Laser processing device and laser processing method

Abstract

To make it possible to easily measure a distance between a laser head and a work-piece.SOLUTION: A laser head 20 is provided with a detection part 25. The detection part 25 detects measurement light S reflected by a work-piece W. A calculation part 11 calculates a distance between the laser head 20 and the work-piece W on the basis of a detection time until the measurement light S emitted from the laser head 20 is detected by the detection part 25.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a laser processing apparatus and a laser processing method. [Background technology]

[0002] Patent Document 1 discloses a laser processing method in which the distance between the laser head and the workpiece can be taught to the optimal focal position by moving the laser head up and down and aligning the reflected light of the measurement light displayed on a display with a cross target. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-042775 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the invention of Patent Document 1, the measurement light is emitted to the workpiece at a predetermined angle inclined with respect to the optical axis of the laser light, which may cause problems during the measurement operation.

[0005] 9, there is a risk that a jig 101 for pressing down the workpiece W may enter the emission trajectory of the measurement light S during the measurement operation. In this case, the measurement light S may be blocked by the jig 101 before it reaches the workpiece W, and there is a risk that the distance between the laser head 100 and the workpiece W may not be measured.

[0006] The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to make it possible to easily measure the distance between a laser head and a workpiece. [Means for solving the problem]

[0007] A first invention is a laser processing apparatus having a laser head that emits a laser light for processing onto a workpiece, wherein the laser head is configured to emit measurement light having a different wavelength from the laser light along the emission direction of the laser light, and is provided with a detection unit that detects the measurement light reflected by the workpiece, and a calculation unit that calculates the distance between the laser head and the workpiece based on the detection time until the measurement light emitted from the laser head is detected by the detection unit.

[0008] In the first invention, the measurement light used to measure the distance between the laser head and the workpiece is emitted along the emission direction of the laser light for processing, which makes it possible to suppress problems that occur when the measurement light is emitted to the workpiece from an angle other than the optical axis of the laser light.

[0009] Specifically, if measurement light is emitted toward the workpiece from an angle other than the optical axis of the laser light, there is a risk that the jig used to hold down the workpiece will get on the emission trajectory of the measurement light, blocking the measurement light.

[0010] In contrast, if the configuration is such that the measurement light can be emitted along the emission direction of the laser light, the problem of the measurement light being blocked by the jig does not occur, and the distance between the laser head and the workpiece can be easily measured.

[0011] In addition, during the teaching operation, there is no need to worry about whether the measurement light will be blocked by the jig; it is sufficient to simply move the laser head to the processing point on the workpiece and register the posture of the laser head, thereby improving the efficiency of the teaching operation.

[0012] A second invention relates to the laser processing apparatus of the first invention, and further includes a workpiece holding section that is detachably provided on the laser head and holds the workpiece at a position a predetermined distance away from the emission end of the laser head.

[0013] In the second invention, the distance to the workpiece is preset based on the dimensions of the workpiece holding portion, and by detecting the measurement light by the detection portion in this state, the detection time until the measurement light is detected by the detection portion can be correlated with the distance between the laser head and the workpiece.

[0014] A third invention is a laser processing apparatus of the first invention, which is provided with a robot that changes the position of the laser head relative to the workpiece, and the robot moves the laser head between a first height position facing the workpiece and a second height position farther from the workpiece than the first height position, and the detection unit detects the measurement light at the first height position and the second height position, respectively, and the calculation unit calculates a first distance and a second distance between the laser head and the workpiece based on a first detection time and a second detection time until the measurement light is detected by the detection unit at the first height position and the second height position.

[0015] In the third invention, the first distance and the second distance are calculated at the first height position and the second height position, so that the distance between the laser head and the workpiece can be grasped more accurately.

[0016] Specifically, when calculating the distance between the laser head and the workpiece based on the detection time until the measurement light is detected by the detection unit, the error tends to increase as the distance from the workpiece increases.

[0017] Therefore, the first distance and the second distance are calculated at a first height position and a second height position which have different distances from the workpiece, respectively, and the distance from the workpiece is estimated based on, for example, the actual movement amount of the laser head and the amount of change in the first distance and the second distance.

[0018] A fourth invention is a laser processing apparatus of any one of the first to third inventions, which is provided with a memory unit that stores a table showing the relationship between the material of the workpiece, the detection time, and the distance between the laser head and the workpiece.

[0019] In the fourth invention, a table showing the relationship between the material of the workpiece, the detection time, and the distance is stored in the storage unit. Specifically, the reflectance of the measurement light varies depending on the material of the workpiece. Therefore, even if the distance between the laser head and the workpiece is the same, the detection time and the distance calculated based on the detection time will differ depending on the material of the workpiece.

[0020] Therefore, by reading a table from the memory unit according to the material of the workpiece to be processed and calculating the distance from the detection time according to the material of the workpiece, the distance between the laser head and the workpiece can be determined more accurately.

[0021] A fifth invention is a laser processing apparatus according to any one of the first to third inventions, comprising a robot that changes the position of the laser head relative to the workpiece, a teaching pendant that operates the robot, and a display unit provided on the laser head, and information indicating the distance calculated by the calculation unit is displayed on at least one of the display unit and an operation screen of the teaching pendant.

[0022] In the fifth invention, information indicating the distance to the workpiece is displayed on at least one of the display unit provided on the laser head and the operation screen of the teaching pendant, making it easier for the operator to perform teaching operations while visually grasping the distance to the workpiece.

[0023] A sixth invention is a laser processing apparatus according to any one of the first to third inventions, which is provided with a robot that changes the position of the laser head relative to the workpiece, wherein the robot moves the laser head horizontally, the detection unit detects the measurement light at multiple positions on the workpiece while the laser head is moving horizontally, and the calculation unit calculates multiple distances between the laser head and the workpiece at the multiple positions.

[0024] In the sixth aspect of the present invention, the inclination of the workpiece can be detected by calculating a plurality of distances at a plurality of positions on the workpiece while moving the laser head in the horizontal direction.

[0025] Specifically, when the workpiece is tilted, the distance between the workpiece and the laser head moved horizontally will be different at different positions in the horizontal direction, so the tilt and tilt angle of the workpiece can be estimated based on the amount of change between the horizontal position on the workpiece and the distance calculated at that position.

[0026] A seventh invention is a laser processing apparatus according to any one of the first to third inventions, wherein the detection unit is detachably provided from the laser head, and is attached to the laser head when the measurement light is emitted, and is detached from the laser head when the laser light is emitted.

[0027] In the seventh invention, if the detection unit is attached to the laser head during laser oscillation, the receiving unit of the detection unit may be damaged by heat due to the reflected light of the laser light for processing. Furthermore, the detection unit may be configured to be removed from the optical path while being attached inside the laser head, but this configuration still leaves a risk that the detection unit may be moved into the optical path of the laser light during laser processing.

[0028] In contrast, when the configuration of the present invention is applied, the detection unit can be attached during teaching and removed during laser processing. This prevents the detection unit from being damaged by reflected laser light, and the life of the detection unit can be maintained in a highly reliable state for a long time. This makes the detection value of the detection unit more reliable.

[0029] The eighth invention is a laser processing method comprising the steps of: emitting measurement light having a different wavelength from the laser light used for processing from a laser head to a workpiece along the emission direction of the laser light; detecting the measurement light reflected from the workpiece by a detection unit provided in the laser head; and calculating the distance between the laser head and the workpiece based on the detection time taken for the measurement light emitted from the laser head to be detected by the detection unit.

[0030] In the eighth invention, the measurement light used to measure the distance between the laser head and the workpiece is emitted along the emission direction of the laser light for processing, thereby suppressing problems that occur when the measurement light is emitted to the workpiece from an angle other than the optical axis of the laser light. Effect of the Invention

[0031] According to the present invention, it is possible to easily measure the distance between the laser head and the workpiece. [Brief description of the drawings]

[0032] [Figure 1] 1 is a diagram showing an overall configuration of a laser processing apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a side view showing the configuration of a laser head. [Diagram 3] 1 is a side view showing a state in which a workpiece holding portion is attached to a laser head. FIG. [Figure 4] FIG. 11 is a flowchart showing a procedure for calculating the distance between the laser head and the workpiece. [Diagram 5] 4 is a side view showing the configuration of a display unit provided on the laser head. FIG. [Figure 6] FIG. 4 is a side view illustrating a first height position and a second height position. [Figure 7] FIG. 13 is a diagram showing the relationship between the distance between a laser head and a workpiece and the material of the workpiece. [Figure 8] FIG. 11 is a side view illustrating detection of inclination of a workpiece. [Figure 9]11 is a side view of a conventional example in which measurement light is emitted to a workpiece from an angle different from the optical axis of the laser light. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses.

[0034] As shown in FIG. 1, the laser processing apparatus 1 includes a laser oscillator 2, an optical fiber 3, a robot 5, a control unit 10, a teaching pendant 15, and a laser head 20.

[0035] The laser oscillator 2 receives power supply from a power source (not shown) and oscillates a laser light L and a measurement light S. During laser processing, the laser light L is emitted to the workpiece W in order to laser process the workpiece W. The wavelength of the laser light L is, for example, 970 to 1070 nm.

[0036] The measurement light S has a different wavelength from the laser light L. The wavelength of the measurement light S is, for example, 650 nm. The measurement light S is emitted to the workpiece W in order to measure the distance between the laser head 20 and the workpiece W during a teaching operation.

[0037] The optical fiber 3 transmits the laser light L oscillated by the laser oscillator 2 or the measurement light S to the laser head 20 .

[0038] The laser head 20 is attached to the tip of the robot 5. The laser head 20 emits laser light L to the workpiece W.

[0039] The robot 5 receives a signal from the control unit 10 based on a teaching program and moves the laser head 20 to trace a predetermined trajectory. The robot 5 controls the position of the laser head 20 so that the distance between the tip of the laser head 20 and the workpiece W becomes a predetermined target distance during laser processing.

[0040] The control unit 10 controls the output of the laser oscillator 2. The control unit 10 controls the power supplied from the power source, the temperature of the laser oscillator 2, and the like, so that the laser light L and the measurement light S are emitted with desired intensities.

[0041] The control unit 10 controls the operation of the robot 5. Based on a teaching program or the like, the control unit 10 outputs signals to drive or stop the joint axes of the robot 5 so that the tip of the robot 5, that is, the tip of the laser head 20, draws a predetermined trajectory.

[0042] The control unit 10 supplies the robot 5 with a signal for controlling the position of the laser head 20, specifically, the position of the robot 5, so that the distance between the tip of the laser head 20 and the workpiece W becomes a target distance.

[0043] The control unit 10 includes a calculation unit 11 and a storage unit 13. The calculation unit 11 calculates a distance H between the laser head 20 and the workpiece W based on the measurement light S reflected by the workpiece W. The calculation unit 11 will be described later.

[0044] The memory unit 13 stores a teaching program. The teaching program is created by an operator using the teaching pendant 15 to perform a teaching operation of moving the laser head 20 along the processing direction of the workpiece W. The teaching pendant 15 is provided with an operation screen 15a.

[0045] The memory unit 13 stores a table showing the relationship between the material of the workpiece W, the detection time until the measurement light S emitted from the laser head 20 is detected by the detection unit 25 described later, and the distance H between the laser head 20 and the workpiece W.

[0046] Laser head configuration 2, the laser head 20 has a collimator lens 21, a focus lens 22, a protective glass 23, and a detection unit 25. The laser head 20 is configured to be able to emit measurement light S having a different wavelength from the laser light L along the emission direction of the laser light L.

[0047] The collimator lens 21 collimates the laser light L or the measurement light S emitted from the emission end of the optical fiber 3 .

[0048] The focus lens 22 focuses the laser light L or the measurement light S collimated by the collimator lens 21. The laser light L or the measurement light S focused by the focus lens 22 passes through a protective glass 23 and is emitted to the workpiece W.

[0049] The protective glass 23 is disposed downstream in the emission direction from the focus lens 22. The protective glass 23 protects the focus lens 22 so that fumes and spatters generated during laser processing of the workpiece W do not adhere to the focus lens 22.

[0050] The detection unit 25 is provided at the emission end of the laser head 20. The detection unit 25 detects the measurement light S reflected by the workpiece W. The detection unit 25 is composed of, for example, a photodiode. Here, since the measurement light S reflected by the workpiece W is diffused, it is preferable to arrange at least one or more photodiodes constituting the detection unit 25. When there are multiple photodiodes, it is preferable to arrange multiple photodiodes at intervals in the circumferential direction around the optical axis of the laser head 20, for example.

[0051] When laser processing the workpiece W, the laser head 20 emits a laser beam L to the workpiece W. When performing a teaching operation to measure a distance H to the workpiece W, the laser head 20 emits a measurement beam S to the workpiece W.

[0052] 1 calculates the distance H between the laser head 20 and the workpiece W based on the detection time until the measurement light S emitted from the laser head 20 is detected by the detection unit 25. In other words, the longer the distance H between the laser head 20 and the workpiece W, the longer the detection time.

[0053] <About creating tables> Incidentally, the reflectance of the measurement light S differs depending on the material of the workpiece W. For this reason, for example, in a workpiece W made of a material with high reflectance, the detection time until the measurement light S is detected by the detection unit 25 tends to be short, whereas in a workpiece W made of a material with low reflectance, the detection time until the measurement light S is detected by the detection unit 25 tends to be long.

[0054] In other words, the longer the detection time until the measurement light S is detected by the detection unit 25, the greater the calculated distance H between the laser head 20 and the workpiece W becomes, and the greater the error from the actual distance H becomes.

[0055] Below, we will consider the case where the distance between the laser head 20 and the workpiece W is 201 mm. Below, the average value obtained by measuring 20 times using a laser distance meter is shown.

[0056] For example, when the material of the workpiece W is SPCC, the measured value of distance H is 201 mm. When the material of the workpiece W is SUS304, the measured value of distance H is 203.1 mm. When the material of the workpiece W is A5052, the measured value of distance H is 202.05 mm. When the material of the workpiece W is ceramic, the measured value of distance H is 203.25 mm. When the material of the workpiece W is brass, the measured value of distance H is 207.8 mm. When the material of the workpiece W is copper, the measured value of distance H is 213.2 mm.

[0057] Therefore, in this embodiment, a table showing the relationship between the material of the workpiece W, the detection time, and the distance H between the laser head 20 and the workpiece W is created in advance, and the table can be read out from the memory unit 13 depending on the material of the workpiece W to be processed.

[0058] 3, a workpiece holder 30 is detachably provided on the laser head 20. The workpiece holder 30 holds the workpiece W at a position spaced a predetermined distance from the emission end of the laser head 20.

[0059] The workpiece holding unit 30 has a pedestal unit 31 and a support unit 32. The workpiece W is placed on the pedestal unit 31. The pedestal unit 31 is supported by the support unit 32. The support unit 32 is set to a length such that the surface of the workpiece W and the focal position of the measurement light S coincide with each other.

[0060] The laser head 20 emits measurement light S to the workpiece W while the workpiece W is held by the workpiece holding unit 30. The measurement light S reflected by the workpiece W is detected by the detection unit 25. At this time, a distance H to the workpiece W is set in advance based on the dimensions of the support portion 32 of the workpiece holding unit 30. By detecting the measurement light S by the detection unit 25 while the distance H to the workpiece W is set in advance, it is possible to correlate the detection time until the measurement light S is detected by the detection unit 25 with the distance H between the laser head 20 and the workpiece W.

[0061] This makes it possible to create in advance a table showing the relationship between the material of the workpiece W, the detection time, and the distance H between the laser head 20 and the workpiece W. In addition, by replacing the workpiece W held in the workpiece holding unit 30 with a workpiece W made of a different material and emitting the measurement light S, a table can also be created for the workpiece W made of a different material.

[0062] Then, a table is read from the memory unit 13 according to the material of the workpiece W to be processed, and the distance H is calculated from the detection time according to the material of the workpiece W, thereby making it possible to more accurately grasp the distance H between the laser head 20 and the workpiece W.

[0063] Calculating the distance between the laser head and the workpiece As shown in FIG. 4, in step S11, a table corresponding to the material of the workpiece W is read from the storage unit 13, and the process proceeds to step S12.

[0064] In step S12, a teaching operation is performed, and the process proceeds to step S13. In the teaching operation, the distance from the emission end of the laser head 20 to the workpiece W is set in order to align the focal position of the laser light L with the surface of the workpiece W at multiple processing points on the workpiece W.

[0065] In step S13, a measurement light S having a wavelength different from that of the processing laser light L is emitted from the laser head 20 to the workpiece W along the emission direction of the laser light L, and the process proceeds to step S14.

[0066] In step S14, the detection unit 25 detects the measurement light S reflected by the workpiece W, and the process proceeds to step S15.

[0067] In step S15, the distance H between the laser head 20 and the workpiece W is calculated based on the detection time until the measurement light S emitted from the laser head 20 is detected by the detection unit 25, and the process proceeds to step S16. Specifically, the detection time tends to be longer as the distance H between the laser head 20 and the workpiece W increases.

[0068] In step S16, information indicating the distance H calculated by the calculation unit 11 is displayed, and the process ends.

[0069] Specifically, as shown in Fig. 5, the laser head 20 is provided with a display unit 28. The display unit 28 is provided at the emission end of the laser head 20. Information indicating the distance H is displayed on at least one of the display unit 28 and the operation screen 15a of the teaching pendant 15. This makes it easier for the operator to perform a teaching operation while visually grasping the distance H to the workpiece W.

[0070] Regarding errors in calculated distance However, when calculating the distance H between the laser head 20 and the workpiece W based on the detection time until the measurement light S is detected by the detection unit 25, the error tends to become larger as the distance H from the workpiece W increases.

[0071] Therefore, in this embodiment, it is possible to grasp the distance H between the laser head 20 and the workpiece W more accurately.

[0072] Specifically, as shown in FIG. 6, during the teaching operation, the laser head 20 is moved between a first height position facing the workpiece W and a second height position farther away from the workpiece W than the first height position.

[0073] At the first height position, the detection unit 25 detects the measurement light S. The calculation unit 11 calculates a first distance H1 between the laser head 20 and the workpiece W based on a first detection time until the measurement light S is detected by the detection unit 25.

[0074] At the second height position, the detection unit 25 detects the measurement light S. The calculation unit 11 calculates a second distance H2 between the laser head 20 and the workpiece W based on a second detection time until the measurement light S is detected by the detection unit 25.

[0075] Here, the actual movement amount of the laser head 20 can be accurately calculated based on the operation of the robot 5. Therefore, the distance from the workpiece W may be estimated based on the actual movement amount of the laser head 20 and the amount of change in the first distance H1 and the second distance H2.

[0076] In addition, the error in the calculated distance H caused by the distance H between the laser head 20 and the workpiece W becoming larger may be stored in advance in the memory unit 13 so that the error in the distance H can be corrected during the teaching operation.

[0077] 7, it can be seen that, depending on the material of the workpiece W, the error in the measured distance H tends to increase as the distance H between the laser head 20 and the workpiece W increases. Therefore, the error in the calculated distance H caused by the increase in the distance H between the laser head 20 and the workpiece W for each material of the workpiece W may be stored in advance in the storage unit 13.

[0078] <Detecting workpiece inclination> As shown in Fig. 8, during the teaching operation, the laser head 20 is moved in the horizontal direction. The detection unit 25 detects the measurement light S at each of a plurality of positions on the workpiece W (a first position P1 and a second position P2 in the example shown in Fig. 8) while the laser head 20 is moving in the horizontal direction.

[0079] The calculation unit 11 calculates a first distance H1 and a second distance H2 between the laser head 20 and the workpiece W at the first position P1 and the second position P2.

[0080] In this way, by calculating a plurality of distances at a plurality of positions on the workpiece W while moving the laser head 20 in the horizontal direction, the inclination of the workpiece W can be detected.

[0081] Specifically, when the workpiece W is tilted, the distance between the laser head 20 moved horizontally and the workpiece W is different at different positions in the horizontal direction. Therefore, the tilt and tilt angle θ of the workpiece W can be estimated based on the amount of change between the horizontal position on the workpiece W and the distance calculated at that position.

[0082] In this way, by estimating the inclination angle θ of the workpiece W, the laser head 20 can be positioned perpendicular to the workpiece W along the laser processing direction. Also, the position of the laser head 20 can be easily changed from the perpendicular position to any forward or backward angle with respect to the laser processing direction, improving the accuracy of the teaching operation.

[0083] Other Embodiments In this embodiment, the detection unit 25 may be provided so as to be detachable from the laser head 20. The detection unit 25 may be attached to the laser head 20 when the measurement light S is emitted, and may be detached from the laser head 20 when the laser light L is emitted.

[0084] Specifically, if the detection unit 25 is attached to the laser head 20 during laser oscillation, the receiving unit of the detection unit 25 may be damaged by heat due to the reflected light of the processing laser light L. Furthermore, the detection unit 25 may be configured to remove the detection system from the optical path while being attached inside the laser head 20, but this configuration leaves a risk that the detection unit 25 may be moved into the optical path of the laser light L during laser processing.

[0085] In contrast, when the configuration of this embodiment is applied, the detection unit 25 can be attached during teaching and removed during laser processing. This prevents the detection unit 25 from being damaged by the reflected light of the laser light L, and the life of the detection unit 25 can be maintained in a highly reliable state and over a long period of time. This makes the detection value of the detection unit 25 more reliable. [Industrial Applicability]

[0086] INDUSTRIAL APPLICABILITY As described above, the present invention provides the highly practical effect of being able to easily measure the distance between a laser head and a workpiece, and is therefore extremely useful and has high industrial applicability. [Explanation of symbols]

[0087] 1 Laser processing equipment 5. Robot 11 Arithmetic section 13 Storage section 15 Teaching Pendant 15a Operation screen 20 Laser Head 25 Detection unit 28 Display section 30 Work holding part H distance H1 1st distance H2 2nd distance L Laser light P1 1st position P2 2nd position S measurement light Double work

Claims

1. A laser processing apparatus including a laser head that emits a laser beam for processing a workpiece, the laser head is configured to be able to emit measurement light having a wavelength different from that of the laser light along an emission direction of the laser light, a detection unit provided in the laser head for detecting the measurement light reflected by the workpiece; A calculation unit that calculates a distance between the laser head and the workpiece based on a detection time until the measurement light emitted from the laser head is detected by the detection unit. Laser processing equipment.

2. 2. The laser processing apparatus according to claim 1, A workpiece holder is provided detachably on the laser head and holds the workpiece at a position a predetermined distance away from the emission end of the laser head. Laser processing equipment.

3. 2. The laser processing apparatus according to claim 1, a robot for changing a position of the laser head relative to the workpiece; The robot moves the laser head between a first height position facing the workpiece and a second height position farther away from the workpiece than the first height position, The detection unit detects the measurement light at the first height position and the second height position, The calculation unit calculates a first distance and a second distance between the laser head and the workpiece based on a first detection time and a second detection time until the measurement light is detected by the detection unit at the first height position and the second height position. Laser processing equipment.

4. In the laser processing apparatus according to any one of claims 1 to 3, A storage unit is provided for storing a table showing the relationship between the material of the workpiece, the detection time, and the distance between the laser head and the workpiece. Laser processing equipment.

5. In the laser processing apparatus according to any one of claims 1 to 3, a robot for changing a position of the laser head relative to the workpiece; A teaching pendant for operating the robot; A display unit provided on the laser head, Information indicating the distance calculated by the calculation unit is displayed on at least one of the display unit and the operation screen of the teaching pendant. Laser processing equipment.

6. In the laser processing apparatus according to any one of claims 1 to 3, a robot for changing a position of the laser head relative to the workpiece; The robot moves the laser head in a horizontal direction, The detection unit detects the measurement light at a plurality of positions on the workpiece while the laser head is moving in a horizontal direction, The calculation unit calculates a plurality of distances between the laser head and the workpiece at the plurality of positions. Laser processing equipment.

7. In the laser processing apparatus according to any one of claims 1 to 3, The detection unit is The laser head is detachably provided, When the measurement light is emitted, the laser head is attached to the measurement light. When the laser light is emitted, the laser head is removed. Laser processing equipment.

8. A step of emitting a measurement light having a wavelength different from that of a laser light for processing from a laser head to a workpiece along an emission direction of the laser light; detecting the measurement light reflected by the workpiece by a detection unit provided in the laser head; and calculating a distance between the laser head and the workpiece based on a detection time until the measurement light emitted from the laser head is detected by the detection unit. Laser processing method.

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