Welding joint of metal additive manufacturing members and joint method of the same

Abstract

To provide a welding joint which enables easy aligning and positioning of metal additive manufacturing members formed by metal additive manufacturing and also enables improvement of its strength in a bending direction by shortening a welding length.SOLUTION: A welding joint 10 is a joint comprising metal additive manufacturing members 20, 30 formed by metal additive manufacturing. The metal additive manufacturing members 20, 30 include: a first metal additive manufacturing member 20; and a second metal additive manufacturing member 30 to be butted with the first metal additive manufacturing member 20. The second metal additive manufacturing member 30 is butted with the first metal additive manufacturing member 20 to restrain a degree of freedom in three directions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a welded joint of a metal additive manufacturing component produced by metal additive manufacturing. [Background technology]

[0002] Laser welding is a method of joining metals by focusing laser light with a lens and locally irradiating it with the metal, causing it to melt and solidify. Compared to conventional arc welding, this technology allows for high-speed welding with little thermal distortion because the energy density at the irradiated area is much higher.

[0003] High-energy density welding methods, such as laser welding and electron beam welding, can realize joint shapes that are difficult to achieve with conventional arc welding. Examples include the I-shaped butt joint shown in Figure 9(F), which does not use any welding material, and the lap penetration welded joints shown in Figures 9(G) and (H). Compared to the typical arc-welded joints shown in Figures 9(C), (D), and (E), these joints offer many advantages, including reduced material costs, weight reduction, suppression of deformation and distortion, and reduced labor.

[0004] Recently, metal additive manufacturing (MA) components have been used to weld metal additive manufacturing (MA) components. Metal additive manufacturing (MA) devices can manufacture complex shapes in a relatively short time that are difficult to manufacture using conventional manufacturing processes. MA components are widely used, particularly for short-term prototypes and the manufacture of high-value-added parts. Because the manufacturing size of a metal additive manufacturing (MA) component is limited by the device, when a component larger than the device's specified size is required, the manufactured component must be welded. Furthermore, because metal additive manufacturing (MA) components have a unique structure and surface irregularities that are formed during the process, welding can require ingenuity. The welded joint described in Patent Document 1 is known as a technology for welding such metal additive manufacturing (MA) components.

[0005] The welded joint of Patent Document 1 is a metal additive manufacturing (AM) member formed by stacking weld beads, and has multiple rod-shaped portions formed to protrude in the joining direction. The rod-shaped portions are butted together, and adjacent joint portions are welded along the longitudinal direction. Specifically, as shown in Figure 9(A), the welded joint 100 of Patent Document 1 includes multiple rod-shaped portions 103 in a first member 101 and multiple rod-shaped portions 104 in a second member 102. During welding, the multiple rod-shaped portions 103 and the multiple rod-shaped portions 104 are butted together so as to interlock with each other, as shown in Figure 9(B).

[0006] However, in the metal additive manufacturing component of Patent Document 1, the rod-shaped sections are butted together so that they interlock with each other, which causes the weld line to move back and forth in a wavy pattern, making the weld length longer and requiring a large amount of welding material depending on the weld length. Since the joint requires that the many rod-shaped sections be butted together so that they all interlock at once, alignment is difficult. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-76912 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above, the present invention aims to provide a welded joint that can easily align and position metal additive manufacturing components, shorten the weld length, and join without the need for welding material. [Means for solving the problem]

[0009] [1] A welded joint of a metal additive manufacturing component by metal additive manufacturing, the metal additive manufacturing member includes a first metal additive manufacturing member and a second metal additive manufacturing member abutted against the first metal additive manufacturing member; The method is characterized in that the degrees of freedom in three directions are constrained by butting the second metal additive manufacturing member against the first metal additive manufacturing member.

[0010] With this configuration, the weld joint of the metal additive manufacturing member can be easily aligned and positioned because the degrees of freedom in three directions are constrained by butting the second metal additive manufacturing member against the first metal additive manufacturing member.

[0011] [2] Preferably, the first metal additive manufacturing member comprises a first main body portion serving as a main body, a first abutment end portion provided on the first main body portion and abutting against the second metal additive manufacturing member, a first direction restricting protrusion provided on the first abutment end portion and protruding in the abutment direction, and a second direction restricting protrusion provided on the first direction restricting protrusion portion or the first abutment end portion and protruding in a direction intersecting the abutment direction, The second metal additive manufacturing member is characterized by comprising a second main body portion that forms the main body, a second abutment end portion provided on the second main body portion that abuts against the first metal additive manufacturing member, a first direction restriction receiving portion provided on the second abutment end portion that is recessed along the abutment direction and into which the first direction restriction protrusion fits, and a second direction restriction receiving portion provided on the first direction restriction receiving portion or the second abutment end portion that is recessed in a direction intersecting the abutment direction and into which the second direction restriction protrusion fits.

[0012] According to this configuration, the first metal additive manufacturing member includes a main body portion, a first abutment end portion, a first direction restricting protrusion portion, and a second direction restricting protrusion portion, and the second metal additive manufacturing member includes a second main body portion, a second abutment end portion, a first direction restricting receiving portion, and a second direction restricting receiving portion. Simply by fitting the first direction restricting protrusion portion protruding in the butt direction into the first direction restricting receiving portion and the second direction restricting protrusion portion protruding in a direction intersecting the butt direction into the second direction restricting receiving portion, and then abutting the first abutment end portion against the second metal additive manufacturing member, alignment and positioning can be easily achieved while restricting the degrees of freedom in three directions. Because the shape of the butt portion of the welded joint is simple, requiring only two recesses and protrusions to fit together, the weld length can be shortened.

[0013] Furthermore, in the embodiments of the present invention, additive manufacturing is performed using a 3D printer that can freely create shapes, so even for metal components, the design freedom can be utilized to create a shape where the butt joints between metal additive manufacturing components are joined, combining concave and convex shapes like wood joints, and the overlapping parts can be fully welded using laser welding or electron beam welding, thereby improving the efficiency of the welding process. Furthermore, the relative positions of the metal additive manufacturing components are determined simply by butting them together, and they can be joined using a single-pass full-penetration welding along the shortest path, reducing the welding man-hours and enabling high-speed, low-heat-input joining with minimal deformation.

[0014] [3] Preferably, the first metal additive manufacturing member and the second metal additive manufacturing member have a tubular shape; The first direction restricting protrusion is formed in an annular shape, and the first direction restricting receiving portion is an annular groove.

[0015] According to this configuration, the first metal additive manufacturing member and the second metal additive manufacturing member are tubular. The annular first direction restricting protrusion is simply fitted into the annular groove of the first direction restricting receiving portion, allowing for easy alignment and positioning. Because the first direction restricting protrusion and the first direction restricting receiving portion are annular, fitting them together allows for easy alignment and positioning while restricting the degrees of freedom in three directions.

[0016] [4] Preferably, the first metal additive manufacturing member and the second metal additive manufacturing member have a tubular shape; The first direction restricting protrusion is formed in an annular shape and is tapered so that its diameter decreases in the butting direction, and the first direction restricting receiving portion is formed in an annular shape and is tapered so that its diameter increases in the butting direction.

[0017] With this configuration, the first metal additive manufacturing member and the second metal additive manufacturing member are tubular, the first direction restricting protruding portion is annular and tapered so that its diameter decreases in the direction of joining, and the first direction restricting receiving portion is annular and tapered so that its diameter increases in the direction of joining, so the tapered portions act as guides, making alignment and positioning easier. Because the first direction restricting protruding portion and the first direction restricting receiving portion are annular, fitting them together makes alignment and positioning easier while restricting the degrees of freedom in three directions.

[0018] [5] Preferably, the first metal additive manufacturing member and the second metal additive manufacturing member have a plate shape, The first direction restricting protrusion is formed linearly, and the first direction restricting receiving portion is a linear groove.

[0019] According to this configuration, the first metal additive manufacturing member and the second metal additive manufacturing member are plate-shaped. The linearly formed first direction restricting protrusion simply fits into the linearly formed first direction restricting receiving portion, which is a groove, and therefore alignment and positioning can be easily achieved. Because the first direction restricting protrusion and the first direction restricting receiving portion are linear, fitting them together allows for easy alignment and positioning while restricting the degrees of freedom in three directions.

[0020] [6] Preferably, the first metal additive manufacturing member and the second metal additive manufacturing member have a plate shape, The first direction restriction protrusion is a step formed in a straight line, and the first direction restriction receiving portion is a step formed in a straight line.

[0021] According to this configuration, the first metal additive manufacturing member and the second metal additive manufacturing member are plate-shaped. The first direction restricting protrusion formed on the linear step simply fits into the first direction restricting receiving portion also formed on the linear step, allowing for easy alignment and positioning. Because the first direction restricting protrusion and the first direction restricting receiving portion are linear, fitting them together allows for easy alignment and positioning while restricting the degrees of freedom in three directions.

[0022] [7] Preferably, the weld joint between the first metal additive manufacturing member and the second metal additive manufacturing member is joined by full penetration welding.

[0023] According to this configuration, the weld joint between the first metal additive manufacturing member and the second metal additive manufacturing member is joined by full penetration welding, thereby increasing the strength of the welded portion. Because the weld joint has a simple shape, the weld length can be shortened. Furthermore, because full penetration welding such as laser welding is used, no welding material is required. Thus, this embodiment of the present invention is a joint using full penetration welding that combines the advantages of laser welding, which has low heat input and deep penetration, with the advantages of metal additive manufacturing, which allows for freedom in shape. [Effects of the Invention]

[0024] Metal additive manufacturing components can be easily aligned and positioned using metal additive manufacturing, the weld length can be shortened, and a welded joint can be provided that does not require welding material. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a perspective view of a tubular metal additive manufacturing member according to an embodiment of the present invention. [Figure 2] Fig. 2(A) is a perspective view of a state in which the weld joints of tubular metal additive manufacturing members are butted together, and Fig. 2(B) is a perspective view of a state in which the weld joints of tubular metal additive manufacturing members are welded. [Figure 3] Fig. 3(A) is a side view of the welded joint of the example before butt welding. Fig. 3(B) is a side view of the welded joint of the example after butt welding. Fig. 3(C) is a side view of the welded joint of the example after welding. Fig. 3(D) is a side view of the welded joint of the comparative example after welding. [Figure 4] FIG. 10 is a perspective view of a tubular metal additive manufacturing member of another aspect according to the embodiment. [Figure 5]Fig. 5(A) is a side view of a welded joint of another embodiment before butt welding, Fig. 5(B) is a side view of a welded joint of another embodiment after butt welding, and Fig. 5(C) is a side view of a welded joint of another embodiment after welding. [Figure 6] FIG. 1 is a perspective view of a plate-shaped metal additive manufacturing member according to an embodiment. [Figure 7] Fig. 7(A) is a side view of the plate-shaped weld joint of the embodiment in a butt-jointed state, Fig. 7(B) is a plan view of the plate-shaped weld joint of the embodiment in a welded state, and Fig. 7(C) is a side view of the plate-shaped weld joint of the embodiment in a welded state. [Figure 8] Fig. 8(A) is a perspective view of another embodiment of a plate-shaped weld joint before butt welding, Fig. 8(B) is a plan view of another embodiment of a plate-shaped weld joint after butt welding, Fig. 8(C) is a side view of another embodiment of a plate-shaped weld joint after butt welding, and Fig. 8(D) is a plan view of another embodiment of a plate-shaped weld joint after welding. [Figure 9] FIG. 9(A) is a perspective view of a prior art welded joint before butt welding. FIG. 9(B) is a perspective view of a prior art welded joint after butt welding. FIG. 9(C) is a perspective view of a prior art butt welded joint. FIG. 9(D) is a perspective view of a prior art T-welded joint. FIG. 9(E) is a perspective view of a prior art lap welded joint. FIG. 9(F) is a side view of a laser welded butt welded joint. FIG. 9(G) is a side view of a laser welded T-welded full penetration welded joint. FIG. 9(H) is a side view of a laser welded lap penetration welded joint. DETAILED DESCRIPTION OF THE INVENTION

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. [Example]

[0027] 1 and 2, a welded joint 10 according to an embodiment of the present invention is a joint between metal additive manufacturing members 20 and 30 manufactured by metal additive manufacturing. The metal additive manufacturing members 20 and 30 are members manufactured by metal additive manufacturing.

[0028] Methods for manufacturing metal additive manufacturing members 20, 30 using additive manufacturing devices generally include the powder head method, in which metal powder is spread out and irradiated with a laser or electron beam on the area to be shaped, melting and solidifying it to form the layer; the deposition method, in which material powder such as metal and a laser or electron beam are simultaneously irradiated on the area to be shaped, melting and forming it to form the layer; and the binder jetting method, in which a binder made of a liquid binding agent is sprayed onto metal powder, etc., to selectively form the material.

[0029] In the examples, metal additive manufacturing components 20 and 30 are used, which are additively manufactured using the powder head method, but this is not limited to this, and any type of metal additive manufacturing component can be used, such as the deposition method, binder jetting method, or even additively manufactured.

[0030] Furthermore, in the additive manufacturing of the examples, titanium alloy is manufactured using an electron beam metal additive manufacturing device, but this is not limited to this, and other metal materials may be used, such as maraging steel, nickel alloy, iron, etc. Currently, the largest manufacturing area using additive manufacturing devices is 2500 mm x 900 mm x 1000 mm, but the welded joint of the present invention can be applied regardless of the size.

[0031] Next, the weld joint 10 of the metal additive manufacturing members 20, 30 will be described. The metal additive manufacturing members 20, 30 that make up the weld joint 10 have a first metal additive manufacturing member 20 and a second metal additive manufacturing member 30 that is butted against the first metal additive manufacturing member 20, and the degrees of freedom in three directions are restricted by butting the second metal additive manufacturing member 30 against the first metal additive manufacturing member 20. The first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 are tubular in shape.

[0032] The first metal additive manufacturing member 20 comprises a first main body portion 21 that forms the main body, a first abutment end portion 24 that is provided on the first main body portion 21 and abuts against the second metal additive manufacturing member 30, a first direction restricting protrusion 22 that is provided on the first abutment end portion 24 and protrudes in the abutment direction, and a second direction restricting protrusion 23 that is provided on the first direction restricting protrusion 22 or the first abutment end portion 24 and protrudes in a direction intersecting (orthogonal to) the abutment direction. Lamination marks 27 due to additive manufacturing are formed on an inner surface 25 and an outer surface 26 of the first main body portion 21.

[0033] The second metal additive manufacturing member 30 comprises a second main body portion 31 that forms the main body, a second abutment end portion 34 that is provided on the second main body portion 31 and abuts against the first metal additive manufacturing member 20, a first direction restriction receiving portion 32 that is provided on the second abutment end portion 34 and into which the recessed first direction restriction protrusion 22 fits along the abutment direction, and a second direction restriction receiving portion 33 that is provided on the first direction restriction receiving portion 32 or the second abutment end portion 34 and into which the recessed second direction restriction protrusion 23 fits in a direction intersecting (orthogonal to) the abutment direction. Lamination marks 37 due to additive manufacturing are formed on an inner surface 35 and an outer surface 36 of the second main body portion 31.

[0034] The first direction restricting protrusion 22 is formed in an annular shape, and the first direction restricting receiving portion 32 is an annular groove. The second direction restricting protrusion 23 is formed on both sides of the first direction restricting protrusion 22. The second direction restricting receiving portions 33 are formed in a notched shape connected to both sides of the groove of the first direction restricting receiving portion 32.

[0035] Next, the function of the welded joint 10 will be described. 3(A) is a side view of the welded joint 10 of the embodiment before butting, in which the thickness of the first metal additive manufacturing member 20 and the second metal additive manufacturing member is L1. The protrusion height of the first direction restricting protrusion 22 of the first metal additive manufacturing member 20 is L2, and the recess depth of the first direction restricting receiving portion 32 of the second metal additive manufacturing member 30 is L2 or greater.

[0036] 3(B) is a side view of the welded joint 10 of the embodiment in a butted state, with the first direction restricting protrusion 22 fitted into the first direction restricting receiving portion 32 and the first abutting end portion 24 abutting against the second abutting end portion 34. At this time, the second direction restricting protrusion 23 (see FIG. 2) is fitted into the second direction restricting receiving portion 33. In this state, the welded joint 10 is welded by irradiating it with a laser beam over a width greater than width L2. The laser irradiation at this time may be a wobbling motion.

[0037] 3(C) is a side view of the welded joint 10 of the embodiment, in which the width of the weld 11 is L3, and because the weld width L3 is greater than the protrusion height L2 of the first direction restricting protrusion 22, the entire weld joint 10 is welded, resulting in a good weld condition. In this way, the method of joining metal additive manufacturing members 20, 30 of the embodiment joins the weld joint 10 made of the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 by full penetration welding.

[0038] Figure 3(D) is a side view of the welded joint 10 of the comparative example. If the weld width L3 is smaller than the protrusion height L4 of the first direction restricting protrusion 22, there will be an unwelded area between the first direction restricting protrusion 22 and the first direction restricting receiving portion 32, and the weld will not be in good condition.

[0039] Next, weld joints 10 of tubular metal additive manufacturing members 20, 30 of another embodiment will be described. 4, the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 are tubular. The first direction restricting protrusion 22 is formed in an annular shape and is tapered so that its diameter decreases in the butting direction, while the first direction restricting receiving portion 32 is formed in an annular shape and is tapered so that its diameter increases in the butting direction.

[0040] The second direction restricting protrusion 23 of the first metal additive manufacturing member 20 is formed to protrude from the inclined surface of the tapered first direction restricting protrusion 22 in a direction perpendicular to the axis of the first metal additive manufacturing member 20. The second direction restricting receiving portion 33 of the second metal additive manufacturing member 30 is formed to be recessed from the inclined surface of the tapered first direction restricting receiving portion 32 in a direction perpendicular to the axis of the second metal additive manufacturing member 30.

[0041] Next, the function of the weld joint 10 of the alternative tubular metal additive manufacturing members 20, 30 will be described. Figure 5(A) is a side view of another embodiment of the welded joint 10 before butting, in which the protrusion height of the first direction restricting protrusion 22 of the first metal additive manufacturing member 20 and the depth of the recess of the first direction restricting receiving portion 32 of the second metal additive manufacturing member 30 are L5.

[0042] 5(B) is a side view of another embodiment of the welded joint 10 in a butt-jointed state, with the first direction restricting protrusion 22 abutting (fitting) with the first direction restricting receiving portion 32, and the first abutting end portion 24 abutting with the second abutting end portion 34. At this time, the second direction restricting protrusion 23 (see FIG. 4) is fitted into the second direction restricting receiving portion 33. In this state, the welded joint 10 is welded by irradiating it with a laser beam over a width greater than width L5. The laser irradiation at this time may be a wobbling motion.

[0043] Figure 5(C) is a side view of a different type of welded joint 10 after welding. The width of the welded portion 11 is L6, and since the weld width L6 is greater than the protrusion height L5 of the first direction restricting protrusion 22, the entire welded joint 10 is welded, resulting in a good weld condition.

[0044] Next, the weld joint 10 of the plate-shaped metal additive manufacturing members 20, 30 according to the embodiment will be described. 6, the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 are plate-shaped. The first direction restricting protrusion 22 is formed linearly, and the first direction restricting receiving portion 32 is a linear groove.

[0045] The second direction restricting protrusion 23 of the first metal additive manufacturing member 20 is formed to protrude perpendicularly from the side surface of the linearly formed first direction restricting protrusion 22. The second direction restricting receiving portion 33 of the second metal additive manufacturing member 30 is formed as a notch recessed perpendicularly from the side surface of the groove of the linearly formed first direction restricting receiving portion 32.

[0046] Next, the function of the welded joint 10 of the plate-shaped metal additive manufacturing members 20, 30 according to the embodiment will be described. 7(A) is a side view of the plate-shaped welded joint 10 of the embodiment when butted together, with the first direction restricting protrusion 22 fitted into the first direction restricting receiving portion 32 and the first abutting end portion 24 abutting against the second abutting end portion 34. At this time, the second direction restricting protrusion 23 (see FIG. 6) is fitted into the second direction restricting receiving portion 33. In this state, the welded joint 10 is welded by irradiating it with a laser over a width greater than the protruding height of the first direction restricting protrusion 22 (the width of the welded joint 10).

[0047] 7(B) is a plan view of the plate-shaped welded joint 10 of the embodiment after welding, with the weld 11 formed in a straight line. Therefore, unlike the prior art, the weld length does not become long, and in the embodiment, no welding material is required, making it possible to minimize the weld length.

[0048] Figure 7(C) is a side view of the plate-shaped weld joint 10 of the embodiment after welding, in which the welded portion 11 is formed from the outer surfaces 26, 36 of the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 to the inner surfaces 25, 35.

[0049] Next, a welded joint 10 of plate-shaped metal additive manufacturing members 20, 30 according to another embodiment will be described. 8(A) is a perspective view of another embodiment of a plate-shaped welded joint 10 before butting, in which the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 are plate-shaped. The first direction restricting protrusion 22 is a linearly formed step, and the first direction restricting receiving portion 32 is a linearly formed step.

[0050] The second direction restricting protrusion 23 of the first metal additive manufacturing member 20 is formed to protrude perpendicularly from the side surface of the step of the linearly formed first direction restricting protrusion 22. The second direction restricting receiving portion 33 of the second metal additive manufacturing member 30 is formed as a notch recessed perpendicularly from the side surface of the step of the linearly formed first direction restricting receiving portion 32.

[0051] Next, the function of the welded joint 10 of the plate-shaped metal additive manufacturing members 20, 30 according to another embodiment will be described. 8(B) is a plan view of another embodiment of plate-shaped welded joints 10 in a butt-jointed state, in which the first abutting end portion 24 abuts against the second abutting end portion 34. The second direction restricting protrusion 23 is fitted into the second direction restricting receiving portion 33.

[0052] 8(C) is a side view of another embodiment of plate-shaped welded joints 10 butted together, with the step of the first direction restricting protrusion 22 fitted into (in contact with) the step of the first direction restricting receiving portion 32. In this state, the welded joint 10 is welded by irradiating it with a laser beam over a width greater than the protrusion height of the first direction restricting protrusion 22 (the width of the welded joint 10).

[0053] 8(D) is a plan view of another embodiment of a plate-shaped welded joint 10 after welding, in which the weld 11 is formed in a straight line. This prevents the weld length from becoming long as in the prior art, and in this embodiment, no welding material is required, making it possible to minimize the weld length.

[0054] Next, the function and effect of the above-described welded joint 10 will be described. In an embodiment of the present invention, the weld joint 10 between the metal additive manufacturing members 20, 30 can be easily aligned and positioned because the degrees of freedom in three directions are constrained by butting the second metal additive manufacturing member 30 against the first metal additive manufacturing member 20. Furthermore, the weld joint 10, whose degrees of freedom in three directions are constrained, can increase the strength in the bending direction.

[0055] Furthermore, the first metal additive manufacturing member 20 includes a main body 21, a first abutment end portion 24, a first direction restricting protrusion 22, and a second direction restricting protrusion 23, and the second metal additive manufacturing member 30 includes a second main body 31, a second abutment end portion 34, a first direction restricting receiving portion 32, and a second direction restricting receiving portion 33. Simply by fitting the first direction restricting protrusion 22, which protrudes in the butt direction, into the first direction restricting receiving portion 32, and the second direction restricting protrusion 23, which protrudes in a direction intersecting the butt direction, into the second direction restricting receiving portion 33, and abutting the first abutment end portion 24 against the second metal additive manufacturing member 30, alignment and positioning can be easily achieved while restricting the degrees of freedom in three directions. Because the shape of the butt portion of the welded joint 10 is simple, requiring only two recesses and protrusions to fit together, the weld length can be shortened. The welded joint 10, in which the degrees of freedom in three directions are constrained, can increase the strength in the bending direction.

[0056] In an embodiment of the present invention, additive manufacturing is performed using a 3D printer that can freely form shapes, so even for metal members, the design freedom can be utilized to form the butt joints when joining the metal additive manufacturing members 20, 30 with a shape that combines recesses and protrusions like wood joints, and the overlapping portions can be fully welded using laser welding or electron beam welding, thereby improving the efficiency of the welding process. Furthermore, the relative positions of the metal additive manufacturing members 20, 30 are determined simply by butting them together, and they are joined using a so-called one-pass full-penetration welding along the shortest path, reducing the welding man-hours and enabling high-speed, low-heat-input joining with minimal deformation.

[0057] Furthermore, the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 are tubular. They can be easily aligned and positioned by simply fitting the annular first direction restricting protrusion 22 into the annular groove of the first direction restricting receiving portion 32. Because the first direction restricting protrusion 22 and the first direction restricting receiving portion 32 are annular, fitting them together allows them to be easily aligned and positioned while restricting the degrees of freedom in three directions, thereby increasing the bending strength of the weld joint 10.

[0058] Furthermore, the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 are tubular, the first direction restricting protrusion 22 is annular and tapered so that its diameter decreases in the butt-joint direction, and the first direction restricting receiving portion 32 is annular and tapered so that its diameter increases in the butt-joint direction, so that the tapered portions act as guides and allow for easier alignment and positioning. Because the first direction restricting protrusion 22 and the first direction restricting receiving portion 32 are annular, fitting them together allows for easy alignment and positioning while restricting the degrees of freedom in three directions, and the bending strength of the weld joint 10 can be increased.

[0059] Furthermore, the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 are plate-shaped. They can be easily aligned and positioned by simply fitting the linearly formed first direction restricting protrusion 22 into the linearly formed first direction restricting receiving portion 32, which is a groove. Because the first direction restricting protrusion 22 and the first direction restricting receiving portion 32 are linear, by fitting them together they can be easily aligned and positioned while restricting the degrees of freedom in three directions, and the strength of the weld joint 10 in the bending direction can be increased.

[0060] Furthermore, the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 are plate-shaped. They can be easily aligned and positioned by simply fitting (abutting) the first direction restricting protrusion 22 formed on the linear step into the first direction restricting receiving portion 32 formed on the linear step. Because the first direction restricting protrusion 22 and the first direction restricting receiving portion 32 are linear, by fitting them together they can be easily aligned and positioned while restricting the degrees of freedom in three directions, and the strength of the weld joint 10 in the bending direction can be increased.

[0061] Furthermore, the weld joint 10 between the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 is joined by full penetration welding, which increases the strength of the welded portion. Because the weld joint 10 has a simple shape, the weld length can be shortened. Furthermore, because full penetration welding such as laser welding is used, no welding material is required. Thus, this embodiment of the present invention is a joint using full penetration welding that combines the advantages of laser welding, which has low heat input and deep penetration, with the advantages of metal additive manufacturing, which allows for freedom in shape.

[0062] In the embodiment, the second direction restricting protrusion 23 protrudes in a direction perpendicular to the first direction restricting protrusion 22, but this is not limited to this, and the protrusion direction may be any direction, such as 45 degrees, 60 degrees, or 75 degrees, as long as the second direction restricting protrusion 23 is formed in a direction intersecting the extension direction of the first direction restricting protrusion 22 and can restrict movement in the second direction. Similarly, the recess direction of the second direction restricting receiving portion 33 relative to the first direction restricting receiving portion 32 is not limited to the perpendicular direction, and may be any direction, such as 45 degrees, 60 degrees, or 75 degrees.

[0063] In addition, in the embodiment, the welding is performed by laser welding, but this is not limitative and an electron beam may be used, or any method may be used as long as it is full penetration welding.

[0064] In addition, in the examples, the shapes of the first metal additive manufacturing member 20 and the second metal additive manufacturing member 30 are cylindrical tubular or plate-shaped, but this is not limited to this and they may also be curved or tubular with a polygonal cross section, and the shape of the members is not important as long as they can be fully welded.

[0065] That is, the present invention is not limited to the examples as long as the functions and effects of the present invention are exhibited. [Industrial Applicability]

[0066] The technology of the present invention is suitable for welded joints of metal additive manufacturing components produced by metal additive manufacturing. [Explanation of symbols]

[0067] 10... Welded joint 11... Welded section (weld bead) 20... First metal additive manufacturing member 21... First main body 22... First direction regulation protrusion 23…Second direction regulation protrusion 24... First abutment end 30... Second metal additive manufacturing member 31... Second main body 32... First direction restriction receiving part 33... Second direction restriction receiving part 34... Second abutment end

Claims

1. A welded joint of a metal additive manufacturing member produced by metal additive manufacturing, The metal additive manufacturing member includes a first metal additive manufacturing member and a second metal additive manufacturing member abutted against the first metal additive manufacturing member, A welded joint of a metal additive manufacturing member, characterized in that the degrees of freedom in three directions are restricted by butting the second metal additive manufacturing member against the first metal additive manufacturing member.

2. The welded joint of the metal additive manufacturing member according to claim 1, The first metal additive manufacturing member includes a first main body portion that serves as a main body, a first abutment end portion provided on the first main body portion and abutting the second metal additive manufacturing member, a first direction restricting protrusion portion provided on the first abutment end portion and protruding in a butt direction, and a second direction restricting protrusion portion provided on the first direction restricting protrusion portion or the first abutment end portion and protruding in a direction intersecting the butt direction, The second metal additive manufacturing member is characterized in that it comprises a second main body portion that forms the main body, a second abutment end portion provided on the second main body portion and abutting the first metal additive manufacturing member, a first direction restriction receiving portion provided on the second abutment end portion that is recessed along the butt direction and into which the first direction restricting protrusion fits, and a second direction restriction receiving portion provided on the first direction restriction receiving portion or the second abutment end portion that is recessed in a direction intersecting the butt direction and into which the second direction restricting protrusion fits.

3. The welded joint of the metal additive manufacturing member according to claim 2, the first metal additive manufacturing member and the second metal additive manufacturing member are tubular; A welded joint of a metal additive manufacturing component, characterized in that the first direction restricting protrusion portion is formed in a ring shape, and the first direction restricting receiving portion is an annular groove.

4. The welded joint of the metal additive manufacturing member according to claim 2, the first metal additive manufacturing member and the second metal additive manufacturing member are tubular; A welded joint of a metal additive manufacturing component, characterized in that the first direction restricting protrusion portion is formed in an annular shape and has a taper that reduces in diameter toward the butt direction, and the first direction restricting receiving portion is formed in an annular shape and has a taper that increases in diameter toward the butt direction.

5. The welded joint of the metal additive manufacturing member according to claim 2, The first metal additive manufacturing member and the second metal additive manufacturing member have a plate shape, A welded joint of a metal additive manufacturing component, characterized in that the first direction restricting protrusion portion is formed in a straight line, and the first direction restricting receiving portion is a straight line groove.

6. The welded joint of the metal additive manufacturing member according to claim 2, The first metal additive manufacturing member and the second metal additive manufacturing member have a plate shape, A welded joint of a metal additive manufacturing component, characterized in that the first direction restricting protrusion portion is a step formed in a straight line, and the first direction restricting receiving portion is a step formed in a straight line.

7. The method for joining a metal additive manufacturing member according to claim 1 or 2, A method for joining metal additive manufacturing members, characterized in that the weld joint between the first metal additive manufacturing member and the second metal additive manufacturing member is joined by full penetration welding.

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