Laser measuring apparatus and laser processing system

Abstract

To provide one example of a laser measuring apparatus capable of accurately irradiating a measurement object part with measurement light.SOLUTION: A laser measuring apparatus 20 of a laser processing system 1 can execute scanning control of scanning measurement light so as to track processing light along the trajectory of the processing light. Thereby, the laser measuring apparatus 20 can accurately irradiate a key hole with the measurement light. A measurement control part 23 can execute filter processing of a processing content which is previously determined for a measurement value measured using surveying control. Thereby, even if metal in a molten state is corrugated, the laser measuring apparatus 20 can measure appropriate depth information.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a laser measurement device and a laser processing system including the laser measurement device.

Background Art

[0002] For example, in the invention described in Patent Document 1, measurement light transmitted through an optical waveguide is coaxially superimposed on a processing laser, focused into a keyhole, and then light reflected from the bottom of the keyhole is coupled into the optical waveguide to measure the depth of the keyhole.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to accurately measure a measurement target site such as the depth of a keyhole, it is necessary to accurately irradiate the measurement target site with measurement light. In view of this point, the present disclosure discloses an example of a laser measurement device capable of accurately irradiating a measurement target site with measurement light.

Means for Solving the Problems

[0005] A laser measurement device applied to a laser processing device that irradiates a processing object with laser light and measures a measurement target site generated on the backward side of the traveling direction of the laser light (hereinafter referred to as processing light) preferably includes at least one of the following constituent elements.

[0006] That is, the constituent elements include an emitting unit (21) that emits laser light (hereinafter referred to as measurement light) for measuring a measurement target site, a scanning unit (22) that scans the measurement light, and a control unit (23) that controls the operation of the scanning unit (22), where the control unit (23) is capable of performing "scanning control for scanning the measurement light so as to follow the processing light along the trajectory of the processing light", and a measurement unit (23) that measures using the reflected measurement light.

[0007] That is, in the laser processing apparatus, the position of the measurement target site also changes along with the progress of the processing light. And in the laser measurement apparatus, since "scanning control for scanning the measurement light so as to follow the processing light along the trajectory of the processing light" is executable, it may be possible to accurately irradiate the measurement light to the measurement target site.

[0008] Note that the laser measurement apparatus preferably includes an information acquisition unit (23A) that acquires at least "information indicating the position of the processing point by the processing light" from the laser processing apparatus, and performs scanning control using the position information of the processing point acquired by the information acquisition unit (23A).

[0009] Incidentally, the reference numerals in each of the above parentheses are an example showing the correspondence with the specific configuration and the like described in the embodiments to be described later, and the present disclosure is not limited to the specific configuration and the like indicated by the reference numerals in the above parentheses.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

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Modes for Carrying Out the Invention

[0011] The following "Embodiments of the Invention" show an example of embodiments belonging to the technical scope of the present disclosure. That is, the invention-specific matters described in the claims are not limited to the specific configurations, structures, etc. shown in the following embodiments.

[0012] Unless otherwise stated, at least one member or part described with a reference sign is provided at least one. The laser processing system shown in the present disclosure includes at least one of the components such as members or parts described with a reference sign and the structural parts shown in the drawings.

[0013] (First Embodiment) <1. Outline of Laser Processing System> This embodiment is an example in which the laser measurement device according to the present disclosure is incorporated into a laser processing system. As shown in FIG. 1, the laser processing system 1 includes at least a laser processing device 10 and a laser measurement device 20.

[0014] The laser processing device 10 is a device that processes a workpiece, which is an object to be processed, by irradiating the workpiece with laser light (hereinafter referred to as processing light). Note that the processing is, for example, processing using the thermal energy of laser light such as welding or cutting.

[0015] The laser processing device 10 has at least a laser oscillator 11, a processing head 12, and a processing head control unit 13. The laser oscillator 11 generates processing light having a predetermined wavelength and output, and outputs it to the processing head 12.

[0016] The processing head 12 is an example of a processing light scanning unit, and irradiates the workpiece while scanning the processing light. The processing head control unit 13 is an example of a processing light control unit, and controls the operation of the processing head 12. That is, the scanning of the processing light is controlled by the processing head control unit 13.

[0017] Note that the processing head 12 according to the present embodiment is displaceably supported by a robot arm (not shown). The operation of the robot arm is controlled by a robot control unit 14.

[0018] Therefore, the position of the processing point of the laser processing apparatus 10 according to the present embodiment is determined by the sum of the movement amount of the processing head 12 by the robot arm and the scanning amount of the processing light by the processing head 12. The processing point is the focusing point (focus) of the processing light emitted from the laser oscillator 11.

[0019] The processing head control unit 13, the robot control unit 14, and the laser oscillator 11 can communicate with each other. Incidentally, the processing head control unit 13 scans the processing head 12, that is, the processing light, according to the scanning program specified by the robot control unit 14.

[0020] Note that each of the processing head control unit 13 and the robot control unit 14 is configured by a computer having an arithmetic unit such as a CPU, a ROM, a RAM, etc. Each of the processing head control unit 13 and the robot control unit 14 controls the processing head 12 and the robot arm according to a program stored in advance in a non-volatile storage unit.

[0021] The laser measuring device 20 measures a specific part of the workpiece (hereinafter referred to as the measurement target part). Note that the measurement target part according to the present embodiment measures the depth of a part (specifically, a keyhole) generated on the backward side in the traveling direction of the processing light with respect to the processing point.

[0022] The laser measuring device 20 according to the present embodiment measures the depth of the keyhole by irradiating the measurement target part (the bottom of the keyhole in the present embodiment) with a laser beam having a wavelength different from that of the processing light (hereinafter referred to as the measurement light). Note that in the present embodiment, the wavelength of the measurement light is longer than the wavelength of the processing light.

[0023] The laser measurement device 20 divides the chirped pulsed light into reference light and measurement light that are directed toward the reference mirror, and measures the measurement target site by using the interference light generated when the reference light reflected by the reference mirror and the measurement light reflected by the measurement target site are combined.

[0024] <2. Details of the Laser Measurement Device> <2.1 Configuration of the Laser Measurement Device> The laser measurement device 20 has a configuration similar to that of the measurement device described in, for example, Japanese Patent No. 7300165. Specifically, the laser measurement device 20 includes at least an interference optical unit 21, a measurement light scanning unit 22, and a measurement control unit 23.

[0025] The interference optical unit 21 has an emission unit that emits laser light for measuring the measurement target site, that is, measurement light, and outputs a signal indicating the interference light between the reference light and the measurement light (hereinafter referred to as an interference signal) to the measurement control unit 23.

[0026] The measurement light scanning unit 22 is an example of a scanning unit that scans the measurement light. The measurement light scanning unit 22 according to the present embodiment includes a galvanometer scanner and a dichroic mirror. The measurement light scanned by the galvanometer scanner is irradiated onto the keyhole through the dichroic mirror.

[0027] The measurement control unit 23 also serves as a measurement unit that controls the mirror scanning angle of the measurement light scanning unit, that is, the galvanometer scanner, and calculates the depth of the keyhole by using the interference signal. The measurement control unit 23 is configured by a computer having an arithmetic unit, a ROM, a RAM, and the like.

[0028] Then, the measurement control unit 23 executes control of the mirror scanning angle and calculation of the depth of the keyhole according to a program stored in advance in the non-volatile storage unit. An interface unit 23A is provided in the measurement control unit 23.

[0029] The interface unit 23A is an example of an information acquisition unit for communicating between the laser oscillator 11, the processing head control unit 13, and the robot control unit 14. Then, the measurement control unit 23 acquires "information indicating the position of the processing point" from the laser processing apparatus 10 through the communication.

[0030] The "information indicating the position of the processing point" is coordinate data indicating the processing point (hereinafter referred to as processing point coordinates). That is, the measurement control unit 23 acquires the processing point coordinates using the control information of the processing head control unit 13 and the robot control unit 14.

[0031] In addition to the processing point coordinates, the measurement control unit 23 can also acquire information on the moving speed of the processing point, the incident angle of the processing light, and the intensity of the processing light (output of the processing light). Note that the measurement control unit 23 acquires the moving speed of the processing point based on the differential value of the processing point coordinates.

[0032] The measurement control unit 23 can transmit the calculated depth of the keyhole (hereinafter referred to as depth information) to at least the processing head control unit 13 and the robot control unit 14 via the interface unit 23A.

[0033] Thereby, the processing head control unit 13 and the robot control unit 14 can adjust the moving speed of the processing point and the incident angle of the processing light, etc., using the depth information. Note that the measurement control unit 23 according to the present embodiment issues a command to output the processing light of the determined output to the laser oscillator 11 after determining the output of the processing light using the depth information.

[0034] <2.2 Control of Measurement Light Scanning Unit (Galvanometer Scanner)> The measurement control unit 23 controls the measurement light scanning unit 22 by scanning control and exploration control. The scanning control is a control for scanning the measurement light so as to follow the processing point along the trajectory of the processing light, as shown in FIG. 2.

[0035] The "trajectory of the processing light (hereinafter referred to as the processing trajectory)" refers to the trajectory drawn by the processing point projected onto a virtual plane perpendicular to the processing light. Note that "perpendicular to the processing light" means that the virtual plane is macroscopically perpendicular to the linear processing light.

[0036] And "tracking the processing point" ideally means that the trajectory of the measurement light (hereinafter referred to as the measurement trajectory) projected onto the virtual plane overlaps with the processing trajectory. At this time, the leading part of the measurement trajectory is located on the retreat side of the advancing direction of the leading part of the processing trajectory.

[0037] The measurement trajectory refers to the trajectory drawn by the measurement point projected onto the virtual plane. The measurement point is the part of the workpiece (in this case, the keyhole) where the emitted measurement light hits. As is also clear from FIG. 2, the depth position of the measurement point and the depth position of the processing point do not necessarily coincide.

[0038] The distance between the leading part of the measurement trajectory and the leading part of the processing trajectory is determined by the moving speed of the processing point, the incident angle of the processing light, the intensity of the processing light, the material of the workpiece (welding target), etc. Note that FIG. 2 is an example in which two plate materials are stacked one on top of the other and welded. In this example, it is desirable that the above interval be determined in consideration of the thickness dimension of the upper plate.

[0039] Then, the measurement control unit 23 always acquires the changing processing point coordinates according to a predetermined sampling frequency, determines the position a predetermined distance or a predetermined time behind the processing point as the keyhole position, and then controls the measurement light scanning unit 22 so that the measurement light is irradiated to the determined keyhole position.

[0040] Note that the sampling frequency when acquiring the processing point coordinates, determining the keyhole position, and scanning the measurement light to the keyhole position is desirably a frequency higher than the control frequency of the laser processing apparatus 10.

[0041] Probe control is a control method in which, as shown in Fig. 3, during the execution of scanning control, the measurement point vibrates with respect to the machining locus, and the center of the vibration moves along the machining locus. That is, in probe control, the measurement point periodically moves back and forth between one side (the upper side of the machining locus in Fig. 3) and the other side (the lower side of the machining locus in Fig. 3) across the machining locus with the machining locus as the center, and the center moves along the machining locus so as to follow the machining point.

[0042] In the probe control shown in Fig. 3, the measurement point vibrates in the shape of the number "8". In this example, the point where the trajectories of the measurement light intersect (the intersection of the "8" character) is the center of the vibration, and the center moves along the machining locus.

[0043] Incidentally, the vibration frequency of the measurement point is set to 5 kHz or more, the vibration amplitude is about several hundred μm, and the sampling frequency of the laser measuring device 20 is preferably around 10 MHz. Then, the measurement control unit 23 according to the present embodiment executes a filter process with a predetermined process content on the measured measurement value, and outputs the value after the filter process as a measurement value (depth information).

[0044] The predetermined process content is, for example, a process in which, among a large number of measured measurement values (see Fig. 4B), the value with the largest depth is used as a reference value, only the measurement positions within a predetermined range from the reference value are extracted, and the average value of the extracted large number of measurement values (see Fig. 4A) is used as the measurement value (depth information).

[0045] This is because the metal existing in the keyhole becomes molten liquid metal, and the liquid metal is in a wavy state, so the measurement point is displaced. In the present embodiment, appropriate depth information can be obtained by using the average value of a large number of extracted measurement values as the measurement value.

[0046] <3. Features of the laser processing system (particularly, the laser measuring device) according to the present embodiment> The laser measurement device 20 according to this embodiment is capable of executing "scanning control for scanning measurement light so as to follow the processing light along the trajectory of the processing light". Therefore, in the laser measurement device 20, regardless of whether the traveling direction of the processing point is linear or curved, it may always be possible to accurately irradiate the keyhole with the measurement light.

[0047] Since the measurement control unit 23 executes scanning control using the moving speed of the processing point, the incident angle of the processing light, and the intensity of the processing light, the laser measurement device 20 may be able to irradiate the keyhole with the measurement light more accurately.

[0048] That is, when any one of the moving speed of the processing point, the incident angle of the processing light, and the intensity of the processing light changes, the relative positional relationship between the processing point and the keyhole may change. In particular, due to the difference in wavelength between the processing light and the measurement light, when the incident angle of the processing light changes, there is a possibility that the relative positional relationship may change significantly.

[0049] On the other hand, in this embodiment, since scanning control is executed using the moving speed of the processing point, the incident angle of the processing light, and the intensity of the processing light, the laser measurement device 20 may be able to absorb changes in the relative positional relationship between the processing point and the keyhole.

[0050] The measurement control unit 23 is capable of performing filter processing with predetermined processing content on the measurement values measured using exploration control. Thereby, even when the molten metal is in a wavy state, the laser measurement device 20 may be able to measure appropriate depth information.

[0051] By the way, in this embodiment, since statistical processing (average processing in this embodiment) is performed on a large number of extracted measurement values, the more the number of extracted measurement values, the more possible it is to obtain appropriate depth information.

[0052] In contrast, the laser measurement device 20 according to the present embodiment measures chirped pulsed light using reference light and measurement light directed toward a reference mirror, so that it is possible to obtain more measurement positions in a shorter time than other types of laser measurement devices. Therefore, it is possible to reliably obtain appropriate depth information.

[0053] (Second Embodiment) The laser processing system according to the above-described embodiment was an on-the-fly control capable of moving the processing head 12 with a robot arm. In contrast, the laser processing system according to the present embodiment is an example applied to a laser processing system including a jig control unit 14A that disables the robot arm and displaces the workpiece in the X and Y directions.

[0054] Also in the present embodiment, the measurement control unit 23 controls the measurement light scanning unit 22 by scanning control and search control. Note that the same components as those in the above-described embodiment are denoted by the same reference numerals. Therefore, in the present embodiment, redundant descriptions are omitted.

[0055] (Other Embodiments) The laser processing apparatus 10 in the above-described embodiment was a welding apparatus or a cutting apparatus that uses laser light as processing light. However, the present disclosure is not limited to this. That is, the present disclosure is applicable to, for example, metal additive manufacturing, laser ablation, laser brazing, laser arc hybrid welding, or laser dicing of a silicon wafer.

[0056] In the search control according to the above-described embodiment, an example was given in which the measurement point vibrates so as to draw the number “8”. However, the present disclosure is not limited to this. That is, the present disclosure may be, for example, search control in which the measurement point vibrates so as to draw a circle or an ellipse.

[0057] In the above-described embodiment, the exploration control was also executed during the execution of the scanning control. However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that, for example, the exploration control is abolished.

[0058] The laser measurement device according to the above-described embodiment was a laser measurement device that measures a measurement target site generated on the backward side in the traveling direction of the processing light. However, the present disclosure is not limited to this. That is, the present disclosure is also applicable to, for example, a laser measurement device that measures a measurement target site generated on the forward side in the traveling direction of the processing light. Thereby, it becomes possible to inspect the workpiece surface before processing in front of the processing point.

[0059] When measuring a measurement target site generated on the forward side in the traveling direction of the processing light, a process (processing point estimation process) for estimating the position of the processing point at a predetermined distance or a predetermined time ahead from the processing point using the processing point coordinates is required.

[0060] The laser measurement device according to the above-described embodiment was a method of measuring chirped pulsed light using reference light and measurement light directed toward a reference mirror. However, the present disclosure is not limited to this. That is, the present disclosure may be, for example, a measurement device that uses the difference between the emission time and the reception time of the measurement light without using the interference of the measurement light with the reference light.

[0061] In the above-described embodiment, the configuration was to acquire "information indicating the position of the processing point by the processing light" from the laser processing device. However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that, for example, the laser processing device 10 and the measurement control unit 23 share information regarding the processing point coordinates.

[0062] With such a configuration, it is not necessary for the measurement control unit 23 to acquire the processing point coordinates from the laser processing device. Even with such a configuration, the measurement control unit 23 may be configured to acquire the actual processing point coordinates from the laser processing device.

[0063] In FIG. 3 of the above-described embodiment, the machining locus was depicted as a straight line. However, the present disclosure is not limited to this. That is, the present disclosure can irradiate the measurement light at an appropriate position even when, for example, the machining locus is curved.

[0064] The filter process according to the above-described embodiment was a process of using the average value of a large number of extracted measurement values as the measurement value (depth information). However, the present disclosure is not limited to this. That is, the present disclosure may be, for example, a process of using a statistical processing value other than the average value (for example, the maximum value) as the measurement value.

[0065] In the laser processing system according to the above-described embodiment, each of the laser processing apparatus 10 and the laser measurement apparatus 20 had a control unit. However, the present disclosure is not limited to this. That is, the present disclosure may have a configuration including an integrated control unit that integrally controls the laser processing apparatus 10 and the laser measurement apparatus 20, for example.

[0066] Therefore, in the integrated control unit, while controlling the laser processing apparatus 10 according to a predetermined program, the operation of the laser processing apparatus 10 can be finely adjusted as appropriate using the detection result of the laser measurement apparatus 20.

[0067] In the above-described embodiment, the wavelength of the measurement light was longer than the wavelength of the processing light. However, the present disclosure is not limited to this. That is, the present disclosure may have a configuration in which, for example, the wavelength of the measurement light is shorter than the wavelength of the processing light. In a configuration in which the measurement light is irradiated to the keyhole without passing through a dichroic mirror, the wavelength of the measurement light and the wavelength of the processing light may be the same.

[0068] Furthermore, the present disclosure only needs to conform to the gist of the disclosure described in the above-described embodiment and is not limited to the above-described embodiment. Therefore, a configuration in which at least two of the above-described multiple embodiments are combined, or a configuration in which any one of the configuration elements shown in the drawings or the configuration elements described with reference numerals in the above-described embodiment is abolished may also be acceptable.

Explanation of Reference Numerals

[0069] 1… Laser processing system 10… Laser processing apparatus 11… Laser oscillator 12… Processing head 13… Processing head control unit 14… Robot control unit 20… Laser measuring device 21… Interferometric optical unit 22… Measurement light scanning unit 23… Measurement control unit 23A… Interface unit

Claims

1. A laser measurement device applied to a laser processing device that irradiates a workpiece with a laser beam, and measures a measurement target site generated on the backward side in the traveling direction of the laser beam (hereinafter referred to as the processing beam). In the laser measurement device, an emitting unit that emits a laser beam (hereinafter referred to as the measurement beam) for measuring the measurement target site; a scanning unit that scans the measurement beam; a control unit that controls the operation of the scanning unit, and is capable of executing "scanning control for scanning the measurement beam so as to follow the processing beam along the trajectory of the processing beam"; a measurement unit that measures using the reflected measurement beam A laser measurement device comprising.

2. An information acquisition unit that acquires at least "information indicating the position of the processing point by the processing beam" from the laser processing device is provided, The laser measurement device according to claim 1, wherein the control unit executes the scanning control using the position information of the processing point acquired by the information acquisition unit.

3. The information acquisition unit can also acquire at least one piece of information among the moving speed of the processing point, the incident angle of the processing beam, and the intensity of the processing beam, Furthermore, the laser measurement device according to claim 2, wherein the control unit executes the scanning control using at least one piece of information among the moving speed of the processing point, the incident angle of the processing beam, and the intensity of the processing beam.

4. The control unit is capable of executing "search control for scanning such that the center of the vibration moves along the trajectory of the processing beam while the measurement beam vibrates with respect to the trajectory of the processing beam during the execution of the scanning control", Furthermore, the laser measurement device according to any one of claims 1 to 3, wherein the measurement unit is capable of performing a filter process with a predetermined process content on the measured measurement value.

5. The laser measurement device according to claim 4, wherein the measurement unit splits the chirped pulse light into reference light and measurement light directed toward a reference mirror, and measures using the reference light and the measurement light.

6. In a laser measurement device applied to a laser processing device that irradiates a workpiece with a laser beam (hereinafter referred to as the processing beam), an emitting unit that emits a laser beam (hereinafter referred to as the measurement beam) for measuring the measurement target site; a scanning unit that scans the measurement beam; an information acquisition unit that acquires at least "information indicating the position of the processing point by the processing beam" from the laser processing device; a control unit that controls the operation of the scanning unit, and is capable of executing "scanning control for determining the position where the measurement beam is irradiated using the position information of the processing point acquired by the information acquisition unit". A measurement unit that measures using the reflected measurement light A laser measurement device comprising the same. **Claim 7** A laser processing device that irradiates a workpiece with laser light, and In a laser processing system comprising a laser measurement device that measures a measurement target site generated on the backward side in the traveling direction of the laser light (hereinafter referred to as processing light), The laser measurement device is An emitting unit that emits laser light (hereinafter referred to as measurement light) for measuring the measurement target site, A measurement light scanning unit that scans the measurement light, A measurement light control unit that controls the operation of the measurement light scanning unit, and the measurement light control unit is capable of executing "scanning control for scanning the measurement light so as to follow the processing light along the trajectory of the processing light", A measurement unit that measures using the reflected measurement light A laser processing system having the same. **Claim 8** A processing light scanning unit that scans the processing light, and A processing light control unit that controls the processing light scanning unit, and The laser processing system according to claim 7, wherein the measurement light control unit acquires position information of a processing point from the processing light control unit and executes the scanning control using the position information.

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