Manufacturing method of molded object and stacking planning method

Abstract

To provide a method for manufacturing a molded article which enables the manufacture of a molded article the base material of which keeps a pipe bonded with a sufficient bond strength, and a lamination planning method.SOLUTION: A method for manufacturing a molded article for molding a cylindrical pipe 55 on a peripheral surface 53 of cross-sectional arc shape of a base material 51 having the peripheral surface 53 includes: a first path molding step for laminating weld beads B1 along a first path P1 of closed curve shape along the surface shape of the peripheral surface 53 of the base material 51; a second path molding step for laminating weld beads B2 along a second path P2 of closed curve shape parallel to the vertical cross section of the pipe 55; and a difference path molding step for laminating weld beads B3, with respect to an area surrounded with the first path P1 and the second path P2, along a difference path P3 of closed curve shape parallel to the first path P1 or the second path P2. In the difference path molding step, start and end edges B3e of the weld beads B3 along the difference path P3 are arranged at positions separated from the peripheral surface 53 of the base material 51.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a shaped object and a stacking planning method. [Background technology]

[0002] In recent years, there has been a growing need for 3D printers as a means of production, and research and development is being conducted in the aircraft industry, etc., with a view to practical application of 3D printers to metal materials in particular. 3D printers that use metal materials use a heat source such as a laser or arc to melt metal powder or metal wire, and then layer the molten metal to create a model.

[0003] Patent Document 1 discloses a manufacturing method in which a joint is formed by stacking beads of melted and solidified filler metal on the circumferential surface of a first pipe, and then the end face of a second pipe is butted against the end face of this joint and joined by welding. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-130574 Summary of the Invention [Problem to be solved by the invention]

[0005] In the joining structure in which pipes are joined by additive manufacturing a joint as described above, if the start and end points of the beads are included in the joint, the joining strength between the pipes may be reduced. The greater the number of start and end points of the beads in the joint, the greater the concern about this reduction in joining strength.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for manufacturing a molded object and a layering planning method that are capable of manufacturing a molded object in which a pipe is joined to a base material with sufficient joining strength. [Means for solving the problem]

[0007] The present invention comprises the following configurations. (1) A method for manufacturing a shaped object, comprising: laminating weld beads on a peripheral surface of a base material having an arc-shaped cross section to form a cylindrical pipe; a first pass forming process of stacking weld beads along a first pass having a closed curve shape that follows the surface shape of the peripheral surface of the base material; a second pass forming process of stacking weld beads along a second pass having a closed curve parallel to the vertical cross section of the pipe; a differential pass forming process for stacking weld beads along an open curve-shaped differential pass parallel to the first pass or the second pass in an area surrounded by the first pass and the second pass; Including, In the differential pass forming step, a start and end of the weld bead along the differential pass are positioned at positions spaced apart from a peripheral surface of the base material. A method for manufacturing a shaped object. (2) A lamination planning method for forming a cylindrical pipe by laminating weld beads on a peripheral surface of a base material having a peripheral surface with an arc-shaped cross section, the method comprising: a path generating step of generating a first path having a closed curve shape that follows the surface shape of the peripheral surface of the base material and a second path having a closed curve shape that is parallel to the vertical cross section of the pipe; a boundary position setting step of setting a boundary position of an area where the first path and the second path are arranged; a differential path generating step of generating a differential path having an open curve shape by adjusting the path length of the first path or the second path in accordance with the boundary position; Including, In the differential path generating step, the start and end points of the differential path are disposed at positions spaced apart from the peripheral surface of the base material. Stacking planning method. [Effects of the Invention]

[0008] According to the present invention, a shaped object can be manufactured in which a pipe is joined to a base material with sufficient joining strength. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 is a schematic diagram showing the overall configuration of an additive manufacturing system. [Figure 2] FIG. 2 is a perspective view of an example of a shaped object. [Figure 3] FIG. 3 is a flowchart showing the procedure for creating a stacking plan. [Figure 4] FIG. 4 is a schematic diagram showing a model of a shaped object for explaining the generation of the first pass and the second pass. [Figure 5] FIG. 5 is a schematic diagram showing another model of the object when the first pass and the second pass are generated at different boundary positions. [Figure 6] FIG. 6 is a schematic diagram showing a model of a shaped object for explaining generation of a differential path. [Figure 7] FIG. 7 is a schematic diagram showing a model of a shaped object, which explains how to generate another differential path. [Figure 8] FIG. 8 is a schematic front view of a shaped object showing the state of lamination of weld beads along the first pass. [Figure 9] FIG. 9 is a schematic front view of a shaped object showing the state of lamination of weld beads along differential passes. [Figure 10] FIG. 10 is a schematic front view of a shaped object showing the state of lamination of weld beads along the second pass. [Figure 11A] FIG. 11A is a schematic front view of a shaped object illustrating a reference example in which a pipe is shaped by laminating weld beads on a base material without forming a weld bead along the first pass. [Figure 11B] FIG. 11B is a schematic front view of a shaped object illustrating a reference example in which a pipe is shaped by laminating weld beads on a base material without forming a weld bead along the first pass. [Figure 12] FIG. 12 is a schematic diagram showing a model of a shaped object, illustrating the region of the joint between the base material and the pipe, and the determination of whether or not the first pass needs to be generated. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The additive manufacturing system shown here uses a heat source device to melt a filler material (welding wire) held by a manipulator to form a weld bead, and then repeatedly stacks the formed weld beads into a desired shape to form a shaped object made of stacked weld beads.

[0011] <Additive manufacturing system configuration> An example of the configuration of an additive manufacturing system that operates based on the trajectory plan determined by the trajectory planning support device described above will be described. FIG. 1 is a schematic diagram showing the overall configuration of an additive manufacturing system. The additive manufacturing system 100 includes a manufacturing control device 15, a manipulator 17, a filler material supply device 19, a manipulator control device 21, and a heat source control device 23.

[0012] The manipulator control device 21 controls the manipulator 17 and the heat source control device 23. A controller (not shown) is connected to the manipulator control device 21, and an operator can instruct any operation of the manipulator control device 21 via the controller.

[0013] The manipulator 17 is, for example, an articulated robot, and a torch 11 attached to the tip shaft supports the filler material M so that it can be continuously supplied. The torch 11 holds the filler material M protruding from the tip. The position and posture of the torch 11 can be set arbitrarily in three dimensions within the range of the degrees of freedom of the robot arm constituting the manipulator 17. The manipulator 17 preferably has six or more degrees of freedom, and is preferably one that can arbitrarily change the axial direction of the heat source at the tip. The manipulator 17 may be in various forms, such as a four- or more-axis articulated robot as shown in FIG. 1, or a robot equipped with angle adjustment mechanisms on two or more orthogonal axes.

[0014] The torch 11 has a shield nozzle (not shown), through which shielding gas is supplied. The shielding gas blocks the atmosphere and prevents oxidation and nitridation of the molten metal during welding, thereby suppressing welding defects. The arc welding method used in this configuration may be either a consumable electrode type such as shielded metal arc welding or carbon dioxide gas arc welding, or a non-consumable electrode type such as TIG (Tungsten Inert Gas) welding or plasma arc welding, and is selected appropriately depending on the object to be formed. Here, gas metal arc welding will be used as an example. In the case of a consumable electrode type, a contact tip is disposed inside the shield nozzle, and a filler material M to which current is supplied is held by the contact tip. The torch 11 holds the filler material M and generates an arc from the tip of the filler material M in a shielding gas atmosphere.

[0015] The filler material supply device 19 supplies the filler material M toward the torch 11. The filler material supply device 19 includes a reel 19a around which the filler material M is wound, and a feeding mechanism 19b that feeds the filler material M from the reel 19a. The filler material M is fed to the torch 11 by the feeding mechanism 19b while being sent in the forward or reverse direction as needed. The feeding mechanism 19b is not limited to a push type that is arranged on the filler material supply device 19 side and pushes out the filler material M, but may also be a pull type or a push-pull type that is arranged on a robot arm or the like.

[0016] The heat source control device 23 is a welding power source that supplies the power required for welding by the manipulator 17. The heat source control device 23 adjusts the welding current and welding voltage supplied when forming a bead by melting and solidifying the filler material M. In addition, the filler material supply speed of the filler material supply device 19 is adjusted in conjunction with the welding conditions such as the welding current and welding voltage set by the heat source control device 23.

[0017] The heat source for melting the filler material M is not limited to the arc described above. Other heat sources may be used, such as a heating method that combines an arc and a laser, a heating method that uses plasma, or a heating method that uses an electron beam or a laser. Heating with an electron beam or a laser allows for more precise control of the amount of heat, which can maintain the state of the formed bead more appropriately and contribute to further improving the quality of the laminated structure. The material of the filler material M is also not particularly limited. The type of filler material M used may vary depending on the characteristics of the object W, such as mild steel, high-tensile steel, aluminum, aluminum alloy, nickel, or nickel-based alloy.

[0018] The forming control device 15 controls the above-mentioned components in an integrated manner. The forming control device 15 is configured by hardware using an information processing device such as a PC (Personal Computer). Each function of the forming control device 15 is realized by a control unit (not shown) reading and executing a program having a specific function stored in a storage device (not shown). Examples of the storage device include a volatile storage area such as a random access memory (RAM), a non-volatile storage area such as a read-only memory (ROM), and storage such as a hard disk drive (HDD) or a solid state drive (SSD). Examples of the control unit include a processor such as a central processing unit (CPU) or a microprocessor unit (MPU), or a dedicated circuit. In addition to the above-mentioned configurations, the forming control device 15 may be another computer remotely connected to the additive manufacturing system 100 via a network or the like.

[0019] The additive manufacturing system 100 configured as described above operates in accordance with a manufacturing program created based on a lamination plan for the object W. The manufacturing program is composed of numerous command codes and is created based on an appropriate algorithm depending on various conditions, such as the shape, material, and heat input of the object. According to this manufacturing program, the torch 11 is moved while the supplied filler material M is melted and solidified, and a linear weld bead B, which is a molten solid of the filler material M, is formed on the base 13. That is, the manipulator control device 21 drives the manipulator 17 and the heat source control device 23 based on a predetermined program provided by the manufacturing control device 15. In response to a command from the manipulator control device 21, the manipulator 17 moves the torch 11 while melting the filler material M with an arc to form the weld bead B. By sequentially forming and stacking the weld beads B in this manner, a desired object W is obtained.

[0020] <Procedure for creating a model> Next, a procedure for forming the object W by the forming control device 15 will be described. Fig. 2 is a perspective view of an example of a model W. Fig. 3 is a flowchart showing a procedure for creating a stacking plan.

[0021] As shown in FIG. 2, in this configuration example, a shaped object W is formed by forming and joining a pipe 55 to a peripheral surface 53 of a base material 51. The base material 51 is formed in a pipe shape, and as a result, the peripheral surface 53 is formed in an arc shape in cross section. The pipe 55 extends from a part of the peripheral surface 53 of the base material 51 in a direction perpendicular to the base material 51. The base material 51 having a peripheral surface 53 formed in an arc shape in cross section is not limited to a cylindrical pipe, but may also be a member having a semicircular cross section. Note that the base material 51 may also be a structure in which weld beads B are layered. Furthermore, the pipe 55 is not limited to a cylindrical shape, but may also be a rectangular tube, and may extend obliquely from the peripheral surface 53 of the base material 51.

[0022] When forming the object W, the forming control device 15 first creates a lamination plan (steps S1 to S4). Then, based on the created lamination plan, the weld beads B are layered to form the object W (step S5).

[0023] (Lamination plan settings) First, the creation of a stacking plan will be described. 4 to 7 are schematic diagrams showing a model WM of a shaped object W for explaining the generation of each path. As shown in FIG. 4, three-dimensional shape information of pipe 55, which is the part to be laminated, is acquired, and a model WM of pipe 55 created from this three-dimensional shape information is sliced ​​in a direction intersecting the lamination direction of weld bead B to generate a first pass P1 and a second pass P2 for forming weld bead B (step S1). Here, first pass P1 is a closed curved path that follows the surface shape of circumferential surface 53 of base material 51, and second pass P2 is a closed curved path that is parallel to a cross section perpendicular to the extension direction of pipe 55. The closed curve of first pass P1 is a closed curve formed on circumferential surface 53 of base material 51 by projecting a closed curve (circular curve) parallel to second pass P2 from above circumferential surface 53 of base material 51 in the vertical direction (the thin line on circumferential surface 53 in FIG. 2 corresponds to a part of the closed curve of first pass P1).

[0024] Next, a boundary position BL of the area where the first pass P1 and the second pass P2 are located is set (step S2). This boundary position BL can be set arbitrarily. When forming pipe 55 vertically upward relative to base material 51, weld bead B formed along first pass P1 is prone to sagging due to the influence of gravity. For this reason, as shown in FIG. 5, boundary position BL may be positioned closer to base material 51. In this way, by positioning boundary position BL closer to base material 51, the proportion of first pass P1, which is susceptible to the influence of gravity, in weld bead B can be reduced, and the proportion of second pass P2 can be increased.

[0025] As shown in FIG. 6, once the boundary position BL is set, a differential path P3 is generated in accordance with this boundary position BL (step S3). This differential path P3 is a remaining pass other than the first pass P1 and the second pass P2 among the passes for forming the weld bead B that shapes the pipe 55, and is a pass that fills the area between the first pass P1 and the second pass P2. This differential path P3 is a pass obtained by adjusting the path length of the first pass P1, and is generated as a pass parallel to the first pass P1 in the area between the first pass P1 and the second pass P2. Note that, as shown in FIG. 7, the differential path P3 may be generated as a pass parallel to the second pass P2 in the area between the first pass P1 and the second pass P2 by adjusting the path length of the second pass P2.

[0026] Furthermore, when generating the differential path P3 in the region between the first pass P1 and the second pass P2, the start and end points P3e of this differential path P3 are positioned at positions spaced apart from the peripheral surface 53 of the base material 51.

[0027] After generating the first pass P1, the second pass P2, and the differential pass P3, the stacking conditions are set for stacking the weld bead B to form the pipe 55 based on these first pass P1, the second pass P2, and the differential pass P3 (step S4).

[0028] When setting the lamination conditions, the welding conditions may be adjusted for each of the first pass P1, the second pass P2, and the differential pass P3.

[0029] For example, first pass P1, which forms weld bead B along peripheral surface 53 of base material 51, involves a rod operating motion that moves torch 11 in the vertical direction. Therefore, from the perspective of suppressing sagging when forming weld bead B in first pass P1, it is preferable to set welding conditions that result in a lower heat input than the heat input when forming weld bead B along second pass P2.

[0030] Furthermore, even when differential pass P3 is generated as a pass parallel to first pass P1 (see FIG. 6), differential pass P3 involves a rod operating motion that moves torch 11 up and down, similar to first pass P1. Therefore, in this case as well, from the viewpoint of suppressing sagging when forming weld bead B in differential pass P3, it is preferable to set welding conditions that result in a lower heat input than the heat input when forming weld bead B along second pass P2. Note that when differential pass P3 is generated as a pass parallel to second pass P2 (see FIG. 7), welding conditions may be set to match the heat input of second pass P2.

[0031] Note that when differential pass P3 is generated as a pass parallel to first pass P1 (see FIG. 6), start and end points P3e of differential pass P3 are concentrated at boundary position BL. For this reason, from the viewpoint of melting start and end points P3e to reduce and flatten unevenness at start and end points P3e, it is preferable to set welding conditions such that the heat input to weld bead B formed by second pass P2A that contacts boundary position BL in second pass P2 is higher than the heat input to weld bead B formed by other second passes P2.

[0032] Once the lamination plan is created in this way, a weld bead B is formed along the first pass P1, the second pass P2, and the differential pass P3 based on this lamination plan, and a pipe 55 is formed on the peripheral surface 53 of the base material 51 (step S5).

[0033] (modeling process) Next, a case where the pipe 55 is formed based on the created lamination plan will be described. 8 to 10 are schematic front views of a shaped object showing the state of lamination of weld beads B along each pass.

[0034] 8, weld bead B1 is layered on peripheral surface 53 of base material 51 along a first pass P1 that has a closed curve shape that follows the surface shape of peripheral surface 53 (first pass forming process). At this time, if weld bead B1 along first pass P1 is formed under welding conditions that result in a lower heat input than weld bead B2 along second pass P2 that will be layered in a later process, sagging of weld bead B1 can be suppressed.

[0035] 9, in the area surrounded by the first pass P1 and the second pass P2, weld beads B3 are layered along a differential pass P3 having an open curve parallel to the first pass P1 (differential pass forming process). As a result, the start and end points B3e of the weld beads B3 along the differential pass P3 are positioned at a distance from the peripheral surface 53 of the base material 51. When the weld beads B3 are layered along the differential pass P3 in this manner, the start and end points B3e of the weld beads B3 are positioned so that they are concentrated at the boundary position BL. Note that if the differential pass P3 is an open curve parallel to the second pass P2, the weld beads B3 are layered along the open curve differential pass P3 parallel to the second pass P2.

[0036] Then, as shown in FIG. 10, weld bead B2 is layered on top of weld bead B3 layered along differential pass P3 along a second pass P2 in the form of a closed curve parallel to the vertical cross section of pipe 55 (second pass forming process).

[0037] In this case, if differential pass P3 is an open curve parallel to first pass P1, weld bead B2A along second pass P2A, which is tangent to start and end points B3e of weld bead B3 along differential pass P3, is formed under welding conditions that result in a higher heat input than other weld beads B2 along second pass P2. In this way, start and end points B3e of weld bead B3 along differential pass P3 are melted, reducing unevenness at the start and end points B3e and making them flat. This eliminates the need for a cutting process to reduce unevenness at the start and end points B3e of weld bead B3 along differential pass P3.

[0038] In this way, by forming and stacking weld beads B1, B2, and B3 along the generated first pass P1, second pass P2, and differential pass P3, an object W can be produced in which a cylindrical pipe 55 is joined to the cross-sectional arc-shaped peripheral surface 53 of the base material 51.

[0039] 11A and 11B are schematic front views of a shaped object W illustrating a reference example in which a pipe 55 is shaped by laminating weld beads B3 and B2 on a base material 51 without forming a weld bead B1 along a first pass P1. 11A and 11B, in a reference example in which pipe 55 is formed without generating first pass P1, start and end terminals B3e of weld beads B3 along differential pass P3 are concentrated at the joint between base material 51 and pipe 55. Here, as shown in FIG. 12, joint Aj between base material 51 and pipe 55 is a region surrounded by a vertical cross section of pipe 55 that contacts peak 53a of circumferential surface 53 of base material 51 and the circumferential surface 53. In the reference example shown in FIG. 11A, start and end terminals B3e of weld beads B3 formed along circumferential surface 53 of base material 51 are concentrated on the weld bead B2 side at joint Aj, while in the reference example shown in FIG. 11B, start and end terminals B3e of weld beads B3 formed along second pass P2 are concentrated on the circumferential surface 53 side of base material 51 at joint Aj.

[0040] In other words, as in these reference examples, if the start and end B3e of the weld bead B3 are positioned at the joint Aj between the base material 51 and the pipe 55, where localized stress is likely to occur, the joint strength between the base material 51 and the pipe 55 may be reduced.

[0041] In contrast, according to this configuration example, the start and end points B3e of the weld bead B3 formed along the differential pass P3 are formed away from the circumferential surface 53 of the base material 51 so as not to come into direct contact with the circumferential surface 53 of the base material 51, thereby preventing overlap between the start and end points B3e, which are likely to be weak, and the joint points Aj, where stress is likely to concentrate, and ensuring fatigue strength. This makes it possible to manufacture a shaped object W in which the pipe 55 is joined with high strength to the circumferential surface 53 of the base material 51. Furthermore, by separating the start and end points P3e of the differential pass P3 from the joint points Aj and forming the weld bead B along this differential pass P3, a sufficient distance from the points where stress is likely to concentrate can be ensured, further improving fatigue strength.

[0042] In addition, when creating a stacking plan in the above configuration example, a process (maximum dimension calculation step) may be performed to calculate the maximum dimension H along the longitudinal direction of the pipe 55 at the joint Aj between the peripheral surface 53 of the base material 51 and the pipe 55, as shown in Figure 12, based on the shape of the peripheral surface 53 of the base material 51 and the diameter of the pipe 55.

[0043] Here, if the curvature of the peripheral surface 53 of the base material 51 is small, the maximum dimension H along the longitudinal direction of the pipe 55 at the joint Aj between the peripheral surface 53 of the base material 51 and the pipe 55 will be small. In such a case, there will be almost no substantial difference between the first pass P1 and the second pass P2, and the pipe 55 can be formed sufficiently by simply stacking the weld beads B2 along the second pass P2.

[0044] For this reason, the maximum dimension H along the longitudinal direction of the pipe 55 at the joint Aj between the circumferential surface 53 of the base material 51 and the pipe 55 may be calculated, and whether or not the first pass P1 needs to be generated may be determined based on this calculated maximum dimension H. For example, if this maximum dimension H is equal to or greater than a preset threshold, the first pass P1, the second pass P2, and the differential pass P3 are generated, and if the maximum dimension H is less than the threshold, only the second pass P2 is generated. In this way, it is possible to prevent the generation of unnecessarily complex paths and simplify the processing when creating a lamination plan.

[0045] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0046] As described above, the present specification discloses the following: (1) A method for manufacturing a shaped object, comprising: laminating weld beads on a peripheral surface of a base material having an arc-shaped cross section to form a cylindrical pipe; a first pass forming process of stacking weld beads along a first pass having a closed curve shape that follows the surface shape of the peripheral surface of the base material; a second pass forming process of stacking weld beads along a second pass having a closed curve parallel to the vertical cross section of the pipe; a differential pass forming process for stacking weld beads along an open curve-shaped differential pass parallel to the first pass or the second pass in an area surrounded by the first pass and the second pass; Including, In the differential pass forming step, a start and end of the weld bead along the differential pass are positioned at positions spaced apart from the peripheral surface of the base material. According to this method for manufacturing a shaped object, the start and end points of the weld beads formed along the differential path are spaced apart from the circumferential surface of the base material so as not to come into direct contact with the circumferential surface of the base material, thereby preventing overlap between the start and end points, which are prone to being weak, and the joint points, where stress is likely to concentrate, and ensuring fatigue strength. This makes it possible to manufacture a shaped object in which the pipe is joined to the circumferential surface of the base material with high strength.

[0047] (2) A method for manufacturing a molded object according to (1), wherein in the differential pass forming process, a weld bead along the differential pass is formed parallel to the first pass, and the start and end points are positioned on a plane parallel to the second pass. According to this manufacturing method for a molded object, the start and end points of the weld bead formed along the differential pass are positioned on a plane parallel to the second pass, which prevents the start and end points of the weld bead along the differential pass from being positioned at the base of the pipe, thereby preventing the occurrence of non-welding defects at the joint between the base material and the pipe.

[0048] (3) A method for manufacturing a shaped object according to (2), wherein in the second pass forming process, among the weld beads formed along the second pass, the weld beads that contact the start and end points of the weld beads along the differential pass are formed under welding conditions that result in a higher heat input than other weld beads along the second pass. According to this manufacturing method for a molded object, by increasing the heat input to the weld bead along the second pass that contacts the start and end points of the weld bead along the differential pass, the start and end points of the weld bead along the differential pass can be melted and flattened, reducing unevenness at the start and end points. This makes it possible to omit the cutting process for reducing unevenness at the start and end points of the weld bead along the differential pass.

[0049] (4) A method for manufacturing a shaped object according to any one of (1) to (3), wherein the weld bead along the first pass is formed under welding conditions that result in a lower heat input than the weld bead along the second pass. According to this method for manufacturing a shaped object, the weld bead along the first pass formed on the base material side is formed with a low heat input, thereby preventing the weld bead from sagging around the circumferential surface of the base material having an arc-shaped cross section.

[0050] (5) A method for manufacturing a molded object described in any one of (1) to (4), wherein in the differential pass forming process, the start and end points of the weld bead along the differential pass are positioned at positions away from the joint between the base material and the pipe. According to this method for manufacturing a shaped object, by separating the start and end points of the weld bead along the differential path from the joint, a sufficient distance can be secured between the weld bead and areas where stress tends to concentrate, thereby further improving fatigue strength.

[0051] (6) A lamination planning method for forming a cylindrical pipe by laminating weld beads on a peripheral surface of a base material having a peripheral surface with an arc-shaped cross section, the method comprising: a path generating step of generating a first path having a closed curve shape that follows the surface shape of the peripheral surface of the base material and a second path having a closed curve shape that is parallel to the vertical cross section of the pipe; a boundary position setting step of setting a boundary position of an area where the first path and the second path are arranged; a differential path generating step of generating a differential path having an open curve shape by adjusting the path length of the first path or the second path in accordance with the boundary position; Including, In the differential path generating step, a start and end terminals of the differential path are positioned at positions spaced apart from a peripheral surface of the base material. According to this lamination planning method, by forming weld beads along the first pass, the second pass, and the differential pass, it is possible to manufacture a shaped object in which weld beads are layered on the circumferential surface of the base material to form a cylindrical pipe. Moreover, since the start and end points of the weld beads formed along the differential passes are spaced apart from the circumferential surface of the base material so as not to directly contact the circumferential surface of the base material, it is possible to ensure fatigue strength by avoiding overlap between the start and end points, which are prone to weakness, and the joint points, where stress is likely to concentrate. This makes it possible to manufacture a shaped object in which a pipe is joined to the circumferential surface of the base material with high strength.

[0052] (7) The lamination planning method according to (6), wherein in the differential path generating step, the start and end points of the differential path are positioned at positions spaced apart from a joint between the base material and the pipe. According to this stacking planning method, when a weld bead is formed along a differential path, the start and end points of the weld bead can be spaced away from the joint, ensuring a sufficient distance from areas where stress is likely to concentrate, thereby further improving fatigue strength. (8) The method further includes a maximum dimension calculation step of calculating a maximum dimension along the longitudinal direction of the pipe at a joint between the peripheral surface of the base material and the pipe based on the shape of the peripheral surface of the base material and the diameter of the pipe, The lamination planning method according to (6) or (7), wherein whether or not the first path needs to be generated in the path generating step is determined based on the calculated maximum dimension. According to this lamination planning method, whether or not to generate the first pass in the pass generation step is determined based on the maximum dimension along the longitudinal direction of the pipe at the joint between the circumferential surface of the base material and the pipe, thereby preventing the generation of unnecessarily complex passes. [Explanation of symbols]

[0053] 51 Base material 53 Peripheral surface 55 Pipe Aj Joint B, B1, B2, B2A, B3 Weld bead B3e start and end H Maximum dimension P1 First pass P2,P2A 2nd pass P3 Diff Path P3e start and end W sculpture

Claims

1. A method for manufacturing a shaped object, comprising: laminating weld beads on a peripheral surface of a base material having a circular arc cross section to form a cylindrical pipe; a first pass forming process of stacking weld beads along a first pass having a closed curve shape that follows the surface shape of the peripheral surface of the base material; a second pass forming process of stacking weld beads along a second pass having a closed curve shape parallel to a cross section perpendicular to the extension direction of the pipe; a differential pass forming process of stacking weld beads along an open curve-shaped differential pass parallel to the first pass in an area surrounded by the first pass and the second pass; Including, In the differential pass forming process, a start and end of the weld bead along the differential pass are positioned at positions spaced apart from a peripheral surface of the base material; A method for manufacturing a shaped object, wherein in the differential pass forming step, a weld bead along the differential pass is formed parallel to the first pass, and the start and end points are positioned on a plane parallel to the second pass.

2. In the second pass forming step, a weld bead that is in contact with a start and end of a weld bead along the differential pass among the weld beads formed along the second pass is formed under welding conditions that result in a higher heat input than other weld beads along the second pass. The method for manufacturing a shaped object according to claim 1 .

3. A method for manufacturing a shaped object, comprising: laminating weld beads on a peripheral surface of a base material having a circular arc cross section to form a cylindrical pipe; a first pass forming process of stacking weld beads along a first pass having a closed curve shape that follows the surface shape of the peripheral surface of the base material; a second pass forming process of stacking weld beads along a second pass having a closed curve shape parallel to a cross section perpendicular to the extension direction of the pipe; a differential pass forming process of stacking weld beads along an open curve-shaped differential pass parallel to the first pass in an area surrounded by the first pass and the second pass; Including, In the differential pass forming process, a start and end of the weld bead along the differential pass are positioned at positions spaced apart from a peripheral surface of the base material; A method for manufacturing a shaped object, wherein the weld bead along the first pass is formed under welding conditions that result in a lower heat input than the weld bead along the second pass.

4. 1. A lamination planning method for forming a cylindrical pipe by laminating weld beads on a peripheral surface of a base material having a peripheral surface with an arc-shaped cross section, a path generating step of generating a first path having a closed curve shape that follows the surface shape of the peripheral surface of the base material and a second path having a closed curve shape that is parallel to a cross section perpendicular to the extension direction of the pipe; a boundary position setting step of setting a boundary position of an area where the first path and the second path are arranged; a differential path generating step of generating a differential path having an open curve shape by adjusting the path length of the first path or the second path in accordance with the boundary position; Including, In the differential path generating step, the start and end points of the differential path are disposed at positions spaced apart from the peripheral surface of the base material. Stacking planning method.

5. In the differential path generating step, the start and end points of the differential path are positioned at positions spaced apart from a joint between the base material and the pipe. The stacking planning method according to claim 4 .

6. The method further includes a maximum dimension calculation step of calculating a maximum dimension along the longitudinal direction of the pipe at a joint between the peripheral surface of the base material and the pipe based on the shape of the peripheral surface of the base material and the diameter of the pipe, determining whether or not the first path needs to be generated in the path generating step based on the calculated maximum dimension; The stacking planning method according to claim 4 or 5.

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