Laser processing system and jig

Abstract

A laser processing system and a jig are provided. A laser processing system (1) includes a laser oscillator (20) that forms a molten portion (94) in an object (91) by irradiating a laser (L1) to a molten predetermined region (95) of a processing target surface (93) of the object (91); a light meter (4) that measures an intensity of light (L2) from the molten portion (94) of the object (91); and a jig (8) that is disposed so as not to overlap the molten predetermined region (95) on the processing target surface (93) of the object (91) in order to press the object (91). The jig (8) has a reflection surface (82) that is inclined so as to move away from the molten predetermined region (95) as it advances in a normal direction of the processing target surface (93) of the object (91).

Description

Technical Field

[0001] This disclosure generally relates to laser processing systems and fixtures. More particularly, it relates to laser processing systems and fixtures capable of evaluating laser processing. Background Technology

[0002] Laser welding, a type of laser processing, involves irradiating an object with a laser beam emitted from a laser oscillator. The heat from the laser melts a portion of the object, thus welding it to another object, thereby creating a mechanical and electrical connection. Laser welding technology is commonly used in a wide range of fields, including household appliances, precision equipment, and automotive parts.

[0003] In laser welding technology, various adjustments are typically made through trial and error, depending on the laser oscillator, the shape and size of the object. However, there are situations where the desired quality cannot be achieved with trial-and-error adjustments.

[0004] Patent Document 1 discloses a laser processing system. The laser processing system of Patent Document 1 includes: a state quantity observation unit for observing the state quantities of the laser processing system; an action result acquisition unit for acquiring the processing results processed by the laser processing system; a learning unit for receiving outputs from the state quantity observation unit and the action result acquisition unit, and for learning to correlate laser processing condition data with the state quantities and processing results of the laser processing system; and a decision unit for outputting laser processing condition data based on the laser processing condition data learned by the learning unit.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-164801 Summary of the Invention

[0008] One aspect of the laser processing system disclosed herein includes: a laser oscillator for forming a molten portion on a workpiece by irradiating a predetermined molten region onto the workpiece surface; a photometer for measuring the intensity of light from the molten portion of the workpiece; and a fixture configured on the workpiece surface to not overlap with the predetermined molten region. The fixture has a reflective surface inclined away from the predetermined molten region as it moves forward in the normal direction of the workpiece surface.

[0009] In one embodiment of this disclosure, a fixture is configured to not overlap with the predetermined molten region on a workpiece during laser processing, where a laser is irradiated onto a predetermined molten region on the workpiece's surface to form a molten portion. The fixture has a reflective surface that is tilted away from the predetermined molten region as it moves forward in the normal direction of the workpiece's surface. Attached Figure Description

[0010] Figure 1 This is a block diagram illustrating a structural example of a laser processing system according to one embodiment.

[0011] Figure 2 yes Figure 1 A diagram illustrating the movement of light from the molten section in a laser processing system.

[0012] Figure 3 yes Figure 1 A diagram illustrating the relationship between the fixture and the focusing lens in a laser processing system.

[0013] Figure 4 yes Figure 1 A schematic diagram of the structure of a fixture for a laser processing system.

[0014] Figure 5 It is a graph showing the relationship between the intensity of light from the molten section and the time change of the laser output.

[0015] Figure 6 This is a schematic cross-sectional view of the fixture structure of variation example 1.

[0016] Figure 7 This is a schematic cross-sectional view of the fixture structure of variation example 2.

[0017] Figure 8 This is a schematic diagram of the structure of the fixture in variation example 3.

[0018] Figure 9 This is a schematic diagram of the structure of the fixture in variation example 4.

[0019] Symbol Explanation

[0020] 1. Laser processing system;

[0021] 20. Laser oscillator;

[0022] 3. Optical system;

[0023] 31. Condensing lens;

[0024] 4. Light meter;

[0025] 7. Processing device;

[0026] Fixtures 8, 8A, 8B, 8C, and 8D;

[0027] 81, 81A, 81B Pressing Parts;

[0028] 82, 82A, 82B, 83, 84 Reflecting surfaces;

[0029] 91. Object;

[0030] 93. The surface to be machined;

[0031] 94. Melting section;

[0032] 95% melt zone;

[0033] L1 laser L1;

[0034] L2 is light from the molten section;

[0035] A1 Optical axis;

[0036] D1 is the effective diameter;

[0037] D2 Working distance;

[0038] H1 height;

[0039] θ1 is the angle between the optical axis of the condenser lens and the peripheral rays;

[0040] θ2 is the angle between the reflecting surface and the surface of the object being processed. Detailed Implementation

[0041] In the laser processing system described in Patent Document 1, when evaluating the processing results, the light emitted from the object caused by the laser irradiation is measured while laser processing is being performed. In cases where the laser processing is low-output or micro-processing, the laser processing conditions should ideally be kept as constant as possible to avoid deviation. Furthermore, when measuring the light from the object, it is best to ensure sufficient intensity of both the emitted and scattered light from the object.

[0042] This disclosure provides a laser processing system and fixture capable of performing stable laser processing and improving the accuracy of laser processing evaluation.

[0043] (Implementation Method)

[0044] [1-1. Summary]

[0045] Figure 1 This is a block diagram illustrating a structural example of a laser processing system 1 according to one embodiment. The laser processing system 1 processes the object 91 by irradiating it with a laser beam L1. Figure 1In this process, laser processing system 1 is used for laser welding to join object 91 to another object 92. Object 92 is positioned below object 91. By irradiating object 91 with laser L1, a portion of object 91 and object 92 are melted to form a molten portion 94, thereby melting and joining object 91 and object 92 together.

[0046] like Figure 1 As shown, the laser processing system 1 includes a laser oscillator 20, a photometer 4, and a fixture 8. The laser oscillator 20 forms a molten portion 94 on the workpiece 91 by irradiating a laser L1 onto a predetermined molten region 95 of the workpiece surface 93. When the laser L1 is irradiated onto the predetermined molten region 95 of the workpiece surface 93, the molten region 94 is formed, and light L2 is emitted from the molten region 94. The photometer 4 measures the intensity of the light L2 from the molten region 94 of the workpiece 91. The fixture 8 is positioned on the workpiece surface 93 of the workpiece 91 to press the workpiece 91. The fixture 8 has a reflective surface 82 that is tilted so that the further away from the workpiece surface 93 is from the predetermined molten region 95, the further away it is from the workpiece 91.

[0047] exist Figure 1 In the laser processing system 1, the fixture 8 is configured so that the processing surface 93 of the workpiece 91 does not overlap with the predetermined melting region 95 in order to press the workpiece 91. By utilizing the fixture 8, unintentional positional deviation of the irradiation position of the laser L1 irradiating the workpiece 91 can be reduced, enabling stable laser processing. The fixture 8 has a reflective surface 82 that is tilted away from the predetermined melting region 95 as it moves forward in the normal direction of the processing surface 93 of the workpiece 91. Figure 2 As shown, the amount of light incident on the photometer 4 from the light L2 from the molten section 94 can be increased by the reflective surface 82. This allows for an improvement in the accuracy of the laser processing evaluation.

[0048] [1-2. Details]

[0049] The following is about Figure 1 The laser processing system 1 is described in more detail. The laser processing system 1 includes a laser irradiation system 2, an optical system 3, a photometer 4, a laser output sensor 51, a camera 52, a worktable 6, a moving device 60, a processing device 7, and a fixture 8.

[0050] [1-2-1. Laser Irradiation System]

[0051] exist Figure 1 In this system, the laser irradiation system 2 irradiates the object 91 with laser L1 for laser processing. The laser irradiation system 2 includes a laser oscillator 20, a lens barrel 21, a laser transmission fiber 22, and a collimating lens 23.

[0052] The laser oscillator 20 outputs a laser L1 for laser processing of the object 91. The laser oscillator 20 is, for example, a fiber laser. The wavelength of the laser L1 is, for example, 1070 nm. The wavelength of the laser L1 is appropriately set considering the light absorption characteristics of the object 91. For example, when the material of the object 91 is copper or gold, the wavelength of the laser L1 is set to a short wavelength of 405-450 nm. For example, when the material of the object 91 is aluminum, the wavelength of the laser L1 is set to around 800 nm. Regarding this wavelength, since aluminum has good light absorption characteristics, good welding can be performed. The laser L1 can be either a continuous wave or a pulsed wave. If the laser L1 is a continuous wave, the heat input to the object 91 can be increased, thus enabling laser welding with high productivity. If the laser L1 is a pulsed wave, the heat effect during laser processing can be reduced compared to the case where the laser L1 is a continuous wave.

[0053] exist Figure 1 In the laser irradiation system 2, the laser L1 output from the laser oscillator 20 is transmitted to the lens barrel 21 via the laser transmission fiber 22. The laser L1 output from the laser transmission fiber 22 is transformed into parallel light by the collimating lens 23 inside the lens barrel 21 and then output to the optical system 3.

[0054] [1-2-2. Optical System]

[0055] The optical system 3 defines the optical path between the laser irradiation system 2, the photometer 4, the laser output sensor 51, and the camera 52. Specifically, the optical system 3 includes a condenser lens 31 facing the processing surface 93 of the object 91. The optical system 3 uses the condenser lens 31 to focus the laser L1 from the laser oscillator 20 onto the predetermined melting region 95, and directs the light L2 from the molten portion 94 incident on the condenser lens 31 toward the photometer 4. More specifically, the optical system 3 includes mirrors 30, 32, 34, 36, and 38, and condenser lenses 31, 33, 35, 37, and 39.

[0056] like Figure 1 As shown, the reflector 30 reflects a portion of the laser L1 from the laser irradiation system 2 toward the predetermined melting area 95 of the object 91, and transmits the remaining portion to the laser output sensor 51. The reflector 30 is, for example, a beam splitter. The ratio of the light transmitted through the reflector 30 to the light reflected by the reflector 30 is appropriately set. Figure 1 as well as Figure 3 As shown, the condenser lens 31 is positioned opposite the processing surface 93 of the object 91. The condenser lens 31 focuses the laser L1 reflected by the reflector 30 onto the predetermined melting area 95 of the object 91. Figure 3As shown, the condenser lens 31 is configured such that its optical axis A1 corresponds to the region that forms the molten portion 94 (the predetermined molten region 95). The condenser lens 31 is configured such that the focal point of the laser L1 is located on the processing surface 93 of the workpiece 91. In this way, the laser L1 from the laser irradiation system 2 is irradiated onto the predetermined molten region 95 of the workpiece 91, thereby forming the molten portion 94 on the workpiece 91. The optical system 3 then guides the laser L1 to the predetermined molten region 95 of the workpiece 91. Furthermore, the optical system 3 guides the laser L1 to the laser output sensor 51.

[0057] If laser L1 is irradiated onto the predetermined melting area 95 of the processing surface 93 of the object 91, a molten section 94 is formed, and light L2 is emitted from the molten section 94. Figure 1 In the optical system 3, light L2 from the molten portion 94 of the object 91 is transmitted through the condenser lens 31 and the reflector 30, and then incident on the reflector 32. The reflector 32 reflects a portion of the light L2 from the molten portion 94 of the object 91 toward the reflector 34, and transmits the remaining portion. The reflector 32 is, for example, a beam splitter such as a half-reflector. The ratio of the light transmitted through the reflector 32 to the light reflected by the reflector 30 is appropriately set. The condenser lens 33 focuses the light L2 transmitted through the reflector 32 onto the light-receiving portion of the camera 52. In this way, the optical system 3 guides the light L2 from the molten portion 94 of the object 91 to the camera 52.

[0058] The reflector 34 transmits light L3 of a specific wavelength range from the light L2 from the molten portion 94 of the object 91 to the condenser lens 35, and reflects the remaining light L4 towards the reflector 36. The reflector 34 is, for example, a dichroic mirror. The light L3 is, for example, visible light, and the specific wavelength range of the reflector 34 is, for example, 400–700 nm. The reflector 34 can be pre-selected according to the wavelength it transmits, or the ratio of transmitted to reflected light can be varied as needed. The condenser lens 35 focuses the light L3 transmitted through the reflector 34 to the light-receiving part of the light sensor 41 of the photometer 4 (described later). The reflector 36 reflects light L5 of a specific wavelength range from the light L4 reflected by the reflector 34 to the condenser lens 37, and transmits the remaining light L6 towards the reflector 38. The reflector 36 is, for example, a dichroic mirror. The light L5 is, for example, thermal radiation generated by the molten portion 94, and the specific wavelength range of the reflector 36 is, for example, 1300–1550 nm. The condenser lens 37 focuses the light L5 reflected by the reflector 36 onto the photosensitive sensor 42 of the photometer 4 (described later). The reflector 38 reflects the light L6 transmitted through the reflector 36 and directs it onto the condenser lens 39. The wavelength range of the light L1 includes, for example, the wavelength of laser light L1. The condenser lens 39 focuses the light L6 reflected by the reflector 38 onto the photosensitive sensor 43 of the photometer 4 (described later). In this way, the optical system 3 guides the light L2 from the molten portion 94 of the object 91 to the photometer 4. More specifically, the optical system 3 divides the light L2 from the molten portion 94 of the object 91 into light L3, L5, and L6 of different wavelength ranges and guides them to the photosensitive sensors 41, 42, and 43 of the photometer 4, respectively.

[0059] Figure 1 To make the optical system 3 wavelength selective, bandpass filters can be provided between the reflector 34 and the light sensor 41, between the reflector 36 and the light sensor 42, and between the reflector 38 and the light sensor 43. By preventing unwanted wavelength ranges of light from entering the light sensors 41, 42, and 43 through the bandpass filters, more accurate light measurement can be performed.

[0060] [1-2-3. Light Meter]

[0061] The photometer 4 measures the intensity of light L2 from the molten portion 94 of the object 91 and outputs an intensity signal representing the measured intensity of light L2 to the processing device 7. The intensity signal is not particularly limited, but may be, for example, a voltage signal. The light L2 from the molten portion 94 may include light of various wavelength ranges. For example, the light L2 from the molten portion 94 may include at least one of the following: thermal radiation light caused by the melting of the object 91 by irradiation with laser L1; excitation light caused by the excitation of the object 91 by irradiation with laser L1; laser plasma generated by irradiation with laser L1; and reflected light from laser L1 reflected by the object 91. Figure 1 The photometer 4 is equipped with three photosensors 41, 42, and 43 to individually measure the intensity of light in the light L2 from the molten section 94, which may contain various wavelength ranges.

[0062] As described above, the light sensor 41 receives light L3 from the optical system 3. Light L3 is light within a specific wavelength range from the light L2 originating from the molten portion 94 of the object 91. Figure 1 In the laser processing system 1, light L3 is visible light. Light sensor 41 measures the intensity of the visible light and outputs an intensity signal representing the measured intensity to processing device 7. As described above, light sensor 42 receives light L5 from optical system 3. Light L5 is light within a specific wavelength range from light L2 originating from the molten portion 94 of the object 91. Figure 1 In the laser processing system 1, light L5 is thermal radiation light. Light sensor 42 measures the intensity of the thermal radiation light and outputs an intensity signal representing the measured intensity to processing device 7. As described above, light sensor 43 receives light L6 from optical system 3. Light L6 is contained within light L2 from the molten portion 94 of the object 91. Figure 1 In the laser processing system 1, the optical sensor 43 measures the intensity of the light in the light L6 that has the same wavelength as the laser L1, and outputs an intensity signal representing the measured light intensity to the processing device 7.

[0063] The light sensors 41, 42, and 43 are, for example, photodetectors equipped with photodiodes. The photodetectors are configured to have high sensitivity relative to the wavelength range of the light being measured. The measurement resolution is configured, for example, to be capable of measurement with an accuracy of less than 1 / 100th of the measured shape. The measurement area of ​​each of the light sensors 41, 42, and 43 is configured to encompass the entire molten portion 94 at least in the width direction of the molten portion 94.

[0064] As a method to change the measurement area, adjusting the focal length of condenser lenses 31, 35, 37, and 39 can be listed. If the size of the light-receiving part of the light sensors 41, 42, and 43 is set to ds [mm], the size of the measurement area of ​​the light sensors 41, 42, and 43 is set to dm [mm], the focal length of condenser lens 31 is set to f1 [mm], and the focal length of condenser lenses 35, 37, and 39 is set to f2 [mm], then dm = ds × f1 / f2. For example, when f1 is 200mm and f2 is 100mm, the measurement area becomes twice the size of the light-receiving part. In this way, by adjusting the focal lengths f1 and f2, the size dm of the measurement area can be adjusted. Alternatively, the measurable area can be limited by setting apertures in the light sensors 41, 42, and 43 that allow for changing the opening diameter.

[0065] [1-2-4. Laser Output Sensor]

[0066] like Figure 1 As shown, the laser output sensor 51 measures the output of the laser L1 from the laser irradiation system 2 and outputs the output signal representing the output of the laser L1 to the processing device 7. Figure 1 The laser output sensor 51 measures the output of the laser L1 transmitted through the reflector 30. Since there is a correlation between the output of the laser L1 transmitted through the reflector 30 and the output of the laser L1 before it enters the reflector 30, the output of the laser L1 before it enters the reflector 30 can be determined from the output of the laser L1 transmitted through the reflector 30. Furthermore, if the output of the laser L1 transmitted through the reflector 30 exceeds the measurement range of the laser output sensor 51, an optical element that attenuates the laser L1 can be disposed between the reflector 30 and the laser output sensor 51. Additionally, to reduce the reflection of the laser L1 on the surface of the laser output sensor 51 or the optical element, the laser output sensor 51 or the optical element can be configured to be tilted relative to the optical axis of the laser L1 transmitted through the reflector 30.

[0067] [1-2-5. Camera]

[0068] Camera 52 acquires images of the area surrounding the molten portion 94 of the object 91 and outputs the acquired images to processing device 7. As described above, camera 52 receives light L2 from the molten portion 94 of the object 91 from optical system 3. The sampling period (measurement period) of camera 52 is set, for example, to be less than 1 / 100th of the output control time for laser irradiation. The images acquired by camera 52 are used to detect the state of light emission or reflection from the molten portion 94.

[0069] [1-2-6. Workbench]

[0070] The worktable 6 supports the laser-processed object 91. Figure 1 In the process, object 92 is positioned below object 91. Objects 91 and 92 are configured on the workbench 6. Figure 1 In the laser processing system 1, object 91 and object 92 are held by fixture 8 on the worktable 6.

[0071] [1-2-7. Mobile Devices]

[0072] The moving device 60 moves the worktable 6, thereby moving the laser L1 from the laser irradiation system 2 towards the irradiation position of the object 91. The moving device 60 has a power source such as an electric motor to move the worktable 6. The movement of the worktable 6, in turn, moves both the object 91 and the object 92. Figure 1In the middle, the moving device 60 causes the worktable 6 to move along the same path as the worktable 6. Figure 1 It moves in a straight line in a direction orthogonal to the paper. Figure 1 The laser processing system 1 moves synchronously with the worktable 6 to irradiate the object 91 with laser L1, thereby joining the object 91 and object 92 by laser welding.

[0073] [1-2-8. Fixture]

[0074] like Figures 1-3 As shown, in laser processing where a laser L1 is irradiated onto a predetermined molten region 95 of the workpiece surface 93 to form a molten portion 94 on the workpiece 91, the fixture 8 is positioned on the workpiece surface 93 to press the workpiece 91. Considering, for example, sputtering caused by laser L1 irradiation, the material of the fixture 8 is a high-melting-point material such as metal.

[0075] The clamp 8 is used to press the object 91 so that it does not cause a shift in the irradiation position of the laser L1, or a change in the position or shape of the object 91 during laser processing. For example, as Figure 1 As shown, when objects 91 and 92 are stacked for welding, the position of the fixture 8 prevents objects 91 and 92 from floating up at the laser L1 irradiation point. Even when objects 91 and 92 are not stacked for welding, the suppression of positional displacement of object 91 is effective; therefore, the fixture 8 is effective in laser processing. By utilizing the fixture 8, unintentional positional displacement of the laser L1 irradiation point on object 91 can be reduced, enabling stable laser processing.

[0076] Figure 2 yes Figure 1 This diagram illustrates the operation of the light L2 from the molten section 94 in the laser processing system 1. When the laser L1 irradiates the object 91, the molten section 94 is formed. For example, if the object 91 is metal, thermal radiation light caused by temperature rise, inherent luminescence of the metal, and luminescence caused by plasma will be generated in the molten section 94. Furthermore, not all of the laser L1 is used for laser processing; a portion of the laser L1 is reflected by the molten section 94 as return light.

[0077] When measuring the light L2 from the molten region 94 in real time during laser processing, the light L2 from the molten region 94 may include thermal radiation light, visible light, excitation light, laser plasma, and reflected light. The intensity of the light L2 from the molten region 94 is important information reflecting the state of the molten region 94, such as shape changes. For example, by measuring thermal radiation light, visible light, excitation light, laser plasma, and reflected light in real time, it is possible to obtain the intensity of light corresponding to the shape of the molten region 94 corresponding to the laser processing conditions.

[0078] For example, when the shape of the molten portion 94 changes abruptly in the direction opposite to the incident direction of the laser L1 towards the object 91, the reflected light or the luminescent component in the molten portion 94 changes significantly due to the change in its shape. For example, if the width or length of the molten portion 94 changes, the intensity of the light L2 from the molten portion 94 will differ depending on the changed width or length. In other words, the intensity of the light L2 from the molten portion 94 will also change depending on the change in the molten area of ​​the molten portion 94. For example, if the focal position of the laser L1 changes, the point diameter at the irradiation position where the laser L1 irradiates the object 91 changes. If the focal position of the laser L1 changes from precisely focusing, coinciding with the predetermined molten area 95 of the object 91, and thus the point diameter increases, the welding area of ​​the molten portion 94 also increases, thereby increasing the light L2 from the molten portion 94.

[0079] Using this phenomenon, the shape of the molten part 94 can be inferred from the intensity of the light L2 from the molten part 94, or the situation where the current shape of the molten part 94 differs from the shape originally intended to be processed can be determined.

[0080] For example, by measuring or calculating and storing the light L2 during laser processing at the desired melt width, and comparing it with the light L2 during actual laser processing, the status of laser processing can be more precisely understood.

[0081] For example, by measuring the molten portion 94 after processing and by measuring the width of the molten portion 94 based on the processing results, the intensity of light L2 can be correlated with the measured value of the molten portion 94, thereby enabling the detection of measurement results based on the molten area.

[0082] Generally, the shape of the molten portion 94 has a significant impact on the joint strength based on laser welding. Therefore, if the shape of the molten portion 94 can be measured with good accuracy, defects such as joint deviation during laser welding can be reduced, and product quality can be stabilized.

[0083] Generally, when the object 91 is metallic, for welding, although the absorptivity of the material 91 at the wavelength of laser L1 and the irradiation conditions of laser L1 also depend on the material 91, the output of laser L1 needs to be tens to several kW. In particular, when welding is performed with a low-output laser L1, the amount of light L2 from the molten portion 94 decreases as the output of laser L1 decreases. Therefore, it becomes difficult to detect the luminescence state of the molten portion 94.

[0084] Therefore, the amount of light incident on the photometer 4 from the light L2 from the molten section 94 can be increased, thereby enabling a more accurate and better grasp of the molten state of the molten section 94, and thus improving the accuracy of the evaluation of laser processing.

[0085] like Figure 2 As shown, the light L2 from the molten section 94 also depends on the shape of the molten section 94, but it is not directional like a laser; instead, it is isotropically broadened from the molten section 94. The light L2 from the molten section 94 includes, for example, light L21 traveling in the direction reaching the photometer 4, and light L22 traveling in a direction that cannot reach the photometer 4 if there is no clamp 8. Light L21, for example, travels in a direction opposite to the optical axis of the laser L1 and is incident on the condenser lens 31. If there is no clamp 8, light L22, for example, travels in a direction intersecting the optical axis of the laser L1 and does not occur on the condenser lens 31.

[0086] like Figures 1-3 As shown, the fixture 8 has a reflective surface 82. The reflective surface 82 is a conical surface inclined so that it moves away from the predetermined melting region 95 as it advances in the normal direction to the workpiece surface 93 of the workpiece 91. More specifically, the reflective surface 82 is inclined such that the further it moves away from the workpiece surface 93 in the normal direction to the workpiece surface 93 of the workpiece 91, the further it moves away from the predetermined melting region 95 in the surface direction of the workpiece surface 93. Figure 2 In this configuration, the normal direction of the workpiece surface 93 is opposite to the travel direction of the laser L1. The direction along the surface of the workpiece surface 93 is orthogonal to the normal direction of the workpiece surface 93. In other words, the reflecting surface 82 is tilted to reflect the light L2 from the molten section 94 toward the focusing lens 31. Figure 2 As shown, the reflective surface 82 can reflect light L22 in the direction it reaches the photometer 4. Therefore, the amount of light incident on the photometer 4 from the molten section 94 in the light L2 can be increased. As a result, the accuracy of the evaluation of laser processing can be improved.

[0087] The structure of fixture 8 will be described in detail below. Figure 4 This is a schematic diagram of the structure of fixture 8. Figure 4 (A) is a top view showing the state in which the fixture 8 is configured on the machining surface 93 of the object 91. Figure 4 (B) is Figure 4 (A) of (B)-(B) section view.

[0088] The fixture 8 is configured on the workpiece surface 93 so as not to overlap with the predetermined molten region 95 that forms the molten portion 94. Therefore, the fixture 8 is formed to press the workpiece 91 around the predetermined molten region 95 on the workpiece surface 93. On the other hand, when the reflective surface 82 is close to the molten portion 94, the amount of light incident on the photometer 4 from the light L2 from the molten portion 94 can be increased. However, if the reflective surface 82 is too close to the molten portion 94, the width of the molten portion 94 will deviate, and sometimes the laser L1 will illuminate the reflective surface 82. Therefore, the reflective surface 82 is configured to be separated from the predetermined molten region 95 by a given distance, so that the laser L1 does not incident on the reflective surface 82. The given distance is, for example, 1 mm or more.

[0089] like Figure 4 As shown, the fixture 8 has a pair of pressing parts 81. The pair of pressing parts 81 are located on both sides of the predetermined melting area 95 of the workpiece surface 93. Figure 4 In this configuration, the predetermined molten region 95 is linear. This predetermined molten region 95 is set during line welding and other line-machining processes using laser L1. Figure 4 In this configuration, a pair of pressing portions 81 are located on either side of the predetermined melting region 95 in the width direction. The surface of each pressing portion 81 on the side facing the predetermined melting region 95 includes a reflective surface 82. Figure 4 In this design, the pressing part 81 is a rectangular plate extending along the predetermined melting region 95. A pair of pressing parts 81 are parallel to each other. One of the two sides of each pressing part 81 in the width direction is a reflective surface 82. The pressing part 81 is positioned on the workpiece surface 93 with its reflective surface 82 facing the predetermined melting region 95. The reflective surfaces 82 of the pair of pressing parts 81 are opposite each other. The further away from the workpiece surface 93 in the normal direction from the workpiece surface 93, the greater the distance between the reflective surfaces 82 of the pair of pressing parts 81. Figure 4 In this structure, the reflecting surface 82 is an inclined surface tilted at a fixed angle. As long as the angle of the reflecting surface 82 is 1 degree or more, there is a possibility that light L2 from the molten section 94 can pass through the condenser lens 31 and enter the photometer 4. The reflecting surface 82 is a reflective surface that performs specular reflection of light L2 from the molten section 94. The surface roughness of the reflecting surface 82 is less than or equal to that of a mirror. Surface roughness can be evaluated, for example, by any one of the following: arithmetic mean roughness (Ra), maximum height (Ry), ten-point mean roughness (Rz), average spacing of unevenness (Sm), average spacing of local peaks (S), and load length ratio (tp). The reflecting surface 82 is obtained by mirror polishing or other mirror finishing processes. The surface roughness of the reflecting surface 82 can also be less than or equal to that obtained by mirror polishing.

[0090] Figure 3This is an explanatory diagram of the relationship between the fixture 8 and the condenser lens 31. In the fixture 8, the reflecting surface 82 is positioned opposite the region within the effective diameter D1 of the condenser lens 31 along the optical axis A1. This increases the amount of light incident on the photometer 4 from the light L2 originating from the molten section 94. Figure 4 In this configuration, the reflective surface 82 is positioned entirely opposite to the region within the effective diameter D1 of the condenser lens 31 along the optical axis A1. However, it is sufficient that at least a portion of the reflective surface 82 is opposite to the region within the effective diameter D1 of the condenser lens 31 along the optical axis A1. In other words, it is sufficient that the position P1 of the part of the reflective surface 82 closest to the predetermined melting region 95 is located inside the region within the effective diameter D1 of the condenser lens 31.

[0091] exist Figure 3 In this configuration, the pressing part 81 is arranged such that the reflective surface 82 is opposite to the region within the effective diameter D1 of the condenser lens 31 along the optical axis A1 of the condenser lens 31. In this case, the angle of the reflective surface 82 relative to the workpiece surface 93 is set such that the probability of the laser L1 illuminating the reflective surface 82 is reduced. For example... Figure 3 As shown, if the angle between the optical axis A1 of the condenser lens 31 and the peripheral ray L11 is set to θ1 degrees, and the angle between the reflecting surface 82 and the workpiece surface 93 is set to θ2 degrees, then θ2 < 90 - θ1. The peripheral ray L11 is the light in the laser L1 that passes through the circumference defined by the effective diameter D1 of the condenser lens 31. When θ2 satisfies θ2 < 90 - θ1, the possibility of the laser L1 hitting the reflecting surface 82 can be reduced. Furthermore, the height H1 of the reflecting surface 82 is below the working distance D2 of the condenser lens 31. Figure 3 In this configuration, the height H1 of the reflective surface 82 is equal to the height of the pressing part 81. This allows the irradiation position of the laser L1 to be adjusted according to the focal point of the condenser lens 31 when the laser L1 is irradiated onto the object 91. Therefore, interference between the condenser lens 31 and the reflective surface 82 can be prevented when changing the irradiation position of the laser L1.

[0092] [1-2-9. Processing device]

[0093] like Figure 1 As shown, the processing unit 7 is connected to the laser irradiation system 2, the photometer 4, the laser output sensor 51, the camera 52, and the moving device 60. The processing unit 7 performs overall control of the laser processing system 1. The processing unit 7 is implemented, for example, by a computer system containing one or more processors (microprocessors) and one or more memories.

[0094] The processing apparatus 7 performs laser processing, in which laser L1 is irradiated from the laser oscillator 20 onto a predetermined melting area 95 of the object 91 to form a molten portion 94. During laser processing, the processing apparatus 7 controls the laser oscillator 20 such that the output of the laser L1 from the laser irradiation system 2 becomes a given target output. More specifically, the processing apparatus 7 controls the laser oscillator 20 such that the intensity of the laser L1, as indicated by the output signal from the laser output sensor 51, becomes a given target output.

[0095] The processing apparatus 7 performs an evaluation of the laser processing based on the intensity of light L2 from the molten portion 94 measured by the photometer 4. The evaluation of the laser processing includes inferring the melting state of the molten portion 94 based on the intensity of light L2 from the molten portion 94 measured by the photometer 4.

[0096] Figure 5 This is a graph showing the relationship between the intensity of light L2 from the molten section 94 and the time-varying output of laser L1. Figure 5 In the above, light L2 is thermal radiation light.

[0097] exist Figure 5 In this diagram, G1 represents the time-varying output profile of laser L1. The output profile of G1 is a trapezoidal waveform, comprising a slowly rising portion (T1~T2), a flat portion (T2~T3), and a slowly falling portion (T3~T4). The slowly rising and falling portions are designed to prevent sputtering or denting during laser welding. By varying the shape of the output profile according to the laser processing, sputtering or denting can be prevented.

[0098] G2 indicates Figure 1 The laser processing system 1 represents the time-varying intensity of light L2 from the molten section 94, i.e., the light profile. G3 represents the time-varying intensity of light L2 from the molten section 94, i.e., the light profile, in the comparative example's laser processing system. The comparative example's laser processing system differs from the standard system in that it lacks a fixture 8. Figure 1 1. Laser processing system.

[0099] As shown in G1 to G3, with the increase in the output of laser L1 from time T1 to T2, the intensity of the thermal radiation light also increases. When the output of laser L1 is stable, if the molten section 94 also forms stably, the signal waveform is constant or proportional to the irradiation time, and the light intensity increases until the temperature reaches equilibrium. If there is an anomaly in the molten section 94, such as at times T5 to T6 or T7 to T8, even if the output of laser L1 is constant, the intensity of the thermal radiation light changes. With the decrease in the output of laser L1 from time T3 to T4, the intensity of the thermal radiation light also decreases. Thus, the light profile of the thermal radiation light becomes similar in shape to the output profile of laser L1.

[0100] Here, the overall light profile of G2 is larger than that of G3. This is because, in G2, the amount of light incident on the photometer 4 from the light L2 originating from the molten section 94 can be increased by the reflecting surface 82 of the fixture 8. This increases the light profile reflecting the shape of the molten section 94, thus improving the accuracy of laser processing evaluation. Furthermore, since the amount of light incident on the photometer 4 from the light L2 originating from the molten section 94 can be increased, the influence of external interference can be reduced, thereby improving the accuracy of the photometer 4 in measuring the light L2.

[0101] As described above, by measuring the intensity of light L2 from the molten portion 94, the state of the molten portion 94 can be determined. Therefore, by measuring the shape and other states of the molten portion 94 formed by laser processing, the measurement results of the molten portion 94 are correlated with the waveform of the intensity signal from the photometer 4. Thus, the processing device 7 can determine whether any abnormalities have occurred in the molten portion 94 based on the waveform of the intensity signal from the photometer 4. There are no particular limitations on the measurement of the state of the molten portion 94, but a microscope or the like can be used.

[0102] More specifically, the processing device 7 evaluates the laser processing based on a comparison of the measured waveform and a reference waveform. The measured waveform represents the change in intensity of light L2 from the molten section 94 as measured by the photometer 4. The reference waveform includes a normal waveform representing the change in intensity of light L2 from the molten section 94 when the laser processing is normal, and one or more abnormal waveforms representing the change in intensity of light L2 from the molten section 94 when the laser processing is abnormal. Thus, the processing device 7 can infer the melting state of the molten section 94 based on the intensity of light L2 from the molten section 94 measured by the photometer 4.

[0103] The causes of abnormalities in laser processing can be listed as sputtering, smoke generation, plasma generation, laser output variation, spot diameter variation, laser irradiation time variation, and workpiece variations.

[0104] One example of a defect in laser welding is the gap between multiple objects 91 and 92 when they are stacked. In the case of stacked welding where laser L1 is irradiated onto the stacked objects 91 and 92 from the direction in which they are stacked to weld them together, it is best for the objects 91 and 92 to be in close contact with each other. This is because if gaps exist between the objects 91 and 92 due to deformation caused by heat during laser processing or deformation of the objects 91 and 92 before laser processing, problems such as incomplete bonding or insufficient strength at the bonded portion will occur. When gaps exist between the objects 91 and 92, the molten portion 94 may penetrate through one object 91 and fall into the gap. Furthermore, when a gap is formed, the shape of the molten portion 94 changes due to light scattering in the gap, and sometimes the width of the molten portion 94 may become narrower. Therefore, a decrease in the intensity of thermal radiation or reflected light can be observed.

[0105] Therefore, in the case of overlapping welding, the gap between objects 91 and 92 can be inferred by the decrease in the intensity of reflected light. At this time, it is necessary to measure the decrease in the intensity of reflected light with good sensitivity.

[0106] Furthermore, the processing device 7 detects the state of the luminous or reflected light of the molten part 94 based on the image acquired from the camera 52.

[0107] [1-3. Effects, etc.]

[0108] The above description Figure 1 The laser processing system 1 includes a laser oscillator 20, a photometer 4, and a fixture 8. The laser oscillator 20 forms a molten portion 94 on the workpiece 91 by irradiating a laser L1 onto a predetermined molten region 95 of the workpiece surface 93. The photometer 4 measures the intensity of the light L2 from the molten region 94 of the workpiece 91. The fixture 8 is positioned on the workpiece surface 93 of the workpiece 91 to press it down. The fixture 8 has a reflective surface 82 that is tilted so that the workpiece surface 93, further away from the workpiece 91, is further away from the predetermined molten region 95. This allows for stable laser processing and improves the accuracy of laser processing evaluation.

[0109] In addition, Figure 1 In the laser processing system 1, the reflecting surface 82 is a reflective surface that mirrors the light L2 from the molten section 94. This increases the amount of light incident on the photometer 4 from the light L2 from the molten section 94, thereby improving the accuracy of laser processing evaluation.

[0110] also, Figure 1The laser processing system 1 includes an optical system 3. The optical system 3 includes a condenser lens 31 facing the processing surface 93 of the workpiece 91. The optical system 3 focuses the laser L1 from the laser oscillator 20 onto a predetermined melting region 95 via the condenser lens 31. The optical system 3 directs the light L2 from the molten portion 94 incident on the condenser lens 31 toward the photometer 4. The reflecting surface 82 is tilted to reflect the light L2 from the molten portion 94 toward the condenser lens 31. This enables stable laser processing.

[0111] In addition, Figure 1 In the laser processing system 1, the height H1 of the reflecting surface 82 is below the working distance D2 of the focusing lens 31. Therefore, when the irradiation position of the laser L1 is changed, interference between the focusing lens 31 and the reflecting surface 82 can be prevented.

[0112] In addition, Figure 1 In the laser processing system 1, at least a portion of the reflecting surface 82 is aligned with a region within the effective diameter D1 of the condenser lens 31 along the optical axis A1 of the condenser lens 31. This increases the amount of light incident on the photometer 4 from the light L2 from the molten section 94, thereby improving the accuracy of the laser processing evaluation.

[0113] In addition, Figure 1 In the laser processing system 1, if the angle between the optical axis A1 of the focusing lens 31 and the peripheral light rays is set to θ1 degrees, and the angle between the reflecting surface 82 and the processing object surface 93 is set to θ2 degrees, then θ2 < 90 - θ1. This reduces the likelihood of the laser L1 illuminating the reflecting surface 82.

[0114] In addition, Figure 1 In the laser processing system 1, the fixture 8 has a pair of pressing parts 81 located on both sides of the predetermined melting region 95. The surface of each pair of pressing parts 81 on the side of the predetermined melting region 95 includes a reflective surface 82. As a result, stable laser processing can be performed in line processing using laser L1, and the accuracy of laser processing evaluation can be improved.

[0115] In addition, Figure 1 In the laser processing system 1, the light L2 from the melting section 94 includes at least one of the following: thermal radiation light caused by the melting of the object 91 by irradiation of the laser L1; excitation light caused by the excitation of the object 91 by irradiation of the laser L1; laser plasma generated by irradiation of the laser L1; and reflected light from the object 91. This improves the accuracy of the evaluation of laser processing.

[0116] also, Figure 1The laser processing system 1 also includes a processing unit 7. The processing unit 7 performs laser processing by irradiating a predetermined molten region 95 with laser L1 from a laser oscillator 20 to form a molten portion 94. The processing unit 7 evaluates the laser processing based on the intensity of light L2 from the molten portion 94 measured by a photometer 4. This enables stable laser processing and improves the accuracy of the laser processing evaluation.

[0117] In addition, Figure 1 In the laser processing system 1, the evaluation of laser processing includes inferring the melting state of the molten portion 94 based on the intensity of light L2 from the molten portion 94 measured by the photometer 4. Thus, the melting state of the molten portion 94 can be evaluated. In particular, the laser processing system 1 can increase the amount of light incident on the photometer 4 from the light L2 from the molten portion 94, thereby enabling accurate evaluation of the melting state, such as the welding state. The laser processing system 1 can, for example, accurately evaluate the welding quality. By using the laser processing system 1 for welding quality evaluation, it is possible to predict welding anomalies without relying on skill level. Therefore, it is expected to achieve a reduction in the number of defects due to early response to anomalies and an increase in productivity due to reduced equipment downtime.

[0118] The fixture 8 described above is positioned on the workpiece surface 93 of the workpiece 91 to press the workpiece 91 during laser processing, in which a laser L1 is irradiated onto the predetermined melting region 95 of the workpiece surface 93 to form a molten portion 94 on the workpiece 91. The fixture 8 has a reflective surface 82 that is tilted so that the workpiece surface 93, which is further away from the workpiece 91, is further away from the predetermined melting region 95. As a result, stable laser processing can be performed, and the accuracy of laser processing evaluation can be improved.

[0119] (Modified Example)

[0120] The embodiments disclosed herein are not limited to the embodiments described above. Various modifications can be made to the above embodiments, depending on the design, etc., as long as the objectives of this disclosure are achieved. Hereinafter, variations of the above embodiments are listed. The variations described below can be appropriately combined and applied.

[0121] [1. Variation Example 1]

[0122] Figure 6 This is a schematic cross-sectional view of the structure of clamp 8A in modified example 1. Clamp 8A has a pair of pressing parts 81A. The height H1 of the reflective surface 82A of the pressing part 81A is greater than... Figure 4The height H1 of the reflective surface 82 of the pressing part 81 is high and equal to the working distance D2 of the condenser lens 31. Even in Modified Example 1, the irradiation position of the laser L1 can be changed according to the focal position of the condenser lens 31 when the laser L1 is irradiated onto the object 91. Therefore, when changing the irradiation position of the laser L1, interference between the condenser lens 31 and the reflective surface 82A can be prevented. In addition, since the gap between the reflective surface 82A and the condenser lens 31 can be reduced, the amount of light incident on the photometer 4 from the light L2 from the melting part 94 can be increased, thereby improving the accuracy of the laser processing evaluation.

[0123] [2. Variation Example 2]

[0124] Figure 7 This is a schematic cross-sectional view of the structure of fixture 8B in Modified Example 2. Fixture 8B has a pair of pressing portions 81B. The reflecting surface 82B of the pressing portion 81B is not an inclined surface with a fixed angle but a concave surface with a given curvature. The reflecting surface 82B is approximately arc-shaped in a cross-section orthogonal to the length direction of the pressing portion 81B. In the cross-section orthogonal to the length direction of the pressing portion 81B, the maximum value of the angle between the tangent of the reflecting surface 82B and the workpiece surface 93 is set to 90-θ1. As a result, the amount of light incident on the photometer 4 from the light L2 from the melting portion 94 can be increased, and the accuracy of the laser processing evaluation can be improved. The reflecting surface 82B of the pressing portion 81B can also be convex rather than concave, as long as it is a curved surface.

[0125] [3. Variation Example 3]

[0126] Figure 8 This is a schematic diagram of the structure of fixture 8C in variation 3. Figure 8 (A) is a top view showing the state in which the fixture 8C is configured on the machining surface 93 of the object 91. Figure 8 (B) is Figure 8 (A) Sectional view along (B)-(B). The fixture 8C is a cylindrical pressing part that surrounds the predetermined melting area 95 of the workpiece surface 93. The fixture 8C is quadrilateral in top view. The inner circumferential surface of the fixture 8C, which serves as the pressing part, includes a reflective surface 83. Figure 8 In this fixture 8C, the inner circumferential surface is inclined such that the opening increases as it advances along the normal direction of the workpiece surface 93. That is, each of the four inner surfaces constituting the inner circumferential surface of the fixture 8C is an inclined reflective surface 83 that moves away from the predetermined melting region 95 as it advances along the normal direction of the workpiece surface 93. In other words, the fixture 8C is configured such that the reflective surface 83 surrounds the predetermined melting region 95. This increases the amount of light incident on the photometer 4 from the light L2 from the molten section 94, improving the accuracy of laser processing evaluation. Figure 8Such a molten predetermined area 95 is set, for example, during spot processing using laser L1, such as spot welding. Therefore, in spot processing using laser L1, stable laser processing can be performed, and the accuracy of laser processing evaluation can be improved. The top view shape of the fixture 8C is not limited to a quadrilateral, but can also be a polygon other than a quadrilateral. That is, the inner peripheral surface of the fixture 8C can be composed of three or more inner surfaces, or at least one of the three or more inner surfaces can be a reflecting surface 83.

[0127] In Modification 3, the fixture 8C has a cylindrical pressing part that surrounds the predetermined melting area 95. The inner circumferential surface of the pressing part includes a reflective surface 83. According to Modification 3, in point processing using laser L1, stable laser processing can be performed, and the accuracy of laser processing evaluation can be improved.

[0128] [4. Variation Example 4]

[0129] Figure 9 This is a schematic diagram of the structure of fixture 8D in variation 4. Figure 9 (A) is a top view showing the state in which the fixture 8D is configured on the machining surface 93 of the object 91. Figure 9 (B) is Figure 9 (A) Sectional view along (B)-(B). The fixture 8D is a cylindrical pressing part that surrounds the predetermined melting area 95 of the machining surface 93 of the object 91. The fixture 8D is circular in top view. The inner circumferential surface of the fixture 8D, which serves as the pressing part, includes a reflective surface 84. Figure 9 In this design, the inner circumferential surface of the fixture 8D is inclined such that the opening increases as it advances along the normal direction of the workpiece surface 93. In other words, the entire inner circumferential surface of the fixture 8D is inclined such that it moves away from the reflecting surface 84 of the predetermined melting region 95 as it advances along the normal direction of the workpiece surface 93. In other words, in the fixture 8D, the reflecting surface 84 surrounds the predetermined melting region 95. This increases the amount of light incident on the photometer 4 from the light L2 from the molten portion 94, thereby improving the accuracy of laser processing evaluation. Figure 9 Such a molten predetermined area 95 is set, for example, during spot processing using laser L1, such as spot welding. Therefore, in spot processing using laser L1, stable laser processing can be performed, and the accuracy of laser processing evaluation can be improved. The top view shape of the fixture 8D is not limited to a perfect circle, but can also be elliptical.

[0130] In Modification 4, the fixture 8D has a cylindrical pressing part that surrounds the predetermined melting region 95. The inner circumferential surface of the pressing part includes a reflective surface 84. According to Modification 4, in point processing using laser L1, stable laser processing can be performed, and the accuracy of laser processing evaluation can be improved.

[0131] [5. Other variations]

[0132] In a variation, the fixture 8 may be a part, rather than an integral part, disposed on the workpiece surface 93 of the workpiece 91 for pressing the workpiece 91. In short, the fixture 8 may be either the pressing part disposed on the workpiece surface 93 of the workpiece 91 for pressing the workpiece 91, or a structure that includes the pressing part.

[0133] In a variation, the reflective surface 82 may also comprise multiple inclined surfaces tilted at different angles. The reflective surface 82 may also comprise multiple curved surfaces with different curvatures. In short, the reflective surface 82 only needs to be tilted such that the further away from the workpiece surface 93 is from the object 91, the further away from the predetermined melting region 95 it is.

[0134] In a variation, the reflecting surface 82 may not be opposite to the region within the effective diameter D1 of the condenser lens 31 along the optical axis A1 of the condenser lens 31. That is, the position P1 of the part of the reflecting surface 82 closest to the predetermined melting region 95 may also be outside the region within the effective diameter D1 of the condenser lens 31. In this case, θ2 may also be set to ≥ 90 - θ1.

[0135] exist Figure 1 In the laser processing system 1, a structure is configured to simultaneously measure light in multiple wavelength ranges, thereby enabling detailed understanding of the physical phenomena generated during laser processing based on light in various wavelength ranges. Therefore, it is preferable to select the wavelength range of optical elements such as mirrors or lenses according to the wavelength range of the light to be measured. For example, when measuring visible light and thermal radiation light, a wavelength-selective reflective film that transmits visible light is formed on the mirror, through which light is distributed to the light sensor measuring thermal radiation light and the light sensor measuring visible light. By utilizing such a wavelength-selective reflective film, light in different wavelength ranges can be measured simultaneously. In a variation, the laser processing system 1 may also be a structure that measures light in a single wavelength range.

[0136] exist Figure 1 In the laser processing system 1, the laser L1 output from the laser oscillator 20 is transmitted to the lens barrel 21 by the laser transmission fiber 22, but the laser L1 output from the laser oscillator 20 can also be transmitted to the lens barrel 21 by optical elements such as a reflector.

[0137] exist Figure 1 In the laser processing system 1, the object 91 is irradiated with laser L1. At this time, the molten portion 94 can be formed either as a point or by scanning the laser L1 to form a continuously extending linear molten portion 94. Figure 1In the laser processing system 1, laser L1 can be scanned by moving the worktable 6 via the moving device 60. Alternatively, the moving device 60 can move the lens barrel 21 instead of the worktable 6 to scan the laser L1. A robot can also be used to move either the lens barrel 21 or the worktable 6, instead of the moving device 60. Furthermore, a galvanometer reflector can be used to scan the laser L1 relative to the object 91.

[0138] In one variation, when a continuously extending molten section 94 is formed by scanning with laser L1, the measurement area of ​​the photosensitive sensors 41, 42, and 43 can be set to include the entire predetermined molten region 95 corresponding to such molten section 94. When laser processing is performed by scanning with laser L1, light is emitted in the molten section 94 based on the energy received from laser L1, even at an irradiation position preceding the current irradiation position of laser L1. Therefore, by setting a region wider than the irradiation position of laser L1 as the measurement area for light from the molten section 94, phenomena occurring during melting, such as sputtering or the effects of molten liquid generated before solidification after laser L1 irradiation, can be detected.

[0139] In one variation, the laser processing system 1 can measure not only the intensity of the light L2 from the molten section 94, but also the temperature of the molten section 94 and the vibration of the object 91.

[0140] In a modified example, the correlation between the variation in the intensity signal during the measurement time and the change in the shape of the molten part 94 during the processing time can be obtained by comparing the measurement time of the intensity signal obtained from the photometer 4 with the actual processing time obtained by dividing the length of the molten part 94 of the object 91 by the laser processing speed. Thus, the processing device 7 can quantify the change in the shape of the molten part 94 based on the variation in the intensity signal obtained from the photometer 4. Regarding the number of samples measured in the photometer 4, a sufficient number of samples is needed to capture the characteristics of the laser processing process, such as the local values ​​of physical quantities like the curvature of the curve of the laser L1 output profile, in order to evaluate laser processing. Therefore, the sampling period (measurement period) in the photometer 4 is preferably less than 1 / 100th of the time for laser irradiation output control.

[0141] In one variation, by changing the conditions during laser processing to various conditions and acquiring the intensity signal of light L2 from the molten zone 94, upper and lower limits are set relative to the value represented by the intensity signal. This allows for the phased prediction or evaluation of the laser processing conditions based on the value represented by the intensity signal. For example, if an opening occurs in the molten zone 94 during welding, the value represented by the intensity signal increases because light is generated instantaneously at the time of opening. Therefore, by detecting the instantaneous peak value of light L2 from the molten zone 94 during laser processing, the cause can be evaluated in real time. In this case, the processing device 7 can determine whether there is an abnormality by whether the value represented by the intensity signal is between the upper and lower limits.

[0142] In one variation, the waveform of the intensity signal and the melting state of the molten part 94 are used as a training dataset. Through teacher-guided machine learning, a learned model can be generated that has learned the correlation between the waveform of the intensity signal and the melting state of the molten part 94. In this case, the processing device 7 can use the learned model and determine the melting state of the molten part 94 based on the waveform of the intensity signal obtained from the photometer 4.

[0143] For example, by utilizing a learned model that has learned the correlation between the waveforms of the intensity signals measured by light sensors 41, 42, and 43 and the shape of the molten portion 94, the shape of the molten portion 94 can be determined based on the waveforms of the intensity signals from light sensors 41-42. For instance, in the case of laser welding, a learning dataset is used as teacher data, taking the waveforms of the intensity signals from light sensors 41-42 as input and the results of laser welding as output. The results of laser welding include, for example, the width and length of the molten portion 94, and the presence or absence of areas that do not require welding. By utilizing machine learning with teacher data, a learned model that has learned the correlation between the waveforms of the intensity signals and the results of laser welding can be generated.

[0144] By using a learned model that employs machine learning to study the correlation between the waveform of the intensity signal and phenomena occurring during laser processing, the state of the molten region 94 can be determined with greater accuracy. By displaying the state of the molten region 94 on a monitor or similar device, improvements to the equipment or conditions of the laser processing system 1 can be achieved. Specifically, by using machine learning with a dataset containing the specific causes of welding defects and physical quantities related to the molten state, such as the waveform of the intensity signal of light L2 (including thermal radiation, visible light, and reflected light) from the molten region 94, a learned model can be generated that studies the correlation between the waveform of the intensity signal and the causes of laser processing defects, such as welding defects.

[0145] In one variation, the abnormality of the molten portion 94 is correlated with the waveform of the intensity signal, and the presence or absence of an abnormality is determined by comparing the intensity signal with a threshold, thereby enabling the determination of the cause of the abnormality. For example, the processing device 7 can determine that an abnormality corresponding to a given threshold has occurred when the value of the intensity signal obtained from the photometer 4 exceeds a given threshold.

[0146] (Way)

[0147] As can be seen from the above embodiments and variations, this disclosure includes the following methods. Hereinafter, symbols in parentheses are used only to clearly indicate the correspondence with the embodiments.

[0148] The first method is a laser processing system (1) comprising a laser oscillator (20), a photometer (4), and a fixture (8; 8A; 8B; 8C; 8D). The laser oscillator (20) forms a molten portion (94) on the workpiece (91) by irradiating a predetermined melting area (95) of the workpiece surface (93) with a laser (L1). The photometer (4) measures the intensity of the light (L2) from the molten portion (94) of the workpiece (91). The fixture (8; 8A; 8B; 8C; 8D) is configured on the workpiece surface (93) of the workpiece (91) so as not to overlap with the predetermined melting area (95). The fixture (8; 8A; 8B; 8C; 8D) has a reflective surface (82; 82A; 82B; 83; 84) that is inclined away from the predetermined melting area (95) as it moves forward in the normal direction of the workpiece (91) on the surface (93) of the workpiece. According to this method, stable laser processing can be performed, and the accuracy of laser processing evaluation can be improved.

[0149] The second method is a laser processing system (1) based on the first method. In the second method, the reflecting surfaces (82; 82A; 82B; 83; 84) are reflective surfaces that mirror-reflect light (L2) from the molten section (94). According to this method, the amount of light incident on the photometer (4) from the light (L2) from the molten section (94) can be increased, thereby improving the accuracy of laser processing evaluation.

[0150] The third approach is a laser processing system (1) based on either the first or second approach. In the third approach, the laser processing system (1) includes an optical system (3) comprising a condenser lens (31) facing the processing object surface (93) of the object (91). The optical system (3) focuses the laser (L1) from the laser oscillator (20) onto the predetermined melting region (95) via the condenser lens (31), and directs the light (L2) from the molten part (94) incident on the condenser lens (31) toward the photometer (4). The reflecting surfaces (82; 82A; 82B; 83; 84) are tilted to reflect the light (L2) from the molten part (94) toward the condenser lens (31). According to this approach, stable laser processing can be performed.

[0151] The fourth method is a laser processing system (1) based on the third method. In the fourth method, the height (H1) of the reflecting surface (82; 82A; 82B; 83; 84) is below the working distance (D2) of the condenser lens (31). According to this method, when the irradiation position of the laser (L1) is changed, interference between the condenser lens (31) and the reflecting surface (82; 82A; 82B; 83; 84) can be prevented.

[0152] The fifth method is a laser processing system (1) based on the third or fourth method. In the fifth method, at least a portion of the reflecting surface (82; 82A; 82B; 83; 84) is opposite to a region within the effective diameter (D1) of the condenser lens (31) in the direction along the optical axis (A1) of the condenser lens (31). According to this method, the amount of light incident on the photometer (4) from the light (L2) from the molten part (94) can be increased, and the accuracy of the evaluation of laser processing can be improved.

[0153] The sixth method is a laser processing system (1) based on any one of the methods 3 to 5. In the sixth method, if the angle between the optical axis (A1) of the focusing lens (31) and the peripheral light ray is set to θ1 degrees, and the angle between the reflecting surface (82; 82A; 82B; 83; 84) and the processing object surface (93) is set to θ2 degrees, then θ2 < 90 - θ1. According to this method, the possibility of the laser (L1) shining on the reflecting surface (82; 82A; 82B; 83; 84) can be reduced.

[0154] The seventh method is a laser processing system (1) based on any one of the methods 1 to 6. In the seventh method, the fixture (8; 8A; 8B) has a pair of pressing parts (81; 81A; 81B) located on both sides of the predetermined melting region (95). The surface of each pair of pressing parts (81; 81A; 81B) on the side of the predetermined melting region (95) includes the reflective surface (82; 82A; 82B). According to this method, stable laser processing can be performed in line processing using laser L1, and the accuracy of laser processing evaluation can be improved.

[0155] The eighth method is a laser processing system (1) based on any of the methods 1 to 7. In the eighth method, the fixture (8C; 8D) has a cylindrical pressing part surrounding the predetermined melting area (95). The inner circumferential surface of the pressing part includes the reflective surface (83; 84). According to this method, stable laser processing can be performed in point processing using laser L1, and the accuracy of laser processing evaluation can be improved.

[0156] The ninth method is a laser processing system (1) based on any one of the methods 1 to 8. In the ninth method, the light (L2) from the melting section (94) includes at least one of the following: thermal radiation light caused by the melting of the object (91) by irradiation of the laser (L1); excitation light caused by the excitation of the object (91) by irradiation of the laser (L1); laser plasma generated by irradiation of the laser (L1); and reflected light from the object (91) by the laser (L1). According to this method, the accuracy of the evaluation of laser processing can be improved.

[0157] The tenth method is a laser processing system (1) based on any one of the methods 1 to 9. In the tenth method, the laser processing system (1) further includes a processing device (7). The processing device (7) performs laser processing by irradiating the laser (L1) from the laser oscillator (20) into the molten predetermined area (95) to form the molten portion (94). The processing device (7) performs an evaluation of the laser processing based on the intensity of the light (L2) from the molten portion (94) measured by the photometer (4). According to this method, stable laser processing can be performed, and the accuracy of the laser processing evaluation can be improved.

[0158] The 11th method is a laser processing system (1) based on the 10th method. In the 11th method, the evaluation of the laser processing includes inferring the melting state of the molten part (94) based on the intensity of light (L2) from the molten part (94) measured by the photometer (4). According to this method, the melting state of the molten part (94) can be evaluated.

[0159] The 12th method is a fixture (8; 8A; 8B; 8C; 8D) configured on the workpiece (91) at the workpiece surface (93) for pressing the workpiece (91) in laser processing, where a laser (L1) is irradiated onto a predetermined melting area (95) of the workpiece surface (93) to form a molten portion (94). The fixture (8; 8A; 8B; 8C; 8D) has a reflective surface (82; 82A; 82B; 83; 84) tilted so that the workpiece surface (93) further away from the workpiece (91) is further away from the predetermined melting area (95). According to this method, stable laser processing can be performed, and the accuracy of laser processing evaluation can be improved.

[0160] The 13th method is based on the fixture (8; 8A; 8B; 8C; 8D) of the 12th method. In the 13th method, the reflecting surface (82; 82A; 82B; 83; 84) performs specular reflection of the light (L2) from the molten part (94). According to this method, the amount of light incident on the photometer (4) from the light (L2) from the molten part (94) can be increased, and the accuracy of the evaluation of laser processing can be improved.

[0161] In addition, methods 2 through 11 can be appropriately modified and applied to method 12.

[0162] The method disclosed herein enables stable laser processing and improves the accuracy of laser processing evaluation.

[0163] Industrial availability

[0164] This disclosure can be applied to laser processing systems and fixtures. Specifically, it can be applied to laser processing systems and fixtures for laser processing that can evaluate laser-processed materials, such as workpieces manufactured by laser processing.

Claims

1. A laser processing system comprising: a laser oscillator that forms a molten portion on an object by irradiating a laser to a molten predetermined region of a processing target surface of the object; a light meter that measures an intensity of light from the molten portion of the object; a jig that is configured not to overlap the molten predetermined region on the processing target surface of the object; and an optical system that includes a condenser lens that opposes the processing target surface of the object, the jig having a reflection surface that is inclined so as to move away from the molten predetermined region as it advances in a normal direction of the processing target surface of the object, the optical system condensing the laser from the laser oscillator to the molten predetermined region by the condenser lens and causing light from the molten portion that is incident on the condenser lens to be directed toward the light meter, the reflection surface being inclined so as to reflect light from the molten portion toward the condenser lens.

2. The laser processing system according to claim 1, wherein the reflection surface specularly reflects light from the molten portion.

3. The laser processing system according to claim 1 or 2, wherein a height of the reflection surface is below a working distance of the condenser lens.

4. The laser processing system according to claim 1 or 2, wherein at least a portion of the reflection surface opposes a region within an effective diameter of the condenser lens in a direction along an optical axis of the condenser lens.

5. The laser processing system according to claim 1 or 2, wherein if an angle of an optical axis of the condenser lens and a peripheral light ray of the laser that passes through a circumference defined by an effective diameter of the condenser lens is set to θ1 degrees and an angle of the reflection surface with respect to the processing target surface is set to θ2 degrees, then θ2 < 90 - θ1.

6. The laser processing system according to claim 1 or 2, wherein the jig has a pair of pressing portions that are located on both sides of the molten predetermined region, respectively, and wherein a surface of each of the pair of pressing portions on the molten predetermined region side includes the reflection surface.

7. The laser processing system according to claim 1 or 2, wherein the jig has a cylindrical pressing portion that surrounds the molten predetermined region, and wherein an inner peripheral surface of the pressing portion includes the reflection surface.

8. The laser processing system according to claim 1 or 2, wherein the light from the molten portion includes at least one of heat radiation light caused by melting of the object due to irradiation of the laser, excitation light caused by excitation of the object due to irradiation of the laser, laser plasma generated by irradiation of the laser, and reflected light of the laser reflected by the object.

9. The laser processing system according to claim 1 or 2, further comprising a processing device that performs laser processing that forms the molten portion by irradiating the laser from the laser oscillator to the molten predetermined region and performs evaluation of the laser processing based on the intensity of the light from the molten portion measured by the light meter.

10. The laser processing system according to claim 9, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The evaluation of the laser processing includes estimating a fusion state of the fusion portion based on an intensity of light from the fusion portion determined by the light intensity meter.

11. A jig, in laser processing of forming a fusion portion in an object by irradiating laser light to a predetermined fusion region of a processing target surface of the object with an optical system, the processing target surface of the object being configured not to overlap with the predetermined fusion region, the jig having a reflection surface inclined to be away from the predetermined fusion region as proceeding in a normal direction of the processing target surface of the object, the optical system including a condenser lens opposed to the processing target surface of the object, condensing the laser light to the predetermined fusion region by the condenser lens, and a light intensity meter measuring an intensity of light incident to the condenser lens among light from the fusion portion, the reflection surface being inclined to reflect light from the fusion portion toward the condenser lens.

12. The jig according to claim 11, wherein the reflection surface specularly reflects light from the fusion portion.

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