Trajectory planning support method, trajectory planning support device, additive manufacturing method, additive manufacturing device, and program

Abstract

To enable correctly evaluating the pros and cons of a trajectory plan of a molded object without requiring complicated arithmetic processing even when the trajectory plan is expanded from two-dimensional state into a three dimensional state, so as to allow for creating a trajectory plan capable of obtaining high reproducibility of the molded object.SOLUTION: A trajectory planning support method for supporting creation of a trajectory plan comprises: acquiring shape data of a molded object; decomposing a three-dimensional shape model based on the shape data into multiple linear models each having a polygonal vertical cross section in a longitudinal direction; configuring bead formation trajectories for forming weld beads along the linear models and a bead formation trajectories including order of lamination of the weld beads; creating a plurality of divided polygonal columnar unit blocks into which the linear model is cut by a unit length along the configured bead formation trajectory; and creating a trajectory plan through a simulation simulating formation of a welding bead for each unit block.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a trajectory planning support method, a trajectory planning support device, an additive manufacturing method, an additive manufacturing device, and a program. [Background technology]

[0002] In recent years, there has been an increasing need for 3D printers as a production method, and research and development is underway to commercialize 3D printing using metallic materials. One technique for producing 3D objects using metallic materials is to layer weld beads, which are formed by melting and solidifying a filler metal (welding wire) using a heat source such as an arc, into the desired shape. Furthermore, when producing such a molded object, a technique for modeling the cross-sectional shape of a weld bead for the purpose of computer-aided design or automated control is known (for example, Patent Document 1). Patent Document 1 describes using an elliptical bead model to change the molding conditions so that the difference between the target shape of the molded object and the predicted shape predicted from an actual measurement database is within an allowable value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-27558 Summary of the Invention [Problem to be solved by the invention]

[0004] In additive manufacturing, which involves layering weld beads made by melting and solidifying filler metal, complex three-dimensional shapes are often created. Therefore, it is preferable to determine the trajectory plan for forming the weld bead using a three-dimensional bead formation path, rather than the traditional two-dimensional plan. In particular, three-dimensional trajectory planning is essential for accurately evaluating the impact of the trajectory of each bead formation path on the molding results. However, when the trajectory plan is three-dimensional, it becomes more complex than a two-dimensional plan, which can make it difficult to evaluate the plan itself. Furthermore, while it is possible to fine-tune the shape of the bead model depending on the weld bead formation conditions, this requires complex calculations, and depending on the size of the object, it may be impossible to create a trajectory plan in a realistic amount of time.

[0005] Therefore, an object of the present invention is to provide a trajectory planning support method, a trajectory planning support device, an additive manufacturing method, an additive manufacturing device, and a program that can correctly evaluate the adequacy of a trajectory plan without requiring complicated calculation processing, even when the trajectory plan of a molded object is expanded from two dimensions to three dimensions, thereby making it possible to create a trajectory plan that provides high reproducibility for the molded object. [Means for solving the problem]

[0006] The present invention comprises the following configurations. (1) A trajectory planning support method for forming a weld bead by melting and solidifying a filler material held by a manipulator while moving the manipulator, and stacking the formed weld beads to manufacture a shaped object, the method comprising: acquiring shape data of the object; decomposing the three-dimensional shape model based on the shape data into a plurality of linear models each having a polygonal cross section perpendicular to the longitudinal direction; setting a bead formation trajectory that forms the weld bead along the linear model and the bead formation trajectory that includes a layering order of the weld beads; generating a plurality of polygonal prism-shaped unit blocks by dividing the linear model into unit lengths along the set bead formation trajectory; creating the trajectory plan by simulating the formation of the weld bead for each unit block; A method for supporting trajectory planning. (2) An additive manufacturing method for forming the weld bead based on the trajectory plan determined by the trajectory plan creation support method described in (1). (3) A trajectory planning support device including a control unit that creates the trajectory plan by the trajectory planning support method described in (1). (4) An additive manufacturing device that forms the weld bead based on the trajectory plan determined by the trajectory plan creation support device described in (1). (5) A program that causes a computer to execute the steps of the trajectory planning support method described in (1). [Effects of the Invention]

[0007] According to the present invention, even if the trajectory plan of a model is expanded from two dimensions to three dimensions, the validity of the trajectory plan can be correctly evaluated without requiring complicated calculation processing, thereby enabling the creation of a trajectory plan that can achieve high reproducibility of the model. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the overall configuration of an additive manufacturing device. [Figure 2] FIG. 2 is a schematic diagram of the control unit. [Figure 3] FIG. 3 is a schematic functional block diagram of the control unit. [Figure 4] FIG. 4 is a flowchart showing the procedure for determining a trajectory plan when manufacturing a model. [Figure 5] FIG. 5 is a process explanatory diagram showing, in stages (A) to (C), how a three-dimensional shape model of a shaped object is decomposed into bead models. [Figure 6] FIG. 6 is a schematic diagram showing the shape and dimensions of the weld bead that is formed. [Figure 7] FIG. 7 is an explanatory diagram showing a case where the model of the base material is a linear model having a cross-sectional shape different from that of the shaped object. [Figure 8A]FIG. 8A is a diagram showing a unit block based on a trapezoidal bead model, and is an explanatory diagram showing a cross section of the unit block. [Figure 8B] FIG. 8B is a diagram showing unit blocks based on a trapezoidal bead model, and is an explanatory diagram showing the unit blocks along the bead formation trajectory. [Figure 9] FIG. 9 is an explanatory diagram showing the shapes of various unit blocks and their application locations. [Figure 10] FIG. 10 is a schematic diagram showing an arrangement of unit blocks. [Figure 11] FIG. 11 is a perspective view of a bead model showing the arrangement of unit blocks at the start or end of a weld bead. [Figure 12] FIG. 12 is an explanatory diagram showing a unit block of a shaped object, a base material, and a unit block of a linear model. [Figure 13] FIG. 13 is a schematic perspective view of a unit block shown as an example. [Figure 14] FIG. 14 is a schematic perspective view showing a group of unit blocks in which the unit blocks are arranged in accordance with the bead stacking order and the bead forming trajectory. [Figure 15] FIG. 15 is a schematic perspective view showing a group of unit blocks in which the unit blocks are arranged in accordance with the bead stacking order and the bead forming track. [Figure 16A] FIG. 16A is an explanatory diagram showing, in stages, the arrangement order of unit blocks in the unit block group shown in FIG. [Figure 16B] FIG. 16B is an explanatory diagram showing the arrangement order of the unit blocks in the unit block group shown in FIG. 15 in stages. [Figure 16C] FIG. 16C is an explanatory diagram showing the arrangement order of the unit blocks in the unit block group shown in FIG. 15 in stages. [Figure 17] 17 is a cross-sectional view of the unit block group shown in FIG. 15 taken along line XVII-XVII. [Figure 18] 18 is a cross-sectional view of the unit block group shown in FIG. 15 taken along line XVIII-XVIII. [Figure 19A]FIG. 19A is a diagram showing different arrangements of a plurality of unit blocks, and is an explanatory diagram showing an arrangement having steps. [Figure 19B] FIG. 19B is an explanatory diagram showing a difference in the arrangement of a plurality of unit blocks, and showing a smoothed arrangement. [Figure 20A] FIG. 20A is a diagram showing different arrangements of a plurality of unit blocks, and is an explanatory diagram showing an arrangement having steps. [Figure 20B] FIG. 20B is a diagram showing differences in the arrangement of a plurality of unit blocks, and is an explanatory diagram showing a smoothed arrangement. [Figure 21A] FIG. 21A is a diagram showing unit blocks based on trapezoidal and pentagonal bead models, and is an explanatory diagram showing a cross section of the unit block. [Figure 21B] FIG. 21B is a diagram showing unit blocks based on trapezoidal and pentagonal bead models, and is an explanatory diagram showing unit blocks along a bead formation trajectory. [Figure 22A] FIG. 22A is a diagram showing a divided form of the unit block shown in FIGS. 21A and 21B, and is a front view of the unit block. [Figure 22B] FIG. 22B is a diagram showing a divided form of the unit block shown in FIGS. 21A and 21B, and is a perspective view of the unit block. [Figure 23A] FIG. 23A is a diagram showing another divided form of unit blocks, and is a front view of the unit blocks. [Figure 23B] FIG. 23A is a perspective view of a unit block showing another divided form of the unit block. [Figure 24A] FIG. 24A is a diagram showing a division form of an octahedral unit block, and is a front view of the unit block. [Figure 24B] FIG. 24B is a perspective view of an octahedral unit block, showing a divided form of the unit block. [Figure 25A] FIG. 25A is a diagram showing a division form of an octahedral unit block, and is a front view of the unit block. [Figure 25B] FIG. 25B is a perspective view of an octahedral unit block, showing a divided form of the unit block. [Figure 26A] FIG. 26A is a diagram showing a divided form of a unit block having a droop portion, and is a front view of the unit block. [Figure 26B] FIG. 26B is a perspective view of a unit block showing a divided form of the unit block having a droop portion. [Figure 27A] FIG. 27A is a diagram showing a division form of a decahedral unit block, and is a front view of the unit block. [Figure 27B] FIG. 27B is a perspective view of a unit block, showing a division form of the decahedron unit block. [Figure 28A] FIG. 28A is a diagram showing a divided form of a unit block having a droop portion, and is a front view of the unit block. [Figure 28B] FIG. 28B is a perspective view of a unit block showing a divided form of the unit block having a droop portion. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, we will explain an example of manufacturing a three-dimensional object by stacking a weld bead formed by melting and solidifying a filler material using arc discharge into a desired shape, but the manufacturing method and the configuration of the manufacturing device are not limited to this.

[0010] <Configuration of additive manufacturing equipment> 1 is a diagram showing the overall configuration of an additive manufacturing apparatus 100. The additive manufacturing apparatus 100 includes a manufacturing unit 11 that forms a weld bead B, and a control unit 13 that controls the manufacturing unit 11. The manufacturing unit 11 includes a welding robot 17, which is a manipulator having a welding torch 15 on its tip shaft, a robot drive unit 21 that drives the welding robot 17, a filler material supply unit 23 that supplies filler material (welding wire) M to the welding torch 15, and a welding power supply unit 25 that supplies welding current.

[0011] (Modeling Department) Welding robot 17 is an articulated robot, and a continuously supplied filler material M is supported at the tip of welding torch 15 attached to the tip shaft of the robot arm. The position and posture of welding torch 15 can be set arbitrarily in three dimensions within the range of the degrees of freedom of the robot arm by commands from robot driver 21.

[0012] The welding torch 15 is a gas metal arc welding torch having a shield nozzle (not shown) and supplied with shielding gas from the shield nozzle. The arc welding method 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 welding or plasma arc welding, and is selected appropriately depending on the object to be fabricated. For 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 a melting current is supplied is held by the contact tip. The welding torch 15 holds the filler material M and generates an arc from the tip of the filler material M in a shielding gas atmosphere.

[0013] The filler material supply unit 23 includes a reel 27 around which the filler material M is wound. The filler material M is sent from the filler material supply unit 23 to a feeding mechanism (not shown) attached to a robot arm or the like, and is fed to the welding torch 15 while being fed forward and backward by the feeding mechanism as needed.

[0014] Any commercially available welding wire can be used as the filler metal M. For example, welding wires specified in MAG welding and MIG welding solid wires for mild steel, high-tensile steel, and low-temperature steel (JIS Z 3312), arc welding flux-cored wires for mild steel, high-tensile steel, and low-temperature steel (JIS Z 3313), etc. can be used. Furthermore, filler metals M such as aluminum, aluminum alloys, nickel, and nickel-based alloys can be used depending on the desired properties.

[0015] Robot driving unit 21 drives welding robot 17 to move welding torch 15 and melts continuously supplied filler metal M with a welding current and a welding voltage supplied from welding power supply unit 25 .

[0016] A modeling program corresponding to the object to be manufactured is sent from the control unit 13 to the robot driving unit 21. The modeling program is composed of a large number of command codes and is created based on an appropriate algorithm according to various conditions such as the shape data (CAD data, etc.) of the object, the material, and the amount of heat input.

[0017] The robot driving unit 21 executes the received molding program and drives the welding robot 17, filler material supply unit 23, welding power supply unit 25, etc. to form a weld bead in accordance with the molding program. In other words, the robot driving unit 21 drives the welding robot 17 to move the welding torch 15 along the trajectory (bead formation trajectory) of the welding torch 15 set in the molding program. At the same time, the robot driving unit 21 drives the filler material supply unit 23 and the welding power supply unit 25 in accordance with the welding conditions specified by the molding program to melt and solidify the filler material M at the tip of the welding torch 15 by an arc. As a result, a linear weld bead B is formed on a base material 29 made of, for example, steel. The weld beads B form weld bead layers formed adjacent to each other, and the next weld bead layer is layered on top of this weld bead layer, thereby forming a molded object W having a desired three-dimensional shape.

[0018] Here, welding robot 17 is configured as an articulated robot, but the manipulator that moves welding torch 15 is not limited to this, and may have any other configuration as long as it is a mechanism that allows welding torch 15 to be moved.

[0019] (Control unit) The control unit 13 determines a bead formation trajectory that indicates the order in which welding beads are formed to form a molded object in accordance with the input molding conditions, and generates the above-mentioned molding program. The control unit 13 includes an input unit 31 such as a keyboard, a mouse, or an operation panel, a display unit 33 such as a monitor or a display panel, and a PC (computer) 35, which is the main body of the control unit and to which these are connected.

[0020] FIG. 2 is a schematic diagram of the control unit 13. The PC 35 of the control unit 13 includes an arithmetic processor 37 such as a CPU or an MPU, a memory 39 such as a ROM or a RAM, and a storage unit 41 such as a HD (hard disk drive) or an SSD (solid state drive). The PC 35 also includes an interface 43 that inputs and outputs information between the input unit 31 and the display unit 33, and a communication unit 45 that connects to a network.

[0021] Furthermore, control unit 13 may be configured to be located separately from modeling unit 11 and connected to modeling unit 11 from a remote location via a communication means such as a network. Furthermore, as shown in Fig. 1 , another external control unit 13A having an input unit 31, a display unit 33, and an external PC 36 may be connected separately from control unit 13 via a communication means such as a network. The modeling program may be created by another device such as external PC 36 and input to control unit 13 via communication or a storage medium, in addition to being created by control unit 13.

[0022] FIG. 3 is a schematic functional block diagram of the control unit 13. As shown in FIG. The PC 35 of the control unit 13 includes a data acquisition unit 51, a shape model decomposition unit 53, a database 55, a bead shape trajectory setting unit 57, a unit block generation unit 59, a simulation unit 61, and a condition modification unit 63, which will be described in detail later. Each of the above-mentioned components operates in response to commands from the calculation processor 37, and performs its respective function.

[0023] The above-described configuration of the PC 35 is the same for the external PC 36 of the external control unit 13A, and the external PC 36 can also perform the same functions. In other words, the control unit 13 and the external control unit 13A function as a trajectory planning support device that supports the creation of a bead formation trajectory, which will be described later. The trajectory planning support device is not limited to being attached to the additive manufacturing apparatus 100, and may be provided at another location separate from the additive manufacturing apparatus 100.

[0024] (Trajectory planning support and modeling program generation) Next, a specific procedure for the control unit 13 (or the external control unit 13A) to generate a modeling program will be described. To manufacture the object W, a trajectory plan, such as the bead formation trajectory of the weld bead for forming the shape, welding conditions, etc., is input to the control unit 13, and a manufacturing program is created based on the trajectory plan. Here, the bead formation trajectory is determined from the shape of the object W, and problems that may occur when the weld bead is formed using that bead formation trajectory, such as defects in the weld bead and unreasonable welding conditions, are analytically determined. If problems are found in the analysis results, the trajectory plan is repeatedly corrected until the problems are resolved.

[0025] Fig. 4 is a flowchart showing the procedure for determining a trajectory plan when manufacturing a molded object W. This procedure for determining a trajectory plan is also the procedure of a trajectory plan creation support method for determining a bead formation trajectory. The procedure will be explained below in order based on the flowchart in Fig. 4.

[0026] (Data acquisition) 1 and 2, an operator inputs, into the PC 35, information such as physical property data of the object to be manufactured, shape data (CAD data) representing the target shape, and welding conditions according to the equipment of the modeling unit 11 to be used. The shape data may also include information on the base material 29.

[0027] (shape division processing) 3 reads various pieces of input information (S1). Then, the shape model decomposition unit 53 generates a three-dimensional shape model of the object based on the read shape data, and decomposes this three-dimensional shape model into layers according to the height of the weld bead (S2).

[0028] Fig. 5 is a process explanatory diagram showing, in stages (A) to (C), how the three-dimensional shape model of the object W is decomposed into bead models. As shown in Fig. 5(A), the three-dimensional shape model Mw of the object to be formed on the base material 29 is sliced ​​for each set bead height Hb of the weld bead, and the three-dimensional shape model Mw is decomposed into multiple (four layers in this case) bead layers BL as shown in Fig. 5(B). The layer division method is not limited to this, and other known methods can also be used.

[0029] Then, each decomposed bead layer BL is decomposed according to the bead width Wb of the weld bead, and the three-dimensional shape model Mw is decomposed into multiple bead models (linear models) with rectangular cross sections (S3). For example, one bead model BM0 shown in FIG. 5B is a linear three-dimensional model that is continuous in the depth direction of FIG. 5 and simulates a weld bead. In the following description, the rectangular shape of the continuous cross section of the bead model BM0 that is perpendicular to the longitudinal direction (depth direction) is also referred to as the rectangular bead model BM0. Note that when dividing the rectangular bead model BM0, division conditions may be specified, such as making the bead cross-sectional area in the cross section perpendicular to the bead longitudinal direction constant for each model. Furthermore, the bead extension direction of the rectangular bead model BM0 may be extracted as information on the bead formation trajectory.

[0030] (The cross-sectional shape is approximated to a polygon) The multiple bead models (linear models) represented by the bead model BM0 have a quadrangular cross-sectional shape perpendicular to the longitudinal direction of the bead. The geometric model decomposition unit 53 approximates the cross-sectional shape of this bead model to a polygon corresponding to the weld bead (S4). Here, each bead model (linear model) corresponding to the three-dimensional shape model Mw is approximated to a trapezoid, which is a simple geometric shape. In a vertical cross section in the bead longitudinal direction, the trapezoidal bead model BM has a base side BMa located on the base material 29 side and a top side BMb facing the base side BMa in the bead stacking direction, which are parallel to each other. Furthermore, a pair of side sides BMc, BMd facing the bead arrangement direction in the bead layer BL have four vertices that are not parallel to each other.

[0031] The trapezoidal shape described above can be set arbitrarily, but if the relationship between welding conditions and bead shapes is managed in advance in a database 55, the database 57 can be referenced to select a shape that corresponds to the conditions.

[0032] (Modeling of base material) The above-described three-dimensional shape model Mw is a model of the object to be formed on the base material 29, but a model having a specific cross-sectional shape may also be set for the base material 29. In this case, the three-dimensional shape model of the base material 29 based on the shape data is set as a plurality of linear models whose longitudinal vertical cross sections are polygonal. In this specification, the bead model that models the region of the object and the linear model that models the region of the base material 29 are collectively referred to as "linear models." There are also cases where the base material 29 is formed by a weld bead. In such cases, a bead model corresponding to the weld bead is set as a linear model, just as in the case of the object.

[0033] FIG. 6 is a schematic diagram showing the shape and dimensions of the weld bead B to be formed. The cross section of the weld bead B perpendicular to the bead formation direction is often roughly semicircular. The width of the weld bead B in the cross section perpendicular to the bead formation direction is defined as the bead width Wb, the height from the substrate to the top of the weld bead formed is defined as the bead height H, and the angle between the side wall of the weld bead B and the substrate surface is defined as the inclination angle θ. The cross section of the weld bead B in the longitudinal direction perpendicular to the substrate is defined as the bead cross section area A, and the volume of the weld bead per unit length is defined as the bead unit volume V.

[0034] Model shapes are registered in association with the above-mentioned feature quantities of the bead shape in the database 55. For example, if the cross-sectional shape is a trapezoidal model, various parameters such as the lengths of the base, top, and side edges, and the angle between the base and side edges, are determined by referring to the database 55. At this time, the trapezoidal shape may be appropriately modified, for example, by moving the vertices of the trapezoid in consideration of the overlap between adjacent beads.

[0035] The polygon to be approximated is a simple shape with the number of interior angles between 3 and 8. In other words, polygons include triangles (isosceles triangles, right triangles, etc.), quadrilaterals (trapezoids, parallelograms, rectangles, squares, etc.), pentagons, hexagons, heptagons, octagons, etc.

[0036] On the other hand, the linear model of the base material 29 may be a polygon similar to the bead model described above, but it is preferable that the cross section of the base material 29 has a polygonal shape with eight or more vertices. 7 is an explanatory diagram showing a case where the model of the base material 29 is a linear model PM with a cross-sectional shape different from that of the formed object. Here, the linear model PM has an octagonal cross-sectional shape. If the cross-sectional shape of the linear model PM of the base material 29 is a polygon with octagons or more sides, gaps are less likely to occur between the linear models PM even when the base material 29 is curved, and the base material 29 can better follow the curvature.

[0037] By reproducing the shape of the base material 29 by connecting polyhedral models, it is possible to more easily represent how the first layer of weld beads is positioned and connected on the base material 29. In other words, the layering direction can be relatively easily represented based on the contact points of the polyhedral models corresponding to the base material 29. The polyhedral model used for the base material 29 can be, for example, a decahedron with a predetermined thickness in one direction and an octagonal cross section. In this case, the contact points with the bead model on the molded object can be easily specified. This makes it easier to avoid bugs such as the bead model being unnaturally embedded or floating in the base material 29. The cross section of the polyhedral model constituting part of the base material 29 is not limited to an octagon, and other polygonal shapes may be used. Furthermore, the shape of the base material 29 itself is not particularly limited; it may be a cylindrical base material or a prismatic base material.

[0038] 3 sets a bead formation trajectory including a bead formation trajectory for forming a weld bead along a bead model (linear model) corresponding to the object and the layering order of the weld beads (S5). The bead formation trajectory may be set according to a known algorithm prepared in advance.

[0039] (unit block) Next, the unit block generation unit 59 shown in FIG. 3 converts the bead model BM of the shaped object and the linear model PM of the base material 29 into unit blocks that serve as models to be used in simulations (S6). 8A and 8B are diagrams showing a unit block based on a trapezoidal bead model BM, where Fig. 8A is an explanatory diagram showing a cross section of the unit block, and Fig. 8B is an explanatory diagram showing the unit block along the bead formation trajectory. Here, the cross-sectional shape of the bead model BM is approximated to a trapezoid.

[0040] 8A shows the shapes of two bead models BM1 and BM2 arranged parallel to each other in a plane PL perpendicular to the bead formation direction. One bead model, BM1, is a trapezoid with vertices P1, P2, P3, and P4, while the other bead model, BM2, is a trapezoid with vertices P4, P5, P6, and P7.

[0041] As shown in Fig. 8B, bead model BM1 is arranged along bead forming trajectory PS1, which is the longitudinal direction of the bead, and bead model BM2 is arranged along bead forming trajectory PS2. Then, bead model BM1 is extended back and forth along bead forming trajectory PS1 to generate bead models BM1a and BM1b corresponding to bead model BM1. Bead model BM1a is a trapezoid with vertices P1a, P2a, P3a, and P4a, and bead model BM1b is a trapezoid with vertices P1b, P2b, P3b, and P4b.

[0042] The solid formed by connecting the corresponding vertices of the bead models BM1a and BM1b is defined as a unit block UBa. The unit block UB1 is a columnar body with a trapezoidal cross section, with vertices P1a, P2a, P3a, and P4a, and vertices P1b, P2b, P3b, and P4b. Similarly, for the bead model BM2, a solid formed by connecting corresponding vertices of the bead models BM2a and BM2b is defined as a unit block UBb. The unit block UBb is a columnar body with a trapezoidal cross section, with vertices P4a, P5a, P6a, and P7a, and vertices P4b, P5b, P6b, and P7b.

[0043] In this way, the unit block generation unit 59 generates unit blocks UBa and UBb by adding thickness to the bead model that approximates a polygon. Then, the three-dimensional shape of the weld bead is reproduced by continuously connecting the unit blocks UBa and UBb along the trajectory of each pass. In other words, the three-dimensional shape model Mw, which is the target shape of the molded object, is represented by a plurality of unit blocks UBa and UBb. The unit blocks here are unit blocks UBa and UBb that are columnar with trapezoidal cross sections, but the shape of the unit blocks UBa and UBb is not limited to a hexahedron and may be a pentahedron, heptahedron, octahedron, nonahedron, decahedron, etc.

[0044] The depth distance of the unit blocks UBa and UBb (thickness along the bead formation trajectories PS1 and PS2) can be adjusted as needed. Setting a constant distance (constant thickness) simplifies the generation of unit blocks and reduces the amount of calculation required. A larger depth distance reduces the amount of calculation required, but reduces the reproducibility of the shape of the molded object. A smaller depth distance improves the reproducibility of the shape of the molded object, but increases the number of blocks and the computational load for model generation. Therefore, the thickness of the unit blocks should be set to an appropriate balance depending on the purpose. The volume of the unit blocks UBa and UBb may be adjusted according to the filler metal feed speed and welding speed. Furthermore, the volume (or cross-sectional area) of the unit blocks UBa and UBb may be increased or decreased according to the welding speed and filler metal feed speed during the pass, and the size of the polygon (e.g., trapezoid) may be increased or decreased according to the shape of the starting and ending ends of the weld bead.

[0045] The bead forming trajectories PS1 and PS2 may be set from a bead forming trajectory included in a predetermined trajectory plan, or may be set from information on the bead forming trajectory extracted from the bead extension direction of the rectangular bead model BM0 shown in Figure 5 described above.

[0046] Figure 9 is an explanatory diagram showing the shapes of various unit blocks and their application locations. Here, the xy plane is the plate surface of the base material 29 shown in Figure 1, and the z direction is the vertical direction. The arrangement direction SD of the unit blocks to be applied is also shown.

[0047] The unit blocks UBa and UBb shown in Fig. 8B correspond to the unit block UB1 shown in Fig. 9. This unit block UB1 has a shape suitable for application to a linear arrangement direction SD on the xy plane along the bead forming trajectories PS1 and PS2 shown in Fig. 8B.

[0048] The unit block UB2 shown in FIG. 9 has a shape suitable for application to the arrangement direction SD that curves on the xy plane. FIG. 10 is a schematic diagram showing an arrangement of unit blocks UB2. The unit block UB2 has trapezoidal faces that face each other but are not parallel to each other, with one hypotenuse side of the trapezoid being thinner and the other being thicker. Therefore, when multiple unit blocks UB2 are arranged with their trapezoidal faces overlapping, they will follow the curved arrangement direction SD. In this way, an appropriate unit block shape is selected by changing at least one of the length of the block sides of the unit block and the number of interior angles of the polygon in accordance with the arrangement direction SD, which is the bead formation trajectory set in the molding plan. In other words, the thickness of the unit block UB2 in the direction along the bead formation trajectory is set to a thickness that corresponds to the curvature of the bead formation trajectory. This prevents unnatural gaps or overlaps from occurring where unit blocks UB2 are connected.

[0049] 9 is a pentahedron with triangular bottom and top surfaces and trapezoidal and rectangular side surfaces. In this case, when a plurality of unit blocks UB3 are arranged with their trapezoidal faces overlapping, the unit blocks UB3 are aligned along the curved arrangement direction SD.

[0050] The unit block UB4 is a hexahedron with all trapezoidal side surfaces and rectangular bottom and top surfaces. The top surface has a smaller area than the bottom surface, so the side surfaces are inclined inward. In this case, when multiple unit blocks UB4 are arranged with any of the trapezoidal surfaces overlapping each other, the unit blocks UB4 will be aligned along the arrangement direction SD, which curves upward.

[0051] The unit block UB5 is a pentahedron with a rectangular bottom and trapezoidal and triangular side faces. In this case, when a plurality of unit blocks UB5 are arranged with their trapezoidal or triangular faces overlapping, the unit blocks UB5 are aligned along the arrangement direction SD, which is bent upward.

[0052] The unit block UB6 is a hexahedron with a trapezoidal bottom and side surfaces. This shape can be expressed, for example, as the solid bottom surface of a pyramid with a trapezoidal bottom cut along a plane in a predetermined direction. The shape of the unit block UB6 is suitable for application to the start and end of a weld bead that produces a tapered or bulged tip.

[0053] Figure 11 is a perspective view of a bead model showing the arrangement of a unit block UB6 at the start or end of a weld bead. In actual weld beads, the start of the bead tends to bulge and the end tends to narrow. The rounded shapes at the start and end of the weld bead can be accurately reproduced by using the unit block UB6. Furthermore, when predicting the shape of a weld bead layered on top, sudden height changes due to the model shape can be prevented from adversely affecting the calculation. The narrowed shape of the unit block UB6 can be adjusted by adjusting parameters such as the inclination angle of each face and the thickness of the unit block UB6 to match the shape of the bead model adjacent to the unit block UB6, or the shape can be made different at the start and end of the weld bead.

[0054] The above-mentioned unit blocks are set in the same manner for the linear model PM of the base material 29. Fig. 12 is an explanatory diagram showing the unit blocks of the object, the base material 29, and the unit blocks of the linear model. As shown in Fig. 12, in the region of the three-dimensional shape model Mw that will become the object, a plurality of unit blocks UB corresponding to the above-mentioned bead model BM are arranged, and in the region of the base material 29, a plurality of unit blocks UBp corresponding to the linear model PM are arranged.

[0055] The shape of each unit block is a columnar body having at least a pair of trapezoidal opposing surfaces in the portion simulating the weld bead, and a columnar body having a pair of opposing surfaces that are polygonal with eight or more vertices in the portion simulating a portion of the base material 29 on which the weld bead is laminated.

[0056] (simulation) Next, the simulation unit 61 shown in FIG. 3 uses the above-mentioned polyhedral (pentahedral, hexahedral, etc.) unit blocks to simulate the molding process of the molded object based on predetermined molding conditions (S7). Here, a plurality of unit blocks are arranged along the bead formation trajectory in the bead stacking order of the predetermined molding conditions. A group of unit blocks consisting of the arranged plurality of unit blocks is used as a shape model for the simulation. Although not shown in the figure, unit blocks corresponding to the base material 29 may also be used as a simulation target. In this case, results closer to reality can be obtained.

[0057] Fig. 13 is a schematic perspective view of an example of a unit block UB. Fig. 14 is a schematic perspective view of a unit block group GUB in which the unit blocks UB are arranged in accordance with the bead stacking order and the bead formation track. In the unit block group GUB shown in Fig. 14, the shape of the unit blocks is partially changed depending on the position of the weld bead.

[0058] In the unit block group GUB, the unit blocks located in the top layer and at the end are trapezoidal, and the other unit blocks are parallelograms. In this case, the unit block group GUB shows a case where the end is the outer wall, and the inner part surrounded by the outer wall is filled with a weld bead. In this way, by arranging trapezoidal unit blocks at the end of the bead arrangement and arranging parallelogram-shaped unit blocks inside the end, the hypotenuse of the trapezoid and the hypotenuse of the parallelogram are joined without any gaps. Therefore, it is possible to set a shape model that is closer to the actual weld bead.

[0059] The simulation unit 61 obtains the group of unit blocks GUB shown in FIG. 14 through simulation. Furthermore, as necessary, the group of unit blocks GUB is used as a shape model and subjected to calculation processing based on the inputted molding conditions. In this simulation, the unit blocks are arranged along a bead formation trajectory in a preset molding process to generate a three-dimensional shape model. The simulation unit 61 may use the generated shape model to perform various analyses such as stress analysis, thermal stress analysis, and strain distribution analysis based on a set trajectory plan. Each analysis can utilize a known method such as the finite element method (FEM).

[0060] This allows calculations for the molding process to be performed for each unit block, significantly reducing the computational burden. For example, a shape model with a continuous shape divided into fine meshes could be used, but this would increase the computational burden, and hardware limitations could make it impossible to simulate large-sized objects, or the computation time would be extremely long. However, by simulating the weld bead B and base material 29 using multiple unit blocks with simple shapes, the shape would not become more complex than necessary, and simulation calculation results could be obtained at a sufficient processing speed even on a PC with relatively low processing power.

[0061] Further, a plurality of unit blocks may be arranged along the bead forming trajectory so that adjacent unit blocks are in contact with each other, or a gap may be provided between adjacent unit blocks. In this case, the total number of unit blocks required can be reduced, and the calculation load during simulation can be reduced.

[0062] Fig. 15 is a schematic perspective view showing a unit block group GUB in which unit blocks UB are arranged in accordance with the bead stacking order and the bead formation track. Figs. 16A, 16B, and 16C are explanatory views showing the arrangement order of the unit blocks in the unit block group GUB shown in Fig. 15 in stages.

[0063] To form the unit block group GUB shown in FIG. 15, first, multiple unit blocks UB are arranged along the bead forming trajectory PSa shown in FIG. 16A. Next, multiple unit blocks UB are arranged along the bead forming trajectory PSb shown in FIG. 16B. Then, multiple unit blocks UB are arranged along the bead forming trajectory PSc shown in FIG. 16C. At positions where unit blocks UB overlap each other three-dimensionally, the upper unit block UB is placed on top of the lower unit block UB to maintain a constant shape of the unit blocks UB. In other words, when stacking unit blocks, they are simply stacked without overlapping each other. This allows for a simple shape model to be maintained without fusing the unit blocks (overlapping with common parts). This ensures a constant shape of the unit blocks UB even when the weld beads have multiple intersecting portions, thereby reducing the computational load of the simulation. Note that when the base material has a curved surface, fusing the unit blocks tends to result in large gaps between them. In this case, it is preferable to combine the unit blocks to reduce the gaps, as this allows for a simulation that is closer to reality.

[0064] The results of simulating the manufacturing process based on the information on the unit blocks, bead formation trajectory, and bead stacking order described above can be displayed as a video showing the unit blocks being successively generated along the bead formation trajectory over time. By displaying this video on the display unit 33 shown in Fig. 2, the worker can easily visually recognize the weld bead manufacturing process. This simulation may cover all processes from the start to the end of manufacturing, or may be limited to some of the processes.

[0065] (Verification and condition modification) The simulation of the molding process reproduces in three dimensions the shapes of various positions, such as the start and end of the bead, corners, etc., when forming the molded object with a weld bead. This makes it easy to determine whether the conditions for the bead formation trajectory, etc., are appropriate. Therefore, the results of the above simulation are verified to verify whether the trajectory conditions are appropriate (S8).

[0066] Fig. 17 is a cross-sectional view taken along line XVII-XVII of the unit block group GUB shown in Fig. 15. Fig. 18 is a cross-sectional view taken along line XVIII-XVIII of the unit block group GUB shown in Fig. 15. While no particularly noticeable narrow portion occurs in the block cut surface shown in Fig. 17, a narrow portion 71 occurs between unit blocks UBc and UBd in the block cut surface shown in Fig. 18. The narrow portion 71 can be detected by extracting the portion where the surfaces of adjacent unit blocks intersect at an angle less than a predetermined limit angle. This narrow portion 71 is prone to slag accumulation during weld bead formation, which may lead to the occurrence of welding defects.

[0067] Therefore, if the verification reveals that a defect such as the occurrence of a narrow portion 71 has occurred, the condition correction unit 63 shown in Fig. 2 corrects the building conditions such as the welding speed, filler metal feed speed, bead formation trajectory, and layering sequence as necessary to prevent the defect (S9). After that, the process returns to step S4 (Fig. 4) where the cross section of the linear model is converted into a polygon, and the series of processes up to the execution of the simulation are repeated.

[0068] The generated group of unit blocks GUB may be compared with the model shape acquired by the data acquisition unit 51 shown in Fig. 3 to verify whether there is a shortage of excess metal or an excessively welded portion. Also, as shown in Fig. 14, the group of unit blocks GUB may be cut along a cross section in any direction to generate block cut surface information, and the positional relationship of each pass on the block cut surface may be checked. In this way, it is possible to verify the positional relationship of overlapping weld beads, whether there is a gap between adjacent weld beads, etc.

[0069] The results of the simulation are verified in this way, and if it is confirmed that no problems have occurred, the conditions of the trajectory plan used in the simulation are determined as the trajectory plan (S10). The actual production of the object is carried out by creating a drive program based on this determined trajectory plan and executing the created drive program.

[0070] <Smoothing the placement of unit models> 19A and 19B are diagrams showing different arrangement patterns of a plurality of unit blocks, with FIG. 19A being an explanatory diagram showing an arrangement pattern with steps, and FIG. 19B being an explanatory diagram showing a smoothed arrangement pattern. When multiple unit blocks are arranged along a continuous bead formation path (path PS), if there are existing unit blocks UBs in a lower layer in the height direction (z direction), as shown in Figure 19A, a new unit block UB will be arranged on top of the unit blocks UB in the lower layer. In this case, a sudden step will occur in the unit block UB to be newly arranged along the path PS. In this case, it is preferable to smooth the height position (target position) of the unit block UB and distribute the height change within the same path, as shown in Figure 19B.

[0071] 20A and 20B are diagrams showing different arrangement patterns of a plurality of unit blocks, with FIG. 20A being an explanatory diagram showing an arrangement pattern with steps, and FIG. 20B being an explanatory diagram showing a smoothed arrangement pattern. As shown in Fig. 20A, when unit block UBk1 and unit block UBk2 along path PS have different heights due to differences in welding speeds, etc., a sharp step occurs at the boundary between unit block UBk1 and unit block UBk2. In that case, as shown in Fig. 20B, it is preferable to gradually change the height of unit block UBk3 near the boundary where the height changes by changing the welding conditions (welding speed, etc.), thereby smoothing the height from unit block UBk1 to unit block UBk2.

[0072] In this way, when a sudden step occurs before or after each unit block along the path PS, the unit block can be smoothed out by adjusting the target position, welding conditions, etc. of the unit block to create a smooth connection, thereby making it possible to simulate an apparently unnatural layered shape into a bead shape that is more realistic.

[0073] <Bead model approximated to other polygons> Next, an example of a unit model in which the cross-sectional shape of a bead model (linear model) corresponding to the shaped object is approximated to a polygon other than a trapezoid to more closely resemble the shape of an actual weld bead will be described.

[0074] 21A and 21B are diagrams showing unit blocks based on trapezoidal and pentagonal bead models, with Fig. 21A being an explanatory diagram showing a cross section of the unit block and Fig. 21B being an explanatory diagram showing the unit block along the bead formation trajectory. Figs. 21A and 21B are the same as those shown in Figs. 8A and 8B, except that the other trapezoidal bead model BM2 shown in Figs. 8A and 8B is replaced with a pentagonal bead model BM3, and the hexahedral unit block UBb is replaced with a heptahedral unit block UBc.

[0075] 21A assumes that after a weld bead corresponding to bead model BM1 is formed, a new weld bead is formed along one side of the weld bead, and the model of the latter weld bead is bead model BM3. Bead model BM3 has vertices P4, P5, P6, P7, and P8, and is provided in contact with a portion of one side surface of bead model BM1 (between vertices P4 and P5). This bead model BM3 has a shape that is closer to an actual weld bead.

[0076] 21B, by extending back and forth along the bead forming trajectory, unit blocks UBc having vertices P4a, P5a, P6a, P7a, and P8a and vertices P4b, P5b, P6b, P7b, and P8b are obtained. The unit blocks UBc are columnar bodies with a pentagonal cross section.

[0077] 22A and 22B are diagrams showing division forms of the unit block UBc shown in FIGS. 21A and 21B, where FIG. 22A is a front view of the unit block Ubc and FIG. 22B is a perspective view of the unit block Ubc. The unit block UBc can be divided into a rectangular prism-shaped sub-unit block UBc1 and a triangular prism-shaped sub-unit block UBc2. The divided sub-unit blocks UBc1 and UBc2 can be used individually as shape models for simulation, thereby simplifying the shape of the unit block. This reduces the computational load of the simulation. Note that the division pattern of the unit block is not limited to this and other division forms may be used.

[0078] 23A and 23B show another division form of the unit block UBca, where FIG. 23A is a front view of the unit block Ubca and FIG. 23B is a perspective view of the unit block Ubca. The unit block UBca can be divided into a sub-unit block UBc1a, which is a trapezoidal prism with a cross section, and a sub-unit block UBc2a, which is a triangular prism with a right-angled triangular cross section. The sub-unit block UBc1a has a simple shape, with a pair of trapezoids each having the same base angle α. Thus, compared to the sub-unit blocks UBc1 and UBc2 shown in FIGS. 22A and 22B, the sub-unit blocks UBc1a and UBc2a have a further simplified shape in that the quadrilaterals are trapezoids with an axis of symmetry and one corner of the triangle is a right angle, which is expected to reduce the computational burden of the simulation. In this way, when the number of interior angles of the polygon of the bead model is five, the cross-sectional shape of the bead model is divided into trapezoids and triangles to generate unit blocks including hexahedral and pentahedral sub-unit blocks.

[0079] 24A and 24B are diagrams showing the divided form of an octahedral unit block UBd, where FIG. 24A is a front view of the unit block UBd and FIG. 24B is a perspective view of the unit block UBd. This unit block UBd has a shape that can be applied to a weld bead with a large bead height, and can be divided into a sub-unit block UBd1 that is a prism with a trapezoidal cross section, and a sub-unit block UBd2 that is a prism with a rectangular cross section.

[0080] 25A and 25B are diagrams showing the division form of an octahedral unit block UBe, where FIG. 25A is a front view of the unit block UBe and FIG. 25B is a perspective view of the unit block UBe. This unit block UBe has a shape that can be applied to a weld bead having a nearly circular cross section, and can be divided into sub-unit blocks UBe1 and UBe2, both of which are trapezoidal prisms in cross section.

[0081] 26A and 26B are diagrams showing the division form of a unit block UBf having a drooping portion, where Fig. 26A is a front view of the unit block UBf and Fig. 26B is a perspective view of the unit block UBf. The drooping portion refers to the portion where the molten metal of the weld bead drips down toward the underlying weld bead when the weld bead is formed. This unit block UBf can be divided into a sub-unit block UBf1, which is a prism with a trapezoidal cross section, and two sub-unit blocks UBf2, which are triangular prisms with triangular cross sections, located at the base corners of the trapezoidal cross section on the underside of the sub-unit block UBf1. The existence of the sub-unit block UBf2 allows the volume of the dripping weld bead to be subtracted from the volume of the entire unit block UBf, making it possible to set a unit block with a more accurate volume. This also makes it possible to approximate the shape of an actual weld bead, improving the accuracy of the simulation.

[0082] 27A and 27B are diagrams showing the division form of a decahedron unit block UBg, where FIG. 27A is a front view of the unit block UBg and FIG. 27B is a perspective view of the unit block UBg. This unit block UBg has a shape that can be applied to a weld bead with a cross section that is close to circular, and can be divided into a sub-unit block UBg1 that is a trapezoidal prism with a cross section, a sub-unit block UBg2 that is a rectangular prism with a cross section, and a sub-unit block UBg3 that is a trapezoidal prism with a cross section. Compared to the unit block UBe shown in FIGS. 25A and 25B, since the sub-unit block UBg2 is included, it can be applied to a weld bead having a larger volume.

[0083] In this way, when the number of interior angles of the polygon of the bead model is 6 or more and 8 or less, the cross-sectional shape of the bead model is divided into a trapezoid and a triangle, or a trapezoid and a rectangle, to generate a unit block including a plurality of hexahedral sub-unit blocks, or a plurality of hexahedral and pentahedral sub-unit blocks.

[0084] The number of interior angles of the polygon of the bead model can be further increased. 28A and 28B are diagrams showing a divided form of a unit block UBh having a hanging portion, where FIG. 28A is a front view of the unit block UBh and FIG. 28B is a perspective view of the unit block UBh. This unit block UBh is divided into a sub-unit block UBh1 which is a prism having a trapezoidal cross section, two sub-unit blocks UBh2 which are prisms having a rectangular cross section and are provided at the base corners of the trapezoidal cross section on the underside of the sub-unit block UBh1, and two sub-unit blocks UBh3 which are prisms having a rectangular cross section and connected to the underside of the sub-unit block UBh2. This allows the sub-unit blocks UBh2 and UBh3 to have a larger sagging portion than the unit block UBf shown in Figures 26A and 26B.

[0085] By using unit blocks and sub-unit blocks of such various shapes, the difference between the shape of an actual weld bead and that of the unit blocks becomes smaller, and the accuracy of the simulation can be further improved.

[0086] As described above, a shape model of a weld bead along a bead formation trajectory is determined using unit blocks with simple shapes that mimic a weld bead, and the state of the manufacturing process is determined by simulation using a shape model that is a group of unit blocks consisting of multiple unit blocks. This makes it possible to analytically extract areas where defects such as narrow portions may occur in the weld bead during manufacturing without actually forming the weld bead. Then, various manufacturing conditions such as the bead formation trajectory and welding conditions are adjusted to correct the trajectory plan so that areas where defects are likely to occur do not occur. In this way, it becomes possible to easily create a trajectory plan that can manufacture a high-quality object of a desired shape.

[0087] 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.

[0088] As described above, the present specification discloses the following: (1) A trajectory planning support method for forming a weld bead by melting and solidifying a filler material held by a manipulator while moving the manipulator, and stacking the formed weld beads to manufacture a shaped object, the method comprising: acquiring shape data of the object; decomposing the three-dimensional shape model based on the shape data into a plurality of linear models each having a polygonal cross section perpendicular to the longitudinal direction; setting a bead formation trajectory that forms the weld bead along the linear model and the bead formation trajectory that includes a layering order of the weld beads; generating a plurality of polygonal prism-shaped unit blocks by dividing the linear model into unit lengths along the set bead formation trajectory; creating the trajectory plan by simulating the formation of the weld bead for each unit block; A method for supporting trajectory planning. According to this trajectory planning support method, a 3D shape model based on acquired shape data is decomposed into multiple linear models with polygonal cross-sectional shapes, and the linear models are then divided into unit lengths along the bead formation trajectory to generate multiple polygonal columnar unit blocks. By simulating the formation of a weld bead for each unit block and creating a trajectory plan, it is possible to simulate the molding process for forming a molded object, and the trajectory plan can be easily verified based on the results of the simulation.

[0089] (2) accepting a correction condition for correcting the trajectory plan in accordance with the results of the simulation; (1) The trajectory planning method according to claim 1, wherein the simulation is repeatedly executed based on the correction conditions to correct the trajectory plan. According to this trajectory planning support method, a trajectory plan is created based on the results of a simulation. This allows for a more accurate plan to be created. Furthermore, by repeatedly correcting the trajectory plan, an accurate trajectory plan can be created more reliably.

[0090] (3) A trajectory planning method according to (1) or (2), wherein the portion of the unit block that simulates the weld bead is a columnar body having at least a pair of trapezoidal opposing surfaces, and the portion that simulates a portion of the base material on which the weld bead is laminated is a columnar body having a pair of opposing surfaces that are polygons with eight or more vertices. This trajectory planning support method allows the weld bead and base material to be reproduced in simple shapes. Furthermore, by having the base material have a polygonal surface with eight or more vertices, it becomes easier to identify the positional relationship and contact points between the weld bead and base material, even if the base material surface has a curved surface such as a cylinder. This makes it easier to define the position of the unit block on the weld bead side based on the vertices, center point, etc. of the polygonal shape of the unit block on the base material side.

[0091] (4) A trajectory planning method according to any one of (1) to (3), in which the unit block is a truncated polygonal pyramid with its bottom surface facing in the bead formation direction, at least at one of the start and end of the bead formation trajectory. According to this trajectory planning support method, the rounded shapes of the start and end of the weld bead can be reproduced satisfactorily.

[0092] (5) A trajectory planning method according to any one of (1) to (4), wherein the outer shape of a plurality of unit blocks along the continuous bead formation trajectory is smoothed in accordance with changes in the weld bead formation conditions or stacking position. According to this trajectory planning support method, the apparent unnatural steps and the like that occur due to polygonal approximation can be corrected, and the shape of the weld bead can be made smoother and closer to the actual shape.

[0093] (6) A trajectory planning support method according to any one of (1) to (5), wherein the volume of the unit block is increased or decreased depending on the welding speed during the formation of the weld bead and the feed speed of the filler metal. According to this trajectory planning support method, the volume of the unit block is adjusted according to the welding speed and the filler metal feed speed, so that the shape of the unit block can be made closer to the shape of the actual weld bead, even at the start, end, and corner of the bead.

[0094] (7) A trajectory planning support method according to any one of (1) to (6), wherein, when generating the polygonal prism-shaped unit block, at least one vertex of the polygonal prism is moved according to the distance between the polygonal prism and a vertex of another linear model adjacent to the linear model of the polygon. According to this trajectory planning support method, even when the bead shape changes due to overlapping of the weld beads, it is possible to reproduce a shape that is close to the actual weld bead shape.

[0095] (8) A trajectory planning support method according to any one of (1) to (7), which generates block cross section information representing the positional relationship of a plurality of unit blocks that overlap each other in a cross section obtained by cutting a group of unit blocks in any direction, in which a plurality of the unit blocks are arranged along the bead forming trajectory. According to this trajectory planning support method, the state of each unit block in a unit block group can be easily grasped at any cross section, which can prompt correction of errors in trajectory planning.

[0096] (9) The trajectory planning support method according to (8), wherein the block cut surface information is displayed on a display unit. According to this trajectory planning support method, block cut surface information is displayed on the display unit, allowing the worker to easily visually recognize the state of the unit blocks.

[0097] (10) The trajectory planning support method according to (8), further comprising extracting, from the block cross section information, a narrow section where surfaces of adjacent unit blocks intersect at an angle less than a predetermined limit angle. According to this trajectory planning support method, narrow sections where defects are likely to occur can be extracted, thereby providing the operator with an opportunity to predict the occurrence of defects and set conditions to prevent defects.

[0098] (11) The trajectory planning support method according to (10), further comprising displaying the narrow portion on a display unit. According to this trajectory planning support method, information about narrow sections is displayed on the display unit, allowing the operator to easily visually recognize the occurrence of narrow sections.

[0099] (12) A trajectory planning support method according to any one of (1) to (11), in which at least one of the length of the block side of the unit block and the number of interior angles of the polygon is changed depending on the direction of the bead formation trajectory. According to this trajectory planning support method, when arranging a plurality of unit blocks, the arrangement direction of the unit blocks can be directed in a desired direction, thereby making it possible to easily arrange the unit blocks along the direction in which the weld bead is formed.

[0100] (13) The trajectory planning support method according to any one of (1) to (12), wherein the unit block has a shape with a constant thickness in a direction along the bead formation trajectory. According to this trajectory planning support method, the unit blocks are shaped to a uniform thickness, and the arrangement of the unit blocks can be easily performed.

[0101] (14) A trajectory planning support method according to any one of (1) to (12), wherein the thickness of the unit block in a direction along the bead formation trajectory is set to a thickness according to the curvature of the bead formation trajectory. According to this trajectory planning support method, it is possible to prevent unnatural gaps or overlaps from occurring at the points where unit blocks are connected to each other.

[0102] (15) If the number of interior angles of the polygon is 5, the cross-sectional shape of the bead model is divided into trapezoids and triangles to generate the unit blocks including sub-unit blocks of hexahedrons and pentahedrons; The trajectory planning support method according to any one of (1) to (14), wherein, when the number of interior angles of the polygon is 6 or more and 8 or less, the cross-sectional shape of the bead model is divided into a trapezoid and a triangle, or a trapezoid and a rectangle, and the unit block including a plurality of hexahedral sub-unit blocks, or a plurality of hexahedral and pentahedral sub-unit blocks, is generated. According to this trajectory planning support method, the cross-sectional shape of the bead model can be further decomposed into a plurality of polygons, thereby further simplifying the shape of the unit block.

[0103] (16) A trajectory planning support method according to any one of (1) to (15), wherein, in a region where the weld beads overlap vertically, the unit blocks of an upper layer are arranged without overlapping on the unit blocks arranged in the lower layer. According to this trajectory planning support method, when unit blocks are stacked one on top of the other, they are simply stacked without overlapping each other, which allows simulation to be performed with a simple shape model without fusing the unit blocks.

[0104] (17) A trajectory planning support method according to any one of (1) to (16), wherein, in the area where the weld beads overlap each other, at least a part of the shape of the unit block of the upper layer has a hanging portion that hangs down toward the unit block arranged in the lower layer. This trajectory planning support method can simulate the dripping of molten metal when a weld bead is formed, thereby improving the accuracy of the simulation.

[0105] (18) The trajectory planning support method according to any one of (1) to (17), wherein the plurality of unit blocks are arranged along the bead forming trajectory with gaps between adjacent unit blocks. According to this trajectory planning support method, by providing gaps between unit blocks, the total number of unit blocks required can be reduced, and the calculation load during simulation can be reduced.

[0106] (19) An additive manufacturing method for forming the weld bead based on the trajectory plan determined by the trajectory plan creation support method according to any one of (1) to (18). According to this additive manufacturing method, a trajectory plan is executed that allows the manufacturing results to be predicted through simulation, so that manufacturing can be performed under appropriate conditions that minimize the occurrence of defects.

[0107] (20) A trajectory planning support device including a control unit that creates the trajectory plan by the trajectory planning support method according to any one of (1) to (18). This trajectory planning support device decomposes a 3D shape model based on acquired shape data into multiple linear models with polygonal cross-sectional shapes, and then divides the linear models into unit lengths along the bead formation trajectory to generate multiple polygonal columnar unit blocks. By simulating the formation of a weld bead for each unit block and creating a trajectory plan, it is possible to simulate the molding process for forming a molded object, and the trajectory plan can be easily verified from the results of the simulation.

[0108] (21) The trajectory planning support device according to (20), further comprising a condition correction unit that corrects the trajectory plan in accordance with the results of the simulation. According to this trajectory planning support device, the trajectory plan can be made closer to a more appropriate plan depending on the results of the simulation.

[0109] (22) An additive manufacturing device that forms the weld bead based on the trajectory plan determined by the trajectory plan creation support device described in (20) or (21). This additive manufacturing device executes a trajectory plan that allows the manufacturing results to be predicted through simulation, allowing manufacturing to be performed under appropriate conditions that minimize the occurrence of defects.

[0110] (23) A program that causes a computer to execute the steps of the trajectory planning support method described in (1) to (18). This program decomposes a 3D shape model based on the acquired shape data into multiple linear models with polygonal cross-sectional shapes, and then divides the linear models into unit lengths along the bead formation trajectory to generate multiple polygonal columnar unit blocks. By simulating the formation of a weld bead for each unit block and creating a trajectory plan, the molding process for forming a molded object can be simulated, and the trajectory plan can be easily verified from the simulation results.

[0111] (24) A program that causes a computer to execute a procedure for correcting the trajectory plan created by the program according to (23) in accordance with the results of the simulation. This program allows the trajectory plan to be brought closer to a more appropriate plan based on the results of the simulation. [Explanation of symbols]

[0112] 11 Modeling Department 13 Control Unit 13A External control unit 15 Welding Torch 17 Welding robot 21 Robot drive unit 23 Filler metal supply section 25 Welding power supply unit 27 reels 29 Base material 31 Input section 33 Display section 35 PC 36 External PC 37 Arithmetic Processor 39 Memory 41 Storage section 43 Interface 45 Communications Department 51 Data Acquisition Section 53 Shape decomposition processing section 55 Cross-sectional shape approximation part 57 Databases 59 Unit block generation unit 61 Simulation Department 63 Condition correction section 71 Narrow area 100 Additive manufacturing equipment B Weld bead BL bead layer BM, BM0, BM1, BM1a, BM1b, BM2, BM2a, BM3 Bead model (linear model) BMa base BMb upper edge BMc,BMd side GUB group of unit blocks H bead height Hb bead height M Filler metal (welding wire) Mw 3D shape model P1,P2,P3,P4,P5,P6,P7,P8 Vertices PL plane PM Linear Model PS1, PS2, PSa, PSb, PSc Bead formation trajectory SD array direction UB, UB1, UB2, UB3, UB4, UB5, UB6, UBa, UBb, UBc, UBca, UBd, UBe, UBf, UBg, UBh, UBp, UBk1, UBk2, UBk3 unit blocks UBc1,UBc1a,UBc2,UBc2a,UBd1,UBd2,UBe1,UBe2,UBf1,UBf2,UBg1,UBg2,UBg3,UBh1,UBh2,UBh3 sub-unit blocks V bead unit volume W sculpture Wb Bead width α base angle θ Tilt angle

Claims

1. 1. A trajectory planning assistance method for manufacturing a shaped object by melting and solidifying a filler material held by a manipulator while moving the manipulator to form a weld bead, and stacking the formed weld beads, the method comprising: acquiring shape data of the object; decomposing the three-dimensional shape model based on the shape data into a plurality of linear models each having a polygonal cross section perpendicular to the longitudinal direction; setting a bead formation trajectory that forms the weld bead along the linear model and the bead formation trajectory that includes a layering order of the weld beads; generating a plurality of polygonal prism-shaped unit blocks by dividing the linear model into unit lengths along the set bead formation trajectory; creating the trajectory plan by simulating the formation of the weld bead for each unit block; A method for supporting trajectory planning.

2. accepting a correction condition for correcting the trajectory plan in accordance with a result of the simulation; repeating the simulation based on the modification conditions to modify the trajectory plan; The trajectory planning support method according to claim 1 .

3. The unit block has a portion simulating the weld bead that is a columnar body having at least a pair of trapezoidal opposing surfaces, and a portion simulating a portion of the base material on which the weld bead is laminated that is a columnar body having a cross-sectional shape of a polygon with eight or more vertices. The trajectory planning support method according to claim 1 or 2.

4. The unit block having a truncated polygonal pyramid shape with its bottom surface facing in the bead forming direction is placed at at least one of the start end and the end end of the bead forming locus. The trajectory planning support method according to any one of claims 1 to 3.

5. smoothing the outer shapes of the unit blocks along the continuous bead formation locus in accordance with changes in the welding bead formation conditions or stacking positions; The trajectory planning support method according to any one of claims 1 to 4.

6. The volume of the unit block is increased or decreased depending on the welding speed when the weld bead is formed and the feed speed of the filler metal. The trajectory planning support method according to any one of claims 1 to 5.

7. When generating the polygonal prism-shaped unit block, at least one vertex of the polygonal prism is moved in accordance with the distance between the polygonal prism and a vertex of another linear model adjacent to the polygonal linear model. The trajectory planning support method according to any one of claims 1 to 6.

8. generating block cross section information that represents a positional relationship between the plurality of unit blocks that overlap each other in a cross section obtained by cutting a group of unit blocks in which the plurality of unit blocks are arranged along the bead forming trajectory in an arbitrary direction; The trajectory planning support method according to any one of claims 1 to 7.

9. displaying the block cut surface information on a display unit; The trajectory planning support method according to claim 8.

10. extracting, from the block cut surface information, a narrow portion where surfaces of adjacent unit blocks intersect at an angle less than a predetermined limit angle; The trajectory planning support method according to claim 8.

11. displaying the narrow portion on a display unit; The trajectory planning support method according to claim 10.

12. At least one of the length of a block side of the unit block and the number of interior angles of the polygon is changed according to the direction of the bead forming trajectory. The trajectory planning support method according to any one of claims 1 to 11.

13. The unit block is shaped to have a constant thickness in a direction along the bead forming track. The trajectory planning support method according to any one of claims 1 to 12.

14. a thickness of the unit block in a direction along the bead forming track that corresponds to the curvature of the bead forming track; The trajectory planning support method according to any one of claims 1 to 12.

15. If the number of interior angles of the polygon is five, the shape of the vertical cross section of the linear model is divided into trapezoids and triangles to generate the unit blocks including sub-unit blocks of hexahedrons and pentahedrons; When the number of interior angles of the polygon is 6 or more and 8 or less, the shape of the vertical cross section of the linear model is divided into a trapezoid and a triangle, or a trapezoid and a rectangle, to generate the unit block including a plurality of hexahedral sub-unit blocks, or a plurality of hexahedral and pentahedral sub-unit blocks. The trajectory planning support method according to any one of claims 1 to 14.

16. In a portion where the weld beads are vertically overlapped, the unit block of an upper layer is disposed on the unit block disposed in the lower layer without overlapping therewith. The trajectory planning support method according to any one of claims 1 to 15.

17. In the region where the weld beads are vertically overlapped, at least a part of the shape of the unit block of the upper layer is formed to have a hanging portion that hangs down toward the unit block arranged in the lower layer. The trajectory planning support method according to any one of claims 1 to 16.

18. the plurality of unit blocks are arranged along the bead-forming track with gaps between adjacent unit blocks; The trajectory planning support method according to any one of claims 1 to 17.

19. 19. An additive manufacturing method for forming the weld bead based on the trajectory plan determined by the trajectory planning support method according to claim 1.

20. A trajectory planning assistance device comprising: a control unit that creates the trajectory plan by the trajectory planning assistance method according to any one of claims 1 to 18.

21. a condition correction unit that corrects the trajectory plan in accordance with a result of the simulation; The trajectory planning support device according to claim 20.

22. 22. An additive manufacturing apparatus that forms the weld bead based on the trajectory plan determined by the trajectory plan creation assistance device according to claim 20 or 21.

23. A program that causes a computer to execute the steps of the trajectory planning support method according to any one of claims 1 to 18.

24. 24. A program that causes a computer to execute a procedure of correcting the trajectory plan created by the program according to claim 23 in accordance with the results of the simulation.

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