Laser processing device and laser processing method

Abstract

To enable soiling of a protection glass to be detected with a relatively simple structure.SOLUTION: A laser head 20 is provided with a protection glass 23. A detection part 25 detects measuring light S reflected by a workpiece W. A calculation part 11 calculates a distance between the laser head 20 and the workpiece W based on a detection time that elapses before the detection part 25 detects the measuring light S emitted from the laser head 20.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 head including a probe light generator that generates a probe light, an optical fiber that guides the generated probe light to a fiber collimator, and a light detection element that detects the light intensity of the light that is irradiated from the fiber collimator and transmitted through a protective glass, thereby monitoring dirt, damage, etc., of the protective glass provided in the laser processing head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-196029 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the invention of Patent Document 1, a probe light generator, an optical fiber, a fiber collimator, a light detection element, etc. are separately required to detect dirt on the protective glass, which results in a problem that the device configuration becomes complicated and the cost increases due to the increased number of parts.

[0005] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to make it possible to detect dirt on a protective glass with a relatively simple configuration. [Means for solving the problem]

[0006] A first invention is a laser processing apparatus having a laser head that emits a laser light for processing onto a workpiece, the laser head being configured to emit measurement light having a different wavelength from the laser light along the emission direction of the laser light, and comprising a protective glass provided on the laser head, 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.

[0007] In the first aspect of the present invention, dirt on the protective glass can be detected based on the distance between the laser head and the workpiece.

[0008] Specifically, when fumes and spatters generated during laser processing of a workpiece adhere to the protective glass, the protective glass becomes dirty. Then, the laser light reflected by the workpiece is irradiated onto the dirty portion, generating heat, which changes the transmittance of the protective glass. As a result, the distance between the workpiece and the protective glass calculated by the calculation unit tends to be larger than the distance between the workpiece and the protective glass calculated in advance when a protective glass in an initial state without dirt is used.

[0009] In this way, when the distance between the laser head and the workpiece becomes larger than the actual distance, it can be determined that the protective glass is dirty.

[0010] A second aspect of the present invention is the laser processing apparatus according to the first aspect of the present invention, wherein the detection unit is disposed upstream of the protective glass in the emission direction.

[0011] In the second aspect of the present invention, by arranging the detection unit upstream of the protective glass in the emission direction, it is possible to prevent fumes and sputters from adhering to the detection unit.

[0012] A third invention relates to the laser processing apparatus of the first invention, and further includes a first detection unit that is arranged downstream of the protective glass in the emission direction and detects the measurement light that is diffused when passing through the protective glass.

[0013] In the third aspect of the present invention, contamination on the protective glass can be detected by detecting the measurement light that is diffused when passing through the protective glass.

[0014] Specifically, if dirt is attached to the protective glass, the measurement light is more likely to diffuse when passing through the protective glass, and the amount of diffused measurement light detected by the first detection unit tends to increase.

[0015] In this way, when the amount of diffused measurement light detected by the first detection unit becomes greater than a predetermined threshold, it can be determined that the protective glass is dirty.

[0016] A fourth invention is the laser processing apparatus of any one of the first to third inventions, further comprising a determination unit that compares the distance calculated by the calculation unit with a predetermined threshold value to determine a state of the protective glass.

[0017] In the fourth aspect of the present invention, the state of the protective glass can be determined by comparing the distance calculated by the calculation unit with a predetermined threshold value.

[0018] Specifically, the distance between the workpiece and the protective glass, which is calculated in advance when the protective glass is in an acceptable state for ensuring laser processing quality, that is, when the protective glass is in a state in which there is a risk of laser processing defects occurring if it becomes any more dirty, is set as a predetermined threshold value.

[0019] If the distance to the workpiece calculated by the calculation unit is smaller than the threshold value, the protective glass is not particularly dirty, and the operator can determine that laser processing quality is ensured.

[0020] On the other hand, if dirt adheres to the protective glass during laser processing and the distance to the workpiece calculated by the calculation unit becomes greater than the threshold value, the operator can determine that the protective glass needs to be replaced.

[0021] A fifth aspect of the present invention is the laser processing apparatus according to the fourth aspect of the present invention, further comprising an alarm section that performs a predetermined alarm operation based on the determination result of the determination section.

[0022] In the fifth aspect of the present invention, a predetermined warning operation is performed, so that an operator can determine that replacement of the protective glass is necessary.

[0023] Here, the predetermined warning action may be, for example, displaying an error message on the display screen of the teaching pendant, indicating that the protective glass is dirty and needs to be replaced.

[0024] A sixth 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 with a detection unit, 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.

[0025] In the sixth aspect of the present invention, when the distance between the laser head and the workpiece becomes larger than the actual distance, it can be determined that the protective glass is contaminated. Effect of the Invention

[0026] According to the present invention, dirt on the protective glass can be detected with a relatively simple configuration. [Brief description of the drawings]

[0027] [Figure 1] 1 is a diagram showing an overall configuration of a laser processing device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a side cross-sectional view showing the configuration of a laser head. [Diagram 3] FIG. 11 is a flowchart showing a procedure for determining the state of the protective glass. [Figure 4] FIG. 11 is a side cross-sectional view showing the configuration of a laser head according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] 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.

[0029] First Embodiment As shown in FIG. 1, the laser processing device 1 includes a laser oscillator 2, an optical fiber 3, a robot 5, a control unit 10, a teaching pendant 15, a laser head 20, and an alarm unit 16.

[0030] 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.

[0031] 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.

[0032] 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 .

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The control unit 10 includes a calculation unit 11, a determination unit 12, and a storage unit 13. The calculation unit 11 calculates the distance 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.

[0039] The determination unit 12 compares the distance calculated by the calculation unit 11 with a predetermined threshold value to determine the state of the protective glass 23. The determination unit 12 will be described later.

[0040] 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.

[0041] 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 between the laser head 20 and the workpiece W.

[0042] The warning unit 16 performs a predetermined warning operation based on the judgment result of the judgment unit 12. Here, the predetermined warning operation may be, for example, displaying an error message on the display screen 15a of the teaching pendant 15, indicating that the protective glass 23 is dirty and needs to be replaced. This allows the operator to determine that the protective glass 23 needs to be replaced.

[0043] 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.

[0044] The collimator lens 21 collimates the laser light L or the measurement light S emitted from the emission end of the optical fiber 3 .

[0045] 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.

[0046] 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.

[0047] The detection unit 25 is disposed upstream of the protective glass 23 in the emission direction. In the example shown in FIG. 2, the detection unit 25 is disposed between the focus lens 22 and the protective glass 23. The detection unit 25 detects the measurement light S reflected by the workpiece W. The detection unit 25 is configured with, for example, a photodiode. In this manner, by disposing the detection unit 25 upstream of the protective glass 23 in the emission direction, it is possible to prevent fumes and spatters from adhering to the detection unit 25.

[0048] Although only one detector 25 is provided in the example shown in FIG. 2, a plurality of detectors may be provided at intervals in the circumferential direction around the optical axis of the laser head 20, for example.

[0049] 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 the distance to the workpiece W, the laser head 20 emits a measurement beam S to the workpiece W.

[0050] 1 calculates the distance 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 greater the distance between the laser head 20 and the workpiece W, the longer the detection time.

[0051] <Determining the condition of protective glass> When fumes and spatters generated during laser processing of the workpiece W adhere to the protective glass 23, the protective glass 23 becomes dirty. Then, the measurement light S reflected by the workpiece W is irradiated onto the dirty portion, generating heat, which changes the transmittance of the protective glass 23. When the protective glass 23 becomes dirty, it becomes impossible to ensure laser processing quality, and therefore the protective glass 23 needs to be replaced.

[0052] Therefore, in this embodiment, it is possible to detect dirt on the protective glass 23 with a relatively simple configuration.

[0053] 3, first, in step S11, a teaching operation is performed, and then the process proceeds to step S12. 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 a plurality of processing points on the workpiece W.

[0054] In step S12, 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 S13.

[0055] In step S13, the measurement light S reflected by the workpiece W is detected by the detector 25 arranged upstream of the protective glass 23 of the laser head 20 in the emission direction, and the process proceeds to step S14.

[0056] In step S14, the distance 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 S15. Specifically, the detection time tends to become longer as the distance between the laser head 20 and the workpiece W increases.

[0057] In step S15, the determination unit 12 determines whether the distance calculated by the calculation unit 11 is greater than a predetermined threshold value, thereby determining the state of the protective glass 23.

[0058] Specifically, when dirt is attached to the protective glass 23, the distance between the workpiece W calculated by the calculation unit 11 tends to be greater than the distance between the workpiece W and the protective glass 23 calculated in advance when using an initial state protective glass 23 with no dirt attached.

[0059] Therefore, the distance from the workpiece, which is calculated in advance when using protective glass 23 in an acceptable state for ensuring laser processing quality, that is, protective glass 23 in a state in which laser processing defects may occur if it becomes any more dirty, is set to a predetermined threshold value.

[0060] If the determination in step S15 is "YES", it is determined that the protective glass 23 is dirty due to the laser processing and therefore needs to be replaced, and the process branches to step S16. If the determination in step S15 is "NO", it is determined that the protective glass 23 is not so dirty, and the process ends.

[0061] Since the reflectivity of the measurement light S varies depending on the material of the workpiece W, it is preferable to use a table stored in the memory unit 13 to calculate the distance between the emission end of the laser head 20 and the workpiece W based on the material of the workpiece W and the detection time.

[0062] In step S16, the alarm unit 16 performs a predetermined alarm operation, such as displaying an error message on the display screen 15a of the teaching pendant 15 indicating that the protective glass 23 needs to be replaced, and the process ends.

[0063] Second Embodiment Hereinafter, the same parts as those in the first embodiment will be denoted by the same reference numerals, and only the differences will be described.

[0064] As shown in FIG. 4, the laser head 20 includes a collimator lens 21, a focus lens 22, a protective glass 23, a first detector 31, and a second detector 32.

[0065] The first detection unit 31 is disposed downstream in the emission direction from the protective glass 23. The first detection unit 31 detects diffused light S' of the measurement light S that is diffused when passing through the protective glass 23. The first detection unit 31 is formed of, for example, a photodiode.

[0066] The second detection unit 32 is disposed downstream in the emission direction from the protective glass 23. The second detection unit 32 detects the measurement light S reflected by the workpiece W. The second detection unit 32 is configured with, for example, a photodiode.

[0067] In this manner, by detecting the diffused light S' of the measurement light S that is diffused when passing through the protective glass 23, dirt on the protective glass 23 can be detected.

[0068] Specifically, if dirt is attached to the protective glass 23, the measurement light S is more likely to diffuse when passing through the protective glass 23, and the amount of diffused light S' of the measurement light S detected by the first detection unit 31 tends to increase.

[0069] In this way, when the amount of the diffuse light S' of the measurement light S detected by the first detection unit 31 becomes greater than a predetermined threshold, it can be determined that the protective glass 23 is dirty.

[0070] Furthermore, as described in the first embodiment, the state of the protective glass 23 can be determined by calculating the distance 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 second detection unit 32. [Industrial Applicability]

[0071] INDUSTRIAL APPLICABILITY As described above, the present invention has a highly practical effect of being able to detect dirt on a protective glass with a relatively simple configuration, and is therefore extremely useful and has high industrial applicability. [Explanation of symbols]

[0072] 1 Laser processing equipment 11 Arithmetic section 12 Judgment section 16 Alarm section 20 Laser Head 23 Protective Glass 25 Detection unit 31 First detection unit 32 Second detection section L Laser light S measurement light S' Diffuse 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 protective glass provided on the laser head; A detection unit that detects 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, The detection unit is disposed upstream of the protective glass in the emission direction. Laser processing equipment.

3. 2. The laser processing apparatus according to claim 1, a first detection unit that is disposed downstream of the protective glass in the emission direction and detects the measurement light that is diffused when passing through the protective glass; Laser processing equipment.

4. In the laser processing apparatus according to any one of claims 1 to 3, A determination unit is provided that compares the distance calculated by the calculation unit with a predetermined threshold value to determine the state of the protective glass. Laser processing equipment.

5. 5. The laser processing apparatus according to claim 4, The device further includes an alarm unit that performs a predetermined alarm operation based on the determination result of the determination unit. Laser processing equipment.

6. 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 with a detection unit; 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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