Laser processing apparatus, laser processing method, and program

Abstract

The laser processing apparatus (100) includes a laser irradiation unit (13) that forms a processing hole at a processing point on the workpiece (31) by irradiating it with laser light, and an acquisition unit (15) that acquires distance information used to adjust the distance between the laser irradiation unit (13) and the processing point. The laser processing apparatus (100) performs a circular processing operation in which it repeats laser processing multiple times on the workpiece (31) along at least a portion of the same processing path, and acquires all distance information corresponding to multiple processing points in the first circular processing operation. Then, the laser processing apparatus (100) adjusts the distance between the laser irradiation unit (13) and the processing point based on the acquired distance information.

Description

Technical Field

[0001] The present disclosure relates to a laser processing apparatus, a laser processing method, and a program for forming a processed hole in a workpiece by irradiating the workpiece with laser light.

Background Art

[0002] In laser processing, if the relationship between the focal position of the laser beam and the position of the workpiece is inappropriate, processing defects such as the laser beam being unable to penetrate the workpiece and failing to cut the workpiece may occur. Therefore, when performing laser processing, the position of a processing head, which is a laser irradiation unit that emits laser light, may be adjusted in order to maintain the focal position of the laser light at an appropriate position relative to the workpiece. For example, Patent Document 1 discloses a laser processing apparatus that includes a distance measuring unit that measures the distance between a processing head and a workpiece, and performs laser processing while adjusting the distance between the processing head and the workpiece based on the measurement result of the distance measuring unit.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In the process of laser processing, residues may be generated on the workpiece along with processing, or processing may be performed in the vicinity of a processed hole that has already been formed. In such a case, in the laser processing apparatus of Patent Document 1, the measurement result becomes inaccurate due to the residue or the already formed processed hole, and when this inaccurate measurement result is used, the distance between the processing head and the workpiece cannot be appropriately adjusted, which may cause processing defects.

[0005] This disclosure is made in view of the above circumstances and aims to provide a laser processing apparatus that can perform laser processing by appropriately adjusting the distance between the laser irradiation unit and the workpiece, without being affected by residues on the workpiece generated during the laser processing process or by processed holes already formed. [Means for solving the problem]

[0006] To solve the above-mentioned problems and achieve the objective, the laser processing apparatus according to this disclosure includes a laser irradiation unit that forms a processing hole at a processing point by irradiating it with laser light, and an acquisition unit that acquires distance information used to adjust the distance between the laser irradiation unit and the processing point. , a control unit that controls the laser irradiation unit and the acquisition unit, The laser processing apparatus according to this disclosure performs circular processing, which involves repeating laser processing multiple times on a workpiece along at least a portion of the same processing path, and acquires distance information for all of the processing points in the first circular processing. Then, based on the acquired distance information, it adjusts the distance between the laser irradiation unit and the processing points and performs an irradiation operation to irradiate the multiple processing points with laser light. Furthermore, the control unit determines that, among the multiple processing points, the irradiation operation will be performed during the first circular processing for processing points that do not affect the accuracy of the distance information acquired after the irradiation operation is performed during the first circular processing. [Effects of the Invention]

[0007] The laser processing apparatus described herein has the effect of being able to appropriately adjust the distance between the laser irradiation unit and the workpiece without being affected by residues on the workpiece generated during the laser processing process or by processed holes. [Brief explanation of the drawing]

[0008] [Figure 1] Block diagram showing the functional configuration of the laser processing apparatus according to Embodiment 1 [Figure 2] This figure illustrates an example of a state in which the laser processing apparatus according to Embodiment 1 cannot acquire accurate distance information. [Figure 3] This figure illustrates an example of a state in which the laser processing apparatus according to Embodiment 1 cannot acquire accurate distance information. [Figure 4]A diagram illustrating an example of the sequence of forming processed holes in a laser processing apparatus according to Embodiment 1. [Figure 5] A diagram illustrating the details of the laser irradiation unit and acquisition unit in the laser processing apparatus according to Embodiment 1. [Figure 6] A diagram illustrating how the acquisition unit in the laser processing apparatus according to Embodiment 1 acquires distance information at the processing point. [Figure 7] A diagram illustrating the operation of the laser processing apparatus according to Embodiment 1 in which it acquires a corrected distance based on distance information. [Figure 8] This diagram illustrates the operation by which the laser processing apparatus according to Embodiment 1 adjusts the distance between the laser irradiation unit and the workpiece based on distance information. [Figure 9] Flowchart showing the processing procedure of the laser processing apparatus according to Embodiment 1 [Figure 10] A diagram illustrating the method for acquiring distance information in the laser processing apparatus according to Embodiment 1. [Figure 11] Figure 10 illustrates the correspondence between machining points and distance information in the example shown. [Figure 12] A diagram illustrating the method for acquiring distance information in the laser processing apparatus according to Embodiment 1. [Figure 13] Figure 12 illustrates the correspondence between machining points and distance information in the example shown. [Figure 14] A diagram illustrating a method for associating multiple processing points with a single piece of distance information in a laser processing apparatus according to Embodiment 1. [Figure 15] A modified example of Embodiment 1. Diagram illustrating the determination method by the control unit of the laser processing apparatus. [Figure 16] This figure shows the hardware configuration for realizing the functions of the control unit according to Embodiment 1. [Modes for carrying out the invention]

[0009] Hereinafter, a laser processing apparatus, a laser processing method, and a program according to embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] Embodiment 1. FIG. 1 is a block diagram showing the functional configuration of the laser processing apparatus 100 according to the first embodiment. In FIG. 1, the X-axis, Y-axis, and Z-axis are three mutually perpendicular axes. The X-axis and Y-axis are, for example, axes parallel to the horizontal direction. The Z-axis is, for example, an axis parallel to the vertical direction.

[0011] The laser processing apparatus 100 according to the first embodiment generates heat in a three-dimensional workpiece 31 by condensing and irradiating a laser beam L onto a processing point on the workpiece 31. The laser processing apparatus 100 has a function of changing the shape of the workpiece 31 by melting, evaporating, or otherwise processing the workpiece 31 with the generated heat, and forming a through hole, which is a processed hole, in the workpiece 31. The laser processing apparatus 100 also cuts the workpiece 31 by continuously forming processed holes in the workpiece 31. In this manner, the laser processing apparatus 100 processes the workpiece 31 by irradiating the laser beam L onto the processing point on the workpiece 31. Note that the workpiece 31 may have a two-dimensional shape.

[0012] The workpiece 31 is formed of, for example, fiber-reinforced plastic. Note that the material forming the workpiece 31 is not limited to fiber-reinforced plastic, and various materials can be used.

[0013] The laser processing apparatus 100 includes a laser oscillator 11, an optical path 12, a laser irradiation unit 13, a drive unit 14 that drives the laser irradiation unit 13, an acquisition unit 15, a control unit 20, a work table 32, and a drive unit 33 that drives the work table 32. Note that the broken line shown in FIG. 1 represents the laser beam L.

[0014] The laser oscillator 11 generates laser light L used for processing the workpiece 31. The laser oscillator 11 generates, for example, a pulsed laser as the laser light L. The laser light L emitted from the laser oscillator 11 is supplied to the laser irradiation unit 13 via the optical path 12. In Embodiment 1, the laser oscillator 11 generates a pulsed laser, but the waveform of the laser light L generated by the laser oscillator 11 is not limited to a pulsed laser and may be a continuous wave laser.

[0015] The optical path 12 is the path for transmitting the laser light L output from the laser oscillator 11 to the laser irradiation unit 13. The optical path 12 may be a path for propagating the laser light L in the air, or a path for transmitting the laser light L through an optical fiber. The optical path 12 needs to be designed according to the characteristics of the laser light L.

[0016] The work table 32 holds the workpiece 31 on the work table 32. The work table 32 is driven by the drive unit 33. When the work table 32 is driven by the drive unit 33, the relative position between the laser irradiation unit 13 and the workpiece 31 changes.

[0017] The laser irradiation unit 13 has an optical system that focuses the laser beam L onto the workpiece 31, and irradiates the workpiece 31 with the focused laser beam L. The laser beam L has an output that can penetrate the workpiece 31 with a single irradiation.

[0018] The laser irradiation unit 13 is configured so that its relative position to the workpiece 31 can be adjusted by driving the laser irradiation unit 13 and the work table 32 by the drive units 14 and 33. After adjusting the relative position of the laser irradiation unit 13, laser light L is irradiated from the laser irradiation unit 13 onto the processing points on the workpiece 31, thereby forming a processing hole at the processing point. In the laser processing apparatus 100 according to Embodiment 1, the laser irradiation unit 13 irradiates the workpiece 31 with laser light L while repeatedly moving along at least a portion of a predetermined processing path multiple times, performing circumferential processing to form processing holes at processing points along the processing path. Note that forming a processing hole at a processing point by irradiating it with laser light L from the laser irradiation unit 13 is sometimes referred to as "processing the processing point".

[0019] If the relative position of the laser irradiation unit 13 with respect to the workpiece 31 is adjustable, it is not necessary to drive both the laser irradiation unit 13 and the work table 32; it is sufficient to have a function to change the position of either one of them.

[0020] The drive units 14 and 33 are servo control devices having at least one set of motors and position detectors. The drive units 14 and 33 may employ a drive system using motors and gears, and the drive units 14 and 33 may also be control mechanisms having a rotating shaft.

[0021] The acquisition unit 15 is provided on the laser irradiation unit 13 and is configured to move integrally with the laser irradiation unit 13. That is, the relative position of the acquisition unit 15 with respect to the workpiece 31 is adjusted by the drive units 14 and 33, which drive the laser irradiation unit 13 and the work table 32. The acquisition unit 15 also acquires distance information as information used to adjust the distance between the laser irradiation unit 13 and the processing point when irradiating with laser light L. Based on this distance information, the distance between the laser irradiation unit 13 and the processing point is adjusted, and an irradiation operation is performed to irradiate the processing point with laser light L. In the laser processing apparatus 100 according to Embodiment 1, the distance information is the distance between the tip of the acquisition unit 15 and a point on the workpiece 31. The point on the workpiece 31 from which distance information is acquired is sometimes called the "acquisition point".

[0022] To obtain the distance between the acquisition unit 15 and the workpiece 31, for example, a laser displacement meter that uses the reflection of light from the workpiece to determine the distance, or a capacitance sensor that uses changes in capacitance may be used, but is not limited to these.

[0023] The distance information is not limited to the distance between the acquisition unit 15 and the workpiece 31. For example, the distance information may be the distance between the laser irradiation unit 13 and the workpiece 31.

[0024] The control unit 20 grasps processing information, including the three-dimensional shape of the workpiece 31, the location of the processing point, and the position of the workpiece 31 on the work table 32, in order to generate a processing program for processing the processing point. The control unit 20 generates a processing program based on this grasped information. The control unit 20 also determines acquisition points on the processing path in the processing program based on the location of the processing point and the acquisition method described later. The generated processing program includes the position of the laser irradiation unit 13 when the laser beam L is irradiated, the processing path of the laser irradiation unit 13, the location of the acquisition point, the total number of circulating processing cycles, information on the processing point in which the irradiation operation is performed in each circulating processing cycle, and information for controlling the laser oscillator 11. In the first embodiment, the control unit 20 determines the irradiation cycle for each processing point as information on the processing point in which the irradiation operation is performed in each circulating processing cycle, indicating the circulating processing cycle in which the laser irradiation unit 13 performs the irradiation operation on the processing point among the repeated circulating processing cycles.

[0025] In Embodiment 1, the irradiation cycle is defined as information indicating the circulating process in which the laser irradiation unit 13 performs the irradiation operation among the repeating circulating processes at each processing point. However, information on the processing points to be processed in each circulating process may also be defined, for example, as processing points to be processed for each circulating process. The method for defining the information on the processing points in which the irradiation operation is performed in each circulating process is not limited to these.

[0026] To understand the three-dimensional shape and machining information of the workpiece 31, data called CAD (Computer-Aided Design) data is used, for example, as three-dimensional shape data including the dimensions and machining point locations of the workpiece 31. The CAD data is input to the control unit 20 via a data input unit (not shown). To understand the position of the workpiece 31 on the work table 32, for example, position information of the workpiece 31 provided by the user is used.

[0027] In Embodiment 1, the control unit 20 generates the machining program, but the machining program generation unit is not limited to the control unit 20. For example, the machining program may be generated by an external computer and read from there. Also, the machining program may be generated without using information about the position of the workpiece 31 on the work table 32. In this case, the position of the workpiece 31 on the work table 32 is adjusted before machining begins in accordance with the machining program.

[0028] The control unit 20 stores distance information and associates the processing point with the distance information. The distance between the laser irradiation unit 13 and the processing point is adjusted based on the stored distance information so that the distance between the laser irradiation unit 13 and the processing point becomes a predetermined distance.

[0029] The control unit 20 controls the relative positions of the laser irradiation unit 13 and the acquisition unit 15 with respect to the workpiece 31 by controlling the drive units 14 and 33 and the position of the laser irradiation unit 13 and the acquisition unit 15 provided on the laser irradiation unit 13. The control unit 20 moves the acquisition unit 15 along the processing path and acquires distance information at the acquisition point. Furthermore, the control unit 20 controls the laser oscillator 11 and controls the emission of the laser beam L so that the laser beam L is irradiated onto the processing point on the workpiece 31 according to the set processing conditions for laser processing. At this time, the control unit 20 adjusts the distance between the laser irradiation unit 13 and the processing point to a predetermined distance based on the distance information acquired by the acquisition unit 15, and controls the laser oscillator 11 to perform an irradiation operation in which the laser beam L is irradiated from the laser irradiation unit 13 onto the processing point. In each circumferential processing, when the irradiation operation is performed, the control unit 20 performs the irradiation operation on the predetermined processing point.

[0030] To obtain good processing results, the focal position of the laser beam L relative to the workpiece 31 is important. If the focal position of the laser beam L relative to the workpiece 31 is not appropriate, processing defects may occur, such as the laser beam L not penetrating the workpiece 31 and not being able to obtain a proper processed hole. To obtain good processing results, it is necessary to set an appropriate distance between the workpiece 31 and the laser irradiation unit 13 so that the focal position of the laser beam L relative to the workpiece 31 is appropriate. The focal position of the laser beam L relative to the workpiece 31 that yields good processing results varies depending on the processing conditions.

[0031] The processing conditions include, for example, the material of the workpiece 31, the thickness of the workpiece 31, the surface condition of the workpiece 31, the moving speed of the laser irradiation unit 13, and the focal position of the laser beam L relative to the workpiece 31. The processing conditions further include conditions related to the laser beam L, such as the laser output intensity of the laser oscillator 11, the laser output frequency, and the wavelength. The processing conditions may also include ambient temperature and ambient humidity.

[0032] The distance information will be explained in detail. The control unit 20 generates a processing program for processing the workpiece 31 with laser light L emitted from the laser irradiation unit 13, based on the three-dimensional shape of the workpiece 31. In an ideal state without errors, the laser light L is emitted from the laser irradiation unit 13 according to the processing program, so that the focal position of the laser light L is at an appropriate position relative to the processing point on the workpiece 31.

[0033] However, slight differences exist between the three-dimensional shape of the workpiece 31 and the three-dimensional shape grasped by the control unit 20, as well as errors in the position of the workpiece 31 relative to the work table 32 and errors in the position of the laser irradiation unit 13. Therefore, even if the laser beam L is irradiated from the laser irradiation unit 13 according to the processing program, the focal position of the laser beam L may not be in the appropriate position relative to the processing point.

[0034] Therefore, in order to position the focal point of the laser beam L emitted from the laser irradiation unit 13 appropriately, it is necessary to adjust the distance between the laser irradiation unit 13 and the processing point based on the relative positional relationship between the actual workpiece 31 and the laser irradiation unit 13. The acquisition unit 15 acquires distance information, which is information for adjusting the position of the laser irradiation unit 13 so that the distance between the laser irradiation unit 13 and the processing point is appropriate. The distance between the laser irradiation unit 13 and the processing point that yields good processing results is predetermined by the processing conditions. In addition, when the irradiation operation is performed, the distance between the laser irradiation unit 13 and the processing point is adjusted to the predetermined distance.

[0035] The necessity of acquiring all distance information corresponding to multiple processing points during the first rotational processing will be explained in detail. Figure 2 is a diagram illustrating an example of a state in which the laser processing apparatus 100 according to Embodiment 1 cannot acquire accurate distance information. Figure 2 shows a state in which the acquisition unit 15 acquires distance information at an acquisition point P1 on the workpiece 31 near the processing hole 40, and the residue 42 is between the acquisition unit 15 and the acquisition point P1. In particular, when the workpiece 31 is made of reinforced fiber plastic, the fibers forming the workpiece 31 often protrude after processing. In this case, the fibers that protrude after processing become the residue 42. In such a state, although distance D1 should be acquired as distance information, the residue 42 on the workpiece 31 is mistakenly recognized as the workpiece 31, and therefore distance D2 is acquired as distance information.

[0036] Figure 3, similar to Figure 2, is a diagram illustrating an example of a state in which the laser processing apparatus 100 according to Embodiment 1 cannot acquire accurate distance information. Figure 3 shows the case where the acquisition unit 15 acquires distance information at acquisition point P2, which overlaps with the processing hole 41. In this case, although distance D3 should be acquired as distance information, since the workpiece 31 does not exist at acquisition point P2, distance D3 is not accurately acquired as distance information.

[0037] To obtain accurate distance information, it is necessary to acquire distance information without being affected by residues on the workpiece 31 or pre-processed holes. Therefore, in the laser processing apparatus 100 according to Embodiment 1, the control unit 20 moves the acquisition unit 15 along the processing path and acquires all distance information corresponding to the processing points before processing holes that affect the accuracy of the distance information are formed. Specifically, in the first circular processing along the processing path, the control unit 20 does not perform irradiation and acquires all distance information corresponding to the processing points using the acquisition unit 15. The distance information acquired at this time is accurate because it is not affected by residues on the workpiece 31 or pre-processed holes. In this way, accurate distance information can be obtained by acquiring all distance information corresponding to the processing points without performing irradiation during the first circular processing.

[0038] The control unit 20 processes the workpiece 31 by making the laser irradiation unit 13 circulate along at least a portion of the processing path. During the first circulating process, the control unit 20 acquires all distance information corresponding to multiple processing points using the acquisition unit 15. In subsequent circulating processes, the control unit 20 moves the laser irradiation unit 13 along at least a portion of the processing path and, based on the distance information acquired in the first circulating process, adjusts the distance between the laser irradiation unit 13 and the processing point while irradiating the processing point with laser light L from the laser irradiation unit 13 to form a processing hole. The distance information acquired in the first circulating process is accurate because it is not affected by residues on the workpiece 31 or pre-processed holes. By performing the irradiation operation in subsequent circulating processes based on the distance information acquired in the first circulating process, the focal position of the laser light L becomes appropriate relative to the workpiece 31, resulting in good processing results.

[0039] In the laser processing apparatus 100 according to Embodiment 1, the irradiation operation is not performed during the first circular processing pass, but is performed during the second and subsequent circular processing passes. However, the irradiation operation may be performed during the first circular processing pass for processing points that do not affect the accuracy of the distance information acquired after the irradiation operation is performed during the first circular processing pass.

[0040] The advantages of processing by having the laser irradiation unit 13 circumferentially process along the processing path will be explained. When the workpiece 31 is made of fiber-reinforced plastic, the resin around the processing point may be damaged by heat due to the heat generated during processing, causing changes in physical properties such as deterioration of mechanical strength characteristics. In such cases, the quality of the workpiece 31 deteriorates. Heat damage is particularly likely to occur when forming processing holes continuously in a linear shape. To prevent heat damage, the control unit 20 may have the laser irradiation unit 13 circumferentially process along at least a part of the processing path, form processing holes at some of the processing points in the second circumferential processing, and form processing holes at unprocessed processing points in the third and subsequent circumferential processing.

[0041] A specific example will be explained using Figure 4. Figure 4 is a diagram illustrating an example of the sequence of hole formation in the laser processing apparatus 100 according to Embodiment 1. Figure 4 shows the case where holes are formed continuously in a linear shape. Each row in Figure 4 shows the processing point in each cycle of circumferential processing. The first row of Figure 4 shows the processing point in the first circumferential processing, but no processing point exists in the first circumferential processing because no holes are formed and only positional information is acquired. The second row of Figure 4 shows the processing point in the second circumferential processing, the third row of Figure 4 shows the processing point in the third circumferential processing, the fourth row of Figure 4 shows the processing point in the fourth circumferential processing, and the fifth row of Figure 4 shows the processing point in the fifth circumferential processing. The hatched circles indicate holes formed by irradiation with laser light L, and the dashed lines indicate the processing path K. Circles containing 2 indicate holes machined during the second circumferential machining, circles containing 3 indicate holes machined during the third circumferential machining, circles containing 4 indicate holes machined during the fourth circumferential machining, and circles containing 5 indicate holes machined during the fifth circumferential machining.

[0042] By processing in this manner, it is possible to prevent the laser beam L from continuously irradiating adjacent processing points. Therefore, the effect of residual heat on the workpiece 31 can be reduced, and thermal damage to the workpiece 31 can be suppressed.

[0043] Since there is no need to re-process machining points where machining holes have already been formed, for example, in the third and subsequent circulating machining cycles, the control unit 20 may move the laser irradiation unit 13 along a machining path that does not include machining points where machining holes have already been formed, thereby machining the machining points. In other words, in the third and subsequent circulating machining cycles, the control unit 20 may move the laser irradiation unit 13 along at least a portion of a predetermined machining path, thereby machining the machining points.

[0044] A method for the control unit 20 to adjust the distance between the laser irradiation unit 13 and the processing point using distance information will be described. Distance LF is defined as the distance between the laser irradiation unit 13 and the processing point such that the focal position of the laser beam L is at an appropriate position relative to the processing point. This distance LF is determined by the processing conditions. When the laser beam L is irradiated from the laser irradiation unit 13, the control unit 20 adjusts the position of the laser irradiation unit 13 so that the distance between the laser irradiation unit 13 and the processing point becomes the predetermined distance, distance LF.

[0045] First, the configuration of the laser irradiation unit 13 and acquisition unit 15 according to Embodiment 1 will be described. Figure 5 is a diagram illustrating the details of the laser irradiation unit 13 and acquisition unit 15 in the laser processing apparatus 100 according to Embodiment 1. As shown in Figure 5, the acquisition unit 15 is provided on the laser irradiation unit 13 and is configured to move integrally with the laser irradiation unit 13. The position of the laser irradiation unit 13 when irradiating the processing point N11 with laser light L according to the processing program without adjusting its position based on distance information is defined as position PH1. At this time, the optical axis C1 of the laser light L irradiated from the laser irradiation unit 13 and the surface of the workpiece 31 on the side of the laser irradiation unit 13 intersect perpendicularly at the processing point N11. In an ideal state, when the position of the laser irradiation unit 13 is position PH1, the distance D11 between the laser irradiation unit 13 and the processing point N11 coincides with distance LF, but in reality they do not coincide.

[0046] In the laser processing apparatus 100 according to Embodiment 1, the case in which the control unit 20 acquires distance information with the processing point N11 as the acquisition point will be described. When the position of the laser irradiation unit 13 is position PH1, if the acquisition unit 15 acquires distance information, the acquisition unit 15 acquires the distance D12 between the tip of the acquisition unit 15 and point P11 on the workpiece 31 as distance information. Point P11 is the point where the workpiece 31 intersects with axis C2, which is parallel to the optical axis C1 and has a distance L1 from the optical axis C1, and is located on the surface on the side of the acquisition unit 15. Distance L1 is the distance determined by the positional relationship between the laser irradiation unit 13 and the acquisition unit 15. Thus, in the laser processing apparatus 100 according to Embodiment 1, even if the acquisition unit 15 acquires the distance between the tip of the acquisition unit 15 and the workpiece 31 at position PH1, which is the laser irradiation unit 13 when the laser beam L is irradiated onto the processing point N11, the acquired distance does not become distance information with the processing point N11 as the acquisition point.

[0047] Figure 6 is a diagram illustrating how the acquisition unit 15 in the laser processing apparatus 100 according to Embodiment 1 acquires distance information at the processing point N11. In order to acquire distance information with the processing point N11 as the acquisition point, the control unit 20 controls the drive units 14 and 33 to move the laser irradiation unit 13 to position PH2, which is a position where the acquisition unit 15 can acquire distance information with the processing point N11 as the acquisition point. As shown in Figure 6, when the laser irradiation unit 13 is at position PH2, the axis C2 intersects perpendicularly with the workpiece 31 at the processing point N11. The distance between position PH1 and position PH2 is distance L1. In this way, the control unit 20 uses the acquisition unit 15 to acquire distance D13, which is distance information corresponding to the processing point N11.

[0048] Next, we will explain the operation of adjusting the distance between the laser irradiation unit 13 and the processing point N11 when irradiating the processing point N11 with laser light L based on distance information, which is distance D13. Figure 7 is a diagram illustrating the operation in which the laser processing apparatus 100 according to Embodiment 1 acquires a correction distance based on distance information. As shown in Figure 7, the control unit 20 moves the position of the laser irradiation unit 13 to position PH1 by controlling the drive units 14 and 33.

[0049] Let distance L0 be the distance along the optical axis C1 between the tip of the laser irradiation unit 13 and the tip of the acquisition unit 15. Distance L0, like distance L1, is determined by the laser processing device 100. When the laser irradiation unit 13 is at position PH1, the distance D14 between the laser irradiation unit 13 and the processing point N11 is given by D14 = L0 + D13. If distance D14 is equal to distance LF, the focal position of the laser beam L emitted from the laser irradiation unit 13 at position PH1 is at an appropriate position relative to the workpiece 31, so there is no need to adjust the distance between the laser irradiation unit 13 and the processing point N11.

[0050] However, if distance D13 and distance LF are not equal, the focal position of the laser beam L emitted from the laser irradiation unit 13 at position PH1 is not in an appropriate position relative to the processing point N11, so it is necessary to adjust the distance between the laser irradiation unit 13 and the processing point N11. Figure 8 is a diagram illustrating the operation of the laser processing apparatus 100 according to Embodiment 1 in which the laser irradiation unit 13 adjusts the distance between the laser irradiation unit 13 and the processing point based on distance information. When adjusting the distance between the laser irradiation unit 13 and the processing point N11, the distance by which the laser irradiation unit 13 is brought closer to the processing point N11 by the correction distance ΔD from position PH1 to the processing point N11 is defined as correction distance ΔD. The distance D15 between the laser irradiation unit 13 at position PH3, which is moved closer to the processing point N11 by the correction distance ΔD along the optical axis C1 from position PH1, and the processing point N11 coincides with distance LF. Therefore, the focal position of the laser beam L emitted from the laser irradiation unit 13 at position PH3 is in an appropriate position relative to the processing point N11. Here, ΔD = D14 - LF, so it can be expressed as ΔD = L0 + D13 - LF. Distance L0 is determined by the configuration of the laser processing device 100, and distance LF is determined by the processing conditions. Therefore, distances L0 and LF are fixed when laser light L is irradiated from the laser irradiation unit 13. Thus, by obtaining distance D13, which is distance information corresponding to the processing point N11, the correction distance ΔD at the processing point N11 can be obtained. When laser light L is irradiated from the laser irradiation unit 13 to the processing point N11, the control unit 20 adjusts the distance between the laser irradiation unit 13 and the processing point N11 by moving the position of the laser irradiation unit 13 closer to the processing point N11 by a correction distance ΔD from position PH1, which is the position according to the processing program.

[0051] In this way, the control unit 20 adjusts the distance between the laser irradiation unit 13 and the processing point N11 based on the acquired distance information, and performs an irradiation operation to irradiate the processing point N11 with laser light L from the laser irradiation unit 13. By adjusting the position of the laser irradiation unit 13 in this way, the focal position of the laser light L can be adjusted to an appropriate position, and good processing results can be obtained.

[0052] The distance information is used to adjust the position of the laser irradiation unit 13 so that the distance between the laser irradiation unit 13 and the processing point at the processing point is appropriate. Although the case where the acquisition point and the processing point are made to coincide has been explained, the acquisition point corresponding to the processing point and the processing point may not be made to coincide, and the acquisition point corresponding to the processing point may be a point in the vicinity of the processing point. For example, in the example in Figure 5, the acquisition point corresponding to the processing point N11 may be point P11. In this case, the distance information corresponding to the processing point N11 will be distance D12.

[0053] The processing procedure of the laser processing apparatus 100 according to Embodiment 1 will now be described. Figure 9 is a flowchart showing the processing procedure of the laser processing apparatus 100 according to Embodiment 1. First, in step S010, as preparation for processing, the control unit 20 generates a processing program for processing the workpiece 31 with laser light L irradiated from the laser irradiation unit 13 based on processing information. The generation of the processing program determines the processing points on the workpiece 31, the processing path, acquisition points, the total number of circulating processing passes N, and the number of irradiation passes for each processing point. Since the acquisition points differ depending on the acquisition method, the acquisition points will differ even if the processing points and processing path on the workpiece 31 are the same. When using a processing program generated by an external computer, in step S010, as preparation for processing, the control unit 20 reads the program generated by the external computer. If the processing program is generated without using information about the position of the workpiece 31 on the work table 32, the position of the workpiece 31 on the work table 32 is adjusted before processing starts in accordance with the processing program.

[0054] Once the preparation for machining is complete, the control unit 20 starts machining (step S011). At this time, the control unit 20 sets n=1, where n is the total number of rotations for machining.

[0055] Once machining begins, the control unit 20 controls the laser irradiation unit 13 or the work table 32 by controlling the drive units 14 and 33, and executes the nth circumferential machining from the starting point of the nth circumferential machining (step S012). When circumferential machining is performed along the same machining path, the starting point of the circumferential machining is the same. However, if the machining path does not include machining points where machining holes are formed, for example, the starting point of the circumferential machining may differ. Using the same machining path has the advantage of simplifying the generation of the machining program.

[0056] The operation for acquiring distance information differs between the first and subsequent circulating machining operations. Step S013 divides the processing based on the total number of circulating machining operations. In the first circulating machining operation, where the total number of operations n=1, the acquisition unit 15 acquires all distance information corresponding to the machining points. To acquire distance information, steps S014 and S015 are executed when the total number of operations n=1. In step S014, it is determined whether the acquisition unit 15 is passing above the acquisition points. If the acquisition unit 15 is passing above the acquisition points, step S015 is performed, and the acquisition unit 15 acquires the distance information corresponding to the machining points. The control unit 20 stores the distance information and associates the machining points with the distance information. In the second and subsequent circulating machining operations, where the total number of operations n>1, steps S014 and S015, which are steps for acquiring distance information, are not executed.

[0057] Through this process, all distance information is acquired during the first pass-through machining. Once the correspondence between the machining point and the distance information is established, the control unit 20 can adjust the distance between the laser irradiation unit 13 and the machining point based on the distance information acquired during the first pass-through machining, and then irradiate the machining point with laser light L from the laser irradiation unit 13 to form a machining hole.

[0058] Since the irradiation operation can now be performed, the control unit 20 determines whether the laser irradiation unit 13 is passing over the processing point for which n is set in the irradiation circumference (step S016). If n is set in the irradiation circumference, the control unit 20 performs the irradiation operation on that processing point (step S017). In other words, for each circumference processing, the control unit 20 performs the irradiation operation on the predetermined processing point. In the laser processing apparatus 100 according to Embodiment 1, the control unit 20 does not perform the irradiation operation in the first circumference processing, so step S017 is not performed in the first circumference processing.

[0059] In Embodiment 1, the irradiation operation is not performed during the first pass, but is performed during subsequent passes. However, the irradiation operation may also be performed during the first pass. For example, the user may set a machining point to which the irradiation operation is performed during the first pass. In this case, the irradiation operation will be performed during the first pass.

[0060] Once the acquisition of distance information and irradiation operation at one point on the processing path are complete, the control unit 20 determines in step S018 whether the circulating process has been completed up to the end point of the nth circulating process. If the circulating process has not been completed up to the end point of the processing path, the nth circulating process is continued. That is, the control unit 20 continues to move the laser irradiation unit 13 along the processing path and repeats steps S013 to S018 until the processing is completed up to the end point of the processing path, thereby repeating the acquisition of distance information and irradiation operation at points on the processing path. In the laser processing apparatus 100 according to Embodiment 1, distance information is acquired only during the first circulating process.

[0061] Once the circular machining is complete up to the end point of the nth circular machining cycle, the control unit 20 determines whether the total number of circular machining cycles n has reached the total number of cycles N. That is, it determines whether n=N (step S019). If all circular machining is complete and n=N is true, it means that machining is complete at all machining points on the workpiece 31. In this case, the machining process ends. If n=N is not true, the control unit 20 continues machining the workpiece 31. The control unit 20 executes step S020, which is the process of incrementing the total number of cycles n, and repeats the process of executing the circular machining from the starting point of the (n+1)th circular machining cycle. That is, it repeats the process from step S012 by incrementing n after the completion of the nth circular machining cycle until n=N is true. If n=N is true, machining is complete at all machining points, and the machining process ends.

[0062] By performing this process, the laser processing apparatus 100 according to Embodiment 1 performs circular processing, which involves repeating laser processing multiple times on the workpiece 31 along at least a portion of the same processing path. The acquisition unit 15 acquires all distance information corresponding to multiple processing points during the first circular processing. The control unit 20 then adjusts the distance between the laser irradiation unit 13 and the processing point based on the distance information acquired during the first circular processing, and performs an irradiation operation to irradiate the processing point with laser light L from the laser irradiation unit 13. Furthermore, the control unit 20 performs an irradiation operation on processing points where the total number of circular processing cycles performed at the time of execution matches the number of circular processing cycles set for that processing point during the circular processing that is being executed by the laser irradiation unit 13.

[0063] Next, we will explain the method for acquiring distance information that forms the basis for the control unit 20 to determine acquisition points. As an acquisition method, a method may be selected in which acquisition points are determined so that each piece of distance information corresponds to only one processing point, and distance information is acquired accordingly. Figures 10 and 11 will be used to explain the case in which individual distance information is acquired for each processing point.

[0064] Figure 10 is a diagram illustrating the method for acquiring distance information in the laser processing apparatus 100 according to Embodiment 1. Figure 10 shows the case where distance information is acquired with acquisition points P21 to P24 when processing processing points N21 to N24. The acquisition unit 15, controlled by the control unit 20, moves along the processing path K and acquires distances D21 to D24 as distance information at each of the acquisition points P21 to P24 during the first circular processing.

[0065] Figure 11 is a diagram illustrating the correspondence between machining points and distance information in the example shown in Figure 10. Each machining point is associated with a specific acquisition point and distance information. For example, the acquisition point corresponding to machining point N21 is acquisition point P21, and the distance information corresponding to acquisition point P21 is distance D21. Similarly, the distance information corresponding to machining point N21 is distance D21. Since a specific acquisition point is defined for each machining point and distance information is acquired accordingly, different distance information corresponds to each machining point.

[0066] In the acquisition method, where an individual acquisition point is defined for each processing point to acquire distance information, the number of processing points and the number of acquisition points are the same. The control unit 20 has the advantage of being able to accurately adjust the distance between the laser irradiation unit 13 and the processing point at each processing point. Therefore, good processing results can be obtained at each processing point. Note that in the examples shown in Figures 10 and 11, the processing point and the acquisition point corresponding to the processing point are different points, but the processing point and the acquisition point corresponding to the processing point may be the same point.

[0067] As an acquisition method, a method may be selected in which acquisition points are defined such that at least one of the distance information points corresponds to multiple machining points, and distance information is acquired in this manner. The case in which multiple machining points correspond to distance information will be explained using Figures 12 and 13.

[0068] Figure 12 is a diagram illustrating the method for acquiring distance information in the laser processing apparatus 100 according to Embodiment 1. Figure 12 shows the case where distance information is acquired at acquisition point P31 and acquisition point P32 when processing processing points N31 to N34. The acquisition unit 15, controlled by the control unit 20, moves along the processing path K and acquires distance D31 as distance information at acquisition point P31 and distance D32 as distance information at acquisition point P32 during the first circular processing.

[0069] Figure 13 is a diagram illustrating the correspondence between machining points and distance information in the example shown in Figure 12. One distance information corresponds to multiple machining points. For example, the acquisition point corresponding to machining point N21 is acquisition point P31, and the acquisition point corresponding to machining point N32 is also acquisition point P31, just as in the case of machining point N31. Since the distance information corresponding to acquisition point P31 is distance D31, the distance information corresponding to machining point N31 is distance D31, and the distance information corresponding to machining point N32 is also distance D31, just as in the case of machining point N31.

[0070] In an acquisition method where multiple machining points correspond to a single distance information, there is the advantage of being able to reduce the number of acquisition points relative to the number of machining points. Therefore, it is particularly useful when there are constraints on the number of distance information points that can be stored.

[0071] A specific example of a case where multiple processing points correspond to a single piece of distance information will be explained. For example, in the first circular processing along a predetermined processing path, the control unit 20 may acquire distance information at predetermined intervals after the laser irradiation unit 13 starts circular processing. In this case, the control unit 20 acquires distance information at the start of the first circular processing along the predetermined processing path. Subsequently, the control unit 20 acquires distance information at predetermined intervals while moving the acquisition unit 15 along the predetermined processing path. At this time, it is desirable for the acquisition unit 15 to move at a constant speed in order to evenly distribute the acquisition points on the processing path.

[0072] The control unit 20 may acquire distance information each time the laser irradiation unit 13 moves a predetermined distance after it starts circular machining. In this case, the control unit 20 acquires distance information using the acquisition unit 15 at the start of the first circular machining movement along the predetermined machining path. Thereafter, the control unit 20 moves the laser irradiation unit 13 along the predetermined machining path and acquires distance information each time the laser irradiation unit 13 moves a predetermined distance.

[0073] This section describes an example of how to associate processing points with distance information in an acquisition method where multiple processing points correspond to a single piece of distance information. For example, one method is to use the distance information acquired just before the laser irradiation unit 13 passes above the processing point as the distance information corresponding to the processing point.

[0074] This method will be explained using Figure 14. Figure 14 is a diagram illustrating a method for associating multiple processing points with one piece of distance information in the laser processing apparatus 100 according to Embodiment 1. The acquisition unit 15 moves along a predetermined processing path K, and acquires distance information at acquisition points P41 and P42 while passing over processing points N41 to N46. The distance information acquired at acquisition point P41 is distance D41, and the distance information acquired at acquisition point P42 is distance D42. The distance information acquired immediately before the laser irradiation unit 13 passes over processing points N41 to N43 is distance D41 with acquisition point P41. Therefore, the distance information corresponding to processing points N41 to N43 is distance D41. Also, the distance information acquired immediately before the laser irradiation unit 13 passes over processing points N44 to N46 is distance D42 with acquisition point P42. Therefore, the distance information corresponding to processing points N44 to N46 is distance D42.

[0075] By associating machining points with distance information in this way, users can easily associate machining points with distance information without having to perform complex settings.

[0076] Although we have described cases where the acquisition point is determined using the elapsed time from the start of processing and cases where the acquisition point is determined using the travel distance of the laser irradiation unit 13, the method of determining the acquisition point is not limited to these. For example, the user may set the acquisition point and the processing point corresponding to that acquisition point.

[0077] As described above, the laser processing apparatus 100 according to Embodiment 1 can prevent the distance between the laser irradiation unit 13 and the workpiece 31 from deviating from the set distance due to the influence of residue on the workpiece 31 or pre-processed holes. Therefore, the laser processing apparatus 100 according to Embodiment 1 has the effect of being able to appropriately adjust the distance between the laser irradiation unit 13 and the workpiece 31 without being affected by residue on the workpiece 31 or pre-processed holes generated during the laser processing process.

[0078] Next, a modified example of Embodiment 1 will be described.

[0079] Embodiment 1 described a case where distance information is acquired without performing an irradiation operation during the first circulating process. In a modified version of Embodiment 1, the control unit 20 determines that the irradiation operation will be performed during the first circulating process for processing points that do not affect the accuracy of the distance information acquired after the irradiation operation is performed during the first circulating process. The control unit 20 also determines that the irradiation operation will not be performed during the first circulating process for processing points that do affect the accuracy of the distance information acquired after the irradiation operation is performed during the first circulating process. Performing an irradiation operation on the processing points during the first circulating process allows the workpiece 31 to be processed in a shorter time compared to the case where no irradiation operation is performed during the first circulating process.

[0080] The control unit 20 determines the machining point on which to perform the irradiation operation in the first rotational machining cycle, based on the distance between the machining point and the acquisition point on the workpiece 31 on which distance information is acquired after the irradiation operation is performed on the machining point. The machining point on which the irradiation operation is performed in the first rotational machining cycle is sometimes called the "initial machining point".

[0081] Figure 15 is a diagram illustrating the determination method by the control unit 20 of the laser processing apparatus 100 according to a modified example of Embodiment 1. The acquisition unit 15 moves along a predetermined processing path K, and acquires distance information of acquisition point P51 and acquisition point P52 while passing over processing points N51 to N54. The processing points corresponding to the distance information acquired at acquisition point P51 are processing points N51 and N52, and the processing points corresponding to the distance information acquired at acquisition point P52 are processing points N53 and N54.

[0082] Now, let's consider acquisition point P52. The machining points that may be machined before the acquisition unit 15 acquires distance information at acquisition point P52 are machining points N51 and N52. Of machining points N51 and N52, the machining point that does not affect the accuracy of the distance information acquired at acquisition point P52 after the irradiation operation is performed is the first machining point. In order not to affect the accuracy of the distance information at acquisition point P52, there should be no residue generated by the machining near acquisition point P52, and no machined holes should be near acquisition point P52. These conditions are met at machining points that are sufficiently far from acquisition point P52. Therefore, the control unit 20 determines whether a machining point is the first machining point based on the distance between the machining point and the acquisition point from which distance information is acquired after the irradiation operation is performed on that machining point.

[0083] The details of how the control unit 20 determines whether a machining point is the first machining point based on the distance between the machining point and the acquisition point will be explained. As previously described, a machining point that is sufficiently far from the acquisition point can be designated as the first machining point. Therefore, if the distance between machining point N51 and acquisition point P52 is greater than a predetermined distance, the control unit 20 determines that machining point N51 is the first machining point. Similarly, if the distance between machining point N52 and acquisition point P52 is greater than a predetermined distance, the control unit 20 determines that machining point N52 is the first machining point. Here, the distance L10 is the threshold distance for the control unit 20 to determine whether a point is the first machining point. If the distance L11, which is the distance between machining point N51 and acquisition point P52, is greater than the distance L10, the control unit 20 determines that machining point N51 is the first machining point. Similarly, if the distance L12, which is the distance between the processing point N52 and the acquisition point P52, is greater than the distance L10, the control unit 20 determines that the processing point N52 is the initial processing point.

[0084] In this way, the control unit 20 determines whether a machining point is a first machining point, meaning that performing an irradiation operation in the first rotation will not affect the accuracy of the distance information, based on the distance between the machining point and the acquisition point where distance information is acquired after an irradiation operation is performed on that machining point. The control unit 20 then designates the machining point determined to be a first machining point as the machining point where the irradiation operation will be performed in the first rotation.

[0085] The distance L10 is a different value depending on the machining conditions. The distance L10 may be predetermined by the user based on the machining conditions. Alternatively, the control unit 20 may set the distance L10 based on the distance corresponding to the machining conditions stored in the control unit 20.

[0086] By performing the irradiation operation during the first pass, the amount of movement of the laser irradiation unit 13 can be reduced compared to when the irradiation operation is not performed during the first pass. Therefore, according to the modified laser processing apparatus 100 of Embodiment 1, the workpiece 31 can be processed in a shorter time compared to when the irradiation operation is not performed during the first pass.

[0087] Figure 16 is a diagram showing the hardware configuration for realizing the functions of the control unit 20 according to Embodiment 1. The functions of the control unit 20 of the laser processing apparatus 100 are realized by a computer system comprising a CPU (Central Processing Unit) 201, memory 202, storage device 203, display device 204, and input device 205, as shown in Figure 16. The functions executed by the control unit 20 are realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a computer program and stored in the storage device 203. The CPU 201 realizes the functions of the control unit 20 by reading the software or firmware stored in the storage device 203 into the memory 202 and executing it. In other words, the computer system includes a storage device 203 for storing a program that, when the functions of the control unit 20 are executed by the CPU 201, will consequently execute the steps that carry out the operation of the control unit 20 as described in Embodiment 1. These programs can also be said to cause the computer to execute the processing realized by the functions of the control unit 20. The memory 202 corresponds to a volatile storage area such as RAM (Random Access Memory). The storage device 203 includes non-volatile or volatile semiconductor memory such as ROM (Read Only Memory) and flash memory, as well as magnetic disks. Specific examples of the display device 204 are monitors and displays. Specific examples of the input device 205 are keyboards, mice, and touch panels.

[0088] The configurations shown in the above embodiments are merely examples, and can be combined with other known technologies. It is also possible to omit or modify parts of the configuration without departing from the gist of the invention. [Explanation of Symbols]

[0089] 11 Laser oscillator, 12 Optical path, 13 Laser irradiation unit, 14 Drive unit, 15 Acquisition unit, 20 Control unit, 31 Workpiece, 32 Work table, 33 Drive unit, 40, 41 Processing hole, 42 Residue, 100 Laser processing apparatus

Claims

1. A laser processing apparatus that performs circumferential processing, which involves repeatedly performing laser processing on a workpiece along at least a portion of the same processing path, A laser irradiation unit that irradiates a plurality of processing points along the processing path with laser light to form processing holes at the processing points, An acquisition unit provided in the laser irradiation unit is used to acquire distance information used to adjust the distance between the laser irradiation unit and the processing point when the laser light is irradiated, A control unit that controls the laser irradiation unit and the acquisition unit, Equipped with, The control unit acquires all the distance information corresponding to the plurality of processing points in the first circumferential processing, adjusts the distance between the laser irradiation unit and the processing points based on the acquired distance information, and performs an irradiation operation to irradiate the plurality of processing points with laser light. Of the multiple processing points, the processing points that do not affect the accuracy of the distance information acquired after the irradiation operation is performed in the first circumferential processing are to be specified as being processed in the first circumferential processing. A laser processing apparatus characterized by the following features.

2. The control unit, in each of the circumferential machining operations, executes the irradiation operation on the predetermined machining points. The laser processing apparatus according to feature 1.

3. The control unit determines the machining point on which to perform the irradiation operation in the first circumferential machining, based on the distance between the machining point and the acquisition point on the workpiece from which the distance information is acquired after the irradiation operation is performed on the machining point. The laser processing apparatus according to feature 1 or 2.

4. Each of the aforementioned distance pieces corresponds to only one of the aforementioned processing points. The laser processing apparatus according to feature 1 or 2.

5. At least one of the distance information corresponds to a plurality of processing points. The laser processing apparatus according to feature 1 or 2.

6. The control unit acquires the distance information during the initial rotational processing, at predetermined intervals after the laser irradiation unit starts the rotational processing, or at predetermined intervals after the laser irradiation unit starts the rotational processing and moves a predetermined distance. The laser processing apparatus according to feature 5.

7. The distance information corresponding to the processing point is the distance information acquired immediately before the laser irradiation unit passes above the processing point. The laser processing apparatus according to feature 6.

8. A processing method in a laser processing apparatus that performs circumferential processing, in which laser processing is repeated multiple times on a workpiece along at least a portion of the same processing path, The steps include forming a processed hole at a plurality of processing points along the processing path by irradiating them with laser light from a laser irradiation unit, The steps include: acquiring distance information used to adjust the distance between the laser irradiation unit and the processing point during laser irradiation using an acquisition unit provided in the laser irradiation unit; The first step of determining the machining point where the machining hole will be formed in the circumferential machining, Includes, In the step of acquiring the distance information, all of the distance information corresponding to the plurality of machining points is acquired in the first circumferential machining, In the step of forming a processing hole at the processing point, the distance between the laser irradiation unit and the processing point is adjusted based on the acquired distance information, and an irradiation operation is performed to irradiate the plurality of processing points with laser light. In the step of determining the processing points, it is determined that the irradiation operation will be performed in the first circumferential processing on the processing points among the plurality of processing points that do not affect the accuracy of the distance information acquired after the irradiation operation is performed in the first circumferential processing. A laser processing method characterized by the following features.

9. A program that causes a laser processing device to perform a circular processing operation, which involves repeatedly laser processing an object along at least a portion of the same processing path, The steps include forming a processed hole at a plurality of processing points along the processing path by irradiating them with laser light from a laser irradiation unit, The steps include: acquiring distance information used to adjust the distance between the laser irradiation unit and the processing point during laser irradiation using an acquisition unit provided in the laser irradiation unit; The first step of determining the machining point where the machining hole will be formed in the circumferential machining, Make it run, In the step of acquiring the distance information, all of the distance information corresponding to the multiple machining points is acquired during the first rotational machining. In the step of forming a processing hole at the processing point, the distance between the laser irradiation unit and the processing point is adjusted based on the acquired distance information, and an irradiation operation is performed to irradiate the plurality of processing points with laser light. In the step of determining the processing points, it is determined that the irradiation operation will be performed in the first circumferential processing on the processing points among the plurality of processing points that do not affect the accuracy of the distance information acquired after the irradiation operation is performed in the first circumferential processing. A program characterized by the following features.

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