Laser processing method and laser processing apparatus

Abstract

The present application provides a kind of laser processing method and laser processing device.Laser processing method, laser beam from oscillator is irradiated to the first component and is scanned on the first component in the first direction, and the first component and the second component adjacent to the first component are joined by melting part, laser processing method includes: in the first measurement area and the second measurement area different from the first measurement area, the intensity of any one of welding light including thermal radiation light, plasma light, reflected light radiated from at least one of the first component and the second component by the irradiation of laser beam is measured;And the step of evaluating the processing state based on the intensity of each welding light measured in the first measurement area and the second measurement area, the first measurement area and the second measurement area are arranged in the second direction intersecting the first direction.

Description

Technical Field

[0001] This disclosure relates to laser processing methods and laser processing apparatus. Background Technology

[0002] Previously, as a laser processing method, methods for performing laser welding and evaluating the welding status in real time were known. The welding status was evaluated based on the peak intensity of the welding light emitted from the molten part during laser welding, such as thermal radiation light, plasma light, or laser reflection light, or the integral value of the welding light intensity equivalent to the luminous energy.

[0003] For example, in Patent Document 1, a welding light measuring optical system mounted on a laser processing head is used to monitor laser processing based on the welding light emitted from the molten part during laser welding.

[0004] Furthermore, for example, in Patent Document 2, an optical fiber mounted on the laser processing head is used to transmit the welding light emitted from the molten part during laser welding, and a welding light measuring optical system mounted at its outlet is used to detect the laser welding status.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2018 / 185973

[0008] Patent Document 2: JP Patent No. 3184969 Summary of the Invention

[0009] One aspect of the laser processing method disclosed herein involves irradiating a first component with a laser beam emitted from an oscillator and scanning the first component in a first direction, thereby joining the first component and a second component adjacent to the first component through a molten section. The laser processing method includes: measuring the intensity of welding light, including any one of thermal radiation light, plasma light, or reflected light, radiated from at least one of the first and second components by the laser beam irradiation in a first measurement area and a second measurement area different from the first measurement area; and evaluating the processing state based on the intensity of each welding light measured in the first and second measurement areas, wherein the first and second measurement areas are arranged in a second direction intersecting the first direction.

[0010] One aspect of this disclosure discloses a laser processing apparatus that irradiates a first component with a laser beam and scans it in a first direction, joining the first component and a second component adjacent to the first component via a melting section. The laser processing apparatus includes: an oscillator that emits a laser beam; an irradiation optical system that guides the laser beam to the first component; a worktable that moves the first and second components relative to the laser beam, causing the laser beam to scan in the first direction; a measurement optical system that guides welding light, including thermal radiation light, plasma light, and reflected light, radiated from at least one of the first and second components by the laser beam irradiation from a first measurement area and a second measurement area different from the first measurement area, respectively; a first sensor that measures the intensity of the welding light guided from the first measurement area to the measurement optical system; a second sensor that measures the intensity of the welding light guided from the second measurement area to the measurement optical system; and a judgment unit that evaluates the processing state based on the intensity of each welding light measured in the first and second measurement areas, wherein the first and second measurement areas are arranged in a second direction intersecting the first direction. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a laser processing apparatus according to an embodiment of the present disclosure.

[0012] Figure 2A This is a magnified view of a portion of the laser processing equipment.

[0013] Figure 2B It is along Figure 2A A cross-sectional view along line AA in the diagram.

[0014] Figure 2C It is along Figure 2A A top view of the BB line.

[0015] Figure 3 This is a schematic diagram of the measuring section.

[0016] Figure 4A This is a cross-sectional view of the welding state during normal welding.

[0017] Figure 4B This is a cross-sectional view of the welding state during normal welding.

[0018] Figure 4C This is a cross-sectional view of the welding state during normal welding.

[0019] Figure 4D It is a graph showing the relationship between irradiation power and time during normal welding.

[0020] Figure 5A This is a photograph of the actual molten section.

[0021] Figure 5B This is a photograph of the actual molten section.

[0022] Figure 5C This is a photograph of the actual molten section.

[0023] Figure 5D This is a photograph of the actual molten section.

[0024] Figure 6 This is an explanatory diagram of the measurement area for measuring the thermal radiation of the comparative example.

[0025] Figure 7A This is an explanatory diagram of the signal intensity of thermal radiation light in a comparative example.

[0026] Figure 7B This is an explanatory diagram of the signal intensity of thermal radiation light in a comparative example.

[0027] Figure 7C This is an explanatory diagram of the signal intensity of thermal radiation light in a comparative example.

[0028] Figure 7D This is an explanatory diagram of the signal intensity of thermal radiation light in a comparative example.

[0029] Figure 8A This is a diagram illustrating the signal intensity of thermal radiation light.

[0030] Figure 8B This is a diagram illustrating the signal intensity of thermal radiation light.

[0031] Figure 8C This is a diagram illustrating the signal intensity of thermal radiation light.

[0032] Figure 8D This is a diagram illustrating the signal intensity of thermal radiation light.

[0033] Figure 9A This is a diagram illustrating the signal intensity of thermal radiation light.

[0034] Figure 9B This is a diagram illustrating the signal intensity of thermal radiation light.

[0035] Figure 9C This is a diagram illustrating the signal intensity of thermal radiation light.

[0036] Figure 9D This is a diagram illustrating the signal intensity of thermal radiation light.

[0037] Figure 10A This is a diagram illustrating the signal intensity of thermal radiation light.

[0038] Figure 10B This is a diagram illustrating the signal intensity of thermal radiation light.

[0039] Figure 10CThis is a diagram illustrating the signal intensity of thermal radiation light.

[0040] Figure 10D This is a diagram illustrating the signal intensity of thermal radiation light.

[0041] Figure 11A This is a diagram illustrating the signal intensity of thermal radiation light.

[0042] Figure 11B This is a diagram illustrating the signal intensity of thermal radiation light.

[0043] Figure 11C This is a diagram illustrating the signal intensity of thermal radiation light.

[0044] Figure 11D This is a diagram illustrating the signal intensity of thermal radiation light.

[0045] Figure 12A This is a diagram illustrating the signal intensity of thermal radiation light.

[0046] Figure 12B This is a diagram illustrating the signal intensity of thermal radiation light.

[0047] Figure 12C This is a diagram illustrating the signal intensity of thermal radiation light.

[0048] Figure 12D This is a diagram illustrating the signal intensity of thermal radiation light.

[0049] Figure 13A This is a diagram illustrating the signal intensity of thermal radiation light.

[0050] Figure 13B This is a diagram illustrating the signal intensity of thermal radiation light.

[0051] Figure 13C This is a diagram illustrating the signal intensity of thermal radiation light.

[0052] Figure 13D This is a diagram illustrating the signal intensity of thermal radiation light.

[0053] Figure 14A This is an explanatory diagram of the upper and lower limits of signal strength.

[0054] Figure 14B This is an explanatory diagram of the upper and lower limits of signal strength.

[0055] Figure 14C This is an explanatory diagram of the upper and lower limits of signal strength.

[0056] Figure 15 This is a flowchart for evaluating the welding condition.

[0057] -Symbol Explanation-

[0058] 100 Laser processing equipment

[0059] 1. Laser Oscillator

[0060] 2. Illumination Optical System

[0061] 3. Collimating lens

[0062] 4. Dichroic mirror

[0063] 5 Condensing Lens

[0064] Components 6 and 7

[0065] 8 workbenches

[0066] 9. Workbench Control Department

[0067] 10. Measurement of optical systems

[0068] 11 Total Internal Reflection Mirror

[0069] 12 Imaging Lenses

[0070] 13 optical fibers

[0071] 14 Measurement Department

[0072] 15. Control Department

[0073] 15A Judgment Unit

[0074] 16 Storage Department

[0075] 17 Laser processing head

[0076] 30 Irradiation position

[0077] 31 Melting section

[0078] Measurement areas 41, 42, and 43. Detailed Implementation

[0079] In the laser processing methods described in Patent Documents 1 and 2, welding light near the molten portion around the laser irradiation position is also measured. Therefore, it is difficult to accurately evaluate the detailed state of the laser-molten portion and the melting anomalies occurring around it. Thus, there is room for improvement in the accuracy of the processing state evaluation.

[0080] Therefore, the purpose of this disclosure is to solve the aforementioned existing problems and improve the accuracy of the evaluation of the processing status in laser processing.

[0081] The laser processing method of the first aspect of this disclosure irradiates a first component with a laser beam emitted from an oscillator and scans the first component in a first direction, and joins the first component and a second component adjacent to the first component through a molten section. The laser processing method includes: measuring the intensity of welding light, including any one of thermal radiation light, plasma light, or reflected light, radiated from at least one of the first component and the second component by the irradiation of the laser beam in a first measurement area and a second measurement area different from the first measurement area; and evaluating the processing state based on the intensity of each welding light measured in the first measurement area and the second measurement area, wherein the first measurement area and the second measurement area are arranged in a second direction intersecting the first direction.

[0082] This method allows for the evaluation of the welding light intensity measured in each of two measurement areas. Therefore, it improves the accuracy of evaluating the processing status during laser processing.

[0083] In the laser processing method of the second aspect of this disclosure, the steps that can also be measured include: using an optical system to focus welding light from a first measurement area onto a first optical fiber, and measuring the welding light transmitted through the first optical fiber by a first sensor; using the same optical system as the optical system to focus welding light from a second measurement area onto a second optical fiber, and measuring the welding light transmitted through the second optical fiber by a second sensor.

[0084] According to this method, welding light measured in each measurement area can be transmitted to both the first and second sensors to evaluate the intensity of the welding light. Therefore, the accuracy of evaluating the processing status during laser processing can be further improved. Furthermore, by using the same optical system to focus the welding light from the first and second measurement areas onto an optical fiber, the number of optical systems required for implementing the laser processing method and the associated costs can be reduced.

[0085] In the laser processing method of the third aspect of this disclosure, the first measurement area and the second measurement area may also be arranged in a direction orthogonal to the first direction.

[0086] According to this method, it is possible to configure a measurement area that can more accurately measure the intensity of welding light occurring in the region to the side of the laser beam's irradiation position.

[0087] In the laser processing method of the fourth aspect of this disclosure, the molten portion during normal welding may have a width in a direction orthogonal to the first direction, and the first measurement area and the second measurement area may each have a diameter less than the width of the molten portion. The first measurement area includes the irradiation position of the laser beam during normal welding.

[0088] According to this method, the intensity of weld light occurring in the molten part and the intensity of weld light occurring outside the molten part can be measured separately.

[0089] In the laser processing method of the fifth aspect of this disclosure, the first measuring region and the second measuring region may have a diameter that is the same size as the width of the molten portion.

[0090] According to this method, more weld light can be measured in the molten section.

[0091] In the laser processing method of the sixth aspect of this disclosure, the intensity of the welding light may also be measured in a third measurement area, which is different from the first measurement area and the second measurement area, during the measurement step. The first measurement area, the second measurement area and the third measurement area are arranged adjacent to each other in a direction orthogonal to the first direction. The first measurement area includes the irradiation position of the laser beam during normal welding, and the second measurement area and the third measurement area are arranged with the first measurement area sandwiched between them.

[0092] This method allows for the measurement of welding light intensity at the laser beam's irradiation location and in adjacent areas on both sides, further improving evaluation accuracy.

[0093] In the laser processing method of the seventh aspect of this disclosure, the evaluation steps also include: comparing the signal intensity of the welding light measured in the first measurement area with a preset first threshold; comparing the signal intensity of the welding light measured in the second measurement area with a preset second threshold; and comparing the signal intensity of the welding light measured in the third measurement area with a preset third threshold.

[0094] This method allows for the evaluation of the processing status in each measurement area.

[0095] In the laser processing method of the eighth aspect of this disclosure, the first threshold may be a lower limit, the second threshold may be an upper limit, and the third threshold may be an upper limit. In the evaluation step, if the signal intensity measured in the first measurement area is less than the first threshold, the signal intensity measured in the second measurement area is less than the second threshold, and the signal intensity measured in the third measurement area is greater than the third threshold, it is determined that a melting abnormality has occurred on one side of the molten part.

[0096] This method can identify the areas where melting anomalies occur, thereby further improving the accuracy of evaluating the processing status in laser processing.

[0097] In the laser processing method of the ninth aspect of this disclosure, the first threshold can be an upper limit, the second threshold can be an upper limit, and the third threshold can be an upper limit. In the evaluation step, if the signal intensity measured in the first measurement area is less than the first threshold, the signal intensity measured in the second measurement area is greater than the second threshold, and the signal intensity measured in the third measurement area is greater than the third threshold, it is determined that the focal position of the laser beam deviates along the irradiation direction of the laser beam.

[0098] This method can determine the deviation of the focal position, and can further improve the evaluation accuracy of the processing status during laser processing.

[0099] The laser processing apparatus of the tenth aspect of this disclosure irradiates a first component with a laser beam and scans it on the first component in a first direction, joining the first component and a second component adjacent to the first component by a melting section. The laser processing apparatus includes: an oscillator for emitting a laser beam; an irradiation optical system for guiding the laser beam to the first component; a worktable for moving the first and second components relative to the laser beam and scanning the laser beam in the first direction; and a measurement optical system for guiding the laser beam from a first measurement area and a second measurement area different from the first measurement area. The system includes a welding light radiated from at least one of the first and second components by irradiation with a beam, comprising any one of thermal radiation light, plasma light, or reflected light; a first sensor that measures the intensity of the welding light guided from the first measurement area to the measurement optical system; a second sensor that measures the intensity of the welding light guided from the second measurement area to the measurement optical system; and a judgment unit that evaluates the processing state based on the intensity of each welding light measured in the first and second measurement areas, wherein the first and second measurement areas are arranged in a second direction intersecting the first direction.

[0100] Based on this structure, the intensity of the welding light measured in each measurement area can be evaluated separately. Therefore, the accuracy of evaluating the processing status during laser processing can be improved.

[0101] In the laser processing apparatus of the 11th aspect of this disclosure, the laser processing apparatus may further include: a first optical fiber for transmitting welding light, which is guided from the first measurement area to the measurement optical system, to the first sensor; and a second optical fiber for transmitting welding light, which is guided from the second measurement area to the measurement optical system, to the second sensor.

[0102] With this structure, the welding light measured in each measurement area can be transmitted to the first sensor and the second sensor respectively, allowing for the evaluation of the welding light intensity. Therefore, the accuracy of evaluating the processing status during laser processing can be further improved.

[0103] The laser processing method described below will be explained in detail based on the accompanying drawings.

[0104] (Implementation Method)

[0105] Figure 1 This is a schematic diagram of a laser processing apparatus according to an embodiment of the present disclosure. Figure 2A This is a magnified view of a portion of the laser processing device 100. Figure 2B It is along Figure 2A A cross-sectional view of line AA. Figure 2C It is along Figure 2A A cross-sectional view along the BB line. Figure 2A For convenience, part of the laser processing device 100 is omitted.

[0106] like Figure 1 As shown, the laser processing apparatus 100 is a device that irradiates a laser beam L1 and joins components 6 and 7, which are workpieces, through a molten section 31 formed by the irradiation of the laser beam L1. The laser processing apparatus 100 includes: a laser oscillator 1, an irradiation optical system 2, a worktable 8, a measuring optical system 10, an optical fiber 13, a measuring unit 14, a control unit 15, and a storage unit 16.

[0107] Laser oscillator 1 is a device for oscillating a laser beam L1. The laser beam L1 oscillating from laser oscillator 1 is directed, for example, directly or via a transmission unit such as an optical fiber, to irradiate optical system 2. Laser oscillator 1, for example, oscillates a laser beam L1 having a wavelength of 1070 nm.

[0108] The illumination optical system 2 is an optical system that guides and focuses the laser beam L1 from the laser oscillator 1 onto the surface of the component 6. The illumination optical system 2 includes multiple optical elements, such as a collimating lens 3, a dichroic mirror 4, and a condenser lens 5. The laser beam L1 is made parallel by the collimating lens 3, bent at a right angle by the dichroic mirror 4, and focused by the condenser lens 5, illuminating the surface of the component 6. The surface of the dichroic mirror 4 is coated so that only the wavelength of the laser beam L1 is totally reflected, while all other wavelengths are transmitted. However, in this specification, "total internal reflection" means reflection of more than 99%, with approximately 1% of the laser beam L1 transmitted through the dichroic mirror 4.

[0109] The worktable 8 is a device that supports components 6 and 7 and moves components 6 and 7 relative to the laser beam L1 focused by the irradiated optical system 2. The worktable 8 supports component 7 and component 6, which is arranged overlapping component 7 in the irradiation direction. Component 7 is adjacent to component 6. Furthermore, the worktable 8 is controlled by the worktable control unit 9 and moves linearly while supporting components 6 and 7. If the movement of the worktable 8 is synchronized with the irradiation of the laser beam L1, a molten section 31 is formed along a certain scanning direction (Y direction, first direction). Through the molten section 31, components 6 and 7 are joined, i.e., laser welded. In this embodiment, components 6 and 7 are plate-shaped components. Components 6 and 7 can be components having portions that extend in a surface direction orthogonal to the thickness direction of components 6 and 7, so that each component 6 and 7 can overlap each other in the area of ​​the irradiated object.

[0110] If laser beam L1 is directed at components 6 and 7, a molten portion 31 is formed, and welding light W0 radiates from the surface of component 6. Figure 2A As shown, the welding light W0 includes: welding light W1 radiated from the molten part 31, and welding light W2 and W3 radiated from the surrounding area of ​​the molten part 31, for example. The welding light W0 includes: plasma light as visible light, thermal radiation light that is highly temperature-dependent on the component 6, or reflected light from the laser beam L1, etc. The welding light W0 radiated from the component 6 is guided to the measuring optical system 10, for example, directly or using a transmission unit such as a lens.

[0111] The measuring optical system 10 is an optical system that guides the welding light W0 from the surface of component 6 to the optical fiber 13 and images it. For example... Figure 1 As shown, the measuring optical system 10 includes multiple optical elements, such as a condenser lens 5, a dichroic mirror 4, a total reflection mirror 11, and an imaging lens 12. In this embodiment, the measuring optical system 10 shares the dichroic mirror 4 and the condenser lens 5 with the illumination optical system 2. Furthermore, for convenience, the laser beam L1 and the welding light WO are depicted separately in the condenser lens 5 and the dichroic mirror 4, but in reality, the laser beam L1 and the welding light WO are coaxial. The welding light WO passes through the condenser lens 5 and the dichroic mirror 4, is bent to a right angle by the total reflection mirror 11, and is imaged onto the end face of the optical fiber 13 by the imaging lens 12.

[0112] Furthermore, the measuring optical system 10 and the irradiation optical system 2 are housed together in the laser processing head 17. The laser processing head 17 forms a housing that houses the irradiation optical system 2 and the measuring optical system 10, preventing the laser beam L1 and the welding light WO from leaking outside the housing.

[0113] Fiber 13 is a transmission unit that transmits the welding light WO from the guiding measurement optical system 10 to the measurement unit 14. In this embodiment, the laser processing apparatus 100 includes three optical fibers 13a, 13b, and 13c. Figure 2A As shown, one end of optical fibers 13a, 13b, and 13c is connected to the laser processing head 17 so as to be aligned with the imaging lens 12. Figure 2B As shown, one end of each of the three optical fibers 13a, 13b, and 13c is arranged in a straight, close-fitting configuration along the Z-direction and secured by a retainer 18. Furthermore, as... Figure 1 As shown, the other ends of optical fibers 13a, 13b, and 13c are connected to the measuring unit 14.

[0114] With this configuration, the laser processing device 100 is able to process from... Figure 2A The welding light W1, W2, and W3 radiated from the three different measurement areas 41, 42, and 43 shown are measured. In this specification, the term "measurement area" refers to the surface area of ​​the molten part 31 and the surrounding component 6, which is the area capable of generating welding light during normal or abnormal welding. The term "different measurement areas 41, 42, and 43" refers to areas on the surface of the component 6 that exhibit differences. In other words, measurement areas 41, 42, and 43 are inconsistent areas. Measurement areas 41, 42, and 43 may also be partially overlapping. Furthermore, measurement areas 41, 42, and 43 may also be arranged with intervals relative to each other. In this embodiment, as... Figure 2C As shown, measurement regions 41, 42, and 43 are configured to not overlap, with the first measurement region 41 adjacent to the second measurement region 42, and the first measurement region 41 adjacent to the third measurement region 43. More specifically, the three measurement regions 41, 42, and 43 are adjacent to each other and arranged linearly in a second direction orthogonal to the first direction (hereinafter, the scanning direction K). The first measurement region 41 is positioned between the second measurement region 42 and the third measurement region 43. Figure 2A As shown, welding light W1 radiated from the first measurement region 41 located in the molten section 31 is imaged onto the first optical fiber 13a. Welding light W2 radiated from the second measurement region 42 located on one side of the molten section 31 is imaged onto the second optical fiber 13b. Welding light W3 radiated from the third measurement region 43 located on the other side of the molten section 31 is imaged onto the third optical fiber 13c.

[0115] like Figure 1 as well as Figure 2A As shown, optical fiber 13a transmits welding light W1 to measuring unit 14a, optical fiber 13b transmits welding light W2 to measuring unit 14b, and optical fiber 13c transmits welding light W3 to measuring unit 14c.

[0116] The measuring unit 14 is a device that measures the intensity of the welding light WO transmitted through the optical fiber 13 and transmits a signal corresponding to the intensity to the control unit 15. In this embodiment, the laser processing apparatus 100 includes three measuring units 14a, 14b, and 14c corresponding to the three optical fibers 13a, 13b, and 13c. (See reference...) Figure 3 The detailed structure of measuring sections 14a, 14b, and 14c will now be explained. Figure 3 This is a schematic diagram of the measuring unit 14a. Other measuring units 14b and 14c may also have the same structure as the measuring unit 14a.

[0117] The measuring unit 14a includes multiple optical elements and sensors. For example, the measuring unit 14a includes: a collimating lens 20, mirrors 21a, 21b, and 21c, filters 22a, 22b, and 22c, imaging lenses 23a, 23b, and 23c, light-receiving sensors 24a, 24b, and 24c, and amplifiers 25a, 25b, and 25c. The welding light W1, passing through the optical fiber 13a, becomes parallel light after passing through the collimating lens 20, and is then separated according to each wavelength by the multiple mirrors 21a, 21b, and 21c. In this embodiment, the mirrors 21a, 21b, and 21c separate the welding light W1 into three wavelengths. Specifically, from the welding light W1, mirror 21a separates the plasma light W1a (wavelength 400-700nm), mirror 21b separates the laser reflected light W1b (wavelength 1070nm), and mirror 21c separates the thermal radiation light W1c (wavelength 1300nm). Each mirror 21a, 21b, and 21c has a coating on its front surface to reflect only the separated wavelengths, allowing other wavelengths to pass through. The welding lights W1a, W1b, and W1c reflected by each mirror 21a, 21b, and 21c pass through corresponding filters 22a, 22b, and 22c. The passed welding lights W1a, W1b, and W1c then pass through corresponding imaging lenses 23a, 23b, and 23c and are incident on corresponding light-receiving sensors 24a, 24b, and 24c. The signals from each light-receiving sensor 24a, 24b, 24c are converted into electrical signals corresponding to the intensity by the corresponding amplifiers 25a, 25b, 25c, and then transmitted to the control unit 15.

[0118] The control unit 15 is a controller that performs overall control of the laser processing apparatus 100. The control unit 15 includes a general-purpose processor such as a CPU or MPU that executes programs to perform specified functions. The control unit 15 performs various controls within the laser processing apparatus 100 by retrieving and executing control programs stored in the storage unit 16 (described later). The control unit 15 is not limited to components that perform specified functions through a combination of hardware and software; it can also be a dedicated hardware circuit designed to perform specified functions. That is, the control unit 15 can be implemented using various processors such as CPUs, MPUs, GPUs, FPGAs, DSPs, and ASICs. For example, the control unit 15 performs synchronous control of the laser oscillator 1 and the worktable control unit 9.

[0119] The control unit 15 includes a general-purpose processor such as a CPU or MPU that functions as the judgment unit 15A. The judgment unit 15A evaluates the welding condition based on the intensity of each welding beam W1, W2, and W3 measured in the measurement areas 41, 42, and 43. More specifically, the judgment unit 15A determines whether an abnormality in the welding condition has occurred based on the intensity of the welding beams W1, W2, and W3. Abnormalities in the welding condition include excessive heating or melting, insufficient heating or melting, and irradiation outside the area to be irradiated. For example, the judgment unit 15A compares the intensity signals of the welding beams W1, W2, and W3 with preset reference values ​​to determine whether an abnormality in the welding condition has occurred in the measurement areas 41, 42, and 43.

[0120] Storage unit 16 is a recording medium for recording various types of information. Storage unit 16 may be implemented using, for example, flash memory, SSD (Solid State Device), hard disk, other storage devices, or appropriate combinations thereof. Storage unit 16 stores control programs executed by control unit 15, as well as various information sensed for evaluating the welding status. Storage unit 16 may store, for example, an application 16a for processing the intensity signals of welding beams W1, W2, and W3. Storage unit 16 may also store preset reference values ​​related to welding beams W1, W2, and W3, such as upper limit signal strengths Pau, Pbu, and Pcu, or lower limit signal strengths Pad, as described later.

[0121] Here, refer to Figure 2CThe measurement regions 41, 42, and 43 will be described in more detail below. The first measurement region 41 is a circular region centered on the irradiation position 30 of the laser beam L1 during normal welding and having the same diameter as the melt width D1. The melt width D1 is the width of the molten portion 31 during normal welding, measured later in a second direction orthogonal to the scanning direction K. In other words, the first measurement region 41 is internally tangent to the molten portion 31 during normal welding. The second measurement region 42 and the third measurement region 43 are circular regions on either side of the first measurement region 41, similar to the first measurement region 41, and have the same diameter as the melt width D1. The second measurement region 42 and the third measurement region 43 may also have the same dimensions as the first measurement region 41.

[0122] Furthermore, the relationship between the dimensions of the measurement regions 41, 42, and 43 and the dimensions of the optical fibers 13a, 13b, and 13c will be explained. In this embodiment, the focal lengths of the condenser lens 5 and the imaging lens 12 are equal. In this case, the imaging ratio in the measurement optical system 10 is 1:1, and the dimensions of the measurement regions 41, 42, and 43 are consistent with the dimensions of the end faces of the optical fibers 13a, 13b, and 13c. Therefore, the diameters of the measurement regions 41, 42, and 43 can be determined based on the core diameters of the optical fibers 13a, 13b, and 13c.

[0123] If the core diameter of optical fibers 13a, 13b, and 13c is set as ds, the focal length of the condenser lens 5 is set as f1, and the focal length of the imaging lens 12 relative to optical fibers 13a, 13b, and 13c is set as f2, then the diameter dm of the measurement areas 41, 42, and 43 can be expressed by equation (1).

[0124] dm=ds×f1 / f2···(1)

[0125] For example, if the focal length f1 of the condenser lens 5 is 150 μm and the focal length f2 of the imaging lens 12 to the optical fiber 13a is set to 150 μm, then if an optical fiber 13a with a core diameter of 300 μm is selected, the diameter dm of the first measurement region 41 can be set to 300 μm.

[0126] Next, refer to Figures 4A to 4D This section describes the welding state during normal welding. Normal welding refers to welding in which the designed process does not produce any abnormalities. Figures 4A to 4C This is a cross-sectional view of the welding state during normal welding. Figure 4D It is a graph showing the relationship between irradiation power and time during normal welding.

[0127] like Figure 4AAs shown, at the start of laser welding, laser beam L1 irradiates component 6, which is disposed on component 7. For example, component 7 is made of aluminum material with a thickness of 1 mm, and component 6 is made of aluminum material with a thickness of 0.2 mm. Laser beam L1 is scanned so that it moves relative to component 6 in a straight line along the scanning direction K. In this embodiment, laser beam L1 moves relative to component 6 by moving the stage 8 (not shown) that carries components 6 and 7. For example, the laser output of laser beam L1 is 400 W, and the scanning speed is 500 mm / s.

[0128] like Figure 4B As shown, after being irradiated by laser beam L1, components 6 and 7 form a molten portion 31. (As indicated...) Figure 4C As shown, from the scanning direction K, the molten portion 31 has a molten width D1 of approximately 300 μm and a molten depth D2 of approximately 400 μm.

[0129] like Figure 4D As shown, the output waveform Pl of laser beam L1 is set to a trapezoidal waveform, which, in time Tw, sequentially includes a slowly rising portion, a flat portion, and a slowly falling portion. By setting the slowly rising and slowly falling portions, sputtering and denting during laser welding can be prevented. Because the output waveform Pl of laser beam L1 is a trapezoidal waveform, therefore... Figure 4B Therefore, the cross-sectional shape of the molten section 31 is also an inverted trapezoidal shape. In addition, the full irradiation time of the laser beam L1 is, for example, 4 ms.

[0130] Next, refer to Figures 5A to 5D This will describe the actual welding condition. Figures 5A to 5D This is a photograph of the actual molten section.

[0131] Figure 5A This is a photograph of the molten portion during normal welding. During normal welding, the molten portion 31 has a certain molten width D1, forming a shape corresponding to the designed laser welding.

[0132] Figure 5B This is a photograph of the appearance of the molten section when an abnormal molten section 33 is generated in the center of the molten section 31. Figure 5B This indicates an example of perforation caused by melting anomalies. Perforation anomalies indicate that a portion of the melting did not proceed normally, forming a through hole in component 6 or the molten portion 31 becoming concave, etc., indicating insufficient melting. Insufficient melting can occur, for example, due to material vaporization caused by excessive heating, sputtering, or the influence of foreign matter present in the workpiece.

[0133] Figure 5CThis is a photograph showing the appearance of the melt portion when a left-side melt anomaly portion 34 is formed on one side of the melt portion 31. The left-side melt anomaly portion 34 is a melt anomaly portion formed on the left side of the melt portion 31 relative to the scanning direction K. The left-side melt anomaly portion 34 represents, for example, a state where a melt portion 31 is formed at an unnecessary location due to excessive melting when resin foreign matter is trapped at the joint interface. Therefore, in a part of the melt portion 31 where the left-side melt anomaly portion 34 is formed, the melt width of the melt portion 31 becomes larger.

[0134] Figure 5D This is a photograph showing the appearance of the melt portion when a right-side melt defect 35 is formed on the other side of the melt portion 31. The right-side melt defect 35 is a melt defect formed on the right side of the melt portion 31 relative to the scanning direction K. The right-side melt defect 35 represents, for example, a state where a melt portion 31 is formed at an unnecessary location due to excessive melting when resin foreign matter is trapped at the joint interface. Therefore, in a part of the melt portion 31 where the right-side melt defect 35 is formed, the melt width of the melt portion 31 becomes larger.

[0135] Here, as a comparative example, a laser processing method using a measurement area will be described.

[0136] (Comparative Example)

[0137] First, refer to Figure 6 Let's explain the measurement area in the comparative example. Figure 6 This is an explanatory diagram of the measurement area for measuring the thermal radiation of the comparative example.

[0138] like Figure 6 As shown, a laser beam (not shown) irradiates an irradiation position 130 on component 106. Around the irradiation position 130, component 106 melts and forms a molten portion 131. Welding light (not shown) is generated from the molten portion 131 near the irradiation position 130. The welding light is measured in a measurement area 132. The measurement area 132 is configured to include the irradiation position 130, and the center of the measurement area 132 may also be configured to coincide with the irradiation position 130. The diameter of the measurement area 132 is larger than the molten width of the molten portion 131, for example, three times the molten width. Therefore, the welding light radiated in and around the molten portion 131 is measured simultaneously.

[0139] Next, refer to Figures 7A to 7D Let's illustrate with a comparative example. Figures 7A to 7D This is a diagram illustrating the signal intensity of thermal radiation light in a comparative example. In Figures 7A to 7D In the figures marked "(i)", the welding state is indicated, and the figure marked "(ii)" indicates the signal intensity of the welding light measured in the measurement area 132. Furthermore, in the comparative example, thermal radiation light is measured as an example of welding light.

[0140] Figure 7A This indicates the signal intensity of the thermal radiation light measured during normal welding in the comparative example. For example... Figure 7A As shown in (i), under normal laser welding conditions, component 106 is melted and joined. Furthermore, during laser irradiation, thermal radiation corresponding to the molten state, such as melting temperature and molten area, is emitted. Figure 7A As shown in (ii), in measurement region 132, the signal intensity proportional to the thermal radiation light is measured.

[0141] Figure 7B This indicates the signal intensity of the thermal radiation light measured when an abnormal melting zone was formed in the center of the molten zone 131 in the comparative example. For example... Figure 7B As shown in (i), when a melting anomaly 133, such as a perforation, protrusion, or depression, is generated in the center of the melting portion 131, the melting anomaly 133 is at a higher temperature than the normal melting portion 131, thus the signal intensity of the thermal radiation light also increases sharply and forms a peak. Therefore, as Figure 7B As shown in (ii), it is possible to infer a melting anomaly in the measurement region 132 based on the formation of peak values ​​in the signal intensity.

[0142] Figure 7C This indicates the signal intensity of the thermal radiation light measured when an abnormal melting section was generated on one side of the molten section 131 in the comparative example. For example... Figure 7C As shown in (i), in the case where the left-side melting anomaly 134 is generated, compared to Figure 7B In the case shown in (ii), the change in the signal intensity of the thermal radiation light is small. Therefore, as Figure 7C As shown in (ii), the variation in thermal radiation light from the molten portion 131 under normal conditions makes it difficult to infer the occurrence of melting anomalies.

[0143] Figure 7D This indicates the signal intensity of the thermal radiation light measured when a melting anomaly occurred on the other side of the molten portion 131 in the comparative example. For example... Figure 7D As shown in (i), in the case of generating the left-side melting anomaly section 134, the measurement and... Figure 7C The signal intensity of the thermal radiation light shown in (ii) is the same. Therefore, it is difficult to determine whether the melting anomaly is the left melting anomaly 134 or the right melting anomaly 135.

[0144] On the other hand, in the laser processing method of this embodiment, three measurement areas 41, 42, and 43 are set. (Refer to...) Figures 8A to 13D The laser processing method using measurement areas 41, 42, and 43 is explained. Figures 8A-1 Figure 3 is an illustration of the signal intensity of thermal radiation light. In Figures 8A-1In Figure 3, the figure labeled “(a)” represents the welding state, and the figures labeled “(b)”, “(c)”, and “(d)” represent the signal intensity of the welding light measured in the first measurement area 41, the second measurement area 42, and the third measurement area 43, respectively.

[0145] The three measurement regions 41, 42, and 43 are arranged in a direction orthogonal to the scanning direction K of the laser beam, as described above, and each has a diameter the same as the molten width D1 of the molten portion 31. Furthermore, in the following description, as an example of welding light, the signal intensity of the thermal radiation light emitted from the measurement regions 41, 42, and 43 is set as signal intensity Pa, Pb, and Pc, respectively, when measuring the thermal radiation light.

[0146] first, Figures 8A to 8D The signals Pa, Pb, and Pc represent the signal intensities of the thermal radiation light measured during normal welding. In the first measurement region 41, component 6 melts, and thermal radiation light corresponding to the melting temperature is released, and the signal intensity Pa is measured. On the other hand, in measurement regions 42 and 43, component 6 does not melt and is in a heating state based solely on heat conduction; therefore, the thermal radiation light released from measurement regions 42 and 43 is less than that released from the first measurement region 41. Consequently, the signal intensities Pb and Pc are smaller than the signal intensity Pa.

[0147] Figures 9A to 9D The values ​​Pa, Pb, and Pc represent the signal intensities of thermal radiation light measured when an abnormal melting zone is formed in the center of the molten section 31. For example... Figure 9A As shown, when abnormal melting portions 33, such as perforations, protrusions, and depressions, are formed in the central part of the molten portion 31, the abnormal melting portion 33 is at a higher temperature than the normal molten portion 31. Therefore, as Figure 9C As shown, the signal strength Pa increases sharply and forms a peak. On the other hand, as... Figure 9B , Figure 9D As shown, in the second measurement area 42 and the third measurement area 43, since the emitted thermal radiation light did not change, the signal intensities Pb and Pc did not change. Based on the signal intensities Pa, Pb, and Pc of the thermal radiation light, it can be inferred that a melting anomaly occurred in the central part of the molten section 31.

[0148] Figures 10A to 10D The values ​​Pa, Pb, and Pc represent the signal intensities of thermal radiation light measured when a melting anomaly occurs on one side of the molten portion 31. For example... Figure 10A As shown, when the abnormal melting section 34 on the left side occurs, the thermal radiation emitted from the measurement areas 41 and 43 increases compared to the normal melting section 31. Therefore, as Figure 10B , Figure 10C As shown, the signal intensities Pa and Pc of the thermal radiation light also increase. On the other hand, as... Figure 10DAs shown, in the second measurement region 42, the emitted thermal radiation light did not change, therefore the signal intensity Pb ​​did not change. Based on the signal intensities Pa, Pb, and Pc of the thermal radiation light, it can be inferred that the left-side melting anomaly region 34 was generated.

[0149] Figures 11A to 11D The values ​​Pa, Pb, and Pc represent the signal intensities of thermal radiation light measured when a melting anomaly occurs on the other side of the molten section 31. For example... Figure 11A As shown, when the abnormal melting section 35 on the right side occurs, the thermal radiation emitted from the measurement areas 41 and 42 increases compared to the normal melting section 31. Therefore, as Figure 11C , Figure 11D As shown, the signal intensities Pa and Pb of the thermal radiation light also increase. On the other hand, as... Figure 11B As shown, in the third measurement region 43, the emitted thermal radiation light did not change, therefore the signal intensity Pc did not change. Based on the signal intensities Pa, Pb, and Pc of the thermal radiation light, it can be inferred that the right-side melting anomaly region 35 was generated.

[0150] That is, in this embodiment, the direction (right or left) of the melting anomaly can be determined by the peak value of either signal intensity Pb ​​or signal intensity Pc.

[0151] Figures 12A-12D These represent the signal intensities Pa, Pb, and Pc of the thermal radiation light measured when the focal position deviates. For example... Figure 12A As shown, if the focal position deviates from the laser irradiation direction midway through laser welding, a molten section 31a with an expanded molten width is formed relative to the normal molten section 31. Therefore, thermal radiation from the expanded molten width region, i.e., the molten section 31a, within the molten section 31 is measured in the second measurement region 42 and the third measurement region 43. Figure 12B , Figure 12D As shown, the signal intensities Pb and Pc of the thermal radiation light increase significantly after the molten width expands during the welding process. If both the signal intensities Pb and Pc of the thermal radiation light simultaneously increase, it can be inferred that a focal position deviation has occurred.

[0152] Figures 13A to 13D These represent the signal intensities Pa, Pb, and Pc of the thermal radiation light measured when the irradiation position deviated. For example... Figure 13A As shown, if the irradiation position deviates from the normal molten part 31 in the direction intersecting the scanning direction K during the laser welding process, a molten part 31b that deviates from the scanning direction K will be formed. Figure 13A In the diagram, 31b represents the molten portion that deviates to the left relative to the scanning direction K. Within the molten portion 31b, the thermal radiation primarily measured in the first measurement region 41 is measured in the third measurement region 43. (As shown...) Figures 13B to 13D As shown, the signal intensity Pc measured in the third measurement region 43 has a larger value, while the signal intensities Pa and Pb measured in the first measurement region 41 and the second measurement region 42 have smaller values. If one of the signal intensities Pb and Pc of the thermal radiation light has a larger value at a certain time, while the other two signal intensities have smaller values ​​at the same time, it can be inferred that the irradiation position has deviated to one side.

[0153] Next, the method for evaluating the laser welding state in the embodiment will be described. The evaluation of the welding state is performed by comparing the intensities of the welding lights W1, W2, and W3 with preset reference values. In this embodiment, the upper limit signal intensity and the lower limit signal intensity will be described as examples of reference values.

[0154] First, the normal signal intensity P0(t) of the thermal radiation light during normal welding is measured at time t. The upper and lower limit signal intensities are then calculated based on this normal signal intensity P0(t). Time t is the period from before laser irradiation begins to after laser irradiation ends. The normal signal intensity P0(t) is measured multiple times, typically more than 30 times. The normal signal intensity P0(t) varies over time t according to the waveform of the output Pl of the irradiated laser beam L1, exhibiting a trapezoidal waveform as shown in Figure 4. The normal signal intensity P0(t) includes the normal signal intensities P0a(t), P0b(t), and P0c(t) of each thermal radiation light emitted from measurement areas 41, 42, and 43 during normal welding. Based on the multiple normal signal intensity P0(t) measurements, the standard deviation Pσ(t), representing the average signal intensity Pm(t) and the degree of deviation of the normal signal intensity P0(t), is calculated. The upper limit signal strength Pu(t) and the lower limit signal strength Pd(t) are calculated using the average signal strength Pm(t), the standard deviation Pσ(t), and the sigma level coefficient k, through equations (2) and (3).

[0155] Pu(t)=Pm(t)+k·Pσ(t)···(2)

[0156] Pd(t)=Pm(t)-k·Pσ(t)···(3)

[0157] Since the normal signal strength P0(t) varies over time t, the upper limit signal strength Pu(t) and lower limit signal strength Pd(t) calculated using the normal signal strength P0(t) also vary over time t. For example, when k=3, the probability that the signal strength P(t) is included between the upper limit signal strength Pu(t) = Pm(t) + 3Pσ(t) and the lower limit signal strength Pd(t) = Pm(t) - 3Pσ(t) is statistically 99.73%. Furthermore, when k=4, the probability that the signal strength P is included between the upper limit signal strength Pu(t) = Pm(t) + 4Pσ(t) and the lower limit signal strength Pd(t) = Pm(t) - 4Pσ(t) is statistically 99.94%. The calculated upper limit signal strength Pu(t) and lower limit signal strength Pd(t) are stored in the storage unit 16 as reference values ​​for the intensity of welding lights W1, W2, and W3.

[0158] Figures 14A-14C This is an explanatory diagram of the upper and lower limits of signal strength.

[0159] like Figures 14A-14C As shown, the upper limit signal strengths Pau(t), Pbu(t), and Pcu(t) are calculated for the signal strengths Pa(t), Pb(t), and Pc(t) measured in each measurement region 41, 42, and 43. The lower limit signal strength Pad(t) is calculated for the signal strength Pa(t) measured in the first measurement region 41. The upper limit signal strengths Pau(t), Pbu(t), Pcu(t), and the lower limit signal strength Pad(t) have trapezoidal waveforms at time t, depending on the waveform of the output Pl of the irradiated laser beam L1. The welding condition is evaluated in each measurement region 41, 42, and 43 using the upper limit signal strengths Pau(t), Pbu(t), Pcu(t), and the lower limit signal strength Pad(t). More specifically, if the measured signal strength Pa(t) exceeds the upper limit signal strength Pau(t) or falls below the lower limit signal strength Pad(t) at a specific time t, an abnormality in the welding condition is determined to have occurred. Furthermore, if the measured signal strengths Pb(t) and Pc(t) exceed the respective upper limit signal strengths Pbu(t) and Pcu(t) at a specific time t, an abnormality in the welding state is determined to have occurred. On the other hand, if the signal strength Pa(t) is below the upper limit signal strength Pau(t) and above the lower limit signal strength Pad(t), and the signal strengths Pb(t) and Pc(t) are below the upper limit signal strengths Pbu(t) and Pcu(t), an abnormality in the welding state is determined to have not occurred.

[0160] Next, refer to Figure 15 The evaluation methods for welding condition will be explained in more detail below. Figure 15For simplicity, the signal intensities Pa(t), Pb(t), and Pc(t) in measurement regions 41, 42, and 43 are denoted as Pa, Pb, and Pc, respectively. The same applies to other signal intensities.

[0161] Figure 15 This is a flowchart for evaluating the welding condition.

[0162] First, in measurement areas 41, 42, and 43, the measurement unit 14 measures the signal intensity Pa, Pb, and Pc of the thermal radiation light during laser welding (step S101). As described above, the first measurement area 41 is located in the molten part 31, the second measurement area 42 is located on the right side, and the third measurement area 43 is located on the left side.

[0163] Next, the determination unit 15A determines whether the signal strength Pb released from the second measurement area 42 is less than the upper limit signal strength Pbu stored in the storage unit 16 (step S102).

[0164] Next, if the signal strength Pb is less than the upper limit signal strength Pbu (yes in S102), the determination unit 15A determines whether the signal strength Pc released from the third measurement area 43 is less than the upper limit signal strength Pcu stored in the storage unit 16 (step S103).

[0165] Next, if the signal strength Pc is less than the upper limit signal strength Pcu (yes in S103), the determination unit 15A determines whether the signal strength Pa released from the first measurement area 41 is less than the upper limit signal strength Pau stored in the storage unit 16 (step S104).

[0166] Therefore, if the signal strength Pa is less than the upper limit signal strength Pau (yes in S104), the determination unit 15A determines that the welding is normal. If the signal strength Pa is greater than the upper limit signal strength Pau (no in S104), it is determined that a melting abnormality (such as perforation) has occurred at the center of the molten part 31.

[0167] In step S103, if the signal strength Pc is greater than the upper limit signal strength Pcu (no in S103), the determination unit 15A determines whether the signal strength Pa is greater than the lower limit signal strength Pad stored in the storage unit 16 (step S105).

[0168] Therefore, if the signal intensity Pa is less than the lower limit signal intensity Pad (no in S105), the determination unit 15A determines that an irradiation position deviation has occurred on the right side. If the signal intensity Pa is greater than the lower limit signal intensity Pad (yes in S105), the determination unit 15A determines that a melting anomaly has occurred on the left side.

[0169] In step S102, if the signal strength Pb is greater than the upper limit signal strength Pbu (not in S102), the determination unit 15A determines whether the signal strength Pc is less than the upper limit signal strength Pcu (step S106).

[0170] Next, if the signal strength Pc is less than the upper limit signal strength Pcu (yes in S106), the determination unit 15A determines whether the signal strength Pa is greater than the lower limit signal strength Pad stored in the storage unit 16 (step S107).

[0171] Therefore, if the signal intensity Pa is less than the lower limit signal intensity Pad (no in S107), the determination unit 15A determines that a deviation in the irradiation position to the left has occurred. If the signal intensity Pa is greater than the lower limit signal intensity Pad (yes in S107), the determination unit 15A determines that a melting anomaly has occurred on the right side.

[0172] In step S106, if the signal strength Pc is greater than the upper limit signal strength Pcu (not in S106), the determination unit 15A determines whether the signal strength Pa is less than the upper limit signal strength Pau (step S108).

[0173] Therefore, if the signal strength Pa is less than the upper limit signal strength Pau (yes in S108), the determination unit 15A determines that a focal position deviation has occurred. If the signal strength Pa is greater than the upper limit signal strength Pau (no in S108), the determination unit 15A determines that two or more of the following melting anomalies have occurred: central melting anomaly, right-side melting anomaly, and left-side melting anomaly.

[0174] In this way, by using the signal intensities Pa, Pb, and Pc of the thermal radiation light to perform steps S101 to S108, the laser welding status can be evaluated.

[0175] [Effect]

[0176] The laser processing method and laser processing apparatus 100 described in the embodiments can achieve the following effects.

[0177] The laser processing method according to this embodiment is as follows: a laser beam L1 emitted from a laser oscillator 1 (oscillator) is irradiated onto a component 6 and scanned on the component 6 in a first direction, thereby joining the component 6 and a component 7 adjacent to the component 6. The laser processing method includes a measurement step S101 and evaluation steps S102 to S108. In the measurement step S101, the intensity of welding light W1 and W2 radiated from at least one component 6 and component 7 by irradiation by the laser beam L1 is measured in a first measurement area 41 and a second measurement area 42 different from the first measurement area 41. The welding light W1 and W2 include any of the radiated thermal radiation light, plasma light, and reflected light. In the evaluation steps S102 to S108, the processing state is evaluated based on the intensity of each welding light W1 and W2 measured in the first measurement area 41 and the second measurement area 42. The first measurement area 41 and the second measurement area 42 are arranged in a second direction intersecting the first direction (scanning direction K).

[0178] By setting up two measurement areas 41 and 42, the intensity of the welding light W1 and W2 measured in each measurement area can be evaluated separately. Therefore, the accuracy of evaluating the welding condition during laser processing can be improved. Furthermore, by accurately evaluating anomalies in the welding condition, defective welded products can be prevented from flowing into subsequent processes after laser welding.

[0179] In the laser processing method according to this embodiment, in the measurement step S101, the welding light W1 from the first measurement area 41 is focused onto the first optical fiber 13La using the measurement optical system 10 (optical system). The welding light W1 transmitted through the first optical fiber 13a is measured by the measurement unit 14a (first sensor). Furthermore, the welding light W2 from the second measurement area 42 is focused onto the second optical fiber 13b using the measurement optical system 10, and the welding light transmitted through the second optical fiber 13b is measured by the measurement unit 14b (second sensor).

[0180] This method allows the welding beams W1 and W2 measured in each measurement area 41 and 42 to be transmitted to measurement units 14a and 14b, respectively, to evaluate the intensity of the welding beams W1 and W2. Therefore, the accuracy of evaluating the welding state during laser processing can be further improved. Furthermore, by using the same measurement optical system 10 to focus the welding beam W1 from the first measurement area 41 and the welding beam W2 from the second measurement area 42 onto optical fibers 13a and 13b, the number of optical systems required for implementing the laser processing method can be reduced. Therefore, the design of the optical system for implementing the laser processing method becomes easier, and costs can be suppressed.

[0181] In the laser processing method of this embodiment, the first measurement area 41 and the second measurement area 42 are arranged in a direction orthogonal to the first direction (scanning direction K).

[0182] This method enables the configuration of measurement areas 41 and 42, which can more accurately measure the welding light occurring in the area to the side of the irradiation position 30. Furthermore, it makes it easier to design a measurement optical system 10 that transmits the welding light W1 and W2 to the measurement units 14a and 14b and the control unit 15.

[0183] In the laser processing method according to this embodiment, the molten portion 31 during normal welding has a width D1 in a direction orthogonal to the first direction (scanning direction K). The first measurement region 41 and the second measurement region 42 each have a diameter less than or equal to the width D1 of the molten portion 31. The first measurement region 41 includes the irradiation position 30 of the laser beam L1 during normal welding.

[0184] This method allows for the separate measurement of welding light W1 generated in the molten region 31 and welding light W2 generated at other locations. Therefore, it further improves the accuracy of evaluating the welding condition during laser processing.

[0185] In the laser processing method according to this embodiment, the first measuring region 41 and the second measuring region 42 have a diameter that is the same size as the width D1 of the molten portion 31.

[0186] This method allows for the separate measurement of welding light W1 occurring in the molten zone 31 and welding light W2 occurring at other locations, and enables the measurement of more welding light W1 in the molten zone 31. Therefore, it can further improve the accuracy of evaluating the welding state during laser processing.

[0187] In step S101 of the laser processing method according to this embodiment, the intensity of the welding light W3 is measured in a third measurement region 43, which is different from the first measurement region 41 and the second measurement region 42. The first measurement region 41, the second measurement region 42, and the third measurement region 43 are arranged adjacent to each other in a direction orthogonal to the first direction (scanning direction K). The first measurement region 41 includes the irradiation position 30 of the laser beam L1 during normal welding. The second measurement region 42 and the third measurement region 43 are arranged with the first measurement region 41 sandwiched between them.

[0188] This method allows for real-time measurement of welding beams W1, W2, and W3 in the adjacent areas on both sides of the irradiation position 30 where the molten portion 31 is formed. Furthermore, it enables the evaluation of the overall welding condition, including melting and solidification phenomena in the surrounding area beyond the irradiation position 30. Therefore, the accuracy of welding condition evaluation during laser processing can be further improved. Additionally, it also allows for the evaluation of irradiation position deviation and focal point deviation.

[0189] In the laser processing method according to this embodiment, the signal intensity Pa of the welding light W1 measured in the first measurement region 41 is compared with a preset upper limit signal intensity Pau or lower limit signal intensity Pad (first threshold) (S104, S105, S107, S108). Further, the signal intensity Pb ​​of the welding light W2 measured in the second measurement region 42 is compared with a preset upper limit signal intensity Pbu (second threshold) (S102). Further, the signal intensity Pc of the welding light W3 measured in the third measurement region 43 is compared with a preset upper limit signal intensity Pcu (third threshold) (S103).

[0190] This method allows us to evaluate whether the welding condition is normal. Furthermore, in cases where the welding condition is abnormal, we can determine whether it is due to welding abnormality, irradiation position deviation, or focal spot deviation.

[0191] In the laser processing method of this embodiment, signal intensities Pa, Pb, and Pc are measured in measurement areas 41, 42, and 43. If signal intensity Pa is less than the lower limit signal intensity Pad, signal intensity Pb ​​is less than the upper limit signal intensity Pbu, and signal intensity Pc is greater than the upper limit signal intensity Pcu, it is determined that a melting abnormality has occurred on one side of the molten portion 31.

[0192] This method can pinpoint the location of melting anomalies, further improving the accuracy of welding condition evaluation during laser processing.

[0193] In the laser processing method of this embodiment, signal intensities Pa, Pb, and Pc are measured in measurement areas 41, 42, and 43. If signal intensity Pa is less than the lower limit signal intensity Pad, signal intensity Pb ​​is greater than the upper limit signal intensity Pbu, and signal intensity Pc is greater than the upper limit signal intensity Pcu, it is determined that the focal position of laser beam L1 has deviated along the irradiation direction of laser beam L1.

[0194] This method can determine the deviation of the focal position, and can further improve the evaluation accuracy of the welding status during laser processing.

[0195] The laser processing apparatus 100 of this embodiment irradiates a component 6 with a laser beam L1 and scans it in a first direction on the component 6, joining the component 6 and the adjacent component 7 via a melting section 31. The laser processing apparatus 100 includes: a laser oscillator 1, an irradiation optical system 2, a worktable 8, a measuring optical system 10, a measuring unit 14a (first sensor), a measuring unit 14b (second sensor), and a control unit 15. The laser oscillator 1 emits a laser beam L1. The irradiation optical system 2 guides the laser beam L1 to the component 6. The worktable 8 moves the component 6 and component 7 relative to the laser beam L1, causing the laser beam L1 to scan. The measuring optical system 10 guides welding light W1 and W2, radiated from at least one component 6 and component 7 by irradiation, from a first measuring region 41 and a second measuring region 42 different from the first measuring region 41, respectively. The measuring unit 14a measures the intensity of the welding light W1 guided from the first measuring region 41 to the measuring optical system 10. The measuring unit 14b measures the welding light W2 guided from the second measuring area 42 to the measuring optical system 10. The control unit 15 evaluates the welding state based on the intensity of each welding light W1, W2 measured in the first measuring area 41 and the second measuring area 42. The first measuring area 41 and the second measuring area 42 are arranged in a second direction that intersects the first direction (scanning direction K).

[0196] This structure allows for the separate evaluation of welding light W1 and W2 measured in two measurement regions 41 and 42, respectively. Therefore, it improves the accuracy of evaluating the welding condition during laser processing.

[0197] The laser processing apparatus 100 according to this embodiment further includes a first optical fiber 13a and a second optical fiber 13b. The first optical fiber 13a transmits the welding light W1, which is guided from the first measurement area 41 to the measurement optical system 10, to the measurement unit 14a. The second optical fiber 13b transmits the welding light W2, which is guided from the second measurement area 42 to the measurement optical system 10, to the measurement unit 14b.

[0198] This structure allows the welding beams W1 and W2 measured in each measurement area 41 and 42 to be transmitted to the measurement units 14a and 14b, respectively, to evaluate the intensity of the welding beams W1 and W2. Therefore, the accuracy of evaluating the processing status during laser processing can be further improved.

[0199] This disclosure is not limited to the described embodiments and can be implemented in various other ways.

[0200] Furthermore, this embodiment uses overlapping laser welding as an example for description, but this disclosure is not limited to this. It can also be applied to the evaluation of processing status in other types of lasers or other laser processing methods.

[0201] Furthermore, this embodiment describes an example using three measurement areas 41, 42, and 43, but it is not limited to this. Measuring the weld bead in two or more measurement areas can also improve the accuracy of weld condition evaluation.

[0202] Furthermore, this embodiment describes an example where the three measurement areas 41, 42, and 43 are arranged in a straight line orthogonal to the scanning direction K, but it is not limited to this. Measurement areas 41, 42, and 43 may also be configured as a straight line with an angle relative to the line orthogonal to the scanning direction K. Alternatively, measurement areas 41, 42, and 43 may be configured as a curve. The measurement areas 41, 42, and 43 need only be arranged in a configuration capable of measuring welding light. For example, one measurement area may be set at the irradiation position 30, and the other measurement areas may be arranged in a circular shape centered on that one measurement area.

[0203] Furthermore, in this embodiment, the measurement regions 41, 42, and 43 are described as circular regions with the same diameter as the melt width D1, but this is not a limitation. The measurement regions 41, 42, and 43 can simply have a shape and size that includes the area irradiated by the welding light. For example, the shape of the measurement regions 41, 42, and 43 can be changed according to the shape of the irradiation position 30 of the laser beam L1 or the temperature distribution of the melt portion 31.

[0204] Furthermore, while this embodiment describes an example of measuring welding light based on thermal radiation, it is not limited to this. The welding condition can also be evaluated when measuring other welding lights such as plasma light and laser reflected light. In particular, since laser reflected light is affected by the shape of the molten portion, the shape of the molten portion can be evaluated in more detail by assessing the signal intensity of the laser reflected light.

[0205] This disclosure has been fully described with reference to the accompanying drawings and in relation to preferred embodiments; however, various modifications and alterations will be apparent to those skilled in the art. These modifications and alterations, provided they do not exceed the scope of the invention as defined in the claims, should be understood to be included within the scope of the claims of this disclosure.

[0206] Industrial availability

[0207] The laser processing method applicable to this disclosure can evaluate not only the melting state of the laser irradiation location, but also the overall processing state of the molten or solidified portion surrounding the laser irradiation area.

Claims

1. A laser processing method comprising: irradiating a first component with a laser beam emitted from an oscillator and scanning the first component in a first direction; and joining the first component and a second component adjacent to the first component by means of a molten section; the laser processing method comprising: The step of measuring the intensity of welding light, including any one of thermal radiation light, plasma light, and reflected light, radiated from at least one of the first component and the second component by irradiation with the laser beam, in a first measurement area, a second measurement area different from the first measurement area, and a third measurement area different from both the first and second measurement areas; and The step of evaluating the processing status based on the intensity of each of the welding lights measured in the first measurement area, the second measurement area, and the third measurement area. The first measurement region and the second measurement region are arranged in a second direction that intersects the first direction. The first measurement region, the second measurement region, and the third measurement region are arranged adjacent to each other in a direction orthogonal to the first direction. The first measurement area includes the irradiation position of the laser beam during normal welding. The second and third measurement regions are configured to sandwich the first measurement region. The evaluation steps include: The signal intensity of the welding light measured in the first measurement area is compared with a preset first threshold. The signal intensity of the welding light measured in the second measurement area is compared with a preset second threshold. as well as The signal intensity of the welding light measured in the third measurement area is compared with a preset third threshold. The first threshold is a lower limit, the second threshold is an upper limit, and the third threshold is an upper limit. In the steps of the evaluation, If the signal strength measured in the first measurement region is less than the first threshold... The signal strength measured in the second measurement region is less than the second threshold. The signal strength measured in the third measurement region is greater than the third threshold. This indicates that a melting anomaly occurred on one side of the molten portion.

2. A laser processing method comprising: irradiating a first component with a laser beam emitted from an oscillator and scanning the first component in a first direction; and joining the first component and a second component adjacent to the first component through a molten section; the laser processing method comprising: The steps include measuring the intensity of welding light, comprising any one of thermal radiation light, plasma light, and reflected light, radiated from at least one of the first component and the second component by irradiation with the laser beam in a first measurement area, a second measurement area different from the first measurement area, and a third measurement area different from both the first and second measurement areas; and The step of evaluating the processing status based on the intensity of each of the welding lights measured in the first measurement area, the second measurement area, and the third measurement area. The first measurement region and the second measurement region are arranged in a second direction that intersects the first direction. The first measurement region, the second measurement region, and the third measurement region are arranged adjacent to each other in a direction orthogonal to the first direction. The first measurement area includes the irradiation position of the laser beam during normal welding. The second and third measurement regions are configured to sandwich the first measurement region. The evaluation steps include: The signal intensity of the welding light measured in the first measurement area is compared with a preset first threshold. The signal intensity of the welding light measured in the second measurement area is compared with a preset second threshold. as well as The signal intensity of the welding light measured in the third measurement area is compared with a preset third threshold. The first threshold is an upper limit value, the second threshold is an upper limit value, and the third threshold is an upper limit value. In the steps of the evaluation, If the signal strength measured in the first measurement region is less than the first threshold... The signal strength measured in the second measurement region is greater than the second threshold. The signal strength measured in the third measurement region is greater than the third threshold. It is then determined that the focal position of the laser beam has deviated along the irradiation direction of the laser beam.

3. The laser processing method according to claim 1 or 2, wherein, The steps for performing the measurement include: An optical system is used to focus the welding light from the first measurement area onto a first optical fiber, and a first sensor measures the amount of welding light transmitted through the first optical fiber. Using the same optical system as the optical system, the welding light from the second measurement area is focused onto the second optical fiber, and the welding light transmitted through the second optical fiber is measured by the second sensor.

4. The laser processing method according to claim 1 or 2, wherein, During normal welding, the molten portion has a width in a direction orthogonal to the first direction. The first measuring region and the second measuring region each have a diameter less than the width of the molten portion. The first measurement area includes the irradiation position of the laser beam during normal welding.

5. The laser processing method according to claim 4, wherein, The first measuring region and the second measuring region have a diameter that is the same size as the width of the molten portion.

6. A laser processing apparatus that irradiates a first member with a laser beam and scans the first member in a first direction, and joins the first member and a second member adjacent to the first member by means of a melting section, the laser processing apparatus comprising: Oscillator, emitting laser beam; The irradiation optical system guides the laser beam to the first component; The worktable moves the first component and the second component relative to the laser beam, causing the laser beam to scan in the first direction; The measuring optical system guides welding light, including any one of thermal radiation light, plasma light, and reflected light, radiated from at least one of the first component and the second component, through the irradiation of the laser beam from a first measuring area, a second measuring area different from the first measuring area, and a third measuring area different from the first measuring area and the second measuring area. The first sensor measures the intensity of the welding light guided from the first measurement area to the measurement optical system; The second sensor measures the intensity of the welding light guided from the second measurement area to the measurement optical system; The third sensor measures the intensity of the welding light guided from the third measurement area to the measurement optical system; and The judgment unit evaluates the processing status based on the intensity of each of the welding lights measured in the first measurement area, the second measurement area, and the third measurement area. The first measurement region and the second measurement region are arranged in a second direction that intersects the first direction. The first measurement region, the second measurement region, and the third measurement region are arranged adjacent to each other in a direction orthogonal to the first direction. The first measurement area includes the irradiation position of the laser beam during normal welding. The second and third measurement regions are configured to sandwich the first measurement region. The judgment unit performs the following operations: The signal intensity of the welding light measured in the first measurement area is compared with a preset first threshold. The signal intensity of the welding light measured in the second measurement area is compared with a preset second threshold. as well as The signal intensity of the welding light measured in the third measurement area is compared with a preset third threshold. The first threshold is a lower limit, the second threshold is an upper limit, and the third threshold is an upper limit. The judgment unit performs the following operations: If the signal strength measured in the first measurement region is less than the first threshold... The signal strength measured in the second measurement region is less than the second threshold. The signal strength measured in the third measurement region is greater than the third threshold. This indicates that a melting anomaly occurred on one side of the molten portion.

7. A laser processing apparatus that irradiates a first member with a laser beam and scans the first member in a first direction, and joins the first member and a second member adjacent to the first member by means of a melting section, the laser processing apparatus comprising: Oscillator, emitting laser beam; The irradiation optical system guides the laser beam to the first component; The worktable moves the first component and the second component relative to the laser beam, causing the laser beam to scan in the first direction; The measuring optical system guides welding light, including any one of thermal radiation light, plasma light, and reflected light, radiated from at least one of the first component and the second component, through the irradiation of the laser beam from a first measuring area, a second measuring area different from the first measuring area, and a third measuring area different from the first measuring area and the second measuring area. The first sensor measures the intensity of the welding light guided from the first measurement area to the measurement optical system; The second sensor measures the intensity of the welding light guided from the second measurement area to the measurement optical system; The third sensor measures the intensity of the welding light guided from the third measurement area to the measurement optical system; and The judgment unit evaluates the processing status based on the intensity of each of the welding lights measured in the first measurement area, the second measurement area, and the third measurement area. The first measurement region and the second measurement region are arranged in a second direction that intersects the first direction. The first measurement region, the second measurement region, and the third measurement region are arranged adjacent to each other in a direction orthogonal to the first direction. The first measurement area includes the irradiation position of the laser beam during normal welding. The second and third measurement regions are configured to sandwich the first measurement region. The judgment unit performs the following operations: The signal intensity of the welding light measured in the first measurement area is compared with a preset first threshold. The signal intensity of the welding light measured in the second measurement area is compared with a preset second threshold. as well as The signal intensity of the welding light measured in the third measurement area is compared with a preset third threshold. The first threshold is an upper limit value, the second threshold is an upper limit value, and the third threshold is an upper limit value. The judgment unit performs the following operations: If the signal strength measured in the first measurement region is less than the first threshold... The signal strength measured in the second measurement region is greater than the second threshold. The signal strength measured in the third measurement region is greater than the third threshold. It is then determined that the focal position of the laser beam has deviated along the irradiation direction of the laser beam.

8. The laser processing apparatus according to claim 6 or 7, wherein, The laser processing device also includes: The first optical fiber guides the welding light from the first measurement area to the measurement optical system and transmits it to the first sensor; and The second optical fiber guides the welding light from the second measurement area to the measurement optical system and transmits it to the second sensor.

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