Metal-shaped object manufacturing apparatus and metal-shaped object manufacturing method

Abstract

To provide a metal-shaped object manufacturing apparatus capable of estimating the internal contour shape of a large metal-shaped object.SOLUTION: A metal-shaped object manufacturing apparatus comprises: a robot arm equipped at its tip with a welding torch that forms a metal-shaped object by laminating molten metal materials; a three-dimensional measuring device that measures the three-dimensional shape of a bead formed by melting the metal materials; a three-dimensional scanner that measures the external contour shape of the metal-shaped object; and a control unit that estimates the internal contour shape of the metal-shaped object using the three-dimensional shape of the bead and the external contour shape of the metal-shaped object.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an apparatus for manufacturing a metal object and a method for manufacturing a metal object. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a known device configuration for WAAM (Wire Arc Additive Manufacturing) is one that uses an arc welding robot to laminate metal layers (see Patent Document 1).

[0003] When manufacturing using WAAM, the heat input from the arc welding causes heat to accumulate in the metal object, which causes the bead width to increase as the manufacturing progresses, making it difficult to manufacture with a uniform width. Therefore, to confirm that the metal object is manufactured as designed, it is necessary to measure the 3D shape of the metal object and conduct a contour accuracy inspection of the 3D shape. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-186142 A Summary of the Invention [Problem to be solved by the invention]

[0005] CT scanning using X-rays is known as a method for obtaining 3D shapes. However, X-rays do not penetrate metals as easily as resins, and the thickness through which X-rays penetrate tends to become shorter as the atomic number increases. Although it is possible to shorten the wavelength of X-rays and make them easier to penetrate by increasing the tube voltage of the device, it is difficult to measure the 3D shape of large metal objects.

[0006] Also, 3D scanners are known as a method for acquiring 3D shapes. 3D scanners can measure larger objects than CT scans using X-rays, and some scanners can scan objects up to 10m in size. However, 3D scanners can only measure the area where the irradiated light hits, making it difficult to measure the inner contour shape or the thickness of laminated materials that are not hit by light.

[0007] The present invention has been made in view of the above, and has an object to provide a metal object manufacturing apparatus and a metal object manufacturing method that are capable of estimating the inner contour shape of a large metal object. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, a metal object manufacturing apparatus according to one embodiment of the present invention is characterized in that it includes a robot arm having a welding torch at its tip for depositing molten metal material and forming a metal object, a 3D measuring device for measuring the 3D shape of a bead formed by melting the metal material, a 3D scanner for measuring the outer contour shape of the metal object, and a control unit for estimating the inner contour shape of the metal object using the 3D shape of the bead and the outer contour shape of the metal object.

[0009] In addition, in a metal object manufacturing apparatus according to one aspect of the present invention, the three-dimensional measuring device is attached to a tip of the robot arm, and the control unit uses position information and orientation information of the tip of the robot arm to coordinate convert the measurement results of the three-dimensional measuring device from a robot arm coordinate system, which is a coordinate system that moves with the tip of the robot arm as its origin, to a metal object coordinate system, which is a coordinate system that is stationary with respect to the metal object.

[0010] Furthermore, a metal object manufacturing method according to one embodiment of the present invention is a method for manufacturing a metal object by stacking molten metal material to form a metal object, and is characterized in that it includes measuring a three-dimensional shape of a bead formed by melting the metal material, measuring an outer contour shape of the metal object, and estimating an inner contour shape of the metal object using the three-dimensional shape of the bead and the outer contour shape of the metal object.

[0011] Furthermore, a metal object manufacturing method according to one aspect of the present invention is characterized in that a 3D measuring device that measures the three-dimensional shape of the bead is attached to a tip of a robot arm, and the method includes converting the measurement results of the 3D measuring device from a robot arm coordinate system, which is a coordinate system that moves with the tip of the robot arm as its origin, to a metal object coordinate system, which is a coordinate system that is stationary with respect to the metal object, using position information and orientation information of the tip of the robot arm. Effect of the Invention

[0012] According to the present invention, it is possible to realize an apparatus for manufacturing a metal object and a method for manufacturing a metal object that are capable of estimating the inner contour shape of a large metal object. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a metal object manufacturing apparatus according to the present invention. [Diagram 2] FIG. 2 is an enlarged view of the tip of the robot arm shown in FIG. [Diagram 3] FIG. 3 is a flowchart showing an outline of the process in the metal object manufacturing method according to the present invention. [Figure 4] FIG. 4 is a partially enlarged view of the metal object. [Diagram 5] FIG. 5 is a diagram illustrating a process of estimating the inner contour shape of a metal object. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of a metal object manufacturing apparatus and a metal object manufacturing method according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to these embodiments. The present invention can be generally applied to a metal object manufacturing apparatus and a metal object manufacturing method.

[0015] In addition, in the drawings, the same or corresponding elements are appropriately labeled with the same reference numerals. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from the actual situation. The drawings may also include parts with different dimensional relationships and ratios.

[0016] (Embodiment) [Configuration of the metal mold manufacturing device] Fig. 1 is a schematic diagram of a metal object manufacturing apparatus according to the present invention. The metal object manufacturing apparatus 1 stacks molten metal material to form a metal object. As shown in Fig. 1, the metal object manufacturing apparatus 1 includes a molding robot 3, a three-dimensional shape measuring device 4, a control device 5, and a three-dimensional scanner 7.

[0017] Fig. 2 is an enlarged view of the tip of the robot arm shown in Fig. 1. As shown in Fig. 2, the modeling robot 3 has a robot arm 30 and a welding torch 31. The modeling robot 3 is a fused additive manufacturing (WAAM) three-dimensional printer that uses arc welding.

[0018] The robot arm 30 extends from the robot body. A welding torch 31 is provided at the tip of the robot arm 30.

[0019] 2 shows a partially enlarged view of the tip of the welding torch 31. A welding wire 32 made of a metallic material is supplied from a wire supply device to the welding torch 31. An arc discharge is generated at the tip of the welding wire 32 to melt the welding wire 32, and the welding wire 32 is laminated on the base material B, thereby producing a metal object W.

[0020] The three-dimensional shape measuring device 4 is attached to the tip of the robot arm 30. The three-dimensional shape measuring device 4 is, for example, an in-line profiler, and measures the three-dimensional shape of the bead formed by melting the welding wire 32.

[0021] The control device 5 is a control device that controls the entire metal mold manufacturing apparatus 1. As shown in Fig. 1, the control device 5 has an acquisition unit 51, a control unit 52, and a storage unit 53. In practice, the control device 5 stores programs corresponding to these functional units in a storage device such as a non-volatile memory, and loads these programs into the memory and executes them on the CPU to execute the corresponding processes.

[0022] The acquisition unit 51 acquires various types of information. Specifically, the acquisition unit 51 acquires the three-dimensional shape of the bead from the three-dimensional shape measuring device 4, and stores it in the storage unit 53. The acquisition unit 51 also acquires the outer contour shape of the metal object W, and stores it in the storage unit 53. The acquisition unit 51 also acquires position information and orientation information of the tip of the robot arm 30, and stores it in the storage unit 53.

[0023] The control unit 52 controls the driving of the robot arm 30. The control unit 52 estimates the inner contour shape of the metal object W by using the three-dimensional shape of the bead and the outer contour shape of the metal object W. The control unit 52 uses position information of the tip of the robot arm 30 to perform coordinate conversion of the measurement result of the three-dimensional shape measuring instrument 4 from a robot arm coordinate system, which is a coordinate system that moves with the tip of the robot arm 30 as the origin, to a metal object coordinate system, which is a coordinate system that is stationary with respect to the metal object W.

[0024] The storage unit 53 stores various types of information, such as the three-dimensional shape of the bead, the outer contour shape of the metal object, and the position information and orientation information of the tip of the robot arm 30.

[0025] The three-dimensional scanner 7 measures the outer contour shape of the metal object W.

[0026] [Metal molded object manufacturing method] Next, a description will be given of a metal structure manufacturing method using the metal structure manufacturing apparatus 1. Fig. 3 is a flowchart showing an overview of the processing in the metal structure manufacturing method according to the present invention. As shown in Fig. 3, first, a voltage is applied between the base material B and an electrode disposed at the tip of the welding torch 31 to set the arc ON state so that arc welding is possible (step S1).

[0027] Next, the welding wire 32 is melted, and N layers of welded metal material are laminated (step S2).

[0028] Thereafter, the application of the voltage between the base material B and the electrode is stopped, and the arc is turned off (step S3).

[0029] Next, the process waits for a predetermined time (step S4), as a result of which the temperature of the laminated metal material drops and the shape becomes stable.

[0030] Thereafter, the three-dimensional shape of the bead is measured (step S5). Fig. 4 is a partial enlarged view of a portion A of the metal object W enclosed by a dashed line shown in Fig. 1. The three-dimensional shape measuring instrument 4 measures the bead width BW and the bead height BH as the three-dimensional shape of the bead.

[0031] Next, the outer contour shape of the metal object W is measured by the three-dimensional scanner 7 (step S6).

[0032] Thereafter, the acquisition unit 51 acquires the three-dimensional shape of the bead from the modeling robot 3, and acquires the outer contour shape of the metal object W from the three-dimensional scanner 7 (Step S7). The three-dimensional shape of the bead and the outer contour shape of the metal object W acquired by the acquisition unit 51 are stored in the storage unit 53.

[0033] Then, the control unit 52 uses the position information of the tip of the robot arm 30 to convert the measurement results of the three-dimensional shape measuring device 4 from a robot arm coordinate system C1 (see FIG. 1), which is a coordinate system that moves with the tip of the robot arm 30 as the origin, to a metal object coordinate system C2 (see FIG. 1), which is a coordinate system that is stationary with respect to the metal object W (step S8). Note that the control unit 52 acquires the position information and orientation information of the tip of the robot arm 30 by, for example, having the acquisition unit 51 receive a signal from a six-axis sensor attached to the tip of the robot arm 30.

[0034] The control unit 52 converts the three-dimensional shape of the bead from the three-dimensional shape measuring device 4 and the measurement results of the outer contour shape of the metal object W from the three-dimensional scanner 7 into the metal object coordinate system C2, and estimates the inner contour shape of the metal object W (step S9).

[0035] FIG. 5 is a diagram showing how the inner contour shape of a metal object is estimated. The horizontal axis of FIG. 5 represents the height from the base material B, and the vertical axis represents the distance from the central axis of the metal object W. First, line L1 represents the outer contour shape of the metal object W measured by the three-dimensional scanner 7. By using the three-dimensional shape of the bead (bead width BW and bead height BH) converted into the metal object coordinate system C2 for the outer contour shape of this metal object W, the inner contour shape of the metal object W shown by line L2 can be estimated. In this way, by creating an actual measurement solid model, generating a solid model with the inverse tendency, and using it for stacking the metal material, it is possible to manufacture a metal object W with a more accurate shape. In addition, the center line of the contour of the metal object W may be estimated from the outer contour shape of the metal object W and the inner contour shape of the metal object W.

[0036] Thereafter, the control unit 52 determines whether or not the stacking is completed (step S10).

[0037] When the control unit 52 determines that the stacking is not completed (step S10: No), the process returns to step S1 and repeats the process. In this case, the outer contour shape and the inner contour shape of the metal object W are used to estimate an error in the three-dimensional shape of the metal object W at this point in time, and the subsequent stacking process of the metal material can be performed so as to correct this error.

[0038] On the other hand, if the control unit 52 determines that the stacking is completed (step S6: Yes), the series of processes is terminated.

[0039] According to the embodiment described above, the outer contour shape of the metal object W is measured by the 3D scanner 7, the 3D shape of the bead is acquired by the 3D shape measuring device 4, and the inner contour shape of the modeling robot 3 is estimated from these data. This makes it possible to estimate the inner contour shape of the metal object W even if it is a large metal object W. Furthermore, it becomes possible to compare the estimated 3D shape model of the metal object W (e.g., a STEP or STL file) with the 3D shape model of the metal object W at the time of designing, and to control the robot arm 30 so as to correct errors. Furthermore, the estimated 3D shape model of the metal object W can be utilized for post-processing such as cutting.

[0040] In the above embodiment, an example has been described in which the three-dimensional shape measuring device 4 measures the three-dimensional shape of the bead in step S5 after the arc-off state is established in step S3, but this is not limiting. If the three-dimensional shape measuring device 4 is a device that is not easily affected by the light of the arc, or if the three-dimensional shape measuring device 4 can perform measurements at a position that is not easily affected by the light of the arc, the three-dimensional shape measuring device 4 may measure the three-dimensional shape of the bead before the arc-off state is established.

[0041] In addition, each configuration illustrated in the above embodiment is a functional schematic, and does not necessarily have to be physically configured as illustrated. In other words, the form of distribution and integration of each device and component is not limited to that illustrated, and all or a part of them can be functionally or physically distributed and integrated in any unit according to various usage conditions, etc. [Explanation of symbols]

[0042] 1 Metal model manufacturing equipment 3. Modeling robot 4 3D shape measuring device 5. Control device 7 3D Scanner 30 Robot Arm 31 Welding Torch 32 Wire 51 Acquisition Department 52 Control section 53 Storage section

Claims

1. A robot arm having a welding torch at its tip that deposits molten metal material and forms a metal object; a three-dimensional measuring device that measures a three-dimensional shape of a bead formed by melting the metal material; a three-dimensional scanner that measures an outer contour shape of the metal object; a control unit that estimates an inner contour shape of the metal object by using a three-dimensional shape of the bead and an outer contour shape of the metal object; A metal object manufacturing apparatus comprising:

2. the three-dimensional measuring device is attached to a tip of the robot arm, 2. The metal object manufacturing apparatus according to claim 1, wherein the control unit converts the measurement results of the three-dimensional measuring device from a robot arm coordinate system, which is a coordinate system that moves with the tip of the robot arm as its origin, to a metal object coordinate system, which is a coordinate system that is stationary with respect to the metal object, by using position information and orientation information of the tip of the robot arm.

3. A method for manufacturing a metal object, comprising stacking molten metal material to form a metal object, the method comprising the steps of: measuring a three-dimensional shape of a bead formed by melting the metallic material; Measuring an outer contour shape of the metal object; An inner contour shape of the metal object is estimated using the three-dimensional shape of the bead and the outer contour shape of the metal object. A method for manufacturing a metal object, comprising the steps of:

4. a three-dimensional measuring device for measuring a three-dimensional shape of the bead is attached to a tip of a robot arm; 4. The method for manufacturing a metal object according to claim 3, further comprising: using position information and orientation information of the tip of the robot arm, coordinate conversion of the measurement results of the three-dimensional measuring device from a robot arm coordinate system, which is a coordinate system that moves with the tip of the robot arm as its origin, to a metal object coordinate system, which is a coordinate system that is stationary with respect to the metal object.

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