Control device and control method for laser processing apparatus, laser processing system, laser processing method, and program

Abstract

The present invention provides a control device for a laser processing apparatus that can mitigate energy concentration at the edges in the width direction, even when the bead width is widened. [Solution] Laser processing is performed by moving the reference point on the surface of the workpiece while moving the beam spot so that the first distance from the reference point to the beam spot of the laser beam changes over time and the beam spot orbits around the reference point. The control device acquires a parameter that specifies the frequency of the time change of the first distance, and changes the first distance over time based on the acquired parameter.

Description

Technical Field

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[0001] The present invention relates to a control device and a control method for a laser processing apparatus, a laser processing system, a laser processing method, and a program.

Background Art

[0002] A laser welding method capable of obtaining good welding quality is disclosed in Patent Document 1 below. In the method disclosed in Patent Document 1, wobbling processing is performed by a combination of a scanning motion in which the locus of the laser beam moves along a first direction parallel to the joint surface of the welding target and a rocking motion. The rocking motion includes a first rocking component along the first direction and a second rocking component along a second direction perpendicular to the first direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since wobbling processing can arbitrarily control the bead width, it is used for butt welding where gaps are likely to occur. As the wobble diameter is increased, energy tends to concentrate at the ends in the width direction of the bead. When viewed from the cross-section of the penetration, both sides are relatively deep and the central part becomes relatively shallow. When it is desired to perform welding having a wide bead width and a relatively deep penetration shape at the central part, it is difficult to apply the conventional wobbling processing with an enlarged wobble diameter. The wobbling processing disclosed in Patent Document 1 also cannot meet such requirements.

[0005] The object of the present invention is to provide a control device and control method for a laser processing apparatus, a laser processing system, and a laser processing method that can mitigate energy concentration at the edges in the width direction even when the bead width is wide. Another object of the present invention is to provide a program executed by this control device. [Means for solving the problem]

[0006] According to one aspect of the present invention, A control device for a laser processing apparatus that performs laser processing by moving the reference point on the surface of a workpiece while moving the beam spot so that the first distance from the reference point to the beam spot of the laser beam changes over time and the beam spot moves around the reference point, Obtain a parameter that specifies the frequency of the time variation of the first distance, A control device is provided that changes the first distance over time based on the acquired parameters.

[0007] According to another aspect of the present invention, The control device and, An input device into which the parameters specifying the processing conditions are input, A laser light source, A scanner device that wobbles the laser light output from the laser light source under control from the control device. A laser processing apparatus equipped with [a specific feature] is provided.

[0008] According to yet another aspect of the present invention, A control method for a laser processing apparatus that performs laser processing by moving the reference point on the surface of a workpiece while moving the beam spot so that the first distance from the reference point to the beam spot of the laser beam changes over time, and the beam spot moves around the reference point, Obtain a parameter that specifies the frequency of the time variation of the first distance, A control method is provided for changing the first distance over time based on the acquired parameters.

[0009] According to yet another aspect of the present invention, A laser processing method in which a first distance from a reference point to the beam spot of a laser beam changes over time, and the beam spot is moved so that it orbits the reference point, while the reference point is moved on the surface of the workpiece, wherein the first distance from the reference point to the beam spot of the laser beam changes over time, and the reference point is moved on the surface of the workpiece, A laser processing method is provided which causes the beam spot to orbit the reference point two or more integer times during one period of the temporal change of the first distance.

[0010] According to yet another aspect of the present invention, A function for controlling a laser processing apparatus that performs laser processing by moving the reference point on the surface of a workpiece while moving the beam spot so that the first distance from the reference point to the beam spot of the laser beam changes over time and the beam spot moves around the reference point, A function to obtain a parameter that specifies the period of time change of the first distance, Based on the acquired parameters, a function is provided to change the first distance over time. A program is provided to enable a computer to implement this. [Effects of the Invention]

[0011] Varying the first distance over time changes the size of the beam spot's orbital path. This can mitigate energy concentration at the edges in the width direction. For example, setting the frequency of the first distance's time variation so that the beam spot orbits a reference point two or more times during one period of the first distance's time variation can mitigate energy concentration at the edges in the width direction. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram of a laser processing apparatus equipped with the control device 50 according to the first embodiment. [Figure 2]FIG. 2A is a diagram showing the locus of the beam spot B when the first wobble diameter D1 is 1 mm, the second wobble diameter D2 is 0.3 mm, the wobble frequency f is 200 Hz, and the number of revolutions n is 2. FIG. 2B is a diagram showing the locus of the beam spot B when the reference point Po shown in FIG. 2A is swept at a speed of 10 mm / s along the processing line 45 parallel to the x direction. [Figure 3] FIG. 3 is a flowchart showing the procedure of the laser processing method according to the first embodiment. [Figure 4] FIG. 4A is a diagram showing the locus of the beam spot B when it is assumed that the reference point Po is stationary when the number of revolutions n is 4. FIG. 4B is a diagram showing the locus of the beam spot B when the reference point Po shown in FIG. 4A is swept at a speed of 10 mm / s along the processing line 45 parallel to the x direction. [Figure 5] FIG. 5A is a diagram showing the locus of the beam spot B with respect to the reference point Po when the first wobble diameter D1, the second wobble diameter D2, the wobble frequency f, and the number of revolutions n are set the same as those shown in FIG. 2A and the parameter η is set to 30°. FIG. 5B is a diagram showing the locus of the beam spot B when the reference point Po shown in FIG. 5A is swept at a speed of 10 mm / s along the processing line 45 forming an angle η with the x-axis. [Figure 6] FIG. 6A is a diagram showing the locus of the beam spot B with respect to the reference point Po when the number of revolutions n is set to 4. FIG. 6B shows the locus of the beam spot B when the reference point Po shown in FIG. 6A is swept at a speed of 10 mm / s along the processing line 45 forming an angle η with the x-axis. [Figure 7] FIG. 7 is a schematic diagram of the control device 50 according to the third embodiment and the laser processing device 10 to be controlled.

MODE FOR CARRYING OUT THE INVENTION

[0013] [First Embodiment] The control device of the laser processing apparatus according to the first embodiment will be described with reference to FIGS. 1 to 4B. FIG. 1 is a schematic diagram of a laser processing apparatus equipped with a control device 50 according to the first embodiment. This laser processing apparatus includes a laser light source 11, a laser transmission fiber 12, a scanner device 20, a control device 50, and an input device 60. The laser light output from the laser light source 11 is input into the scanner device 20 via the laser transmission fiber 12.

[0014] The scanner device 20 includes a collimating lens 21, an X scan mirror 22, a Y scan mirror 23, a folding mirror 24, a condenser lens 25, and a stage 26. A processing object 40 is held on the stage 26. For example, wobbling welding of the processing object 40 is performed. The laser light guided to the scanner device 20 is incident on the processing object 40 via the collimating lens 21, the X scan mirror 22, the Y scan mirror 23, the folding mirror 24, and the condenser lens 25.

[0015] The collimating lens 21 collimates the laser light output from the output end of the laser transmission fiber 12. The X scan mirror 22 and the Y scan mirror 23 wobble the laser light respectively, so as to swing the beam spot in the X direction and the Y direction on the surface of the processing object 40. The folding mirror 24 reflects the laser light downward. The condenser lens 25 condenses the laser light on the surface of the processing object 40. For example, an fθ lens is used as the condenser lens 25. For example, an XY stage is used as the stage 26.

[0016] The control device 50 controls the laser light source 11 and the scanner device 20 based on the processing conditions input from the input device 60. As an example, the processing conditions include a wobble frequency f, a first wobble diameter D1, a second wobble diameter D2, a number of revolutions n, and a scanning speed v. The meanings of these processing conditions will be described in detail later.

[0017] The input device 60 may be, for example, a touch panel, a key panel, or a keyboard. Alternatively, the input device 60 may be a removable media reader. For example, a data file containing processing conditions may be created in a separate device from the laser processing machine, and the processing conditions may be input by the input device 60 reading this data file. The input device 60 may also be a communication device that receives the data file.

[0018] The control device 50 includes a parameter storage unit 51, a calculation unit 52, and a drive control unit 53. A program that enables the computer to implement the functions of each of these parts is stored in the storage unit 54. The computer controls the scanner device 20 by executing this program.

[0019] Parameters defining the machining conditions input from the input device 60 are stored in the parameter storage unit 51. The calculation unit 52 calculates the control information necessary to control the X scan mirror 22 and Y scan mirror 23 based on the parameters stored in the parameter storage unit 51. The drive control unit 53 controls the X scan mirror 22 and Y scan mirror 23 based on the control information calculated by the calculation unit 52. Furthermore, it controls the stage 26.

[0020] Next, the parameters that define the machining conditions will be described with reference to Figures 2A to 3B. In wobble machining, the beam spot is moved so that it orbits around a reference point, and the reference point is moved along the line to be machined (e.g., a weld line). The orbital movement of the beam spot around the reference point is performed by controlling the X-scan mirror 22 (Figure 1) and the Y-scan mirror 23 (Figure 1). The movement of the reference point is performed by controlling the stage 26 to move the workpiece 40.

[0021] Figure 2A shows an example of the trajectory of beam spot B, assuming that the reference point Po is stationary. The position of beam spot B is represented by the x and y coordinates in an xy Cartesian coordinate system with reference point Po as the origin. When the X-scan mirror 22 (Figure 1) is operated, beam spot B moves in the x direction, and when the Y-scan mirror 23 is operated, beam spot B moves in the y direction. The distance from reference point Po to beam spot B (hereinafter referred to as the first distance) is denoted as r. The x and y coordinates of beam spot B are calculated using the following formulas. x = r·cos(2πft) y = r·sin(2πft)···(1) Here, f is the frequency at which beam spot B orbits the reference point Po (wobble frequency), and t is time.

[0022] The first distance r is defined by the following equation, using the first wobble diameter D1, the second wobble diameter D2, and the number of rotations n. r=(D1+D2) / 4+((D1-D2) / 4)·sin(2πft / n)···(2) In other words, the first distance r changes over time, and its frequency is f / n. Once the wobble frequency f is determined, the frequency f / n of the time change of the first distance r is determined by dividing the wobble frequency f by the number of cycles n. The number of cycles n can be said to be a parameter that specifies the frequency of the time change of the first distance r. The wobble frequency f and the number of cycles n are input to the control device 50 by the user operating the input device 60 (Figure 1). The control device 50 sets the value obtained by changing the wobble frequency f based on the input number of cycles n as the frequency that changes the first distance r over time, and changes the first distance r over time.

[0023] Equation (2) (D1+D2) / 4 determines the average value of the first distance r that changes over time, and ((D1-D2) / 4) determines the amplitude of the time change of the first distance r.

[0024] The calculation unit 52 (Figure 1) calculates the time change of the coordinates of beam spot B using equations (1) and (2). From the calculated time change, it calculates the control amount for controlling the X scan mirror 22 and Y scan mirror 23. The drive control unit 53 (Figure 1) drives and controls the X scan mirror 22 and Y scan mirror 23 based on the calculated control amount.

[0025] Figure 2A shows the trajectory of beam spot B when the first wobble diameter D1 is 1 mm, the second wobble diameter D2 is 0.3 mm, the wobble frequency f is 200 Hz, and the number of rotations n is 2. It can be seen that a relatively large rotational path L1 and a relatively small rotational path L2 are formed surrounding the reference point Po. Beam spot B alternately repeats rotational motion that traces the large rotational path L1 and rotational motion that traces the small rotational path L2. The trajectories of beam spot B intersect at one point on the x-axis. This intersection point will be called the "intersection". Furthermore, each of the large rotational path L1 and the small rotational path L2 is symmetrical with respect to the line (i.e., the x-axis) passing through the reference point Po and the intersection.

[0026] At time t=0, beam spot B is located at the intersection on the x-axis, and its x-coordinate is (D1+D2) / 4. The x-coordinate of the point where the large circular path L1 intersects with the negative part of the x-axis is D1 / 2, and the x-coordinate of the point where the small circular path L2 intersects with the negative part of the x-axis is D2 / 2. Therefore, the first wobble diameter D1 is a parameter that determines the size of the large circular path L1, and the second wobble diameter D2 is a parameter that determines the size of the small circular path L2.

[0027] The time it takes for beam spot B to complete two revolutions around reference point Po corresponds to one period of the time evolution of the first distance r. In other words, the number of revolutions n represents the number of times beam spot B revolves around reference point Po during one period of the time evolution of the first distance r.

[0028] Figure 2B shows the trajectory of beam spot B when the reference point Po shown in Figure 2A is swept along the processing line 45 parallel to the x-direction at a speed of 10 mm / s. The trajectory of the large-diameter circular path L1 and the trajectory of the small-diameter circular path L2 appear to overlap. Since the trajectory shown in Figure 2A is symmetric with respect to the x-axis, when laser processing is performed along the trajectory shown in Figure 2B, the energy distribution in the direction perpendicular to the processing line 45 is symmetric with respect to the processing line 45.

[0029] Figure 3 is a flowchart showing the procedure for the laser processing method according to the first embodiment. First, the control device 50 acquires the values ​​of parameters that specify the processing conditions, such as the first wobble diameter D1, the second wobble diameter D2, the wobble frequency f, the number of cycles n, and the sweep speed v, and stores them in the parameter storage unit 51 (step SA1). Next, the calculation unit 52 calculates the time change of the x and y coordinates of the beam spot B based on these parameters using equations (1) and (2). Furthermore, it calculates control information for controlling the X scan mirror 22 and the Y scan mirror 23 from the information showing the time change of the x and y coordinates of the beam spot B (step SA2). Next, the drive control unit 53 performs laser processing by controlling the X scan mirror 22 and the Y scan mirror 23 based on the control information (step SA3).

[0030] Next, with reference to Figures 4A and 4B, we will explain the case where the number of rotations n is 4. The first wobble diameter D1, the second wobble diameter D2, and the wobble frequency f are the same as in the example shown in Figures 2A and 2B.

[0031] Figure 4A shows the trajectory of beam spot B assuming that the reference point Po is stationary. Since the number of revolutions n is 4, beam spot B makes 4 revolutions around reference point Po during one period of the time evolution of the first distance r. The trajectory of beam spot B intersects at 3 points. The number of intersections is equal to n-1. All of these intersections are located on the x-axis. Also, the trajectory of beam spot B is symmetric with respect to the x-axis.

[0032] From time t=0, after one period of the wobble frequency f has elapsed, the first distance r reaches its maximum value D1 / 2. After two periods of time, beam spot B returns to its position at time t=0, and after three periods of time, the first distance r reaches its minimum value D2 / 2. The first wobble diameter D1 is a parameter that determines the size of the outermost circular path of beam spot B's trajectory, and the second wobble diameter D2 is a parameter that determines the size of the innermost circular path of beam spot B's trajectory.

[0033] Figure 4B shows the trajectory of beam spot B when the reference point Po shown in Figure 4A is swept along the processing line 45 parallel to the x-direction at a speed of 10 mm / s. In the example shown in Figure 4B, as shown in Figure 4A, the intersection of the beam spot B trajectories lies on a straight line passing through the reference point Po, so the energy distribution in the direction perpendicular to the processing line 45 is almost symmetric with respect to the processing line 45. Furthermore, the degree of energy concentration in the bead width direction is further reduced compared to the case in Figure 2B.

[0034] Next, we will describe the excellent effects of the first embodiment. If the trajectory of the beam spot B orbiting the reference point Po is a simple circle, then when the reference point Po is swept along the processing line, energy tends to concentrate at both ends in the bead width direction. By adopting the method according to the first embodiment, the concentration of energy in the bead width direction can be mitigated.

[0035] For example, in the trajectory of beam spot B shown in Figures 2B and 4B, energy is concentrated in regions with a high distribution density of the trajectory. In the example shown in Figure 2B, in addition to the ends, energy is concentrated at two locations on the inside in the bead width direction. As the number of locations where energy is concentrated increases, the degree of energy concentration is mitigated. In the example shown in Figure 4B, it is not possible to clearly identify the locations where energy is concentrated. Thus, increasing the number of rotations n further enhances the effect of mitigating the degree of energy concentration. To mitigate the degree of energy concentration, it is preferable to make the number of rotations n an integer of 2 or more. That is, it is preferable to make beam spot B rotate an integer number of times, two or more times, around the reference point Po during one period of the temporal change of the first distance r.

[0036] Next, a modified example of the first embodiment will be described. In the examples shown in Figures 2A and 4A, the number of rotations n is set to an even number. If the number of rotations n is set to an odd number, the intersection of the beam spot B's trajectory will appear on the y-axis. Therefore, when sweeping the reference point Po in the y-axis direction, it is best to set the number of rotations n to an odd number.

[0037] [Second Example] Next, the control device for the laser processing apparatus according to the second embodiment will be described with reference to Figures 5A to 6B. The following description will omit explanations of components common to the control device according to the first embodiment, which was described with reference to Figures 1 to 4B.

[0038] In the first embodiment, as shown in equations (1) and (2), the phase of the rotational motion of beam spot B and the phase of the time change of the first distance r are fixed. In contrast, in the second embodiment, the phase of the time change of the first distance r can be changed with respect to the phase of the rotational motion of beam spot B. The first distance r is defined by the following equation. r=(D1+D2) / 4+((D1-D2) / 4)·sin((2πft-η) / n)···(3) By adjusting the parameter η, the phase of the time evolution of the first distance r changes with respect to the phase of the rotational motion of beam spot B.

[0039] Figure 5A shows the trajectory of beam spot B relative to the reference point Po when the first wobble diameter D1, second wobble diameter D2, wobble frequency f, and number of repetitions n are set to the same values ​​as in Figure 2A, and the parameter η is set to 30°. In the example shown in Figure 2A, the intersection of the beam spot B trajectory lies on the x-axis. In contrast, in the example shown in Figure 5A, the intersection of the beam spot B trajectory lies on a straight line that makes an angle η (30°) with respect to the x-axis. Hereafter, the angle η may be referred to as the sweep direction angle.

[0040] Figure 5B shows the trajectory of beam spot B when the reference point Po shown in Figure 5A is swept along the machining line 45, which makes an angle η with the x-axis, at a speed of 10 mm / s. In this case, with respect to the bead width direction, energy is concentrated at two points on the inside, in addition to the ends. As the number of points where energy is concentrated increases, the degree of energy concentration is mitigated. Thus, once the direction of the machining line 45 is determined, it is advisable to adjust the phase of the temporal change in the first distance r so that the line connecting the point where the trajectory of beam spot B, which orbits around the reference point Po, intersects with the reference point Po is parallel to the direction in which the reference point Po is moved. More specifically, the sweep direction angle η should be set to be equal to the angle between the x-axis and the machining line 45.

[0041] Figure 6A shows the trajectory of beam spot B relative to reference point Po when the number of rotations n is set to 4. The first wobble diameter D1, the second wobble diameter D2, and the wobble frequency f are the same as in Figure 5A. The three intersections of the beam spot B trajectory and reference point Po are located on a straight line making an angle η with respect to the x-axis.

[0042] Figure 6B shows the trajectory of beam spot B when the reference point Po shown in Figure 6A is swept along the machining line 45, which makes an angle η with the x-axis, at a speed of 10 mm / s. In the example shown in Figure 6B, the degree of energy concentration is more mitigated compared to the example shown in Figure 5B.

[0043] Next, we will describe the excellent effects of the second embodiment. In the second embodiment, as in the first embodiment, the degree of energy concentration in the bead width direction can be mitigated. Furthermore, by adjusting the sweep direction angle η, it is possible to flexibly accommodate cases where the processed line 45 is inclined with respect to the x-axis.

[0044] [Third Embodiment] Next, the control device for the laser processing apparatus according to the third embodiment will be described with reference to Figure 7. The following description will omit details of components common to the control device for the laser processing apparatus according to the first embodiment, which was described with reference to Figures 1 to 4B.

[0045] Figure 7 is a schematic diagram of the control device 50 and the laser processing apparatus 10 to be controlled according to the third embodiment. In the first embodiment (Figure 1), the stage 26 moves the workpiece 40, thereby moving the reference point Po (Figure 2A, etc.) along the processing line 45 (Figure 2B, etc.). In the third embodiment, however, the wobble head 31 that outputs the laser beam is moved along the processing line.

[0046] Laser light is introduced from the laser light source 11 to the wobble head 31 via the laser transmission fiber 12. The wobble head 31, like the X-scan mirror 22 and Y-scan mirror 23, has the function of wobbling the laser beam in the X and Y directions. The drive control unit 53 of the control device 50 controls the wobbling operation of the wobble head 31.

[0047] The wobblehead 31 is held by the articulated robot 32. The drive control unit 53 of the control device 50 provides the robot control unit 35 with position information of the machining line on the workpiece. Based on the position information of the machining line, the robot control unit 35 controls the articulated robot 32 to move the beam spot of the laser beam output from the wobblehead 31 along the machining line.

[0048] The signal resolution of the beam spot sweep angle η is preferably at least 90°, and more preferably at least 45°. For example, if the actual sweep angle η is between -22.5° and 22.5°, the first distance r is calculated using equation (3) with the sweep angle η = 0°, and if the actual sweep angle η is between 22.5° and 67.5°, the first distance r is calculated using equation (3) with the sweep angle η = 45°.

[0049] Each embodiment is illustrative, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. Similar effects and benefits from similar configurations in multiple embodiments will not be mentioned sequentially for each embodiment. Furthermore, the present invention is not limited to the embodiments described above. For example, it will be obvious to those skilled in the art that various modifications, improvements, and combinations are possible. [Explanation of Symbols]

[0050] 10 Laser processing equipment 11. Laser light source 12 Laser transmission fiber 20 Scanner device 21 Collimating Lenses 22X Scan Mirror 23 Y Scan Mirror 24 Folding mirror 25 Focusing lens 26 stages 31 Wobblehead 32 Articulated Robots 35 Robot Control Unit 40. Object to be processed 45 Processing line 50 Control device 51 Parameter storage unit 52 Arithmetic section 53 Drive control unit 54 Memory section 60 Input devices B Beam Spot L1 Relatively large circular route L2 Relatively small circular route Po reference point

Claims

1. A control device for a laser processing apparatus that performs laser processing by moving the reference point on the surface of a workpiece while moving the beam spot so that the first distance from the reference point to the beam spot of the laser beam changes over time and the beam spot moves around the reference point, Obtain a parameter that specifies the frequency of the time variation of the first distance, A control device that changes the first distance over time based on the acquired parameters.

2. The control device according to claim 1, wherein the frequency at which the beam spot orbits around the reference point is changed according to the parameter is set to be the frequency of the time change of the first distance.

3. Furthermore, the control device according to claim 1 or 2, wherein the phase of changing the first distance over time is adjusted so that the straight line connecting the point where the trajectory of the beam spot revolving around the reference point intersects with the reference point is parallel to the direction in which the reference point is moved.

4. A control device according to claim 1 or 2, An input device into which the parameters specifying the processing conditions are input, A laser light source, A scanner device that wobbles the laser light output from the laser light source under control from the control device. A laser processing device equipped with laser processing equipment.

5. A control method for a laser processing apparatus that performs laser processing by moving the reference point on the surface of a workpiece while moving the beam spot so that the first distance from the reference point to the beam spot of the laser beam changes over time and the beam spot moves around the reference point, Obtain a parameter that specifies the frequency of the time variation of the first distance, A control method for changing the first distance over time based on the acquired parameters.

6. A laser processing method in which a first distance from a reference point to the beam spot of a laser beam changes over time, and the beam spot is moved so that it orbits the reference point, while the reference point is moved on the surface of the workpiece, wherein the first distance from the reference point to the beam spot of the laser beam changes over time, and the reference point is moved on the surface of the workpiece, A laser processing method in which the beam spot is rotated two or more integer times around the reference point during one period of the temporal change of the first distance.

7. The laser processing method according to claim 6, wherein the beam spot is made to orbit such that the trajectory of the beam spot intersects at one point, or intersects on a straight line passing through the reference point, assuming that the reference point is stationary.

8. A function for controlling a laser processing apparatus that performs laser processing by moving the reference point on the surface of a workpiece while moving the beam spot so that the first distance from the reference point to the beam spot of the laser beam changes over time and the beam spot moves around the reference point, A function to obtain a parameter that specifies the period of time change of the first distance, Based on the acquired parameters, a function is provided to change the first distance over time. A program that enables a computer to perform this task.

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