Wire arc lamination molding method, wire arc lamination molding system, control information generation device, control device, and program

Abstract

To provide a wire arc lamination molding method capable of performing lamination molding under more stable temperature conditions.SOLUTION: A wire arc lamination molding method comprising: a first step of generating control information for a robot performing wire arc lamination molding for each lamination height at a pitch finer than a lamination pitch; a second step of detecting a current lamination height; a third step of selecting, from among the control information generated in the first step, the control information corresponding to the current lamination height detected in the second step; and a fourth step of controlling the robot using the control information selected in the third step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a wire arc additive manufacturing method, a wire arc additive manufacturing system, a control information generating device, a control device, and a program. [Background technology]

[0002] Conventionally, a known device configuration for WAAM (Wire arc additive manufacturing) is one that uses an arc welding robot to laminate metal materials. Patent Document 1 discloses an additive manufacturing method that measures the shape of a laminated bead and updates a lamination trajectory plan according to the measured shape. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6797324 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the additive manufacturing method of Patent Document 1, the stacking trajectory plan is updated every time stacking is performed, and this generally requires a long calculation time, and the temperature of the bead changes during the update of the stacking trajectory plan, which causes a problem that the temperature conditions during welding may become unstable. If the temperature conditions during welding become unstable, this may affect the shape or metal structure of the molded object.

[0005] The present invention has been made in consideration of the above circumstances, and provides a wire arc additive manufacturing method, a wire arc additive manufacturing system, a control information generating device, a control device, and a program that enable additive manufacturing to be performed under more stable temperature conditions. [Means for solving the problem]

[0006] The present invention has been made to solve the above-mentioned problems, and one aspect of the present invention is a wire arc additive manufacturing method having a first step of generating control information for a robot performing wire arc additive manufacturing for each stack height at a pitch finer than the stack pitch, a second step of detecting the current stack height, a third step of selecting, from the control information generated by the first step, control information corresponding to the current stack height detected by the second step, and a fourth step of controlling the robot using the control information selected in the third step.

[0007] Another aspect of the present invention is the above-described wire arc additive manufacturing method, wherein the pitch finer than the lamination pitch is a pitch obtained by dividing the lamination pitch by 1 / 3 or less.

[0008] Another aspect of the present invention is a wire arc additive manufacturing system comprising a robot that performs wire arc additive manufacturing, a control device that controls the robot, and a control information generating device that generates control information for the robot used by the control device, wherein the control information generating device generates the control information for each stack height at a pitch finer than the stack pitch, and the control device comprises a stack height acquisition unit that acquires a current stack height, and a robot control unit that selects from the control information control information that corresponds to the current stack height acquired by the stack height acquisition unit and controls the robot using the selected control information.

[0009] Another aspect of the present invention is a control information generating device that generates control information for a robot that performs wire arc additive manufacturing, the control information being generated for each stack height at a pitch finer than the stack pitch.

[0010] Another aspect of the present invention is a control device for a robot that performs wire arc additive manufacturing, comprising a stack height acquisition unit that acquires a current stack height, and a robot control unit that selects control information corresponding to the current stack height acquired by the stack height acquisition unit from control information generated for each stack height at a pitch finer than the stack pitch, and controls the robot using the selected control information.

[0011] Another aspect of the present invention is a program that causes a computer to function as a control information generating device that generates control information for a robot that performs wire arc additive manufacturing, and generates the control information for each stack height at a pitch finer than the stack pitch.

[0012] Another aspect of the present invention is a program for causing a computer of a control device of a robot performing wire arc additive manufacturing to function as a robot control unit that includes a stack height acquisition unit that acquires a current stack height, selects control information corresponding to the current stack height acquired by the stack height acquisition unit from control information generated for each stack height at a pitch finer than the stack pitch, and controls the robot using the selected control information. Effect of the Invention

[0013] According to the present invention, the wire arc additive manufacturing method, the wire arc additive manufacturing system, the control information generating device, the control device, and the program can perform additive manufacturing under more stable temperature conditions. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing the configuration of a wire arc additive manufacturing system 10 according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing the functional configuration of a wire arc additive manufacturing system 10 in the same embodiment. [Diagram 3] 11 is a schematic diagram for explaining control information and height information in the embodiment. FIG. [Figure 4] 2 is a schematic diagram showing an example of the contents stored in a control information storage unit 121 in the embodiment. FIG. [Diagram 5] 4 is an example of a front view of a metal structure in the embodiment. [Figure 6] 11 is a table showing an example of the contents of control information in the embodiment. [Figure 7] 11 is a flowchart illustrating the operation of the control information generating device 11 in the embodiment. [Figure 8] 4 is a flowchart illustrating the operation of a control device 12 in the embodiment. [Figure 9] 11 is a schematic diagram showing another example of division of the layer pitch AP in the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of a wire arc additive manufacturing system 10 according to an embodiment of the present invention. The wire arc additive manufacturing system 10 is a 3D printer of a metal fusion additive manufacturing method (WAAM) that uses an arc welding device. The wire arc additive manufacturing system 10 includes a control information generating device 11, a control device 12, and a robot 13.

[0016] Each of the control information generating device 11 and the control device 12 may be realized by one or more computers reading and executing a program. The control information generating device 11 and the control device 12 may be realized by the same one or more computers, or may be realized by one or more different computers. The control information generating device 11 and the control device 12 may be connected to each other so as to be able to communicate with each other via an IP (Internet Protocol) network or the like, or data may be exchanged via a USB (Universal Serial Bus) memory or the like.

[0017] The control information generating device 11 generates control information for the robot 13 used by the control device 12, which is used to form the metal object 20. The control information generating device 11 generates the control information for each stacking height at a pitch finer than the stacking pitch.

[0018] The control device 12 controls the robot 13 using the control information generated by the control information generating device 11. The control device 12 acquires the current stacking height of the metal molded object 20, selects control information corresponding to the stacking height from among the control information generated by the control information generating device 11, and controls the robot 13 using the control information. The stacking height may be acquired by any method. For example, an in-line profiler provided in the robot 13 may be used, or the stacking height may be predicted from process data (e.g., welding conditions such as welding current, welding voltage, and wire feed speed), or a shape measuring device (not shown) provided separately may be used. In this way, the control device 12 selects and controls from among the control information generated by the control information generating device 11. For this reason, no calculation time is required to update the control information between stacking, and additive manufacturing can be performed under more stable temperature conditions.

[0019] The robot 13, under the control of the control device 12, forms and stacks metal layers with the molten wire (metal material) to form a metal object 20. The robot 13 stacks the metal layers vertically from the bottom to the top.

[0020] 2 is a block diagram showing the functional configuration of the wire arc additive manufacturing system 10 in this embodiment. The control information generating device includes a 3D (three dimensional) model acquiring unit 111, a 3D model slicing unit 112, and a control information generating unit 113. The control device 12 includes a control information storage unit 121, a stacking height acquiring unit 122, a control information selecting unit 123, and a robot control unit 124.

[0021] The 3D model acquisition unit 111 acquires a 3D model of a metal object. The 3D model slice unit 112 slices the 3D model acquired by the 3D model acquisition unit 111 into horizontal planes at a predetermined pitch, and generates cross-sectional information indicating a cross-sectional shape in each horizontal plane. Here, the predetermined pitch is a pitch finer than the lamination pitch by the robot 13. The predetermined pitch may be a pitch obtained by dividing the lamination pitch into a plurality of parts. This pitch may be set by an operator of the control information generation device 11. The predetermined pitch may be a pitch obtained by equally dividing the lamination pitch, and when the pitch is a pitch obtained by equally dividing the lamination pitch into a plurality of parts, the number of divisions may be set by the operator, but is preferably 1 / 3 or less.

[0022] The control information generating unit 113 generates control information indicating a plan of a stacked trajectory of the robot 13 corresponding to each horizontal plane based on the cross-sectional information generated by the 3D model slicing unit 112. The control information generating unit 113 stores the generated control information in the control information storage unit 121 of the control device 12 together with information indicating the corresponding horizontal plane (height information).

[0023] Note that the control information generating unit 113 does not have to directly store the control information and the height information in the control information storage unit 121. For example, the control information generating unit 113 may store the control information in a USB memory or the like, and an operator may instruct copying of the control information from the USB memory to the control information storage unit 121.

[0024] The control information storage unit 121 stores the control information generated by the control information generation unit 113 in association with the height information. The stacking height acquisition unit 122 acquires the current height (stacking height) of the metal object (bead) being additively manufactured by the robot 13. The stacking height may be, for example, the average height of the previously stacked portion. The control information selection unit 123 selects the control information stored in the control information storage unit 121 in association with the height information that is closest to the stacking height acquired by the stacking height acquisition unit 122. The robot control unit 124 controls the robot 13 using the control information selected by the control information selection unit 123.

[0025] FIG. 3 is a schematic diagram for explaining the control information and the height information in this embodiment. In FIG. 3, the X-axis and the Y-axis are axes that are orthogonal to each other in a horizontal plane, and the Z-axis is an axis in the vertical direction. The metal object B is a rotating body about the Z-axis, and is additively manufactured by a welding torch T provided in the robot 13. The layer pitch is a predetermined pitch and corresponds to the height of a bead formed by one layering. The slice plane S of the metal object B is a plane that is orthogonal to the Z-axis, i.e., a horizontal plane, and is provided at a predetermined pitch P. In the example of FIG. 3, this pitch P is a pitch obtained by dividing the layer pitch AP into three equal parts, but may be divided into two equal parts, or into four or more equal parts.

[0026] In FIG. 3, the slice surfaces S are numbered as height information of the slice surfaces S, such as Layerxxxx01-00, Layerxxxx01-01, Layerxxxx01-02, Layerxxxx02-00, Layerxxxx02-01, Layerxxxx02-02, .... Here, xxxx indicates a four-digit number. XXXXXX in LayerXXXXXX-YY indicates the layer pitch of the slice surface S, and YY indicates the layer pitch of the slice surface S. Therefore, the height of the slice surface S can be obtained from XXXXXX and YY.

[0027] Fig. 4 is a schematic diagram showing an example of the contents stored in the control information storage unit 121 in this embodiment. In the example of Fig. 4, control information for additive manufacturing of one metal object is stored in a folder Project. Folders Branch1, Branch2, and Branch3 stored in the folder Project are folders for storing control information for each of a plurality of branches, for example, when a metal object is branched. These folders will hereinafter be referred to as "branches."

[0028] The file Definition ini.txt stored in the folder Branch1 stores information common to the control information stored in the folder (e.g., layer pitch, number of divisions of layer pitch, welding conditions, etc.). The files Layer numberxxxx01-00.txt, Layer numberxxxx01-01.txt, Layer numberxxxx01-02.txt, Layer numberxxxx02-00.txt, ... are control information corresponding to the layer height, and the number part of the file name represents the layer height. For example, if the file name is Layer numberMMMMMM-NN.txt, the layer pitch is AP, and the number of divisions of the layer pitch is N, the corresponding layer height may be MMMMMM x AP + NN x (AP / N).

[0029] Fig. 5 is an example of a front view of a metal object in this embodiment. In Fig. 5, the horizontal axis is the X axis, the vertical axis is the Z axis (vertical axis), and the axis perpendicular to the paper surface is the Y axis. Since the metal object shown in Fig. 5 is branched, the control information for the parts BR1, BR2, and BR3 are stored in the folders Branch1, Branch2, and Branch3 in Fig. 4, respectively. Note that, although the parts BR2 and BR3 branch upward from the part BR1 in Fig. 5, they may branch downward.

[0030] Fig. 6 is a table showing an example of the contents of the control information in this embodiment. The example contents shown in Fig. 6 are stored in the control information storage unit 121 as the file Layer numberxxxx01-00.txt in Fig. 4, for example. In Fig. 6, the numbers are serial numbers of the progress points constituting the plan of the stacking trajectory. The X coordinate, the Y coordinate, and the Z coordinate indicate the position of the tip of the welding torch of the robot 13 at the progress point indicated by the number. The rotations around the X axis, the Y axis, and the Z axis indicate the posture of the welding torch of the robot 13 at the progress point indicated by the number.

[0031] In the example of FIG. 6, the file Layer numberxxxx01-00.txt stores the following, associated with the number "1", as X coordinate "5.3", Y coordinate "7.8", Z coordinate "20.6", X axis rotation "0.5", Y axis rotation "0.6", and Z axis rotation "0.0". Similarly, the following are stored in association with the number "2": X coordinate "5.3", Y coordinate "3.2", Z coordinate "20.6", X axis rotation "0.4", Y axis rotation "0.5", and Z axis rotation "0.5"; the following are stored in association with the number "3": X coordinate "10.6", Y coordinate "3.2", Z coordinate "20.6", X axis rotation "0.5", Y axis rotation "0.6", and Z axis rotation "0.0"; and the following are stored in association with the number "4": X coordinate "7.9", Y coordinate "-11.8", Z coordinate "20.6", X axis rotation "0.4", Y axis rotation "0.5", and Z axis rotation "0.5".

[0032] 7 is a flowchart illustrating the operation of the control information generating device 11 in this embodiment. First, the 3D model acquisition unit 111 acquires a 3D model of a metal object (step Sa1).

[0033] Next, the 3D model slicing unit 112 acquires the layer pitch and the number of divisions (step Sa2). Note that instead of the number of divisions, the size of the pitch into which the layer pitch is divided may be acquired. The 3D model slicing unit 112 may acquire these pieces of information by values ​​set by the operator of the control information generating device 11 using input means such as a mouse, keyboard, or touch pad.

[0034] Next, the 3D model slicer 112 generates cross-sectional information of the 3D model on horizontal planes (slicing planes) for each pitch obtained by dividing the layer pitch by the division number (step Sa3). Note that in step Sa2, if the size of the pitch for dividing the layer pitch is acquired instead of the division number, the 3D model slicer 112 generates cross-sectional information of the 3D model on the slice plane for each pitch of the acquired size.

[0035] Next, the control information generating unit 113 generates control information and height information according to each piece of cross-sectional information (step Sa4). The control information is information for stacking the cross-sectional shapes indicated by the cross-sectional information, and the height information is information indicating the height (e.g., the Z coordinate value) of the slice plane corresponding to the cross-sectional information.

[0036] Next, the control information generator 113 stores the generated control information and height information in the control information storage unit 121 (step Sa5).

[0037] 8 is a flowchart illustrating the operation of the control device 12 in this embodiment. First, the stacking height acquisition unit 122 acquires the current stacking height of the bead (step Sb1). Next, the control device 12 performs steps Sb3 and Sb4 for each branch (step Sb2).

[0038] In step Sb3, the control information selection unit 123 selects, from among the target branches, control information associated with height information that is closest to the stacking height acquired in step Sb1. For example, if the stacking pitch is AP, the number of divisions of the stacking pitch is N, and the acquired stacking height is H, the control information selection unit 123 may select a file Layer numberMMMMMM-NN.txt, where MMMMMM=Floor(H / AP) and NN=mod(H,AP). Here, Floor(X) represents the decimal point of X, and mod(X,Y) represents the remainder when X is divided by Y. In addition, a condition that the control information corresponds to height information whose difference between the stacking height acquired in step Sb1 and the height information is within a predetermined threshold value may be added to the selection conditions of the control information in step Sb3.

[0039] In step Sb4, the robot control unit 124 uses the control information selected in step Sb3 to control the robot 13 to perform additive manufacturing.

[0040] Step Sb5 is a step paired with step Sb2. When all branches have been processed in the loop starting from step Sb2, processing proceeds to step Sb6. When any branch has not been processed, processing returns to step Sb3 for that branch.

[0041] In step Sb6, the control device 12 determines whether or not the additive manufacturing has been completed. If it has not been completed (step Sb6-No), the control device 12 returns to step Sb1. If it has been completed (step Sb6-Yes), the control device 12 ends the process.

[0042] 9 is a schematic diagram showing another example of division of the layer pitch AP in this embodiment. In FIG. 3, the layer pitch AP is divided equally into three to set the pitch between slice planes, but it does not have to be divided equally. In the example of FIG. 9, the pitch P1 close to the layer pitch AP and the pitch P2 away from the layer pitch AP are different, and the pitch P1 is made smaller than the pitch P2. When the layer pitch AP is estimated accurately and there is a high probability that the layer height acquired by the layer height acquisition unit 122 will be a value close to a multiple of the layer pitch AP, it is possible to reduce the number of control information generated and prepare control information close to the layer height in advance.

[0043] In the above-described embodiment, the robot 13 may include a stage to which the metal structure 20 is fixed, and the control information may include control information for rotating or moving the stage.

[0044] The following embodiment may also be adopted. (1) One embodiment is a wire arc additive manufacturing method having a first step of generating control information for a robot performing wire arc additive manufacturing for each stack height at a pitch finer than the stack pitch, a second step of detecting the current stack height, a third step of selecting, from the control information generated by the first step, control information corresponding to the current stack height detected by the second step, and a fourth step of controlling the robot using the control information selected in the third step.

[0045] (2) Another embodiment is the wire arc additive manufacturing method described in (1), in which the pitch finer than the lamination pitch is a pitch obtained by dividing the lamination pitch into multiple parts.

[0046] (3) Another embodiment is a wire arc additive manufacturing system comprising a robot that performs wire arc additive manufacturing, a control device that controls the robot, and a control information generating device that generates control information for the robot used by the control device, wherein the control information generating device generates the control information for each stack height at a pitch finer than the stack pitch, and the control device comprises a stack height acquisition unit that acquires a current stack height, and a robot control unit that selects from the control information control information that corresponds to the current stack height acquired by the stack height acquisition unit and controls the robot using the selected control information.

[0047] (4) Another embodiment is a control information generating device that generates control information for a robot that performs wire arc additive manufacturing, and generates the control information for each stack height at a pitch finer than the stack pitch.

[0048] (5) Another embodiment is a control device for a robot that performs wire arc additive manufacturing, comprising: a stack height acquisition unit that acquires a current stack height; and a robot control unit that selects control information corresponding to the current stack height acquired by the stack height acquisition unit from control information generated for each stack height at a pitch finer than the stack pitch, and controls the robot using the selected control information.

[0049] (6) Another embodiment is a program that causes a computer to function as a control information generating device that generates control information for a robot that performs wire arc additive manufacturing, and generates the control information for each stack height at a pitch finer than the stack pitch.

[0050] (7) Another embodiment is a program for causing a computer of a control device of a robot performing wire arc additive manufacturing to function as a robot control unit that includes a stack height acquisition unit that acquires a current stack height, selects control information corresponding to the current stack height acquired by the stack height acquisition unit from control information generated for each stack height at a pitch finer than the stack pitch, and controls the robot using the selected control information.

[0051] 1 and 2 may be realized by recording a program for realizing the functions of the control information generating device 11 and the control device 12 in a computer-readable recording medium, and reading and executing the program recorded in the recording medium into a computer system. Note that the "computer system" here includes hardware such as an OS and peripheral devices.

[0052] In addition, if a WWW system is used, the "computer system" also includes the homepage providing environment (or display environment). In addition, "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into computer systems. Furthermore, "computer-readable recording medium" also includes those that dynamically hold a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and those that hold a program for a certain period of time, such as volatile memory inside a computer system that serves as a server or client in such cases. Furthermore, the above program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0053] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not deviate from the gist of the present invention are also included. [Explanation of symbols]

[0054] 10. Wire Arc Additive Manufacturing System 11 Control information generator 12 Control device 13. Robot 20 Metal objects 111 3D Model Acquisition Department 112 3D model slice section 113 Control information generation unit 121 Control information storage unit 122 Stack height acquisition unit 123 Control information selection unit 124 Robot control unit

Claims

1. A wire arc additive manufacturing method, comprising: A first step of generating control information for a robot performing wire-arc additive manufacturing for each stack height at a pitch finer than the stack pitch; a second step of detecting a current stack height; a third step of selecting control information corresponding to the current stacking height detected in the second step from the control information generated in the first step; a fourth step of controlling the robot using the control information selected in the third step; A wire arc additive manufacturing method having the above structure.

2. The wire-arc additive manufacturing method according to claim 1 , wherein the pitch finer than the lamination pitch is a pitch obtained by dividing the lamination pitch by ⅓ or less.

3. A robot that performs wire arc additive manufacturing, A control device for controlling the robot; a control information generating device that generates control information for the robot used by the control device; A wire arc additive manufacturing system comprising: The control information generating device comprises: The control information is generated for each stack height at a pitch finer than the stack pitch; The control device includes: A stacking height acquisition unit for acquiring a current stacking height; a robot control unit that selects, from the control information, control information corresponding to the current stacking height acquired by the stacking height acquisition unit, and controls the robot using the selected control information; A wire arc additive manufacturing system comprising:

4. A control information generation device that generates control information for a robot that performs wire arc additive manufacturing, The control information is generated for each stack height at a pitch finer than the stack pitch. Control information generating device.

5. A control device for a robot that performs wire arc additive manufacturing, A stacking height acquisition unit for acquiring a current stacking height; a robot control unit that selects control information corresponding to the current stack height acquired by the stack height acquisition unit from among control information generated for each stack height at a pitch finer than the stack pitch, and controls the robot using the selected control information; A control device comprising:

6. Computer, A program that functions as a control information generating device that generates control information for a robot that performs wire arc additive manufacturing, The control information is generated for each stack height at a pitch finer than the stack pitch. program.

7. The computer of the control device of the robot that performs wire arc additive manufacturing, a stack height acquisition unit for acquiring a current stack height; A robot control unit that selects control information corresponding to the current stack height acquired by the stack height acquisition unit from among control information generated for each stack height at a pitch finer than the stack pitch, and controls the robot using the selected control information. A program to function as a

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