Laser processing method, programming tool and laser processing machine

Abstract

A laser processing method for forming a through hole in a workpiece using a laser processing machine that scans a laser beam emitted from a laser oscillator with a galvanometer mirror and focuses the laser beam on a workpiece placed on a table to perform a hole drilling process, the method including a first processed hole forming step and a second processed hole forming step. In the first processed hole forming step, a processed hole forming process is performed on a first processed surface of the workpiece, in which a scanning area that can be scanned by the galvanometer mirror moves by moving the table every time a hole drilling process in one scanning area is completed, so that a circular path that causes a scanning area to rotate along a direction parallel to the outer periphery of the processed surface of the workpiece moves from the outer periphery side to the inside of the workpiece. In the second processed hole forming step, a processed hole forming process is performed on the second processed surface. The first processed hole forming step and the second processed hole forming step are performed multiple times so that the positions of the through holes connected to the processed holes formed by a pair of the first processed hole forming step and the second processed hole forming step are different.

Description

[Technical field]

[0001] The present disclosure relates to a laser processing method, a programming tool, and a laser processing machine for forming a through hole in an object to be processed by irradiating it with laser light. [Background technology]

[0002] A laser processing method using a laser beam is used to form through holes in a printed circuit board. Patent Document 1 discloses a laser through hole (LTH) processing method in which holes formed by laser processing from the front and back surfaces of a three-layer printed circuit board with copper foil formed on both the front and back surfaces of a resin plate are connected to form through holes, in which a plurality of scanning areas, which are areas where a laser beam can be scanned by a galvanometer mirror, are set on the printed circuit board, and holes are processed in the scanning areas in sequence from the edge of the printed circuit board toward the center in a spiral manner. By using such a laser processing method, it is possible to suppress sudden and partial shrinkage of the printed circuit board and suppress the positional deviation of the processed hole from the target position where the hole is to be drilled in the printed circuit board that occurs before and after the shrinkage of the printed circuit board. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6793892 Summary of the Invention [Problem to be solved by the invention]

[0004] Although it depends on the type of material constituting the printed circuit board to be processed, the technique described in Patent Document 1 can be used when forming about 1.3 million to 1.5 million through holes in one printed circuit board. However, in recent years, the number of through holes formed in printed circuit boards has been increasing to more than 1.3 million to 1.5 million, and when the technique described in Patent Document 1 is used to form such a number of through holes in a printed circuit board, the processed holes are formed densely, which causes a problem that the printed circuit board warps when the front surface is processed. In addition, even if the printed circuit board is fixed on a table with a clamp or the like after the front surface is processed and the back surface is processed while suppressing the warp, the positional deviation between the processed holes formed on the front surface and the processed holes formed on the back surface becomes large, which causes a problem that the through holes cannot be formed with high accuracy.

[0005] The present disclosure has been made in consideration of the above, and aims to provide a laser processing method that, when forming holes on the front and back surfaces of a workpiece to form through holes, can suppress the occurrence of warping of the workpiece after forming holes on one side and suppress misalignment of the holes formed on the front and back surfaces compared to conventional methods. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the present disclosure provides a laser processing method for forming a through hole in a workpiece using a laser processing machine that scans a laser beam emitted from a laser oscillator with a galvanometer mirror and focuses the laser beam on a workpiece placed on a table to perform a hole drilling process, the method including a first processed hole forming step and a second processed hole forming step. In the first processed hole forming step, a processed hole forming process is performed on a first processed surface of the workpiece, in which the scanning area is moved by moving the table every time drilling within one scanning area is completed, so that a circular path that causes a scanning area that can be scanned by the galvanometer mirror to circle along a direction parallel to the outer periphery of the processed surface of the workpiece moves from the outer periphery side of the workpiece toward the inside. In the second processed hole forming step, a processed hole forming process is performed on a second processed surface opposite to the first processed surface. In order to make the positions of the through holes connected to the processed holes formed by a pair of the first processed hole forming step and the second processed hole forming step different, For the same workpiece The first hole forming step and the second hole forming step are performed a plurality of times. Effect of the Invention

[0007] The laser processing method according to the present disclosure has the advantage that, when forming holes on the front and back surfaces of a workpiece to form through holes, the occurrence of warping of the workpiece after forming holes on one side can be suppressed compared to conventional methods, and misalignment of the holes formed on the front and back surfaces can be suppressed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a schematic configuration example of a laser processing machine according to a first embodiment; [Diagram 2] FIG. 1 is a diagram showing an example of the arrangement of scanning areas and the processing sequence in a laser processing method according to a conventional technology. [Diagram 3] FIG. 1 is a diagram showing an example of a state of a workpiece after a hole is formed by a conventional technique. [Figure 4] FIG. 1 is a diagram for explaining an overview of a laser processing method according to a first embodiment. [Diagram 5]FIG. 1 is a diagram showing an example of a functional configuration of a programming tool for a laser processing machine according to a first embodiment; [Figure 6] 1 is a flowchart showing an example of a procedure of a laser processing method according to a first embodiment. [Figure 7] 1 is a flowchart showing an example of a procedure of a laser processing method according to a first embodiment. [Figure 8] 1 is a flowchart showing an example of a procedure of a laser processing method according to a first embodiment. [Figure 9] FIG. 1 is a diagram showing an example of a procedure of a laser processing method according to the first embodiment. [Figure 10] FIG. 1 is a diagram showing an example of a procedure of a laser processing method according to the first embodiment. [Figure 11] FIG. 1 is a diagram showing an example of a procedure of a laser processing method according to the first embodiment. [Figure 12] FIG. 1 is a diagram showing an example of a procedure of a laser processing method according to the first embodiment. [Figure 13] FIG. 1 is a diagram showing an example of a procedure of a laser processing method according to the first embodiment. [Figure 14] FIG. 1 is a diagram showing an example of a procedure of a laser processing method according to the first embodiment. [Figure 15] A diagram explaining a case where through-hole position data is simply divided into three parts and laser processing is performed using conventional technology. [Figure 16] FIG. 13 is a diagram showing characteristic information showing an example of the relationship between the number of revolutions and the amount of positional deviation of a processed hole in the laser processing method according to the second embodiment. [Figure 17] FIG. 13 is a diagram showing an example of a processing sequence of the laser processing method according to the second embodiment; [Figure 18] FIG. 13 is a diagram showing an example of a processing sequence of the laser processing method according to the second embodiment; [Figure 19] FIG. 13 is a diagram showing an example of a processing sequence of the laser processing method according to the second embodiment; [Figure 20] FIG. 13 is a diagram showing a schematic configuration example of a laser processing machine according to a third embodiment; [Figure 21] FIG. 1 is a diagram showing an example of the configuration of a control circuit that realizes a control device for a laser processing machine according to first to third embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A laser processing method, a programming tool, and a laser processing machine according to embodiments of the present disclosure will be described in detail below with reference to the drawings.

[0010] Embodiment 1 FIG. 1 is a diagram showing a schematic configuration example of a laser processing machine according to the first embodiment. The laser processing machine 10 is a device that performs a hole drilling process on a workpiece W, which is a processing target, by irradiating a pulsed laser light L. An example of the workpiece W is a printed circuit board or an IC (Integrated Circuit) package board mounted on an electronic device or the like. An example of the printed circuit board is a resin board with copper foil formed on the front and back surfaces. Note that the workpiece W may be anything other than the above-mentioned printed circuit board or IC package board as long as it is an object in which a through hole can be formed.

[0011] In Fig. 1, the X-axis, Y-axis, and Z-axis are three axes perpendicular to each other. The X-axis and Y-axis are two mutually orthogonal axes taken within the mounting surface of the table 15. The Z-axis is an axis perpendicular to both the X-axis and Y-axis directions. The laser processing machine 10 performs a drilling process to quickly form a plurality of holes distributed in the X-axis and Y-axis directions.

[0012] The laser processing machine 10 includes a laser oscillator 11 that emits laser light L, galvanometer mirrors 12Y, 12X that deflect and scan the laser light L, galvanometer scanners 13Y, 13X that rotate the galvanometer mirrors 12Y, 12X, an fθ lens 14 which is a focusing lens that focuses the laser light L, a table 15 that holds the workpiece W, a camera 16 that images the table 15 and the workpiece W, and a control device 20 that controls the entire laser processing machine 10.

[0013] The laser oscillator 11 emits a pulsed laser light L. The pulsed laser light L is, for example, infrared light. An example of the laser oscillator 11 is a carbon dioxide (CO2) laser. The peak wavelength of the pulsed laser light L is in the range of 9.3 μm to 10.6 μm. Hereinafter, the pulsed laser light L will be referred to as laser light L.

[0014] The galvanometer mirror 12Y is driven by the galvanometer scanner 13Y to scan the laser light L. The galvanometer scanner 13Y is a servo motor used to position the galvanometer mirror 12Y. The galvanometer scanner 13Y rotates the galvanometer mirror 12Y by control according to a position command. That is, the galvanometer scanner 13Y adjusts the position and angle of the laser light L incident on the fθ lens 14 by driving the galvanometer mirror 12Y. In this example, the galvanometer scanner 13Y moves the irradiation position of the laser light L in the Y-axis direction by rotating the galvanometer mirror 12Y within a specific range of swing angles.

[0015] The galvanometer mirror 12X is driven by the galvanometer scanner 13X to scan the laser light L. The galvanometer scanner 13X is a servo motor used to position the galvanometer mirror 12X. The galvanometer scanner 13X rotates the galvanometer mirror 12X by control according to a position command. That is, the galvanometer scanner 13X adjusts the position and angle of the laser light L incident on the fθ lens 14 by driving the galvanometer mirror 12X. In this example, the galvanometer scanner 13X moves the irradiation position of the laser light L in the X-axis direction by rotating the galvanometer mirror 12X within a specific range of swing angles.

[0016] In this example, the laser light L from the laser oscillator 11 is incident on the galvanometer mirror 12Y, and the laser light L from the galvanometer mirror 12Y is incident on the galvanometer mirror 12X; however, it is also possible that the laser light L from the laser oscillator 11 is incident on the galvanometer mirror 12X, and the laser light L from the galvanometer mirror 12X is incident on the galvanometer mirror 12Y.

[0017] The fθ lens 14 is a lens that collects the laser light L reflected by the galvanometer mirror 12X and irradiates the workpiece W with the laser light L perpendicularly.

[0018] The table 15 carries the workpiece W to be drilled, and is movable by a table drive mechanism in a direction parallel to the mounting surface, i.e., in at least one of the X-axis direction and the Y-axis direction. The table drive mechanism has a drive mechanism for the X-axis direction and a drive mechanism for the Y-axis direction. At least one of the drive mechanisms for the X-axis direction and the Y-axis direction is driven in accordance with a position command, thereby allowing the position of the table 15 to change within the XY plane.

[0019] The movable range of the galvanometer mirrors 12Y, 12X by driving the galvanometer scanners 13Y, 13X, i.e., the change of the irradiation position of the laser light L in the X-axis direction and the Y-axis direction by the galvanometer mirrors 12Y, 12X, is limited to an extremely narrow range. For this reason, it is difficult to perform drilling on the entire workpiece W only by changing the irradiation position of the galvanometer mirrors 12Y, 12X by driving the galvanometer scanners 13Y, 13X. Therefore, after the processing in the movable range of the galvanometer mirrors 12Y, 12X by driving the galvanometer scanners 13Y, 13X is completed, the position of the workpiece W is changed using the table 15, and processing is performed again in the movable range of the galvanometer mirrors 12Y, 12X by driving the galvanometer scanners 13Y, 13X. This allows the entire workpiece W to be drilled.

[0020] The table 15 has a fixing mechanism. In the example of FIG. 1, the fixing mechanism is a suction mechanism. That is, the suction mechanism has a plurality of suction holes 151 provided in the table 15, and a vacuum pump (not shown) connected to the suction holes 151 via piping or the like. By operating the vacuum pump, the workpiece W placed on the placement surface of the table 15 is vacuum-sucked and fixed. The fixing mechanism is not limited to the suction mechanism, and may be any mechanism capable of fixing the workpiece W. In one example, the workpiece W may be fixed to the table 15 by a clamp mechanism.

[0021] The camera 16 captures an image of an alignment mark provided for measurement of the workpiece W fixed on the table 15. The camera 16 outputs the captured image data to the control device 20.

[0022] The control device 20 has a programming tool 21 that generates a machining program from through-hole position data having position data indicating the positions of through-holes to be formed in the workpiece W, and a numerical control (NC) device 22 that controls the operations of the laser oscillator 11, the galvano scanners 13Y and 13X, the table drive mechanism of the table 15, etc. based on the machining program. The control device 20 is connected to the laser oscillator 11, the galvano scanners 13Y and 13X, the table 15, and the camera 16 via wiring 18.

[0023] The programming tool 21 reads the through-hole position data and generates a machining program in a format readable by the NC device 22 so that a hole is drilled at a position specified by the through-hole position data. The NC device 22 generates a position command for the table 15, a laser output command for the laser oscillator 11, and a position command for the galvano scanners 13Y and 13X. The position command for the table 15 is output to a drive mechanism for the table 15 in the X-axis direction and a drive mechanism for the table 15 in the Y-axis direction. The laser output command is output to the laser oscillator 11. The position commands for the galvano scanners 13Y and 13X are output to the galvano scanners 13Y and 13X.

[0024] When laser processing a workpiece W that is larger than the scanning area SA that can be scanned by the galvanometer mirrors 12Y, 12X alone, the scanning area SA that can be scanned by the galvanometer mirrors 12Y, 12X alone is defined as one section, and multiple scanning areas SA are set on the workpiece W. After the settings, the galvanometer mirrors 12Y, 12X are controlled to scan the laser light L in one scanning area SA to perform hole processing, and then the table 15 is controlled to move to the next scanning area SA and perform hole processing. By repeating this processing hole formation process, the entire workpiece W is processed.

[0025] Here, the hole drilling using the laser processing method described in Patent Document 1 and the problems associated with it will be described. When drilling a workpiece W, the material constituting the workpiece W at the portion where the hole is drilled is removed, so that stress is generated in the workpiece W toward the center of the processed hole, and this stress acts in a direction that causes the workpiece W to shrink toward the center of the processed hole. Although the stress generated by one processed hole is minute, when more than 100,000 processed holes are laser-processed in the workpiece W, the number of processed holes occupying the entire workpiece W becomes large, and the sum of all the stresses generated by the many processed holes becomes a value that cannot be ignored. For this reason, when performing fine hole drilling, the effect of shrinkage of the workpiece W becomes greater.

[0026] When performing hole drilling on the workpiece W, the programming tool 21 converts through hole position data, which lists position data of holes to be processed by laser, into a processing program in a format readable by the NC device 22. The NC device 22 also reads this processing program, corrects the position of the holes using correction information generated based on the alignment marks measured by the camera 16, and controls the laser light L to be irradiated at the corrected position. If the workpiece W shrinks and changes its shape during laser processing, the position of the alignment mark measured before processing shifts as the workpiece W shrinks, and as the laser processing progresses, a shift occurs between the original coordinates where the holes should be drilled, which are written in the processing program, and the coordinates on the workpiece W where the holes are actually to be drilled. As a result, defective workpieces W with shifted processing positions are produced.

[0027] When there are many machined holes in the center of the workpiece W, shrinkage occurs in the center, resulting in a large degree of deformation near the periphery of the workpiece W. On the other hand, when there are many machined holes in the vicinity of the periphery of the workpiece W, shrinkage occurs near the periphery but the central part of the workpiece W does not shrink, and as a result, the degree of shrinkage of the entire workpiece W is suppressed compared to when there are many machined holes in the central part of the workpiece W.

[0028] The technique described in Patent Document 1 solves the problem that the workpiece W shrinks when a large number of holes are formed in the workpiece W. FIG. 2 is a diagram showing an example of the arrangement of scanning areas and the processing sequence in the laser processing method according to the conventional technique. For the sake of convenience, an example is shown in which the number of holes 51 is smaller than the actual number. The same applies to the following examples. In the laser processing method described in Patent Document 1, first, a scanning area SA61 that can be scanned only by the galvanometer mirrors 12Y and 12X is set at the corner of the outermost periphery of the workpiece W, and then a scanning area SA62 that can be scanned only by the galvanometer mirrors 12Y and 12X is set at the outermost periphery, that is, sequentially along the path Pa. This corresponds to the first round of circular processing. When the laser processing of the outermost periphery is completed, a scanning area SA63 that can be scanned only by the galvanometer mirrors 12Y and 12X is set inside the outermost periphery, and a scanning area SA that can be scanned only by the galvanometer mirrors 12Y and 12X is set sequentially along the path Pb inside the outermost periphery. This corresponds to the second round of orbital machining. When the laser processing of the area one step inside the outermost periphery is completed, a scanning area SA64 that is two steps inside the outermost periphery and can be scanned only by the galvanometer mirrors 12Y and 12X is set, and the scanning areas SA that can be scanned only by the galvanometer mirrors 12Y and 12X are sequentially set along the path Pc two steps inside the outermost periphery. This corresponds to the third round of orbital machining. In this way, by sequentially setting the scanning areas SA from the outermost periphery of the workpiece W to the inside and performing multiple orbital machining, the above-mentioned sudden and partial shrinkage of the workpiece W can be suppressed, and it is possible to suppress the positional deviation of the processed hole 51 from the target position where the hole is to be drilled in the workpiece W that occurs before and after the shrinkage of the workpiece W.

[0029] For the back surface, starting from the scanning area SA on the back surface of the workpiece W, which is located at the same position as the scanning area SA61 on the front surface of the workpiece W, circular machining is performed on the outermost periphery in the order of path Pa as viewed from the back surface side so that machined holes are formed in the same order as on the front surface. Then, circular machining is similarly performed from the outermost periphery toward the inside. This causes the positions of the machined holes 51 formed on the front surface to match the positions of the machined holes formed on the back surface, resulting in the formation of through holes.

[0030] In recent years, the number of through holes formed in the workpiece W has reached more than 3 million holes, and even more than 9 million holes have been reported. When the number of through holes is about 1.3 million to 1.5 million holes, the technology described in Patent Document 1 can form the through holes with high precision. However, when the technology described in Patent Document 1 is used to form through holes in a number exceeding 1.3 million to 1.5 million holes, the workpiece W warps when the formation of the processed holes 51 on the front surface is completed. FIG. 3 is a diagram showing an example of the state of the workpiece after the formation of the processed holes by the conventional technology. As shown in FIG. 3, when the number of processed holes 51 exceeding 1.3 million to 1.5 million holes is formed on the front surface Wf, which is the processing surface, the front surface Wf shrinks in the in-plane direction relative to the back surface Wb, causing warping.

[0031] Furthermore, even if the warped workpiece W is fixed on the table 15 with a clamp or the like to suppress the warp and process the back surface Wb, the positional deviation between the machined holes 51 formed on the front surface Wf and the machined holes formed on the back surface Wb becomes large, making it impossible to form through holes with good accuracy. For this reason, when the number of through holes formed in the workpiece W exceeds 1.3 million to 1.5 million holes, there has been a demand for a technology that suppresses warping when processing one side is completed and that improves the accuracy of the positions at which the machined holes are formed on the front surface Wf and the back surface Wb.

[0032] Therefore, in the laser processing method and the laser processing machine 10 according to the first embodiment, the through hole position data, which is data indicating the positions at which the through holes are formed, is divided into m pieces of divided hole position data so that the number of holes per unit area is equal to or less than the reference density, specifically, the number of holes formed in one hole forming process is equal to or less than the reference hole number, and the holes are distributed over the entire processing surface of the workpiece W, and the laser processing to form the holes on the front and back surfaces is performed m times. Here, m is an integer of 2 or more. The reference hole number is the maximum number of holes formed by the hole forming process by the laser processing machine 10 at which the workpiece W does not warp and the positional deviation of the holes formed on the front and back surfaces is within the range of error. The reference hole number may vary depending on the characteristics of the workpiece W, such as the material, size, and thickness, and therefore the reference hole number may be determined for each characteristic of the workpiece W. Alternatively, when the type of workpiece W to be processed by the laser processing machine 10 is determined, the type of workpiece W to be processed that has the smallest reference number of holes may be adopted as the reference number of holes that does not depend on the characteristics of the workpiece W in this laser processing machine 10. The reference number of holes may be 1.5 million holes, for example. The reference density is the reference number of holes divided by the area of ​​the front or back surface, which is the processing surface of the workpiece W. As with the reference number of holes, the reference density may also vary depending on the characteristics of the workpiece W, such as the material, size, and thickness, so that the reference density may be determined for each characteristic of the workpiece W. Alternatively, when the type of workpiece W to be processed by the laser processing machine 10 is determined, the type of workpiece W to be processed that has the smallest reference density may be adopted as the reference density that does not depend on the characteristics of the workpiece W in this laser processing machine 10.

[0033] 4 is a diagram for explaining an outline of the laser processing method according to the first embodiment. The through hole position data D0 includes position data which is data indicating the position of the through hole to be formed in the workpiece W. In one example, the through hole position data D0 is a list of position data in which the position of the through hole is indicated using XY coordinates provided on the table 15. The processing image I0 is an image which typically shows a state in which a processed hole 51 is opened in the workpiece W according to the through hole position data D0.

[0034] Here, it is assumed that the through hole position data D0 contains position data of the machining holes 51 in a number exceeding the reference number of holes. Therefore, when machining holes 51 are formed on one machining surface of the workpiece W using the through hole position data D0 with the technology described in Patent Document 1, warping occurs in the workpiece W, and when machining on both sides, deviations occur in the positions of the machining holes 51 on the front and back surfaces, making it impossible to machine well as in the machining image I0.

[0035] Therefore, the through hole position data D0 is divided into a plurality of data so as to satisfy the following conditions A and B. A. The number of holes 51 formed in one hole forming process is set to be equal to or less than a reference hole number that does not cause warping of the workpiece W and that causes the positional deviation of the holes 51 formed on both sides to be within the range of error. B. The holes 51 formed in one hole forming process are dispersed over the entire machining surface of the workpiece W.

[0036] In B, it is sufficient to confirm by visual inspection or observation using a magnifying device such as a microscope that the machined holes 51 are dispersed throughout the entire machining surface of the workpiece W. This only requires that it be confirmed that the machined holes 51 are not concentrated in a specific area, but it is also possible to confirm by calculation that the machined holes 51 are dispersed throughout the entire machining surface of the workpiece W.

[0037] In the example of Fig. 4, the through hole position data D0 is divided into three divided machining hole position data D1-D3. Machining image I1 is an image that shows a state in which a machined hole 51 is formed in a workpiece W using the divided machining hole position data D1 with the technology described in Patent Document 1. Machining image I2 is an image that shows a state in which a machined hole 51 is formed in a workpiece W using the divided machining hole position data D2 with the technology described in Patent Document 1. Machining image I3 is an image that shows a state in which a machined hole 51 is formed in a workpiece W using the divided machining hole position data D3 with the technology described in Patent Document 1.

[0038] Using the divided machining hole position data D1, machined holes 51 are formed on the front surface of the workpiece W, and then machined holes 51 are formed on the back surface using divided machining hole position data in which the positions of the machined holes 51 are mirror images of the positions formed by the divided machining hole position data D1. At this time, since the number of position data of the machined holes 51 included in the divided machining hole position data D1 is equal to or less than the reference hole number, the workpiece W is not warped by this machining, and through holes can be formed in which the positional deviation of the machined holes 51 formed on the front surface and back surface is within the error range.

[0039] Next, using the divided machining hole position data D2, a machined hole 51 is formed on the front surface of the workpiece W in which a through hole has been formed using the divided machining hole position data D1, and then, using divided machining hole position data in which the position of the machined hole 51 is a mirror image of the position formed by the divided machining hole position data D2, a machined hole 51 is formed on the back surface. At this time, since the number of position data of the machined holes 51 included in the divided machining hole position data D2 is equal to or less than the reference hole number, the workpiece W does not warp due to this machining, and through holes can be formed in which the positional deviation of the machined holes 51 formed on the front surface and back surface is within the error range. Note that the machining image I2 shows only the machined holes 51 corresponding to the position data included in the divided machining hole position data D2.

[0040] Then, using the divided machining hole position data D3, a machined hole 51 is formed on the front surface of the workpiece W in which a through hole has been formed using the divided machining hole position data D1 and D2, and then, using divided machining hole position data in which the position of the machined hole 51 is a mirror image of the position formed by the divided machining hole position data D3, a machined hole 51 is formed on the back surface. At this time, since the number of position data of the machined holes 51 included in the divided machining hole position data D3 is equal to or less than the reference hole number, the workpiece W does not warp due to this machining, and through holes can be formed in which the positional deviation of the machined holes 51 formed on the front surface and back surface is within the error range. Note that the machining image I3 shows only the machined holes 51 corresponding to the position data included in the divided machining hole position data D3.

[0041] In this way, by machining both sides of the workpiece W using the divided machining hole position data D1, machining both sides of the workpiece W using the divided machining hole position data D2, and machining both sides of the workpiece W using the divided machining hole position data D3, a workpiece W is obtained that has through holes that exceed the standard number of holes as shown in the machining image I0, while suppressing the occurrence of warping and ensuring that the positional deviation of the machining holes 51 formed on both sides is within the range of error.

[0042] A laser processing machine 10 according to a first embodiment capable of performing laser processing by such a method will be described. As described above, the process of generating the divided processing hole position data for the front and back sides from the through hole position data and controlling the laser oscillator 11, the galvano scanners 13Y, 13X and the table 15 is performed by the control device 20 of the laser processing machine 10 in Fig. 1. The following describes the more detailed functions of the programming tool 21 and the NC device 22 of the control device 20. Note that it is assumed here that the through hole position data has position data for a number of holes exceeding the reference number.

[0043] The programming tool 21 divides the through hole position data to generate divided machining hole position data, and generates a divided machining program, which is a machining program for drilling, for each of the generated divided machining hole position data.

[0044] 5 is a diagram showing an example of a functional configuration of a programming tool for the laser processing machine according to embodiment 1. The programming tool 21 has a data reading unit 211, a data dividing unit 212, a back surface processing data generating unit 213, and a processing program generating unit 214.

[0045] The data reading unit 211 reads through-hole position data. The data reading unit 211 may read the through-hole position data from a storage unit (not shown) of the control device 20, may read the through-hole position data via a communication line such as a network, or may read the through-hole position data from a storage medium such as a memory card. In one example, the through-hole position data is text data in which position data indicating the position on the XY coordinate system where the through-hole is formed is recorded. Although not shown in FIG. 4, the through-hole position data has header information indicating the position data of an alignment mark provided on the workpiece W. The through-hole position data indicates design position data, and in one example, is generated using the XY coordinate system provided on the table 15.

[0046] The data division unit 212 distributes the position data in the through hole position data into a plurality of divided machining hole position data for the front surface of the workpiece W so that the number of through holes per unit area is equal to or less than the reference density, specifically, so that the number of position data is equal to or less than a determined reference number of holes and the positions indicated by the position data are distributed over the entire machining surface of the workpiece W. The front surface corresponds to the first machining surface. In one example, the data division unit 212 distributes the position data in the through hole position data into m divided machining hole position data so that the positions indicated by the position data for each of the plurality of divided machining hole position data are distributed over the entire machining surface of the workpiece W, where m is an integer of 2 or more. Here, the number of position data included in each of the m divided machining hole position data is the quotient when the number of all the position data of the through hole position data is divided by m, or the number obtained by adding "1" to this quotient. Furthermore, the data division unit 212 divides the position data in the through hole position data into m pieces of divided machining hole position data so that the density of the machining holes 51 formed in the scanning area SA in the machining hole forming process using one divided machining hole position data is 1 / m of the density of the through holes finally formed on the machining surface. Here, it is not necessary to be 1 / m exactly, but it is sufficient that it is 1 / m within the margin of error. In this way, the data division unit 212 generates divided machining hole position data for the front surface.

[0047] Specifically, the data division unit 212 calculates a quotient by dividing the number of position data in the through hole position data by the number of reference holes, and if there is no remainder, the quotient is set as the division number m, and if there is a remainder, the quotient is added with "1" to set the division number m. As shown in FIG. 4, the data division unit 212 generates m divided machining hole position data from the first divided machining hole position data to the m-th divided machining hole position data. The m divided machining hole position data generated here includes only header information and does not include position data. Next, the data division unit 212 divides the position data in the through hole position data into m equal parts so that, in one example, the density of the machining holes 51 in a certain scanning area SA formed by the m divided machining hole position data is 1 / 3 of the hole density of the through holes in the machining surface formed by the through hole position data. In one example, the data dividing unit 212 divides the position data in the through hole position data in the order of arrangement, from the first divided machining hole position data to the m-th divided machining hole position data, such that the first position data is the first divided machining hole position data, the second position data is the second divided machining hole position data, ..., the m-th position data is the m-th divided machining hole position data, the m+1-th position data is the first divided machining hole position data, ..., etc. In other words, when the through hole position data includes text data in which position data indicating the coordinates of the through hole is listed, the data dividing unit 212 distributes the position data in the through hole position data to m divided machining hole position data in order from the top. As a result, m divided machining hole position data is obtained.

[0048] Before generating the through-hole position data, the data dividing unit 212 may sort the included position data with respect to at least one of the X coordinate and the Y coordinate. By dividing the through-hole position data thus sorted into m groups, the positions of the machined holes 51 can be dispersed within the machined surface of the workpiece W.

[0049] The rear surface processing data generating unit 213 generates split processing hole position data for the rear surface using the split processing hole position data for the front surface generated by the data dividing unit 212. For the through holes formed at the positions of the workpiece W designated by the through hole position data, the positions of the through holes when the front surface is the upper surface and the positions of the through holes when the rear surface is the upper surface are in a mirror image relationship. For this reason, by specifying the size and shape of the workpiece W, the split processing hole position data for the rear surface can be obtained by mirroring the split processing hole position data for the front surface. In other words, the rear surface processing data generating unit 213 generates split processing hole position data for the rear surface facing the front surface, which includes position data indicating a position that is in a mirror image relationship with the position indicated by the included position data, for each of the multiple split processing hole position data for the front surface. The rear surface corresponds to the second processing surface. The rear surface processing data generating unit 213 also corresponds to the second processing surface processing data generating unit.

[0050] The machining program generating unit 214 converts each of the plurality of divided machining hole position data for the front surface and the back surface into a divided machining program, which is a computer program in a format that allows the NC device 22 to perform hole drilling using the laser processing machine 10. That is, the machining program generating unit 214 generates a divided machining program that controls the operation of the laser oscillator 11, the galvano scanners 13Y, 13X, and the table 15 so that the machined holes 51 are formed at the positions of the position data included in the divided machining hole position data by irradiating the laser light L. The divided machining program generated at this time is a program that performs a machined hole forming process on the machined surface of the workpiece W by moving the table 15 to move the scanning area SA by setting a plurality of scanning areas SA that are ranges that can be scanned by the galvano mirrors 12Y, 12X within the machined surface of the workpiece W as described in FIG. 2, so that the circulating path of the scanning area SA circulating in a direction parallel to the outer periphery of the machined surface of the workpiece W moves from the outer periphery side to the inside of the machined surface of the workpiece W every time drilling within one scanning area SA is completed. The machining program generating unit 214 is realized by a tool generally called CAD (Computer Aided Design) conversion. Hereinafter, one of the m divided machining programs is called the i-th divided machining program, where i is an integer between 1 and m. Also, the divided machining programs for the front and back surfaces are called divided machining programs when there is no need to distinguish them from one another.

[0051] The NC device 22 reads the division machining program generated by the programming tool 21, and controls the operations of the laser oscillator 11, the galvano scanners 13Y, 13X, and the table 15. The machining sequence in the NC device 22 is such that the i-th division machining program for the front surface is executed first, followed by the i-th division machining program for the back surface, in the order of the division number i from "1" to "m".

[0052] Before executing the division processing program, the NC device 22 captures an image of the processing surface of the workpiece W by the camera 16, and generates first correction information using the positions of a plurality of alignment marks provided on the workpiece W in the captured data. The first correction information is information indicating the deviation of the state of the processing surface of the workpiece W fixed on the table 15 from the design value. In one example, the alignment marks are provided at the four corners of the processing surface of the workpiece W. In one example, the NC device 22 uses the four alignment marks to calculate the length of the processing surface of the workpiece W based on the alignment marks, the angular deviation of the XY coordinate system provided on the processing surface of the workpiece W when viewed from the XY coordinate system provided on the table 15, and the offset amount from the origin of the XY coordinate system provided on the processing surface of the workpiece W from the origin of the XY coordinate system provided on the table 15. Then, the NC device 22 uses these as the first correction information to correct the coordinates of the machining hole 51 that are read when the divided machining program is executed, and generates a position command for the table 15, a laser output command for the laser oscillator 11, and a position command for the galvano scanners 13Y and 13X.

[0053] Next, the laser processing method according to the first embodiment will be described. The outline of the laser processing method according to the first embodiment is a method of forming a through hole in the workpiece W by using a laser processing machine 10 that scans the laser light L emitted from the laser oscillator 11 with the galvanometer mirrors 12Y, 12X and focuses the laser light L on the workpiece W placed on the table 15 to perform a hole drilling process. The laser processing method according to the first embodiment also includes a first processed hole forming process in which a processed hole forming process is performed on the front surface of the workpiece W by moving the table 15 every time a hole drilling process in one scanning area SA is completed so that a circulating path in which the scanning area SA that can be scanned by the galvanometer mirrors 12Y, 12X revolves along a direction parallel to the outer periphery of the processing surface of the workpiece W moves from the outer periphery side to the inside of the workpiece W, and a second processed hole forming process in which a processed hole forming process is performed on the back surface opposite to the front surface. The first and second processed hole forming steps are performed multiple times so that the positions of the through holes connected to the processed holes 51 formed by one set of the first and second processed hole forming steps are different. Also, the first and second processed hole forming steps may be performed alternately.

[0054] Next, the laser processing method will be described in detail. Figures 6 to 8 are flow charts showing an example of the procedure of the laser processing method according to the first embodiment. When the number of position data included in the through hole position data is equal to or less than the reference number of holes, processing is possible using the laser processing method according to the conventional technology, so the description is omitted here, and the case where the number of position data included in the through hole position data exceeds the reference number of holes will be described as an example.

[0055] First, the programming tool 21 reads through hole position data including position data indicating the positions of through holes to be formed in the workpiece W (step S11), and the programming tool 21 determines the division number m of the through hole position data (step S12). In one example, the programming tool 21 obtains a quotient by dividing the number of position data of the through hole position data by the number of reference holes, and determines the quotient as the division number m if there is no remainder, and determines the number obtained by adding "1" to the quotient as the division number m if there is a remainder. Next, m pieces of divided machining hole position data for the front surface are generated, including header information of the through hole position data but not including position data (step S13).

[0056] Thereafter, the programming tool 21 distributes all the position data included in the through hole position data into m divided machining hole position data for the front surface (step S14). At this time, the programming tool 21 distributes the data so that the positions indicated by the position data are not biased to a certain area in the machining surface of the workpiece W, and distributes the data so that the positions are distributed over the entire machining surface. In one example, the data is distributed to m divided machining hole position data for the front surface, starting from the first position data included in the through hole position data. The above steps S12 to S14 correspond to a data division step of dividing the through hole position data into a plurality of divided machining hole position data for the front surface so that the number of through holes per unit area is equal to or less than a reference density, specifically, the number of position data is equal to or less than a determined reference number of holes, and the positions of the through holes are distributed over the entire machining surface.

[0057] Thereafter, the programming tool 21 generates a front surface division machining program for each of the generated m front surface division machining hole position data. Here, a plurality of scanning areas SA, which are ranges that can be scanned by the galvano scanners 13Y and 13X, are set within the machining surface of the workpiece W, and a machining hole forming process is executed on the machining surface of the workpiece W by moving the table 15 every time a hole drilling process within one scanning area SA is completed, so that the rotation path of the scanning area SA moving in a direction parallel to the outer periphery of the machining surface of the workpiece W moves from the outer periphery side to the inside of the machining surface of the workpiece W.

[0058] Next, the programming tool 21 generates m pieces of split machining hole position data for the back surface using the m pieces of split machining hole position data for the front surface (step S16). Specifically, the programming tool 21 generates split machining hole position data for the back surface having position data indicating positions that are mirror images of the positions indicated by the split machining hole position data for the front surface for each of the m pieces of split machining hole position data for the front surface. At this time, the position data in the split machining hole position data for the back surface are arranged in the same order as the corresponding position data in the split machining hole position data for the front surface. The process of step S16 corresponds to a second surface machining data generating process.

[0059] Thereafter, the programming tool 21 generates a divided machining program for the back surface for each of the m pieces of divided machining hole position data for the back surface (step S17). In one example, a divided machining program for the back surface is generated in which a plurality of scanning areas SA are set within the machining surface of the workpiece W, and a machining hole forming process is performed on the machining surface of the workpiece W by moving the table 15 every time a hole drilling process in one scanning area SA is completed so that a circulating path for circulating the scanning area SA along a direction parallel to the outer periphery of the machining surface of the workpiece W moves from the outer periphery side to the inside of the machining surface of the workpiece W. However, as for the order of circulating process, the scanning area SA is moved on the back surface onto which the scanning area SA in the circulating process of the front surface is projected in the same order as the circulating process of the scanning area SA on the front surface.

[0060] Next, the workpiece W is placed on the table 15 and fixed thereon (step S18). The upper surface in this state is assumed to be the front surface of the workpiece W. The workpiece W may be placed by an operator, or the workpiece W may be placed on the table 15 from a storage container by a loader (not shown).

[0061] The NC device 22 sets the number of executions i to "1" (step S19). After that, the NC device 22 captures an image of the workpiece W with the camera 16 (step S20), and generates first correction information using the alignment marks of the workpiece W in the captured image data (step S21). The first correction information is information that represents a deviation of the state of the machined surface of the actual workpiece W fixed on the table 15 from the state of the ideal machined surface of the workpiece W fixed on the table 15 assumed in design.

[0062] The NC device 22 reads the i-th divided machining program for the front surface (step S22). In this case, since i=1, the first divided machining program for the front surface is read.

[0063] Then, the NC device 22 executes hole forming processing to form machined holes 51 by irradiating the front surface of the workpiece W with laser light L while correcting the position of the i-th divided machining program for the front surface with the first correction information (step S23). The process of step S23 corresponds to a first machined hole forming process in which machined hole forming processing is performed using the divided machined hole position data for the front surface. As a result, about 1 / m number of machined holes 51 are formed in the front surface of the workpiece W as the number of machining data included in the through hole position data. At this time, circular processing along the outer periphery of the machining surface of the workpiece W is performed in order from the outermost periphery toward the inside.

[0064] Thereafter, the workpiece W on the table 15 is turned over and fixed (step S24). As a result, the upper surface of the workpiece W on the table 15 becomes the back surface. The workpiece W may be turned over by an operator. Alternatively, the workpiece W may be stored in a storage container from on the table 15 by an unloader (not shown), the storage container may be turned upside down, and the storage container may be moved to a loader, after which the turned-over workpiece W may be placed from the storage container onto the table 15 by the loader.

[0065] Next, the NC device 22 captures an image of the workpiece W with the camera 16 (step S25), and generates first correction information using the alignment marks of the workpiece W in the captured data (step S26). Note that the first correction information generated in step S21 is used when executing the i-th divided machining program for the front surface in step S23, and is overwritten by the first correction information generated in step S26.

[0066] Thereafter, the NC device 22 reads the i-th divided machining program for the back surface (step S27). In this case, since i=1, the first divided machining program for the back surface is read. The i-th divided machining program for machining the back surface is a program for forming a machining hole 51 from the back surface at the same position on the back surface as the machining hole 51 formed on the front surface.

[0067] Then, the NC device 22 performs hole forming processing to form the processed holes 51 by irradiating the laser light L onto the back surface of the workpiece W while correcting the position of the i-th divided processing program for the back surface with the first correction information (step S28). At this time, on the back surface onto which the scanning area SA in the circular processing of the front surface is projected, the laser processing is performed while moving the scanning area SA in the same order as the circular processing of the scanning area SA on the front surface. In one example, the processed holes 51 are formed on the back surface in the order of the positions in which the processed holes 51 are formed on the front surface. As a result, about 1 / m of the number of processed holes 51 corresponding to the number of processing data included in the through hole position data are formed on the back surface of the workpiece W. The process of step S28 corresponds to a second processed hole forming process in which the processed hole forming process is performed using the divided processed hole position data for the back surface.

[0068] As described above, the number of machining data included in the divided machining hole position data is equal to or less than the reference hole number, so the workpiece W does not warp due to this machining, and the positional deviation between the machining holes 51 formed on the front surface and the machining holes 51 formed on the back surface is suppressed. Therefore, a through hole is formed at a desired position, connecting the machining holes 51 formed on the front surface and the machining holes 51 formed on the back surface.

[0069] Next, the NC device 22 adds "1" to the number of executions i (step S29) and checks whether all the divided machining programs have been executed (step S30). That is, it is determined whether the number of executions i is greater than the number of divisions m. If all the divided machining programs have not been executed, that is, if the number of executions i is equal to or less than the number of divisions m (No in step S30), the workpiece W on the table 15 is turned over and fixed (step S31). As a result, the upper surface of the workpiece W on the table 15 becomes the front surface. The workpiece W may be placed by an operator. Alternatively, the workpiece W may be stored in a storage container from the table 15 by an unloader, the storage container may be turned upside down, and the storage container may be moved to the loader, after which the workpiece W may be placed on the table 15 from the storage container by the loader.

[0070] After that, the process returns to step S20. Then, the process from step S20 to step S31 is repeatedly executed until all the division machining programs are executed in step S30, that is, until the number of executions i becomes larger than the division number m. In other words, the machining hole forming process on the front surface and the machining hole forming process on the back surface are executed alternately, and the through holes are formed at positions different from the positions formed previously.

[0071] When all the divided machining programs have been executed in step S30, that is, when the number of executions i is greater than the number of divisions m (Yes in step S30), all the divided machining programs have been executed for the front and back surfaces, and the workpiece W is removed from the table 15 (step S32). The workpiece W may be removed by an operator, or may be stored in a storage container from the table 15 by an unloader. This completes the laser machining method.

[0072] 9 to 14 are diagrams showing an example of the procedure of the laser processing method according to the first embodiment. Here, the through hole position data is divided into three divided processing hole position data, and the processing hole formation process on the front surface and the back surface is performed three times each. First, as shown in FIG. 9, a processing hole 51 is formed on the front surface Wf of the workpiece W at a position corresponding to the first divided processing hole position data by the first divided processing program for the front surface. Here, processing is started from a scanning area SA1F located around the corner of the outermost periphery of the workpiece W, and when the scanning of the laser light L in the scanning area SA1F is completed, the table 15 is moved so that the laser light L is irradiated to the next scanning area SA2F along the path Pa. In this way, among the multiple scanning areas SA set on the processing surface of the workpiece W, the scanning area SA located on the outermost periphery is processed in a direction parallel to the outer periphery of the processing surface, that is, along the path Pa.

[0073] After forming the machining hole 51 in the scanning area SA at the outermost periphery, the table 15 is moved to perform circular machining along the path Pb for the scanning area SA one area inside the outermost periphery. In this example, machining is started from the scanning area SA3F, and when the scanning of the laser light L in the scanning area SA3F is completed, the table 15 is moved along the path Pb so that the laser light L is irradiated to the next scanning area SA. Then, of the multiple scanning areas SA set on the machining surface of the workpiece W, circular machining is performed in sequence for the scanning area SA one area inside the outermost periphery in a direction parallel to the outer periphery of the machining surface, i.e., along the path Pb.

[0074] After forming the machining hole 51 in the scanning area SA that is one position inside the outermost circumference, the table 15 is moved to perform circular machining along the path Pc for the scanning area SA that is two positions inside the outermost circumference. In this example, machining is started from the scanning area SA4F, and when the scanning of the laser light L in the scanning area SA4F is completed, the table 15 is moved along the path Pc so that the laser light L is irradiated to the next scanning area SA. Then, of the multiple scanning areas SA set on the machining surface of the workpiece W, circular machining is performed in sequence for the scanning areas SA that are two positions inside the outermost circumference in a direction parallel to the outer periphery of the machining surface, i.e., along the path Pc.

[0075] In this way, the circular machining along the outer periphery of the machining surface is performed in order from the outer periphery to the inside of the machining surface. The shrinkage of the workpiece W caused by the circular machining of the outermost periphery occurs only in the outermost periphery, and the inside of the workpiece W is not affected by the shrinkage. As a result, in the laser machining starting from the scanning area SA3F located one step inside the outermost periphery to be laser-machined next, and sequentially performing the circular machining of the innermost periphery along the path Pb while rotating in the circumferential direction, there is no deviation between the coordinates where the hole should be originally written in the machining program and the coordinates on the workpiece W where the hole is actually to be made. Similarly, in the laser machining starting from the scanning area SA4F located further inside to be laser-machined next, and sequentially performing the circular machining of the innermost periphery along the path Pc while rotating in the circumferential direction, there is no deviation between the coordinates where the hole should be originally written in the machining program and the coordinates on the workpiece W where the hole is actually to be made.

[0076] When the laser processing of the front surface Wf of the workpiece W according to the first division processing program for the front surface is completed, the laser processing of the back surface Wb of the workpiece W according to the first division processing program for the back surface is performed. As shown in Fig. 10, the laser processing is performed in the following order: starting from the scanning area SA1B on the back surface Wb of the workpiece W, which is located at the same position as the scanning area SA1F on the front surface Wf, the circular processing is performed by moving the scanning area SA along the path Pma, starting from the scanning area SA3B on the back surface Wb, which is located at the same position as the scanning area SA3F on the front surface Wf, the circular processing is performed by moving the scanning area SA along the path Pmb, and starting from the scanning area SA4B on the back surface Wb, which is located at the same position as the scanning area SA4F on the front surface Wf, the circular processing is performed by moving the scanning area SA along the path Pmc. As a result, the processing hole 51 formed on the front surface Wf and the processing hole 51 formed on the back surface Wb are connected to each other, and a through hole is formed.

[0077] When the laser processing of the back surface Wb of the workpiece W according to the first divided processing program for the back surface is completed, the laser processing of the front surface Wf of the workpiece W is performed according to the second divided processing program for the front surface. As shown in Fig. 11, the laser processing is performed in the following order: starting from the scanning area SA1F on the front surface Wf of the workpiece W, circular processing is performed by moving the scanning area SA along the path Pa, starting from the scanning area SA3F, circular processing is performed by moving the scanning area SA along the path Pb, and starting from the scanning area SA4F, circular processing is performed by moving the scanning area SA along the path Pc.

[0078] When the laser processing of the front surface Wf of the workpiece W according to the second division processing program for the front surface is completed, the laser processing of the back surface Wb of the workpiece W is performed according to the second division processing program for the back surface. As shown in Fig. 12, the laser processing is performed in the following order: starting from the scanning area SA1B on the back surface Wb of the workpiece W, the circular processing is performed by moving the scanning area SA along the path Pma, starting from the scanning area SA3B, the circular processing is performed by moving the scanning area SA along the path Pmb, and starting from the scanning area SA4B, the circular processing is performed by moving the scanning area SA along the path Pmc. As a result, the processing hole 51 formed on the front surface Wf and the processing hole 51 formed on the back surface Wb are connected to each other, and a through hole is formed.

[0079] When the laser processing of the back surface Wb of the workpiece W according to the second divided processing program for the back surface is completed, the laser processing of the front surface Wf of the workpiece W is performed according to the third divided processing program for the front surface. As shown in Fig. 13, the laser processing is performed in the following order: starting from the scanning area SA1F on the front surface Wf of the workpiece W, circular processing is performed by moving the scanning area SA along the path Pa, starting from the scanning area SA3F, circular processing is performed by moving the scanning area SA along the path Pb, and starting from the scanning area SA4F, circular processing is performed by moving the scanning area SA along the path Pc.

[0080] When the laser processing of the front surface Wf of the workpiece W according to the third divided processing program for the front surface is completed, the laser processing of the back surface Wb of the workpiece W is performed according to the third divided processing program for the back surface. As shown in Fig. 14, the laser processing is performed in the following order: starting from the scanning area SA1B on the back surface Wb of the workpiece W, the circular processing is performed by moving the scanning area SA along the path Pma, starting from the scanning area SA3B, the circular processing is performed by moving the scanning area SA along the path Pmb, and starting from the scanning area SA4B, the circular processing is performed by moving the scanning area SA along the path Pmc. As a result, the processing hole 51 formed on the front surface Wf and the processing hole 51 formed on the back surface Wb are connected to each other, and a through hole is formed.

[0081] As described above, the shrinkage of the workpiece W caused by the circular machining of the outermost part occurs only in the outermost part, and the shrinkage does not affect the inside of the workpiece W. As a result, in the circular machining of the next part inside the outermost part to be laser-machined, there is no deviation between the coordinates where the hole should be written in the machining program and the coordinates on the workpiece W where the hole is actually to be drilled. Similarly, in the circular machining of the next part inside the outermost part to be laser-machined, there is no deviation between the coordinates where the hole should be written in the machining program and the coordinates on the workpiece W where the hole is actually to be drilled. In other words, by sequentially setting the scanning area SA from the outermost part of the workpiece W to the inside and performing multiple circular machining, it is possible to suppress the positional deviation of the processed hole 51 from the target position where the hole is to be drilled in the workpiece W, which occurs before and after the shrinkage caused by the drilling of the workpiece W.

[0082] Furthermore, since the number of holes drilled is equal to or less than the reference number when a single hole forming process is performed, warping does not occur in the workpiece W after the hole forming process is completed. Furthermore, since the number of holes drilled is equal to or less than the reference number when the hole forming process is performed on the back surface Wb of the workpiece W, which does not cause warping and can suppress shrinkage during the hole forming process on the front surface Wf, warping does not occur in the workpiece W after the hole forming process is completed. Furthermore, by repeatedly performing the process of drilling the number of holes equal to or less than the reference number, it is possible to finally form the desired number of through holes in the desired positions.

[0083] 15 is a diagram for explaining a case where through hole position data is simply divided into three and laser processing is performed using a conventional technology. Consider a case where the position data in the through hole position data D10 is divided at a position that is 1 / 3 and a position that is 2 / 3 from the beginning to generate divided processed hole position data D11, D12, and D13. That is, the position data from the beginning to 1 / 3 of the through hole position data D10 is set as divided processed hole position data D11, the position data from the beginning to 1 / 3 of the through hole position data D10 is set as divided processed hole position data D12, and the position data from the beginning to 2 / 3 of the through hole position data D10 is set as divided processed hole position data D13.

[0084] In this case, as shown in the machining image I11, the machining holes 51 designated by the divided machining hole position data D11 are distributed in the region R11 of the machining surface of the workpiece W. As shown in the machining image I12, the machining holes 51 designated by the divided machining hole position data D12 are distributed in the region R12 of the machining surface of the workpiece W. As shown in the machining image I13, the machining holes 51 designated by the divided machining hole position data D13 are distributed in the region R13 of the machining surface of the workpiece W. When the position data in the through hole position data D10 is divided in this manner, the machining holes 51 are not distributed over the entire machining surface of the workpiece W, so the technology described in Patent Document 1 cannot be used. In addition, when machining is performed using the divided machining hole position data D11, D12, and D13 divided in this manner, the machining holes 51 are densely present only in a specific region, and the shrinkage of the workpiece W becomes severe, making it impossible to form the desired number of through holes at the desired position.

[0085] On the other hand, the laser processing method according to the first embodiment is a method for forming a through hole in a workpiece W using a laser processing machine 10 that performs a drilling process by scanning a laser beam L emitted from a laser oscillator 11 with galvanometer mirrors 12Y, 12X and focusing the laser beam L on a workpiece W placed on a table 15, and includes a first processed hole forming process in which a processed hole forming process is performed on a first surface of the workpiece W, in which the scanning area SA is moved by moving the table 15 every time drilling in one scanning area SA is completed so that a circular path that causes the scanning area SA in the processing surface of the workpiece W to revolve in a direction parallel to the outer periphery of the workpiece W moves from the outer periphery side to the inside of the workpiece W, and a second processed hole forming process in which the processed hole forming process is performed on a second surface opposite to the first surface. Then, the first processed hole forming process and the second processed hole forming process are performed multiple times so that the positions of the through holes connected to the processed holes 51 formed by a set of the first processed hole forming process and the second processed hole forming process are different. Specifically, when m is an integer of 2 or more, the position data in the through hole position data is distributed to m divided machining hole position data so that the positions indicated by the position data for each of the divided machining hole position data are distributed over the entire machining surface of the workpiece W. The number of position data included in each divided machining hole position data is set so that the number of machining holes 51 formed in one machining hole forming process is equal to or less than the reference hole number at which no warping occurs in the workpiece W and the positional deviation of the machining holes 51 formed on both sides is within the error range. This has the effect of suppressing the occurrence of warping of the workpiece W after the machining holes 51 are formed on one side and suppressing the positional deviation of the machining holes 51 formed on the front side Wf ​​and back side Wb when forming the machining holes 51 on the front side Wf ​​and back side Wb of the workpiece W to form the through holes.

[0086] Embodiment 2 When multiple revolutions are performed as shown in FIG. 2, the shrinkage of the workpiece W varies for each revolution. Therefore, if the shrinkage varies more significantly for each revolution, the machining position may be corrected by the amount of positional deviation between the coordinates where the hole should be drilled as written in the machining program and the coordinates on the workpiece W where the hole is actually to be drilled, by using the galvanometer mirrors 12Y, 12X and the table 15, by the amount of shrinkage for each revolution. FIG. 16 is a diagram showing characteristic information representing an example of the relationship between the number of revolutions and the amount of positional deviation of the machined hole in the laser machining method according to the second embodiment. In FIG. 16, the horizontal axis shows the number of revolutions, and the vertical axis shows the amount of positional deviation. In FIG. 16, information showing the relationship between the number of revolutions and the amount of positional deviation of the machined hole 51 is obtained for each number of executions i, and for each front surface and back surface in each number of executions i. The NC device 22 calculates the amount of positional deviation for each revolution by referring to FIG. 16, and corrects the machining position. Therefore, the information showing the relationship between the number of revolutions and the amount of positional deviation of the machined hole 51 shown in FIG. 16 can be called second correction information.

[0087] The amount of shrinkage of the workpiece W varies depending on the type and thickness of the material. For this reason, it is advisable to obtain in advance as a database characteristic information showing the relationship between the number of revolutions and the amount of positional deviation of the machined hole 51 as shown in Fig. 16 for each type and thickness of the material of the workpiece W. The relationship between the number of revolutions and the amount of positional deviation of the machined hole 51 is calculated by actually laser processing the workpiece W and measuring the amount of shrinkage.

[0088] The laser processing method according to the second embodiment further includes a positional deviation measuring step for measuring the positional deviation caused by the shrinkage of the workpiece W generated by drilling holes on the processing surface of the workpiece W while rotating for each circular path, for the front and back surfaces of each of the plurality of divided processing hole position data before the first processing hole forming step. Then, in the first processing hole forming step and the second processing hole forming step, the position data when performing the processing hole forming process using each of the plurality of divided processing hole position data is corrected by the corresponding positional deviation.

[0089] The specific processing sequence of the laser processing method according to the second embodiment is as follows. Fig. 17 to Fig. 19 are diagrams that show an example of the processing sequence of the laser processing method according to the second embodiment. As shown in Fig. 17, first, the NC device 22 performs laser processing according to the first divided processing hole position data for the front surface. At this time, the NC device 22 performs laser processing on a scanning area SA221 that is located on the outermost periphery of the workpiece W and includes one reference hole 52 that serves as a reference, and the NC device 22 measures the position of the reference hole 52 with the position measurement camera 16. The reference hole 52 may be a part of a product pattern in the scanning area SA21 that is located on the outermost periphery of the workpiece W where the processing hole 51 is actually drilled.

[0090] 18, when the laser processing of the scanning area SA21 is completed, the table 15 is moved to the next scanning area SA on the outermost periphery of the workpiece W, and the first round of circumferential processing is performed along the outer periphery of the processing surface of the workpiece W. As a result, a processed processing area PA is formed on the outermost periphery of the workpiece W. When the first round of circumferential processing is completed, the NC device 22 measures the position of the reference hole 52 again with the camera 16, compares the position measured by the camera 16 before the first round of circumferential processing with the position measured by the camera 16 after the first round of circumferential processing, and stores the difference, that is, the position deviation amount, as the correction value for the first round.

[0091] When the processing area PA is formed on the outermost circumference of the workpiece W, as shown in FIG. 19, a circular processing is performed one step inside the outermost circumference. In this case, the scanning area SA22, which is located inside the processing area PA machined on the outermost circumference of the workpiece W and includes one reference hole 53 as a reference, is laser processed. The NC device 22 measures the position of the reference hole 53 with the position measurement camera 16. Then, a second circular processing is performed along the outer circumference of the processing surface of the workpiece W. When the second circular processing is completed, the NC device 22 measures the position of the reference hole 53 again with the camera 16, and stores the position deviation amount, which is the difference between the position measured by the camera 16 before and after the second circular processing, in the control device 20 as a correction value for the second round. Then, this process is repeated every time the circular processing is performed. As a result of the above, characteristic information indicating the relationship between the number of revolutions for the front surface of the first group and the position deviation amount of the processing hole 51 is obtained.

[0092] By sequentially executing the above-mentioned process for the first front surface, the first back surface, the second front surface, the second back surface, ..., the mth front surface, and the mth back surface, characteristic information is obtained that indicates the relationship between the number of revolutions on each surface and the amount of positional deviation of the processed hole 51. Then, the characteristic information that indicates the relationship between the number of revolutions on the front surface and the back surface from the first to the mth and the amount of positional deviation of the processed hole 51 is compiled into the second correction information shown in FIG.

[0093] Acquisition of such characteristic information representing the relationship between the number of revolutions and the amount of positional deviation of the machining hole 51 is performed, for example, during laser machining of the first workpiece W. Then, when laser machining of the second or subsequent workpiece W is performed after completion of laser machining of the first workpiece W, the NC device 22 does not measure the positions of the reference holes 52, 53 with the camera 16, but performs revolution machining while correcting the position of the i-th divided machining program using the first correction information and the second correction information acquired during laser machining of the first workpiece W.

[0094] In the laser processing method according to the second embodiment, since the shrinkage amount of the workpiece W varies depending on the type and thickness of the material, the second correction information, which is characteristic information representing the relationship between the number of revolutions and the positional deviation amount of the processed hole 51 for each type and thickness of the material of the workpiece W, is acquired by actually laser processing the workpiece W for each of the front and back surfaces that are divided and processed. In one example, the characteristic information representing the relationship between the number of revolutions and the positional deviation amount of the processed hole 51 is acquired when the first workpiece W is laser processed. Then, when the second or subsequent workpieces W are laser processed, the second correction information, that is, the positional deviation amount of the processed hole 51 in the number of revolutions of the corresponding processed surface, is used as a correction value to perform the revolution processing. In this way, by performing position correction due to shrinkage of the workpiece W using the characteristic information representing the relationship between the number of revolutions and the positional deviation amount of the processed hole 51, it is possible to further suppress the positional deviation of the processed hole 51 from the target position where the hole is to be drilled in the workpiece W that occurs before and after the shrinkage of the workpiece W.

[0095] Embodiment 3 In the laser processing method according to the second embodiment, the first workpiece W is laser processed to obtain second correction information including characteristic information representing the relationship between the number of revolutions and the positional deviation amount of the processed holes 51 for each material type and thickness of the workpiece W, and when laser processing the second and subsequent workpieces W, the revolution processing is performed using the second correction information. In the second embodiment, even if the material, thickness, and number of through holes to be formed are the same as those of the workpiece W previously processed, the process of obtaining the second correction information is performed for the first workpiece W. If it is experimentally known that the second correction information is almost the same for the workpieces W of the same material, thickness, and number of through holes to be formed, the already obtained second correction information can be used.

[0096] In the laser processing method according to the third embodiment, second correction information having characteristic information expressing the relationship between the number of revolutions corresponding to the type of material, thickness, and number of through holes of the workpiece W previously subjected to laser processing and the amount of positional deviation of the processed holes 51 is stored as a database in the control device 20. That is, in the positional deviation measurement step of the laser processing method according to the third embodiment, the measured amount of positional deviation is stored in association with the material, thickness, and number of through holes formed in the workpiece W, and in the first processed hole forming step and the second processed hole forming step, the position data when performing the processed hole forming process is corrected using the amount of positional deviation corresponding to the material, thickness, and number of through holes formed in the workpiece W to be processed.

[0097] 20 is a diagram showing a schematic example of a configuration of a laser processing machine according to embodiment 3. The same components as those described in embodiment 1 are given the same reference numerals, and the description thereof will be omitted. In the laser processing machine 10 according to embodiment 3, the control device 20 further includes a second correction information storage unit 23. As described above, the second correction information storage unit 23 stores second correction information associated with the type of material of the workpiece W, its thickness, and the number of through holes to be formed.

[0098] When performing laser processing, if the second correction information of the workpiece W having the same material type, thickness, and through holes is in the second correction information storage unit 23, the NC device 22 acquires the second correction information and applies it when performing laser processing. This makes it possible to suppress the positional deviation of the processed hole 51 from the target position where the hole is to be drilled in the workpiece W, which occurs before and after the shrinkage of the workpiece W. Note that, when performing laser processing next time, if the second correction information of the workpiece W having the same material type, thickness, and through holes is not in the second correction information storage unit 23, the NC device 22 executes the process described in the second embodiment, and stores the obtained second correction information in the second correction information storage unit 23 in association with the material type, thickness, and number of through holes to be formed of the workpiece W.

[0099] In the laser processing machine 10 according to the third embodiment, the second correction information associated with the type of material of the workpiece W, the thickness, and the number of through holes to be formed is stored in the second correction information storage unit 23. As a result, when the second correction information of the workpiece W that is the same as the type of material, the thickness, and the number of through holes to be formed is stored in the second correction information storage unit 23, it is not necessary to measure the amount of shrinkage of the workpiece W before processing. Therefore, it is possible to reduce the time required to calculate the position correction due to the shrinkage of the workpiece W, and it is not necessary to use the material of the workpiece W to calculate the position correction due to the shrinkage of the workpiece W, which makes it possible to reduce material costs.

[0100] Next, the hardware for realizing the control device 20 of the laser processing machine 10 according to the first to third embodiments will be described. The control device 20 is realized by a processing circuit. The processing circuit may be a circuit in which a processor executes software, or may be a dedicated circuit. When the processing circuit is realized by software, the processing circuit is, for example, a control circuit.

[0101] 21 is a diagram showing an example of the configuration of a control circuit that realizes the control device for a laser processing machine according to embodiments 1 to 3. The control circuit 100 includes an input unit 101, a processor 102, a memory 103, and an output unit 104. The input unit 101 is an interface circuit that receives data input from outside the control circuit 100 and provides the data to the processor 102. The output unit 104 is an interface circuit that sends data from the processor 102 or the memory 103 to outside the control circuit 100.

[0102] When the processing circuit is the control circuit 100 shown in FIG. 21, the control device 20 is realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 103. The processing circuit realizes each function of the control device 20 by the processor 102 reading and executing the program stored in the memory 103. That is, the processing circuit includes the memory 103 for storing the program that will result in the processing of the control device 20 being executed. It can also be said that these programs cause a computer to execute the procedures and methods of the control device 20.

[0103] The processor 102 is a CPU (Central Processing Unit). The processor 102 may be a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor). The memory 103 is, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc).

[0104] 21 shows an example of hardware in which the control device 20 is realized by a general-purpose processor 102 and memory 103, but the control device 20 may be realized by a dedicated hardware circuit. Also, the control device 20 may be realized by combining the control circuit 100 with a hardware circuit.

[0105] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0106] 10 laser processing machine, 11 laser oscillator, 12Y, 12X galvanometer mirror, 13Y, 13X galvanometer scanner, 14 fθ lens, 15 table, 16 camera, 18 wiring, 20 control device, 21 programming tool, 22 NC device, 23 second correction information storage unit, 51 machining hole, 52, 53 reference hole, 100 control circuit, 101 input unit, 102 processor, 103 memory, 104 output unit, 151 suction hole, 211 data reading unit, 212 data division unit, 213 back surface processing data generation unit, 214 processing program generation unit, D0, D10 through hole position data, D1, D2, D3, D11, D12, D13 division processing hole position data, I0, I1, I2, I3, I11, I12, I13 processing image, L Laser light, PA processing area, Pa, Pb, Pc, Pma, Pmb, Pmc path, R11, R12, R13 area, SA, SA1B, SA1F, SA2F, SA3B, SA3F, SA4B, SA4F, SA21, SA61, SA62, SA63, SA64 scanning area, W workpiece, Wb back surface, Wf front surface.

Claims

1. A laser processing method for forming through holes in a workpiece using a laser processing machine that scans a laser beam emitted from a laser oscillator with a galvanometer mirror and focuses the laser beam onto a workpiece placed on a table to perform drilling, A first machining hole forming step is performed on the first machining surface of the workpiece, such that the scanning area scannable by the galvanometer mirror is moved along a circular path parallel to the outer circumference of the workpiece's machining surface, and the circular path moves from the outer circumference to the inside of the workpiece, and the scanning area is moved by moving the table each time a hole is drilled within one of the scanning areas is completed. A second machining hole forming step, in which the machining hole forming process is performed on a second machining surface facing the first machining surface, Includes, A laser processing method characterized by performing the first and second processing hole formation steps multiple times on the same workpiece such that the positions of the through holes formed by a set of the first and second processing hole formation steps are different.

2. A data division step of dividing through-hole position data, which includes position data indicating the location of the through-hole, into a plurality of divided machining hole position data for the first machined surface such that the number of through-holes per unit area is less than or equal to a standard density, A second surface machining data generation step, which generates divided machining hole position data for the second machining surface, having position data indicating a position that is a mirror image of the position indicated by the divided machining hole position data for the first machining surface, for each of the plurality of divided machining hole position data for the first machining surface, It further includes, In the first machining hole formation step, the machining hole formation process is performed using the divided machining hole position data for the first machining surface. In the second machining hole formation step, the machining hole formation process is performed using the divided machining hole position data for the second machining surface. The laser processing method according to claim 1, characterized in that the first processing hole formation step and the second processing hole formation step are performed alternately.

3. The laser processing method according to claim 2, characterized in that, in the data division step, when m is an integer of 2 or more, the position data in the through-hole position data is distributed to m of the divided processing hole position data such that the positions indicated by the position data for each of the multiple divided processing hole position data are distributed across the entire processed surface of the workpiece.

4. The laser processing method according to claim 3, characterized in that in the data division step, the position data is distributed to the m divided processing hole position data such that the density of the processing holes formed in the scanning area in the first processing hole formation step and the second processing hole formation step is 1 / m of the density of the through holes ultimately formed on the processing surface.

5. The through-hole position data includes text data that lists the position data indicating the location of the through-hole, The laser processing method according to claim 3, characterized in that the data division step distributes the position data in the through-hole position data to m divided processing hole position data in order from the beginning.

6. The laser processing method according to claim 2, characterized in that, in the second surface processing data generation step, the position data in the divided processing hole position data for the second processing surface is arranged in the same order as the corresponding position data in the divided processing hole position data for the first processing surface.

7. The laser processing method according to claim 2, characterized in that the reference density is the value obtained by dividing 1.5 million holes by the area of ​​the first processed surface or the second processed surface of the workpiece.

8. The process further includes a positional displacement measurement step performed before the first machining hole formation step for each of the multiple divided machining hole position data, for the first machining surface and the second machining surface, to measure the amount of positional displacement due to shrinkage of the workpiece that occurs when drilling holes in the machining surface of the workpiece while it is rotating along the aforementioned circular path. The laser processing method according to claim 2, characterized in that in the first processing hole formation step and the second processing hole formation step, the position data used when performing the processing hole formation process is corrected by the corresponding positional deviation amount using each of the plurality of divided processing hole position data.

9. In the above-mentioned displacement measurement step, the measured displacement is stored in correspondence with the material, thickness, and number of through holes formed in the workpiece. The laser processing method according to claim 8, characterized in that in the first processing hole formation step and the second processing hole formation step, the position data used when performing the processing hole formation process is corrected using the amount of positional deviation corresponding to the material, thickness, and number of through holes formed in the workpiece to be processed.

10. A data reading unit reads through-hole position data that has position data indicating the locations of through-holes exceeding the number of reference holes to be formed in the workpiece, A data division unit divides the position data in the through-hole position data into m parts when m is an integer of 2 or more, so that the number of through-holes per unit area is less than or equal to a standard density, and generates a plurality of divided machining hole position data for a first machining surface used in a single machining hole formation process that forms machining holes less than or equal to the standard number of holes on the entire machining surface of the workpiece. A second machining surface machining data generation unit generates divided machining hole position data for a second machining surface facing the first machining surface, which includes, for each of the plurality of divided machining hole position data for the first machining surface, position data indicating a position that is in a mirror image relationship with the position indicated by the included position data, A processing program generation unit sets multiple scanning areas for each of the multiple divided hole position data for the first and second processing surfaces, which can be scanned by a galvanometer mirror that scans the laser beam emitted from a laser oscillator within the processing surface of the workpiece, and converts them into a divided processing program in a format that allows drilling to be performed using a laser processing machine by a numerical control device. A programming tool characterized by having the following features.

11. The through-hole position data includes text data listing the position data, The programming tool according to claim 10, characterized in that the data division unit distributes the position data in the through-hole position data to each of the plurality of divided machining hole position data for the first machining surface in order from the beginning.

12. The programming tool according to claim 10 or 11, characterized in that the reference density is the value obtained by dividing the maximum number of holes formed by the laser drilling process, in which no warping occurs in the workpiece and the misalignment of the holes formed on the first and second processing surfaces is within the margin of error, by the area of ​​the first or second processing surface of the workpiece.

13. The laser oscillator that emits the aforementioned laser light, The galvanometer mirror, which is driven by a galvanometer scanner and scans the laser light, A table on which the workpiece to be drilled is placed, and which can be moved in a direction parallel to the mounting surface by a table drive mechanism, A control device for controlling the operation of the laser oscillator, the galvanometer scanner, and the table drive mechanism according to the laser processing method described in any one of claims 1 to 9, A laser processing machine characterized by being equipped with the following features.

Images