 is 20 mm.

[0037] <Support Body> The support body 3 is formed simultaneously with the shaped body 2 so as to be in contact with the side surfaces of the protrusions 21. The bottom surface 32 of the support body 3 is in contact with the upper surface 10 of the substrate 1. The support body 3 is a structure that is formed together with the shaped body 2 only during the manufacture of the shaped body 2. The support body 3 is finally removed after the shaped body 2 is formed. In this example, the support body 3 is in contact with the side surfaces of the corners 21c. In this example, as shown in FIG. 3 , a total of six support bodies 3 are arranged, two on each side surface of each corner 21c.

[0038] <Occurrence and Reduction of Cracks in Protrusions> The reason why cracks and the like occur in the protrusions 21 during the formation of the shaped body 2 is thought to be as follows. When a powder layer is irradiated with laser light to form a solidified layer, the portion irradiated with the laser light is heated and then cooled, causing expansion and contraction. In the portion of the shaped body 2 near the bottom surface 22 that contacts the top surface 10 of the substrate 1, heat is easily dissipated through the substrate 1, and the portion is easily cooled. In the protrusions 21, the volume decreases toward the tip of the protrusion 21, and increases with increasing distance from the tip. The portion near the tip of the protrusion 21 has a small volume, so the cooling rate is fast. The portion farther from the tip of the protrusion 21 has a large volume, so the cooling rate is slow. The amount of contraction differs between the portion near the tip of the protrusion 21 and the portion farther from the tip of the protrusion 21, resulting in non-uniform thermal stress. Furthermore, because the portion near the tip of the protrusion 21 is cooled first, the temperature difference causes greater thermal stress in the portion farther from the tip of the protrusion 21. This difference in thermal stress may cause cracks to occur in the protruding portion 21 or cause the protruding portion 21 to peel off from the upper surface 10 of the substrate 1. Here, cracks and lifting that occur in the protruding portion 21 are collectively referred to as "cracks, etc."

[0039] In particular, when the interior angle of the protrusion 21 is less than 90°, the volume of the protrusion 21 becomes small, which makes it more likely for cracks to occur in the protrusion 21. Furthermore, when the height of the shaped body 2 is 10 mm or greater, thermal stress is more likely to occur, which makes it more likely for cracks to occur in the protrusion 21.

[0040] If the support body 3 is simultaneously formed so as to contact the side surface of the protrusion 21, heat is transferred from the support body 3 to the protrusion 21. Because the protrusion 21 is slow to cool, the temperature difference between the portion close to the tip of the protrusion 21 and the portion distant from the tip of the protrusion 21 becomes smaller. By having the support body 3 in contact with the portion close to the tip of the protrusion 21, the difference in the amount of contraction between the portion distant from the tip of the protrusion 21 and the portion close to the tip of the protrusion 21 becomes smaller. Because the support body 3 relieves thermal stress in the protrusion 21, the occurrence of cracks and the like in the protrusion 21 can be reduced.

[0041] Furthermore, since the support 3 is directly bonded to the upper surface 10 of the base material 1, it is easy to reduce the occurrence of lifting of the protrusion 21.

[0042] Examples of the position, width, height and volume of the support body 3 are shown below.

[0043] (Position of Support Body) The position where the support body 3 contacts the side surface of the protrusion 21 is, for example, within 10 mm from the tip of the protrusion 21. In other words, on the side surface 23, the distance in the X direction from the tip of the protrusion 21 to the position where the support body 3 contacts is within 10 mm. The position where the support body 3 contacts is the center position of the width where the support body 3 contacts the side surface of the protrusion 21. The "X direction" is a direction parallel to the upper surface 10 of the substrate 1, and is the direction from the tip of the protrusion 21 toward the center of the side surface 23. The position where the support body 3 contacts may be within 8 mm from the tip of the protrusion 21. Note that if the tip of the protrusion 21 is a curved surface, the intersection of the extension lines of the side surface when calculating the interior angle of the protrusion 21 described above is considered to be the tip.

[0044] The position where the support body 3 contacts may be 2 mm or more away from the tip of the protrusion 21. The position where the support body 3 contacts may be in a range of 2 mm to 10 mm, or even in a range of 3 mm to 8 mm, from the tip of the protrusion 21.

[0045] The closer the contact position of the support body 3 is to the tip of the protrusion 21, the smaller the difference in contraction amount and temperature difference between the portion close to the tip of the protrusion 21 and the portion farther from the tip of the protrusion 21. This makes it easier to alleviate thermal stress in the protrusion 21. If the position of the support body 3 is within 10 mm from the tip of the protrusion 21, it is easier to reduce the occurrence of cracks and the like in the protrusion 21.

[0046] (Width of Support Body) The width of the contact area of ​​the support body 3 with the side surface of the protrusion 21 is, for example, 0.5 mm or more and 2.5 mm or less. The "width" here refers to the dimension in the X direction. The contact area of ​​the support body 3 may be 1 mm or more and 2 mm or less.

[0047] If the contact width of the support body 3 is 0.5 mm or more, the contact area between the support body 3 and the protrusion 21 is large, and heat is easily transferred from the support body 3 to the protrusion 21. Since the protrusion 21 is less likely to cool, the temperature difference between the portion close to the tip of the protrusion 21 and the portion far from the tip of the protrusion 21 is likely to be small. Therefore, the effect of alleviating thermal stress in the protrusion 21 is easily obtained. A support body 3 having such a width is likely to reduce the occurrence of cracks and the like in the protrusion 21. Furthermore, if the contact width of the support body 3 is 2.5 mm or less, the support body 3 is easily removed from the protrusion 21.

[0048] (Height of Support Body) The height of the support body 3 is, for example, 3 mm or more and equal to or less than the height of the shaping body 2. The height of the support body 3 may further be 5 mm or more. The height of the support body 3 may be equal to or less than ½, or even equal to or less than ¼ of the height of the shaping body 2. The height of the support body 3 may be equal to or greater than 3 mm and equal to or less than 15 mm, or even equal to or greater than 5 mm and equal to or less than 10 mm.

[0049] If the height of the support body 3 is 3 mm or more, the contact area between the support body 3 and the protrusion 21 is large, and heat is easily transferred from the support body 3 to the protrusion 21. Since the protrusion 21 is less likely to cool, the temperature difference between the portion close to the tip of the protrusion 21 and the portion far from the tip of the protrusion 21 is likely to be small. Therefore, the effect of alleviating thermal stress in the protrusion 21 is easily obtained. A support body 3 having such a height is likely to reduce the occurrence of cracks and the like in the protrusion 21. If the height of the support body 3 is made too large, not only will the above effect saturate, but the amount of metal powder used as the material will actually increase. From the perspective of reducing the amount of metal powder used, the height of the support body 3 may be 15 mm or less.

[0050] (Volume of Support Body) The volume of the support body 3 is, for example, 10 mm ３ That's all. The volume of the support body 3 is further increased to 20 mm ３ The upper limit of the volume of the support body 3 may be, for example, 200 mm ３ The volume of the support body 3 is 10 mm ３ More than 200 mm ３ Below that, another 20 mm３ More than 100 mm ３ It may be the following:

[0051] The volume of the support body 3 is 10 mm ３ If the volume is more than this, the difference in the amount of contraction and the temperature difference between the portion close to the tip of the protrusion 21 and the portion far from the tip of the protrusion 21 are likely to be small. Therefore, the effect of mitigating thermal stress in the protrusion 21 is likely to be obtained. A support body 3 having such a volume is likely to reduce the occurrence of cracks in the protrusion 21. If the volume of the support body 3 is made too large, not only will the above effect saturate, but the amount of metal powder used as material will increase. From the perspective of reducing the amount of metal powder used, the height of the support body 3 is set to 200 mm. ３ It may be the following:

[0052] (Shape of Support Body) The shape of the support body 3 is not particularly limited, and various shapes are possible. In this example, the shape of the support body 3 is T-shaped in a plan view of the support body 3 viewed from above, as shown in FIGS. 4 and 5 . The T-shaped support body 3 is easy to design so that the width of the support body 3 in contact with the side surface of the protrusion 21 and the volume of the support body 3 satisfy the above-mentioned conditions. The support body 3 in this example has a first portion 3a that contacts the side surface of the protrusion 21 and a second portion 3b formed integrally with the first portion 3a. The second portion 3b is positioned away from the side surface of the protrusion 21. The second portion 3b and the protrusion 21 are connected by the first portion 3a. The second portion 3b in this example is a plate-like portion that is positioned parallel to the side surface of the protrusion 21. In this example, the cross-sectional shape of the support body 3 parallel to the top surface 10 of the substrate 1 is constant in a direction perpendicular to the top surface 10.

[0053] The support body 3 may be tapered as shown in FIG. 6 . In this case, the area of ​​a cross section of the support body 3 parallel to the top surface 10 of the substrate 1 increases toward the substrate 1. That is, the area of ​​the bottom surface 32 of the support body 3 is larger than the area of ​​the top surface of the support body 3. The tapered support body 3 shown in FIG. 6 has a larger volume than the straight support body 3 without a tapered shape, as shown in FIG. 5 , assuming the top surface area of ​​the support body 3 is the same. Furthermore, the tapered support body 3 has a larger bottom surface 32, which increases the bonding area with the top surface 10 of the substrate 1. This makes it easier to reduce the occurrence of cracks in the protrusions 21. The taper angle between the outer peripheral surface of the tapered support body 3 and a line perpendicular to the bottom surface 32 is, for example, 1° or more and 45° or less. The taper angle may further be 2° or more and 30° or less, or 3° or more and 15° or less. The support body 3 shown in FIG. 6 has tapered first and second portions 3a and 3b. That is, the first portion 3a and the second portion 3b are narrower toward the top and wider toward the bottom surface 32. The side surfaces of the first portion 3a are inclined. The end surfaces of the second portion 3b, which are flat, and the side surfaces, which are curved, are also inclined. The taper angle of each inclined surface is 5°.

[0054] Other examples of the shape of the support body 3 are shown in Figures 7 to 9. The support body 3 shown in Figure 7 has a first portion 3a and a second portion 3b, similar to the support body 3 shown in Figure 5. In the support body 3 shown in Figure 7, the second portion 3b has a cylindrical shape. The support body 3 shown in Figure 8 has a trapezoidal shape in a plan view. The support body 3 shown in Figure 8 is arranged so that the shorter of the opposing parallel sides of the trapezoid contacts the side surface of the protrusion 21. The support body 3 shown in Figure 9 has a rectangular shape in a plan view.

[0055] (Step of Removing Support Body) The manufacturing method of a shaped body according to the embodiment may further include a step of removing the support body 3 after forming the shaped body 2 and the support body 3. The support body 3 can be removed by cutting it with a milling cutter, a discharge wire cutter, a laser cutter, or the like. The manufacturing method of a shaped body according to the embodiment may further include a step of removing the shaped body 2 from the substrate 1. The shaped body 2 can be removed from the substrate 1 by cutting it with a milling cutter, a discharge wire cutter, a laser cutter, or the like.

[0056] Test Example 1 A powder bed type metal 3D printer was used to form a shaped body 2, and an evaluation was made to see whether cracks or the like occurred at the corners 21c of the formed shaped body 2.

[0057] In Test Example 1, a substrate 1 made of a general structural rolled steel material was prepared. The substrate 1 had a cylindrical shape. High-speed steel powder was used as the metal powder material. The average particle size of the high-speed steel powder was 40 μm.

[0058] The metal 3D printer used was an OPM350L manufactured by Sodick Co., Ltd. The laser light irradiation conditions were as follows: Output: 400 W, Scanning pitch: 0.1 mm, Scanning speed: 700 mm / s.

[0059] The shape of the shaped body 2 is a regular triangular prism. One side of the equilateral triangle at the base is 40 mm. The height of the shaped body 2 is 20 mm.

[0060] In Test Example 1, Samples No. 1 and No. 2 were manufactured in which the support body 3 was formed simultaneously with the shaped object 2, and Sample No. 10 in which no support body 3 was formed. In Samples No. 1 and No. 2, as shown in FIG. 3 , a total of six support bodies 3 were arranged, two on each side of the corner 21 c.

[0061] (Sample No. 1) The shape of the support body 3 of Sample No. 1 is T-shaped, as shown in Figures 4 and 5. The support body 3 of Sample No. 1 is straight and not tapered. The dimensions of the upper surface of the support body 3 of Sample No. 1 are as follows: Width Wa of the first portion 3a: 1 mm Length La of the first portion 3a: 1 mm Thickness Tb of the second portion 3b: 1 mm Width Wb of the second portion 3b: 4 mm Height of the support body 3: 5 mm Volume of the support body 3: Approximately 24 mm ３

[0062] The support body 3 was positioned such that the distance in the X direction from the tip of the corner 21 c to the center of the width of the first portion 3 a was 3 mm. In other words, the first portion 3 a of the support body 3 was located between 2.5 mm and 3.5 mm from the tip of the corner 21 c in the X direction.

[0063] (Sample No. 2) As shown in FIG. 6, the shape of the support body 3 of Sample No. 2 is T-shaped. The support body 3 of Sample No. 2 differs from the support body 3 of Sample No. 1 in that it is tapered. The taper angle is 5°. The volume of this support body 3 is approximately 34 mm ３ is.

[0064] For Sample No. 1 and Sample No. 2 in which the support body 3 was formed, after the shaped body 2 and the support body 3 were formed, the support body 3 was cut and removed.

[0065] Each sample was visually inspected to determine whether cracks or the like had occurred at the corners 21c of the shaped body 2. In sample No. 10, which did not have a support body 3, cracks were found to have occurred at the corners 21c. In contrast, in samples No. 1 and No. 2, which did have a support body 3, no cracks or the like were found to have occurred at the corners 21c. In sample No. 10, the crack that had occurred at the corners 21c was located approximately 4 mm from the tip of the corners 21c.

[0066] Test Example 2 For each sample in Test Example 1, thermal stress analysis was performed on the corner 21c during the formation of the molded body 2. Commercially available finite element analysis software was used for the thermal stress analysis. Figure 10 shows an enlarged view of the stress distribution at the corner 21c of Sample No. 10. In Figure 10, base point A is the position of the tip of the corner 21c. Similar to Figure 2, Figure 10 also shows an enlarged view of the lower right corner 21c when one side surface 23 of the molded body 2, which is a regular triangular prism, is viewed from the front. In Figure 10, arrow X represents the X direction from the tip of the corner 21c toward the center of the side surface, and arrow Z represents the Z direction from the bottom surface 22 of the molded body 2 toward the top surface of the molded body 2. Figure 10 shows that thermal stress is small near base point A and increases with increasing distance from base point A. Point O in Figure 10 is located 4 mm from base point A in the X direction, and the thermal stress at this position is approximately 3 × 10 ５ MPa.

[0067] 11 to 13 show the relationship between the distance from the tip of the corner 21c and the stress for each sample. Fig. 11 is a graph for sample No. 10. Fig. 12 is a graph for sample No. 1. Fig. 13 is a graph for sample No. 2. In each figure, the horizontal axis represents the distance in the X direction from the tip of the corner 21c. The vertical axis represents the thermal stress.

[0068] In sample No. 10, as shown in Figure 11, the stress increases between the distances of 3 mm and 5 mm. The stress difference between the distances of 3 mm and 5 mm is approximately 4 x 10 ５ In sample No. 10, the difference in stress was large between the distances of 3 mm and 5 mm, which is presumably why cracks occurred.

[0069] In contrast, in sample No. 1, as shown in Figure 12, the stress increases sharply between the distances of 2 mm and 2.5 mm, and the change in stress becomes more gradual between the distances of 2.5 mm and 5 mm. The stress difference between the distances of 2.5 mm and 5 mm is approximately 2 x 10 ５MPa. In sample No. 2, as shown in Figure 13, the stress increases sharply between the distances of 1.5 mm and 2 mm, and the change in stress becomes more gradual between the distances of 2 mm and 5 mm. The stress difference between the distances of 2 mm and 5 mm is approximately 2 x 10 ５ MPa. In Sample No. 1 and Sample No. 2, stress was alleviated between 3 mm and 5 mm, which is presumably why the occurrence of cracks and the like was reduced. This is thought to be because the provision of support body 3 acted to shift the position where the amount of change in stress per unit length was large toward the tip between 3 mm and 5 mm from the tip of corner 21c. This shift in the position where the amount of change in stress was large reduces the volume of the region from that position to the tip. This reduction in the volume of the tip region is thought to reduce the amount of contraction in the tip region and also reduce the tensile stress between the tip region and regions other than the tip region.

[0070] REFERENCE SIGNS LIST 1 base material 10 upper surface 2 shaped body 21 protrusion 21c corner 22 bottom surface 23 side surface 3 support body 3a first portion 3b second portion 32 bottom surface A base point Wa width La length Tb thickness Wb width

Claims

1. providing a substrate; disposing a metal powder in a layer on an upper surface of the substrate to form a powder layer; and forming a solidified layer in which the metal powder is bonded by irradiating a predetermined portion of the powder layer with laser light, by repeating the step of forming the powder layer and the step of forming the solidified layer, a shaped body in which the solidified layer is stacked on the base material, and a support body juxtaposed to the shaped body are formed; the shaped body has at least one protrusion that protrudes in a direction parallel to the upper surface of the base material; The interior angle of the protrusion is less than 90°; the support body is in contact with a side surface of the protrusion, The position where the support body contacts the side surface of the protrusion is within 10 mm from the tip of the protrusion. A method for manufacturing a shaped object.

2. The volume of the support body is 10 mm ３ The method for producing a shaped body according to claim 1 , wherein the method is as described above.

3. The method for manufacturing a shaped body according to claim 1 or 2, wherein a width of the support body in contact with the side surface of the protrusion is 0.5 mm or more and 2.5 mm or less.

4. The method for manufacturing a shaped body according to claim 1 or 2, wherein the height of the support body is 3 mm or more and is equal to or less than the height of the shaped body.

5. The method for manufacturing a shaped body according to claim 1 or 2, wherein an area of ​​a cross section of the support body parallel to an upper surface of the base material increases toward the base material.

6. The method for manufacturing a shaped body according to claim 1 or 2, wherein the metal powder is made of high-speed steel.