Laser processing method and laser processing device

Abstract

To obtain a laser processing method that prevents variations in teaching accuracy by a worker and enables highly accurate laser processing with high work efficiency.SOLUTION: A laser processing method includes: a calibration step in which an offset amount between an irradiation position of laser light and a position of the camera center of an imaging camera 7 is determined using a calibration jig 3; a teaching step in which a robot arm 5 is moved so as to capture a processing point with the imaging camera 7 and teach the position of the processing point; and a processing step in which the robot arm 5 is moved to the taught position of the processing point, the robot coordinates are obtained when the camera center of the imaging camera 7 and the processing point match, the robot arm 5 is moved to a position offset by the offset amount from the robot coordinates, and the processing point is irradiated with the laser light.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a laser processing method and a laser processing apparatus that perform processing using laser light as a heat source. [Background technology]

[0002] In laser processing including laser welding, laser cutting, laser drilling, etc., a laser processing robot with a laser irradiation device attached to the tip of the robot arm is used, and the laser irradiation device is moved along a pre-taught processing line to perform the laser processing. Laser welding requires high positioning accuracy because energy is concentrated at one point compared to other welding. For this reason, in laser welding, a camera is used to check the processing line in an image, and the laser processing is performed while correcting the processing error of the workpiece and the deviation of the workpiece mounting position.

[0003] In Patent Document 1, a master invariant edge image, which is an edge image of an invariant surface that does not shift in position relative to a welding point in a master product that serves as a reference among multiple products, is pattern matched with a work invariant edge image, which is an edge image of an invariant surface of a work product other than the master product, to obtain the amount of deviation between the two as a correction amount for the welding point, and the welding point set in the processing program for welding the master is corrected by the correction amount to generate a correction processing program for welding the work. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-213933 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the method disclosed in Patent Document 1, the welding points of the master product must be taught by an operator, which leads to problems such as difficulty in obtaining the accuracy required for laser processing, time-consuming teaching leading to reduced work efficiency, and processing accuracy being affected by the skill level of the operator.

[0006] The present disclosure has been made in consideration of the above, and aims to provide a laser processing method that prevents variation in teaching accuracy between workers and enables high-precision laser processing with high work efficiency. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the laser processing method of the present disclosure performs laser processing of a processing point using a robot having a robot arm provided with a laser irradiation device that irradiates laser light and an imaging camera that images the processing point. The laser processing method includes a calibration step of using a calibration jig to obtain a first offset amount, which is an offset amount between the irradiation position of the laser light and the position of the camera center of the imaging camera, a teaching step of moving the robot arm so that the imaging camera captures the processing point and teaching the position of the processing point, and a processing step of moving the robot arm to the taught processing point position, acquiring first robot coordinates when the camera center of the imaging camera and the processing point coincide, moving the robot arm to a position offset by the first offset amount from the first robot coordinates, and irradiating the processing point with laser light.

[0008] According to the laser processing method of the present disclosure, it is possible to prevent variation in teaching accuracy between workers, and to perform highly accurate laser processing with high work efficiency. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of a laser processing device according to a first embodiment. [Diagram 2] FIG. 1 is a plan view of a calibration jig of a laser processing apparatus according to a first embodiment, viewed from above; [Diagram 3]FIG. 1 is a plan view of a calibration jig of a laser processing apparatus according to a first embodiment, seen from above during a calibration process; [Figure 4] FIG. 1 is a diagram showing an image of a calibration jig captured by an imaging camera in the laser processing apparatus according to the first embodiment; [Diagram 5] 1 is a flowchart showing a procedure of a calibration process of a laser processing apparatus according to a first embodiment. [Figure 6] FIG. 1 is a diagram for explaining a teaching process of the laser processing device according to the first embodiment; [Figure 7] FIG. 1 is an explanatory diagram of a case where a processing point is image-recognized in a teaching process of the laser processing device according to the first embodiment; [Figure 8] 1 is a flowchart showing a procedure of a teaching process of the laser processing device according to the first embodiment. [Figure 9] 1 is a flowchart showing a procedure of a laser processing step of a laser processing apparatus according to a first embodiment. [Figure 10] FIG. 13 is a schematic diagram showing a configuration of a laser processing device according to a second embodiment. [Figure 11] 10 is a flowchart showing a procedure of a calibration process for a laser displacement meter of a laser processing device according to a second embodiment. [Figure 12] 11 is a flowchart showing a procedure of a teaching process of a laser processing device according to a second embodiment. [Figure 13] 11 is a flowchart showing the procedure of a laser processing step of a laser processing apparatus according to a second embodiment. [Figure 14] 11 is a flowchart showing a procedure of a teaching process for a focal height position of a laser irradiation position in a laser processing device according to a third embodiment. [Figure 15] FIG. 11 is a schematic diagram showing the relationship between the focal height and the line width at the laser irradiation position in the laser processing device according to the third embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A laser processing method and a laser processing apparatus according to embodiments will be described in detail below with reference to the drawings.

[0011] Embodiment 1 FIG. 1 is a schematic diagram showing a configuration of a laser processing apparatus 100 according to a first embodiment. FIG. 1 shows an XYZ coordinate system. The Z direction is the height direction, and the X and Y directions are directions perpendicular to the Z direction. The Z direction corresponds to the optical axis direction of the laser light. The laser processing apparatus 100 includes a robot 10. The robot 10 has a robot arm 5, and a laser irradiation device 6 and an imaging camera 7 are attached to the tip of the robot arm 5. The laser irradiation device 6 irradiates a laser light. The imaging camera 7 images the processing point.

[0012] The laser processing apparatus 100 includes a work table 1 and a calibration jig 3. A workpiece 2 to be laser processed is placed on the work table 1, and the laser processing is performed. The work table 1, the workpiece 2, and the calibration jig 3 are each installed within the operating range of a robot arm 5.

[0013] The laser processing apparatus 100 includes a robot control device 51, a laser oscillator 61, an image processing device 71, and a system control device 81. The robot control device 51 stores the teaching points of the robot 10 and moves the robot arm 5. The laser oscillator 61 is connected to the laser irradiation device 6 by an optical fiber 62 and emits a laser beam. The image processing device 71 takes in an image captured by the imaging camera 7 and performs feature extraction such as edge detection. The system control device 81 communicates with the robot control device 51, the laser oscillator 61, and the image processing device 71, and performs integrated control of the entire laser processing apparatus 100. The system control device 81 is, for example, a PLC (Programmable Logic Controller). A monitor 72 may be connected to the image processing device 71.

[0014] Next, the laser processing method using the laser processing apparatus 100 according to the first embodiment will be described in the order of a calibration step, a teaching step, and a laser processing step.

[0015] <Calibration process> The calibration process of the laser irradiation device 6 and the imaging camera 7 of the laser processing apparatus 100 will be described with reference to Figs. 2 to 5. Fig. 2 is a plan view of the calibration jig 3 of the laser processing apparatus 100 according to the first embodiment as viewed from above. Fig. 3 is a plan view of the calibration jig 3 of the laser processing apparatus 100 according to the first embodiment as viewed from above during the calibration process. Fig. 4 is a diagram showing a captured image of the calibration jig 3 captured by the imaging camera 7 in the laser processing apparatus 100 according to the first embodiment. Fig. 5 is a flowchart showing the procedure of the calibration process of the laser processing apparatus 100 according to the first embodiment. In the calibration process, a first offset amount, which is an offset amount between the irradiation position of the laser light and the position of the camera center of the imaging camera 7, is obtained using the calibration jig 3.

[0016] 2, the upper surface of the calibration jig 3 is a horizontal plane, and two axes that intersect at right angles at center 3a are drawn on the upper surface of the calibration jig 3. Hereinafter, the two axes that intersect at right angles at center 3a will be referred to as cross markings.

[0017] In addition to a processing laser beam (hereinafter referred to as laser beam), the laser irradiation device 6 emits a visible laser beam for alignment. In the prior art laser processing device, it is necessary to use this visible laser beam to accurately align the laser irradiation device 6 with the processing point, which is the point where the workpiece 2 is to be laser processed, and this causes problems such as variations in accuracy depending on the operator and time-consuming work. In contrast, in the first embodiment, it is not necessary for the operator to align the irradiation position of the laser beam with the processing point, making it possible to solve these problems.

[0018] In the laser processing apparatus 100 according to the first embodiment, first, an operator operates the robot arm 5 to roughly move the laser irradiation device 6 onto the center 3a of the cross marking on the calibration jig 3 (step S101). The system control device 81 records the robot coordinates (XL, YL, ZL) when the laser irradiation device 6 is moved and stopped onto the center 3a of the cross marking (step S102). The robot coordinates (XL, YL, ZL) are set as the robot coordinates R0. At this time, it is not necessary to move the laser irradiation device 6 exactly onto the center 3a of the cross marking. Note that the robot coordinates are coordinates in the robot coordinate system. Also, although the robot coordinates originally have six degrees of freedom, for convenience, the description will be given with three degrees of freedom.

[0019] Here, "approximately move" means that it is sufficient to move to a position where the image processing device 71 can capture an image of the circle 3c to such an extent that the center of the circle can be correctly captured when the circle 3c, which is the laser irradiated portion irradiated with the laser light, is imaged by the imaging camera 7. Specifically, although it depends on the angle of view and resolution of the imaging camera 7 and the diameter of the circle 3c, for example, if the angle of view of the imaging camera 7 is 50 mm x 50 mm and the diameter of the circle 3c is 30 mm, the entire circle 3c can be captured by the imaging camera 7 as long as the positional deviation between the camera center and the center of the circle 3c is within a range of about ±10 mm.

[0020] 3, the operator fixes the sample plate 3b on the calibration jig 3 and actually draws a circle 3c centered on the robot coordinate R0 (XL, YL, ZL) that was previously taught on the sample plate 3b with a laser beam (step S103). There is no problem even if the center 3a of the cross marking and the center R0 of the drawn circle 3c are misaligned.

[0021] 4, the operator operates the robot arm 5 to roughly move the imaging camera 7 onto the calibration jig 3 (step S104). At this time, the system control device 81 records the robot coordinates (XC', YC', ZC') of the camera center 7a. Next, the system control device 81 captures an image of the circle 3c drawn with the laser light with the imaging camera 7, and obtains the coordinates of the center R0 of the circle 3c with the image processing device 71. Finally, the system control device 81 calculates the positional deviation (ΔX, ΔY) between the camera center 7a and the coordinates R0 of the center of the circle 3c (step S105).

[0022] Next, the operator operates the robot arm 5 to move it roughly to the robot coordinates (XC'+ΔX, YC'+ΔY, ZC'), captures the image of the circle 3c again with the imaging camera 7, and calculates the deviation (ΔX, ΔY) between the center of the circle 3c and the camera center 7a again. This operation is repeated until ΔX and ΔY become smaller than the allowable value, and finally, the robot coordinates (XC, YC, ZC) are obtained when the center of the captured circle 3c and the camera center 7a coincide with each other. Here, the coincidence of the center of the captured circle 3c and the camera center 7a means that ΔX and ΔY are smaller than the allowable value, and the allowable value is, for example, 0.1 mm. That is, the system control device 81 judges whether ΔX and ΔY are smaller than the allowable value (step S106), and if the judgment result is No, the procedure proceeds to step S104, and if the judgment result is Yes, the robot coordinates (XC, YC, ZC) are recorded (step S107). Then, the operator stores (XL-XC, YL-YC, ZL-ZC) in the system control device 81 as the offset amount between the irradiation position of the laser light and the camera center 7a (step S108). The offset amount (XL-XC, YL-YC, ZL-ZC) corresponds to the first offset amount.

[0023] <Teaching process> Next, a procedure in which an operator teaches a processing point of the workpiece 2 in the first embodiment will be described with reference to Fig. 6 to Fig. 8. Fig. 6 is a diagram for explaining a teaching process of the laser processing apparatus 100 according to the first embodiment. Fig. 7 is an explanatory diagram when a processing point is image-recognized in the teaching process of the laser processing apparatus 100 according to the first embodiment. Fig. 8 is a flowchart showing a procedure of the teaching process of the laser processing apparatus 100 according to the first embodiment. In the teaching process, the position of the processing point is taught.

[0024] After the calibration process, as shown in Fig. 6, the operator places the workpiece 2 to be laser-machined on the worktable 1 (step S201), and sequentially teaches a plurality of processing points 21, 22, ..., 2n to be laser-machined on the workpiece 2. The teaching of the n-th processing point 2n will be described below. When teaching the n-th processing point 2n, the operator operates the robot arm 5 to move the imaging camera 7 roughly above the processing point 2n (step S202), and confirms that the processing point 2n is captured roughly at the center of the monitor 72 of the image processing device 71.

[0025] Next, as shown in FIG. 7, the worker captures an image of the processing point 2n with the imaging camera 7, and sets the image recognition processing content for the processing point 2n (step S203). In setting the image recognition processing content, feature extraction such as edge detection is performed according to the type of processing point. Next, the worker checks whether the image processing in the image processing device 71 operates normally (step S204). In this step S204, for example, the positional deviation (ΔX, ΔY) between the processing point 2n and the camera center 7a is calculated, but it is sufficient to simply check that the image processing operates normally, and there is no need to fine-tune the robot coordinates until the positional deviation (ΔX, ΔY) is reduced.

[0026] If the image processing does not operate normally (step S204: No), the procedure returns to step S202 and changes the image recognition processing contents. If the image processing operates normally (step S204: Yes), the operator stores the robot coordinates (Xn, Yn, Zn) as the teaching coordinates of the processing point 2n in the system control device 81 (step S205). Next, it is determined whether teaching of all processing points has been completed (step S206), and the same process is repeated until teaching of all processing points has been completed. In this teaching process, the robot coordinates at which each processing point can be normally photographed by the imaging camera 7 are taught as the teaching coordinates.

[0027] In this teaching process, accurate adjustment of the camera position is not required, and it is only necessary to confirm that image recognition of all the processing points 21, 22, ..., 2n has been performed normally, which simplifies the teaching process.

[0028] <Laser processing process> Next, the laser processing step (processing step) in the first embodiment will be described with reference to Fig. 9. Fig. 9 is a flow chart showing the procedure of the laser processing step of the laser processing device 100 according to the first embodiment. In the laser processing step, the imaging camera 7 is moved to the position of the taught processing point, and the processing point is irradiated with laser light by shifting its position by the offset amount determined in the calibration step from the robot coordinates when the camera center 7a of the imaging camera 7 coincides with the processing point. The laser processing step is automatically executed under the control of the system control device 81.

[0029] An operator places the workpiece 2 to be laser-processed on the worktable 1 (step S301). When the laser processing device 100 is started, processing is performed in order starting from the first stored processing point 21. The laser processing operation of the nth processing point 2n will be described below. When processing the nth processing point 2n, the system control device 81 moves the robot arm 5 to the robot coordinates (Xn, Yn, Zn), which are the teaching coordinates of the stored processing point 2n (step S302), and the processing point 2n becomes ready to be imaged by the imaging camera 7.

[0030] The system control device 81 captures the processing point 2n with the imaging camera 7, performs image recognition for extracting features such as edge detection depending on the type of processing point, and calculates the positional deviation (ΔX, ΔY) between the processing point 2n and the camera center 7a (step S303).

[0031] The system control device 81 again moves the robot arm 5 to the robot coordinates (Xn+ΔX, Yn+ΔY, Zn), captures the processing point 2n with the imaging camera 7, and calculates the positional deviation (ΔX, ΔY) between the processing point 2n and the camera center 7a. This operation is repeated until ΔX and ΔY become smaller than the allowable value, and when the captured processing point 2n and the camera center 7a finally match, for example, when ΔX and ΔY become 0.1 mm or less (step S304), the system control device 81 stores the robot coordinates (Xn', Yn', Zn') at this time (step S305).

[0032] The system control device 81 applies the offset amount (XL-XC, YL-YC, ZL-ZC) between the laser light irradiation position and the camera center 7a obtained in the calibration process to the robot coordinates (Xn', Yn', Zn') where the captured processing point 2n and the camera center 7a coincide, and moves the robot arm 5 to the robot coordinates (Xn'+(XL-XC), Yn'+(YL-YC), Zn'+(ZL-ZC)) (step S306). When the type of laser processing is spot welding or drilling, which processes one point, the system control device 81 operates the laser irradiation device 6 at this moved position and performs laser processing of the processing point 2n (step S307).

[0033] Next, it is determined whether or not the laser processing of all the processing points has been completed (step S308), and the same process is repeated until the laser processing of all the processing points has been completed.

[0034] On the other hand, when processing a line connecting processing point 2n and processing point 2n+1, such as by butt welding or laser cutting, processing point 2n and processing point 2n+1 are imaged by imaging camera 7, and the robot coordinates (Xn', Yn', Zn') where the imaged processing point 2n coincides with camera center 7a, and the robot coordinates (Xn+1', Yn+1', Zn+1') where the imaged processing point 2n+1 coincides with camera center 7a are obtained in advance.

[0035] Next, when the robot moves to the coordinates (Xn'+(XL-XC), Yn'+(YL-YC), Zn'+(ZL-ZC)), this movement position becomes the laser light irradiation position of processing point 2n. Laser processing can be performed while moving from this movement position to the robot coordinates (Xn+1'+(XL-XC), Yn+1'+(YL-YC), Zn+1'+(ZL-ZC)).

[0036] Furthermore, when machining two or more points continuously, for example when machining from machining point 2n to machining point 2n+m continuously, the machining points 2n, 2n+1, ..., 2n+m are each imaged by the imaging camera 7, and the robot coordinates (Xn', Yn', Zn'), (Xn+1', Yn+1', Zn+1'), ..., (Xn+m', Yn+m', Zn+m') where the imaged machining points 2n, 2n+1, ..., 2n+m coincide with the camera center 7a are first obtained.

[0037] Next, when the robot moves to the robot coordinates (Xn'+(XL-XC), Yn'+(YL-YC), Zn'+(ZL-ZC)), this movement position becomes the laser light irradiation position of processing point 2n. Laser processing can be performed by moving from this movement position to the robot coordinates (Xn+1'+(XL-XC), Yn+1'+(YL-YC), Zn+1'+(ZL-ZC)), ..., (Xn+m'+(XL-XC), Yn+m'+(YL-YC), Zn+m'+(ZL-ZC)).

[0038] In this way, the processing point is captured at the camera center 7a of the imaging camera 7, and then the laser processing is performed by moving from that position by the offset amounts (XL-XC, YL-YC, ZL-ZC) determined in the calibration process described above, thereby enabling accurate laser processing of the processing point of the workpiece 2.

[0039] In the first embodiment, an example is shown in which the direction of laser processing is vertically downward. Therefore, the imaging camera 7 also captures images vertically downward, and the positional deviation obtained therefrom is within the XY plane, and is therefore represented as ΔX and ΔY. Therefore, for example, if the direction of laser processing is horizontal (positive direction of the Y axis), it is clear that the imaging camera 7 also captures images horizontally, and the positional deviation obtained therefrom should be corrected as ΔX and ΔZ.

[0040] Thus, according to the first embodiment, in the calibration process, the offset amount between the irradiation position of the laser light and the position of the camera center 7a of the imaging camera 7 is acquired using the calibration jig 3, and in the laser processing process, the imaging camera 7 is moved to the position of the taught processing point, and the position of the camera center 7a is shifted by the offset amount from the robot coordinate when the camera center 7a of the imaging camera 7 and the processing point coincide with each other, and the processing point is irradiated with the laser light. Therefore, the operator does not need to know the irradiation position of the laser light, and the teaching process of the processing point is automatically completed by simply aligning the processing point within the field of view of the imaging camera 7. Therefore, it is possible to prevent variation in teaching accuracy due to the operator and perform high-precision laser processing with high work efficiency.

[0041] Embodiment 2 Fig. 10 is a schematic diagram showing the configuration of a laser processing apparatus 200 according to the second embodiment. The laser processing apparatus 200 of the second embodiment further includes a laser displacement meter 9 at the tip of the robot arm 5. By providing the laser displacement meter 9, the laser processing apparatus 200 of the second embodiment enables correction in the Z-axis direction in addition to the X-axis direction and the Y-axis direction. That is, the laser displacement meter 9 detects the deviation of the laser light in the optical axis direction. The same components as those in Fig. 1 are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0042] <Calibration process> First, a calibration process using the laser processing apparatus 200 according to the second embodiment will be described. In the second embodiment, similarly to the first embodiment, the procedure of steps S101 to S108 in Fig. 5 is executed to obtain and store the offset amounts (XL-XC, YL-YC, ZL-ZC) between the laser irradiation position and the camera center 7a. This operation procedure is similar to that of the first embodiment, and therefore a duplicated description will be omitted.

[0043] In the second embodiment, in addition to the calibration process shown in Fig. 5, a calibration process for the laser displacement meter 9 shown in Fig. 11 is executed. Fig. 11 is a flowchart showing the procedure of the calibration process for the laser displacement meter 9 of the laser processing apparatus 200 according to the second embodiment.

[0044] In this step, first, an operator operates the robot arm 5 to move the laser displacement meter 9 onto the calibration jig 3. The operator aligns the measurement point 9a (not shown) of the laser displacement meter 9 with the center 3a of the cross marking on the calibration jig 3 (step S401), and adjusts the position of the laser displacement meter 9 in the Z-axis direction by driving the robot arm 5 so that the measurement value of the laser displacement meter 9 becomes the origin (0.0 mm), and records the robot coordinates (XS, YS, ZS) at the completion of the adjustment (step S402).

[0045] Next, the operator moves the imaging camera 7 roughly above the calibration jig 3, and aligns the camera center 7a with the center 3a of the cross marking on the monitor 72 of the image processing device 71 (step S403). The system control device 81 records the robot coordinates (XCs, YCs, ZCs) at the completion of the alignment (step S404). Next, the system control device 81 calculates and stores the offset amount (XS-XCs, YS-YCs, ZS-ZCs) between the measurement point 9a of the laser displacement meter 9 and the camera center 7a from the robot coordinates (XS, YS, ZS) recorded in step S402 and the robot coordinates (XCs, YCs, ZCs) recorded in step S404 (step S405). The offset amount (XS-XCs, YS-YCs, ZS-ZCs) corresponds to the second offset amount.

[0046] <Teaching process> Next, a procedure for an operator to teach a processing point of the workpiece 2 in the second embodiment will be described with reference to FIG. 12. FIG. 12 is a flowchart showing a procedure of a teaching process of the laser processing device 200 according to the second embodiment. First, an operator places the workpiece 2 to be laser-processed on the worktable 1 (step S501), and sequentially teaches a plurality of processing points to be laser-processed on the workpiece 2. Hereinafter, teaching for the n-th processing point 2n will be described. When teaching the n-th processing point 2n, an operator operates the robot arm 5 to move the laser displacement meter 9 to a position where the height can be stably measured near the processing point 2n (step S502). Furthermore, the position of the laser displacement meter 9 in the Z-axis direction is adjusted by driving the robot arm 5 so that the measurement value of the laser displacement meter 9 becomes the origin (0.0 mm), and the robot coordinates (X, Y, Z) at the time of completion of the adjustment are recorded (step S503).

[0047] Next, the operator operates the robot arm 5 to move the robot arm 5 to the robot coordinates (X-(XS-XCs), Y-(YS-YCs), Z-(ZS-ZCs)) calculated using the robot coordinates (X, Y, Z) at the time when the adjustment of the laser displacement meter 9 is completed and the offset amount (XS-XCs, YS-YCs, ZS-ZCs) between the measurement point 9a of the laser displacement meter 9 and the camera center 7a (step S504), and confirms that the processing point 2n is captured at the approximate center of the monitor 72 of the image processing device 71.

[0048] The worker captures an image of the processing point 2n with the imaging camera 7, and sets the processing contents of the image recognition for the processing point 2n (step S505). In setting the processing contents of the image recognition, feature extraction such as edge detection is performed according to the type of the processing point. Next, the worker checks whether the image processing in the image processing device 71 operates normally (step S506). In this step S506, for example, the positional deviation (ΔX, ΔY) between the processing point 2n and the camera center 7a is calculated, and the camera position is adjusted so that the positional deviation (ΔX, ΔY) falls within a certain range. However, it is sufficient to simply check that the image processing operates normally, and there is no need to fine-tune the robot coordinates until the positional deviation (ΔX, ΔY) is reduced.

[0049] If the image processing does not operate normally (step S506: No), the procedure returns to step S504 and changes the image recognition processing contents. If the image processing operates normally (step S506: Yes), the operator stores the robot coordinates (Xn, Yn, Zn) at this time in the system control device 81 as the teaching coordinates of the processing point 2n (step S507). The same process is repeated until the teaching of all processing points is completed (step S508). In this teaching process, as in the first embodiment, the robot coordinates at which each processing point can be normally photographed by the imaging camera 7 are taught as the teaching coordinates.

[0050] In this teaching process, as in the first embodiment, accurate adjustment of the camera position is not required, and it is only necessary to confirm that image recognition of all processing points has been performed normally.

[0051] <Laser processing process> Next, the laser processing step of the second embodiment will be described with reference to FIG. 13. FIG. 13 is a flow chart showing the procedure of the laser processing step of the laser processing device 200 according to the second embodiment. The laser processing step is automatically executed under the control of the system control device 81. First, the operator places the workpiece 2 to be laser processed on the worktable 1 (step S601). When the laser processing device 200 is started, processing is performed in order from the first processing point 21 stored. The following describes the laser processing operation of the n-th processing point 2n. When processing the n-th processing point 2n, the system control device 81 moves the robot arm 5 to the robot coordinates (Xn+(XS-XCs), Yn+(YS-YCs), Zn+(ZS-ZCs)) calculated using the stored teaching coordinates (Xn, Yn, Zn) of the processing point 2n and the offset amount (XS-XCs, YS-YCs, ZS-ZCs) between the measurement point 9a of the laser displacement meter 9 and the camera center 7a (step S602). When the robot arm 5 is moved to this position, the processing point 2n can be measured by the laser displacement meter 9, and the height error ΔZ can be measured by the laser displacement meter 9 (step S603). The system control device 81 stores the measurement value ΔZ measured by the laser displacement meter 9.

[0052] Next, the system control device 81 automatically moves to the robot coordinates (Xn, Yn, Zn+ΔZ) which are the teaching point of the processing point 2n whose coordinate in the Z direction has been corrected by the error in the height direction ΔZ (step S604). When the robot arm 5 is moved to this position, the processing point 2n can be imaged by the imaging camera 7. Next, the system control device 81 images the processing point 2n by the imaging camera 7, performs image recognition to extract features such as edge detection depending on the type of processing point, and calculates the positional deviation (ΔX, ΔY) in the XY plane between the processing point 2n and the camera center 7a (step S605).

[0053] The system control device 81 again moves the robot arm 5 to the robot coordinates (Xn+ΔX, Yn+ΔY, Zn+ΔZ), captures the processing point 2n with the imaging camera 7, and calculates the positional deviation (ΔX, ΔY) between the processing point 2n and the camera center 7a. This operation is repeated until ΔX and ΔY become smaller than the allowable value, and when the finally captured processing point 2n and the camera center 7a coincide with each other, for example, when ΔX and ΔY become 0.1 mm or less (step S606: Yes), the system control device 81 stores the robot coordinates (Xn', Yn', Zn') at this time (step S607). The robot coordinates (Xn', Yn', Zn') correspond to the first robot coordinates.

[0054] Next, the system control device 81 applies the offset amount (XL-XC, YL-YC, ZL-ZC) calculated in the calibration process to the robot coordinates (Xn', Yn', Zn') where the captured processing point 2n and the camera center 7a coincide, and moves the robot arm 5 to the robot coordinates (Xn'+(XL-XC), Yn'+(YL-YC), Zn'+(ZL-ZC)) (step S608). When the type of laser processing is spot welding or drilling, which processes one point, the system control device 81 operates the laser irradiation device 6 at this moved position and performs laser processing of the processing point 2n (step S609).

[0055] The same process is repeated until the laser processing of all processing points is completed (step S610).

[0056] In the laser processing step, instead of using the processing point itself to extract features, a marker for image processing may be prepared in advance near the processing point, and the marker may be extracted as the position of the processing point. This allows for more accurate laser processing.

[0057] Thus, according to the second embodiment, in addition to the imaging camera 7, the laser displacement meter 9 for correction in the Z-axis direction is provided, so that it is possible to correct processing errors in the Z-axis direction perpendicular to the XY plane and mounting position deviations in addition to the XY plane directions. This prevents the difficulty in extracting features due to the image being out of focus and the incompleteness of laser processing due to focus deviation, enabling finer laser processing.

[0058] Embodiment 3 In the second embodiment, the laser displacement meter 9 is provided in addition to the imaging camera 7, thereby enabling correction of the three-dimensional laser irradiation position. However, in the first and second embodiments, the height position that coincides with the focus at the laser irradiation position needs to be taught by the operator. Hereinafter, for convenience, the height position of the laser irradiation device 6 where the focus of the laser light coincides with the processing point is referred to as the focal height position. Regarding the ZL, which is the height position among the robot coordinates (XL, YL, ZL) when drawing the circle 3c on the sample plate 3b in the calibration process of the first embodiment, the focal height position cannot be corrected even if the position is corrected using the imaging camera 7 and the laser displacement meter 9 after that. In contrast, in the third embodiment, the focal height position of the laser irradiation position can be taught using the imaging camera 7 and the laser displacement meter 9.

[0059] 14 is a flow chart showing the procedure of a teaching process of the focal height position of the laser irradiation position in the laser processing apparatus 200 according to the third embodiment. In this teaching process, first, as in the case of the first embodiment, the operator operates the robot arm 5 to roughly move the laser irradiation device 6 onto the center 3a of the cross marking on the calibration jig 3 (step S701). The operator records the robot coordinates (XL, YL, ZL) at this time (step S702). As described above, it is not necessary to move the laser irradiation device 6 precisely onto the center 3a of the cross marking.

[0060] Next, the worker fixes the first sample plate 3b on the calibration jig 3, and draws a circle 3c centered on the robot coordinates (XL, YL, ZL) on the first sample plate 3b with a laser beam (step S703). Next, the worker operates the robot arm 5 to roughly move the imaging camera 7 onto the calibration jig 3 (step S704). Next, the worker captures an image of the circle 3c on the first sample plate 3b with the imaging camera 7, and calculates the line width Wo of the circle 3c with the image processing device 71 (step S705).

[0061] Next, the worker operates the robot arm 5 to move the laser irradiation device 6 to the robot coordinates (XL, YL, ZL+ΔL) (step S706). Next, in a similar manner, the worker fixes the second sample plate 3b on the calibration jig 3, and draws a circle 3c centered on the robot coordinates (XL, YL, ZL+ΔL) on the second sample plate 3b with laser light (step S707). Next, the worker operates the robot arm 5 to roughly move the imaging camera 7 above the calibration jig 3 (step S708). Next, the worker images the circle 3c on the second sample plate 3b with the imaging camera 7, and measures the line width W of the circle 3c with the image processing device 71. +ΔL is calculated (step S709).

[0062] Next, the worker operates the robot arm 5 to move the laser irradiation device 6 to the robot coordinates (XL, YL, ZL-ΔL) (step S710). Similarly, the worker fixes the third sample plate 3b on the calibration jig 3, and draws a circle 3c centered on the robot coordinates (XL, YL, ZL-ΔL) on the third sample plate 3b with laser light (step S711). Next, the worker operates the robot arm 5 to roughly move the imaging camera 7 above the calibration jig 3 (step S712). Next, the worker images the circle 3c on the third sample plate 3b with the imaging camera 7, and measures the line width W of the circle 3c with the image processing device 71. -ΔL is calculated (step S713).

[0063] Next, the system controller 81 calculates the obtained line width Wo,W +ΔL ,W -ΔL Based on this, the focal height ZL+ΔZ at which the line width W is minimum is calculated by the following method (step S714).

[0064] FIG. 15 is a schematic diagram showing the relationship between the focal height and line width of the laser irradiation position in the laser processing apparatus 200 according to the third embodiment.

[0065] As shown in FIG. 15, if we assume that the focal height ZL+ΔZ at which the line width W is minimum is between (α) and (β), then ΔZ=(-Wo / (Wo+W -ΔL ))·ΔL …(1) :When there is ZL+ΔZ between (α) and (β) ΔZ=(-Wo / (W +ΔL -Wo))·ΔL …(2) :When ZL+ΔZ is outside (β) and (γ) Equation (1) and equation (2) are consistent.

[0066] Similarly, suppose there is ZL+ΔZ between (β) and (γ), then ΔZ=(Wo / (Wo-W -ΔL ))·ΔL …(3) :When ZL+ΔZ is outside (α) and (β) ΔZ=(Wo / (W+ΔL +Wo))·ΔL …(4) :When there is ZL+ΔZ between (β) and (γ) Equation (3) and equation (4) are consistent.

[0067] Finally, suppose that ZL+ΔZ lies outside (α) or outside (γ), then ΔZ=(-Wo / (W +ΔL -Wo))·ΔL …(2) :When ZL+ΔZ is outside (β) and (γ) ΔZ=(Wo / (Wo-W -ΔL ))·ΔL …(3) :When ZL+ΔZ is outside (α) and (β) Equation (2) and equation (3) are consistent.

[0068] To summarize the above, when equations (1) to (4) are calculated, a matching combination of ΔZ (equation (1) and equation (2), or equation (3) and equation (4), or equation (2) and equation (3)) always exists, and ΔZ is uniquely determined. After ΔZ is determined, ZL+ΔZ is set as new ZL (step S715), and the calibration process shown in embodiment 1 or 2 is performed to find the offset amount.

[0069] Thus, according to the third embodiment, a sample plate 3b placed on the calibration jig 3 is irradiated with laser light from the laser irradiation device 6 while changing the height from the sample plate 3b to draw circles 3c on the sample plate 3b, and the drawn circles 3c are imaged by the imaging camera 7 to obtain images of the multiple circles 3c whose heights from the sample plate 3b are changed, and the line widths Wo, W of the multiple circles 3c in the obtained images are calculated. +ΔL ,W -ΔLBased on this, the position in the optical axis direction of the laser beam of the laser irradiation device 6 where the focus of the laser beam coincides with the processing point, i.e., the height position, is obtained. This enables more accurate laser processing. In addition, in the third embodiment, if the focal height teaching of the laser irradiation position among the robot coordinates (XL, YL, ZL) in the calibration process is performed using both the imaging camera 7 and the laser displacement meter 9, it becomes possible to subsequently correct the position of the ZL coordinate, which is the height coordinate, using the imaging camera 7 and the laser displacement meter 9, enabling more accurate laser processing.

[0070] The configurations shown in the above embodiments are examples of the contents of the present disclosure, and may be combined with other known technologies, the configurations of each embodiment may be combined as appropriate, and parts of the configurations may be omitted or modified without departing from the gist of the present disclosure.

[0071] Various aspects of the present disclosure are summarized below as appendices.

[0072] (Appendix 1) A laser processing method for performing laser processing of a processing point using a robot having a robot arm provided with a laser irradiation device that irradiates laser light and an imaging camera that images the processing point, comprising: a calibration step of determining a first offset amount, which is an offset amount between the irradiation position of the laser light and the position of the center of the imaging camera, using a calibration jig; a teaching step of teaching the position of the processing point by moving the robot arm so as to capture the processing point with the imaging camera; a processing step of moving the robot arm to the taught position of the processing point, acquiring first robot coordinates when the camera center of the imaging camera and the processing point coincide with each other, moving the robot arm to a position offset by the first offset amount from the first robot coordinates, and irradiating the processing point with laser light. A laser processing method comprising: (Appendix 2) In the calibration step, a sample plate is placed on the calibration jig, a circle is drawn on the sample plate with the laser light, the circle is imaged by the imaging camera, and the irradiation position of the laser light is determined from the center coordinates of the circle, thereby obtaining the first offset amount. 2. The laser processing method according to claim 1, (Appendix 3) In the calibration step, the first offset amount is obtained using a cross mark provided on the calibration jig. 3. The laser processing method according to claim 1 or 2, (Appendix 4) In the teaching step, the imaging camera is moved so as to capture the processing point at an approximate center of the imaging camera. 4. The laser processing method according to claim 1, (Appendix 5) In the processing step, the processing point is imaged by the imaging camera, and characteristics of the processing point are extracted. 5. The laser processing method according to claim 1, (Appendix 6) The robot arm further includes a laser displacement meter for detecting a position error in a direction of an optical axis of the laser light, In the calibration process, the first offset amount is obtained, and a second offset amount is obtained, which is an offset amount between a measurement position of the laser displacement meter and a camera center of the imaging camera; In the processing step, the robot arm is moved by the second offset amount from the taught position of the processing point, an error in the optical axis direction of the laser light at the processing point is detected by the laser displacement meter, and the robot arm is moved to the position of the processing point where the error has been corrected, thereby acquiring the first robot coordinates. 2. The laser processing method according to claim 1, (Appendix 7) In the calibration step, the first offset amount and the second offset amount are obtained using a cross mark provided on the calibration jig. 7. The laser processing method according to claim 6, (Appendix 8) In the teaching step, after measuring the processing point with the laser displacement meter, the robot arm is moved to a position offset by the second offset amount, and it is confirmed that the processing point is captured approximately at the center of the imaging camera. 8. The laser processing method according to claim 6 or 7, (Appendix 9) In the processing step, after acquiring the first robot coordinates, the robot arm is moved to a position offset by the first offset amount from the first robot coordinates, and the processing point is irradiated with laser light. 9. The laser processing method according to any one of claims 6 to 8, (Appendix 10) In the calibration step, a sample plate placed on the calibration jig is irradiated with the laser light from the laser irradiation device while changing the height from the sample plate to draw circles on the sample plate, and the drawn circles are captured by the imaging camera to obtain captured images of the circles whose height from the sample plate is changed, and a position in the optical axis direction of the laser light of the laser irradiation device where the focus of the laser light and the processing point coincide is determined based on the line widths of the circles in the captured images. 7. The laser processing method according to claim 1 or 6, (Appendix 11) A robot having a robot arm; a laser irradiation device provided on the robot arm and configured to irradiate a laser beam; An imaging camera provided on the robot arm for imaging a processing point; A laser processing apparatus including a calibration jig, a control device which stores a first offset amount, which is an offset amount between the irradiation position of the laser light obtained by using the calibration jig and the position of the camera center of the imaging camera, and a position of the processing point taught by moving the robot arm so as to capture the processing point with the imaging camera, moves the robot arm to the stored position of the processing point, obtains first robot coordinates when the camera center of the imaging camera and the processing point coincide, and moves the robot arm to a position offset by the stored first offset amount from the first robot coordinates to irradiate the processing point with laser light; A laser processing apparatus comprising: (Appendix 12) a laser displacement meter provided on the robot arm for detecting a position error in the optical axis direction of the laser light; The control device includes: The first offset amount, a second offset amount which is an offset amount between the measurement position of the laser displacement meter and the camera center of the imaging camera, and the position of the processing point are stored; The robot arm is moved by the second offset amount from the taught position of the processing point, an error in the optical axis direction of the laser light at the processing point is detected by the laser displacement meter, and the robot arm is moved to the position of the processing point where the error has been corrected, thereby obtaining the first robot coordinates. 12. The laser processing apparatus according to claim 11, (Appendix 13) The control device irradiates a sample plate placed on the calibration jig with the laser light from the laser irradiation device while changing the height from the sample plate to draw circles on the sample plate, and captures the drawn circles with the imaging camera to obtain captured images of the circles with the height from the sample plate changed, and determines a position in the optical axis direction of the laser light of the laser irradiation device where the focus of the laser light and the processing point coincide based on the line widths of the circles in the captured images. 13. The laser processing apparatus according to claim 11 or 12, [Explanation of symbols]

[0073] 1 work table, 2 workpiece, 3 calibration jig, 3a center, 3b sample plate (first sample plate, second sample plate, third sample plate), 3c circle, 5 robot arm, 6 laser irradiation device, 7 imaging camera, 7a camera center, 9 laser displacement meter, 9a measurement point, 10 robot, 21, 22, ..., 2n processing point, 51 robot control device, 61 laser oscillator, 62 optical fiber, 71 image processing device, 72 monitor, 81 system control device, 100, 200 laser processing device.

Claims

1. A laser processing method for performing laser processing of a processing point using a robot having a robot arm provided with a laser irradiation device that irradiates laser light and an imaging camera that images the processing point, comprising: a calibration step of determining a first offset amount, which is an offset amount between the irradiation position of the laser light and the position of the center of the imaging camera, using a calibration jig; a teaching step of teaching the position of the processing point by moving the robot arm so as to capture the processing point with the imaging camera; a processing step of moving the robot arm to a position of the taught processing point, acquiring first robot coordinates when the camera center of the imaging camera and the processing point coincide with each other, moving the robot arm to a position offset by the first offset amount from the first robot coordinates, and irradiating the processing point with laser light. A laser processing method comprising:

2. In the calibration step, a sample plate is placed on the calibration jig, a circle is drawn on the sample plate with the laser light, the circle is imaged by the imaging camera, and the irradiation position of the laser light is determined from the center coordinates of the circle, thereby obtaining the first offset amount.

2. The laser processing method according to claim 1 .

3. In the calibration step, the first offset amount is obtained using a cross mark provided on the calibration jig.

3. The laser processing method according to claim 2.

4. In the teaching step, the imaging camera is moved so as to capture the processing point at an approximate center of the imaging camera.

2. The laser processing method according to claim 1 .

5. In the processing step, the processing point is imaged by the imaging camera, and characteristics of the processing point are extracted.

2. The laser processing method according to claim 1 .

6. The robot arm further includes a laser displacement meter for detecting a position error in a direction of an optical axis of the laser light, In the calibration process, the first offset amount is obtained, and a second offset amount is obtained, which is an offset amount between a measurement position of the laser displacement meter and a camera center of the imaging camera; In the processing step, the robot arm is moved by the second offset amount from the taught position of the processing point, an error in the optical axis direction of the laser light at the processing point is detected by the laser displacement meter, and the robot arm is moved to the position of the processing point where the error has been corrected, thereby acquiring the first robot coordinates.

2. The laser processing method according to claim 1 .

7. In the calibration step, the first offset amount and the second offset amount are obtained using a cross mark provided on the calibration jig.

7. The laser processing method according to claim 6.

8. In the teaching step, after measuring the processing point with the laser displacement meter, the robot arm is moved to a position offset by the second offset amount, and it is confirmed that the processing point is captured approximately at the center of the imaging camera.

7. The laser processing method according to claim 6.

9. In the processing step, after acquiring the first robot coordinates, the robot arm is moved to a position offset by the first offset amount from the first robot coordinates, and the processing point is irradiated with laser light.

7. The laser processing method according to claim 6.

10. In the calibration step, a sample plate placed on the calibration jig is irradiated with the laser light from the laser irradiation device while changing the height from the sample plate to draw circles on the sample plate, and the drawn circles are captured by the imaging camera to obtain captured images of the circles whose height from the sample plate is changed, and a position in the optical axis direction of the laser light of the laser irradiation device where the focus of the laser light and the processing point coincide is determined based on the line widths of the circles in the captured images.

7. The laser processing method according to claim 1 or 6.

11. A robot having a robot arm; a laser irradiation device provided on the robot arm and configured to irradiate a laser beam; An imaging camera provided on the robot arm for imaging a processing point; A laser processing apparatus including a calibration jig, a control device which stores a first offset amount, which is an offset amount between the irradiation position of the laser light obtained by using the calibration jig and the position of the camera center of the imaging camera, and a position of the processing point taught by moving the robot arm so as to capture the processing point with the imaging camera, moves the robot arm to the stored position of the processing point, obtains first robot coordinates when the camera center of the imaging camera and the processing point coincide with each other, and moves the robot arm to a position offset by the stored first offset amount from the first robot coordinates to irradiate the processing point with laser light; A laser processing apparatus comprising:

12. a laser displacement meter provided on the robot arm for detecting a position error in the optical axis direction of the laser light; The control device includes: The first offset amount, a second offset amount which is an offset amount between the measurement position of the laser displacement meter and the camera center of the imaging camera, and the position of the processing point are stored; The robot arm is moved by the second offset amount from the taught position of the processing point, an error in the optical axis direction of the laser light at the processing point is detected by the laser displacement meter, and the robot arm is moved to the position of the processing point where the error has been corrected, thereby obtaining the first robot coordinates.

12. The laser processing apparatus according to claim 11.

13. The control device irradiates a sample plate placed on the calibration jig with the laser light from the laser irradiation device while changing the height from the sample plate to draw circles on the sample plate, and captures the drawn circles with the imaging camera to obtain captured images of the circles with the height from the sample plate changed, and determines a position in the optical axis direction of the laser light of the laser irradiation device where the focus of the laser light and the processing point coincide based on the line widths of the circles in the captured images.

13. The laser processing apparatus according to claim 11 or 12.

Images