Multi-wavelength galvanometer, optical system for laser processing, and laser processing method

Abstract

The application provides a kind of multi-wavelength galvanometer, laser processing optical system and laser processing method, the multi-wavelength galvanometer includes the compound light source, universal adjusting structure, beam combination module, swing mirror and flat field focusing mirror arranged in order of optical path;The multi-wavelength galvanometer includes the compound light source, beam combination module, swing mirror and flat field focusing mirror arranged in order of optical path, the compound light source is fixed with universal adjusting structure, the universal adjusting structure is fixed on the beam combination module, the universal adjusting structure is used to adjust the direction of the compound light source output composite light beam, the laser beam emitted by the collimating mirror in the laser processing optical system and the emission light of the compound light source are projected on the beam combination module, and are emitted to the swing mirror after being adjusted by the beam combination module.The application realizes the cleaning of the welding surface before welding, and the stress relief of the welding surface after welding, greatly improves the applicability and welding effect of welding.

Description

Technical Field

[0001] This invention relates to the field of laser processing equipment technology, specifically to a multi-wavelength galvanometer, an optical system for laser processing having the multi-wavelength galvanometer, and a laser processing method using the optical system. Background Technology

[0002] With the rapid development of China's industrial manufacturing and intelligent manufacturing, lasers, as precision processing tools, are increasingly being used in high-precision machining. Large-format laser welding using oscillating mirrors is particularly well-received by the industry due to its high processing speed. However, due to the differences in the materials being processed, traditional single-laser-beam processing is increasingly hindering the promotion and popularization of laser galvanometer welding. At the same time, because the welding process involves complex materials and structures, proper cleaning before welding and stress relief after welding are particularly important.

[0003] Specifically, the optical path structure of a traditional laser processing device is as follows: Figure 1 As shown, the laser beam output by laser 100 is transmitted to collimating lens 400 via output cap 300 of laser output head 200. Collimating lens 400 collimates the laser beam and transmits it to oscillating mirror 500, which is also a laser galvanometer. A flat-field focusing lens 600 is provided below the laser galvanometer. The flat-field focusing lens 600 ensures that the welding laser beam is kept at the optimal focus across the entire welding processing area. The control system 700 controls the timing of oscillating mirror 500 and laser. The control system 700 first oscillates oscillating mirror 500 to the processing position on processing surface 800 before controlling laser 100 to output laser light. Summary of the Invention

[0004] In view of the background art, the purpose of this invention is to provide a novel laser processing device optical system that enables pre-welding surface cleaning and welding material preheating before welding, stress relief of the welding surface after welding, as well as its key components and application methods of the optical system.

[0005] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0006] A multi-wavelength galvanometer includes a composite light source, a universal adjustment structure, a beam combining module, a wobbling mirror, and a flat-field focusing mirror arranged in optical path order. The multi-wavelength galvanometer includes the composite light source, the beam combining module, the wobbling mirror, and the flat-field focusing mirror arranged in optical path order. The composite light source is fixed to the universal adjustment structure, which is fixed to the beam combining module. The universal adjustment structure is used to adjust the direction of the composite beam output by the composite light source. The laser beam emitted from the collimating lens in the laser processing optical system and the emitted light from the composite light source are both projected onto the beam combining module and then emitted to the wobbling mirror after adjustment by the beam combining module.

[0007] Furthermore, the universal adjustment structure is provided with a light aperture and a connecting part. The light aperture is used to transmit the emitted light from the composite light source, and the connecting part is used to fix the universal adjustment structure and the beam combining module to each other.

[0008] Preferably, the omnidirectional adjustment structure includes a hollow sphere, the composite light source is disposed in the cavity of the hollow sphere, the light aperture is disposed at one end of the hollow sphere, the light aperture communicates with the cavity and faces the beam combining module.

[0009] Furthermore, the connecting part includes a connecting plate disposed on the outer wall of the hollow sphere and a fixing structure that cooperates with the connecting plate.

[0010] Furthermore, the connecting plate is a screw hole plate with multiple screw holes. The fixing structure is a combination of multiple screws or bolts. The screws or bolts pass through the adjusting screw holes to fix the screw hole plate to the fixing plate, thereby fixing the universal adjustment structure to a fixing plate above the beam combining module. The direction of the output beam of the composite light source in the sphere can be adjusted by adjusting the height of the screws or bolts.

[0011] Preferably, the composite light source includes one or more of a cleaning light source, a preheating light source, and a thermal stress relief light source, wherein the cleaning light source is a purple light source, the preheating light source is a green light source, and the thermal stress relief light source is a red light source.

[0012] The present invention also provides an optical system for laser processing, which includes a control system and, arranged in the optical path sequence, a laser, a laser output head, a collimating lens, and the aforementioned multi-wavelength galvanometer. The laser beam emitted from the collimating lens and the emitted light from the composite light source are both projected onto the beam combining module and, after adjustment by the beam combining module, emitted to the oscillating reflector.

[0013] The present invention also provides a laser welding method using the above-described optical system for laser processing, comprising:

[0014] Cleaning: The cleaning light source in the composite light source is turned on by the control system. The cleaning light source is a purple light source and is used to clean the substances and dirt on the welding path. After the cleaning light source is turned on for a period of time, the laser is turned on by the control system. The main welding beam emitted by the laser, i.e., the yellow beam, welds the surface to be welded. At the same time, the purple light continues to clean until the welding work of the main welding beam is completed or after a period of time, the cleaning light source is turned off.

[0015] And / or,

[0016] Preheating: The preheating light source in the composite light source is turned on by the control system. The preheating light source is a green light source. The preheating beam preheats the surface to be welded. When the surface to be welded reaches the predetermined temperature, the main welding beam of the laser is turned on by the control system. The preheating light source continues to work until the main welding beam finishes welding or is turned off after the welding ends.

[0017] And / or,

[0018] Thermal stress relief: After the main welding beam of the laser has been working for a period of time, the red light source in the composite light source used to relieve thermal stress at the weld is turned on by the control system. The red beam continues to work until the main welding beam and other lasers in the composite light source are all turned off.

[0019] Preferably, the beams of the preheating light source, the main welding beam, and / or the cleaning light source have increased time-modulated pulse output power.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] This invention creatively proposes a galvanometer with multiple composite light source input interfaces. The galvanometer stacks multiple sets of composite light sources with universal joint adjustment structures in front of a swinging reflector. The position of the composite light source output to the welding surface is then controlled by a special output timing of the composite light source, which achieves the functions of cleaning the welding surface before welding and relieving stress on the welding surface after welding, greatly improving the applicability and effect of welding. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the optical system of the laser processing apparatus described in the background art;

[0023] Figure 2 This is a schematic diagram of the optical system of the laser processing device according to Embodiment 2 of the present invention;

[0024] Figure 3 This is a three-dimensional structural schematic diagram of the universal adjustment mechanism according to Embodiment 1 of the present invention;

[0025] Figure 4 This is a schematic diagram of the combined structure of the universal adjustment structure and the fixing plate of the present invention;

[0026] Figure 5 This is a schematic diagram of the welding spot on a welding plate using the laser processing device with a multi-wavelength galvanometer mirror according to Embodiment 1 of the present invention.

[0027] Figure 6 This is a graph showing the output power of a composite light source over time according to Embodiment 1 of the present invention.

[0028] Figure 7 This is a graph showing the output power of another composite light source over time, as described in Embodiment 1 of the present invention.

[0029] Figure label:

[0030] Laser: 100; Laser output head: 200; Output cap: 300; Collimating lens: 400;

[0031] Oscillating reflector: 500; Plane focusing lens: 600; Control system: 700; Machined surface: 800

[0032] Multiwavelength galvanometer: 1; Composite light source: 11; Universal adjustment structure: 12;

[0033] 14; 15; 16; 122; 17; 18; 19; 10; 10; 122;

[0034] Fixed plate: 17; First light hole: 121; Second light hole: 171; Adjusting screw hole: 123;

[0035] Output cap: 41; Beam combiner module: 2; Laser: 3; Laser output head: 4; Collimating lens: 5

[0036] Control system: 6; Surface to be welded: 10 Detailed Implementation

[0037] Example 1:

[0038] This embodiment provides a multi-wavelength galvanometer for use in a laser processing optical system. The laser processing optical system can be used in handheld welding torches, conventional welding systems, cladding, and even 3D printing.

[0039] like Figure 2As shown, the multi-wavelength galvanometer 1 includes a composite light source 11, a universal adjustment structure 12, a beam combining module 2, a wobbling reflector 14, and a flat-field focusing lens 15 arranged in optical path sequence. The control interfaces of the wobbling reflector 14 and the composite light source 11 are respectively connected to external control signals to control the trajectory and running speed of the wobbling reflector 14, the power of the composite light source 11, and its on / off state. The composite light source 11 includes multiple laser sources, each fixed in one of the multiple universal adjustment structures 12. The collimated main laser beam for welding is projected into a beam combining module 2. The universal adjustment structure 12 adjusts the direction of the composite beam output from the composite light source 11. The main laser beam and the composite beam, after passing through the beam combining module 2, are then projected onto the desired position on the surface to be processed via the wobbling reflector 14 and the flat-field focusing lens 15. Depending on the characteristics of the material to be processed, the desired spot shape can be achieved by adjusting the universal adjustment structure 12.

[0040] The control interface of the composite light source 11 is set on a circuit board 16, so that external control signals are connected to the circuit board 16. The circuit board 16 controls various control parameters of the composite light source 11 according to the received control signals.

[0041] A fixing plate 17 is provided between the multiple universal adjustment structures 12 and the beam combining module 2. The universal adjustment structures 12 and the fixing plate 17 are connected to each other, and the light emission direction of the composite light source 11 can be adjusted by adjusting the connection relationship between the universal adjustment structures 12 and the fixing plate 17.

[0042] Specifically, such as Figure 3 and Figure 4 As shown, the omnidirectional adjustment structure 12 is a hollow sphere, and the composite light source 11 is disposed inside the cavity of the hollow sphere. One end of the hollow sphere is provided with a first light aperture 121, which communicates with the cavity. Figure 4 As shown, the fixing plate 17 is provided with a second light hole 172, preferably a circular hole. The radial dimension of the second light hole 172 is larger than the radial dimension of the first light hole 121 and smaller than the radial dimension of the universal adjustment structure 12. The end of the universal adjustment structure 12 with the first light hole 121 is disposed in the second light hole, so that the first light hole 121 is located in the second light hole. The emitted light from the composite light source 11 is projected onto the beam combining module 2 through the first light hole 121. The outer wall of the hollow sphere is provided with a ring of screw hole plates 122. A plurality of adjusting screw holes 123 are distributed circumferentially along the screw hole plate 122. Screws matching the adjusting screw holes 123 pass through the adjusting screw holes 123 to fix the screw hole plate 122 to the fixing plate 17, thereby fixing the universal adjustment structure 12 to the fixing plate 17.

[0043] The connection between the screw hole plate 122 and the fixing plate 17 can also be used to adjust the tilt direction and tilt angle of the universal adjustment structure 12, thereby adjusting the direction of the output beam of the composite light source 11 located in the cavity, and ultimately achieving a specific relative position of the beam on the surface to be welded 10 relative to the main welding beam. Specifically, by adjusting the depth to which different screws are inserted into the fixing plate 17, the distance between different positions of the screw hole plate 122 and the fixing plate 17 can be adjusted, thus adjusting the tilt direction and tilt angle of the universal adjustment structure 12. For example, if it is necessary to adjust the universal adjustment structure 12 to tilt downwards at a certain position, the screw corresponding to that position is screwed deeper into the fixing plate 17, pulling that position of the universal adjustment structure 12 closer to the fixing plate 17, so that that position of the universal adjustment structure 12 tilts towards the fixing plate 17, i.e., tilts downwards.

[0044] One embodiment of the composite light source 11 includes:

[0045] A cleaning light source is used to clean substances and dirt on the welding path. A purple light source is preferred to achieve the cleaning function of the surface 10 to be welded.

[0046] A preheating light source is used to preheat the surface to be processed before welding. Considering that the power of the green beam is not high, but the board material has a high absorption of the beam, such as a traditional 975nm semiconductor laser or a 450nm blue semiconductor laser, or even a pulsed laser beam of a specific wavelength, a green light source is preferred.

[0047] Stress-relieving light source, preferably a red light source.

[0048] The output power of the main welding light source (yellow light source) of the above composite light sources and lasers varies with time as shown in the curves. Figure 6 As shown.

[0049] In particular, in order to achieve better welding results, Figure 6 Based on the existing scheme, time-modulated pulse output power can be added to the preheating beam and the main welding beam, such as... Figure 7 As shown. Its function is to change the absorption and stirring of the weld pool by dithering the power of the preheating beam or the main welding beam, thereby achieving better welding results. In addition, the stress relief light source can also be a power-dithered beam, with high and low temperature changes achieving stress release.

[0050] The following describes in detail the roles of various light sources in a composite light source:

[0051] The role of the preheating light source: Because the plate has a high absorption capacity for green laser beams, only a low-energy green laser beam is needed to heat the plate. However, this energy is insufficient for high-power, deep-penetration plate welding. At this point, the yellow laser beam has high energy. Because the plate absorbs the yellow beam poorly when used alone, the welding reaction becomes extremely violent, even leading to numerous pores and spatter in the weld. However, the preheating with green laser significantly enhances the absorption of the yellow laser, greatly reducing spatter and improving the weld surface quality.

[0052] The role of stress-relieving light sources: Due to the very high energy input of the yellow laser beam, the entire weld cools very rapidly after welding, making the weld surface prone to defects such as thermal stress and reducing weld strength. Adding a red beam, with a lower power than the yellow beam, can slow down the weld cooling rate and reduce thermal stress defects. Furthermore, by adjusting the position and power of the red beam relative to the yellow beam, and even adjusting the power and position of the red beam over time, a specific temperature cooling curve can be achieved. This special temperature cooling curve can relieve stress in the weld area, further improving welding quality.

[0053] The number and type of light source in the composite wavelength galvanometer vary depending on the actual application and are not limited to the number and type in this embodiment.

[0054] Example 2:

[0055] This embodiment provides a novel optical system for laser processing, which can be used in handheld welding torches, conventional welding systems, cladding, and even 3D printing.

[0056] like Figure 2 As shown, the optical system includes a control system 6 and, arranged in the optical path sequence, a laser 3, a laser output head 4, a collimating lens 5, and a multi-wavelength galvanometer as described in Embodiment 1.

[0057] The composite light source 11 in the multi-wavelength galvanometer 1 is set according to the absorption wavelength of the welding material. Multiple composite light sources 11 are respectively fixed in multiple universal adjustment structures 12, and each of the multiple universal adjustment structures 12 has a fixed position relative to the beam combining module 2.

[0058] The control system 6 is connected to the control interfaces of the laser 3, the oscillating reflector 14 and the composite light source 11 via signal lines. It is used to control parameters such as the power on / off, laser power amplitude, laser pulse frequency and laser duty cycle of the laser 3, the power and on / off of the composite light source 11, and the trajectory and running speed of the oscillating reflector 14.

[0059] The laser emitted by the laser 3 is transmitted to the collimating lens 5 through the output cap 41 of the laser output head 4. The collimating lens 5 collimates the main laser beam used for welding and transmits it to the multi-wavelength galvanometer 1.

[0060] Example 3:

[0061] This embodiment provides an application method for the laser processing optical system described in Embodiment 2, such as... Figures 5 to 7 As shown, it includes the following:

[0062] Cleaning: The cleaning light source in the composite light source 11 is turned on by the control system. The cleaning light source is a purple light source and is used to clean the substances and dirt on the welding path. After the cleaning light source is turned on for a period of time, the laser is turned on by the control system. The main welding beam emitted by the laser 3, i.e., the yellow beam, welds the surface 10 to be welded. At the same time, the purple light continues to clean until the welding work of the main welding beam is completed or after a period of time, the cleaning light source is turned off. That is, the cleaning action continues throughout the entire welding process.

[0063] Preheating: The preheating light source in the composite light source 11 is turned on by the control system 6. The preheating light source is a green light source. The preheating beam preheats the surface 10 to be welded. When the surface 10 to be welded reaches the predetermined temperature, the main welding beam of the laser is turned on by the control system 6. The preheating light source continues to work until the welding of the main welding beam ends or is turned off after the welding ends.

[0064] Thermal stress relief: After the main welding beam of the laser 3 has been working for a period of time, the red light source in the composite light source used to relieve thermal stress at the weld is turned on by the control system 6. The red beam continues to work until the main welding beam and other lasers in the composite light source 11 are all turned off.

[0065] In particular, in order to achieve better welding results, Figure 6 Based on the proposed scheme, time-modulated pulse output power was added to both the preheating beam and the main welding beam, such as... Figure 7 As shown. Its function is to change the absorption and stirring of the weld pool by dithering the power of the preheating beam or the main welding beam, thereby achieving better welding results.

[0066] Alternatively, the cleaning light source can be set as a pulsed light source. For example, a purple beam used for cleaning can utilize the explosive power of a pulsed laser's high peak energy to clean dirt and oxide film from the surface of the board, resulting in better performance. On the other hand, stress-relieving light sources can also adopt a pulsed power output mode.

[0067] In this invention, the number of light sources and the type of lasers combined in the composite wavelength galvanometer vary depending on the actual application and are not limited to the number and type in this embodiment.

[0068] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A multi-wavelength galvanometer, characterized in that, The system includes a composite light source, a universal adjustment structure, a beam combining module, a wobbling mirror, and a flat-field focusing mirror arranged in optical path order. The multi-wavelength galvanometer comprises, in optical path order: a composite light source, a beam combining module, a wobbling mirror, and a flat-field focusing mirror. The composite light source is fixed to the universal adjustment structure, which is fixed to the beam combining module. The universal adjustment structure is used to adjust the direction of the composite beam output from the composite light source. The laser beam emitted from the collimating lens in the laser processing optical system and the emitted light from the composite light source are both projected onto the beam combining module, adjusted by the beam combining module, and then emitted to the wobbling mirror. The universal adjustment structure has an aperture and a connecting part. The universal adjustment structure includes a hollow sphere, and the composite light source is disposed on the... Inside the cavity of the hollow sphere, the light aperture is located at one end of the hollow sphere, communicating with the cavity and facing the beam combining module; the connecting part includes a connecting plate surrounding the outer wall of the hollow sphere and a fixing structure that cooperates with the connecting plate; a fixing plate is provided between the universal adjustment structure and the beam combining module, the connecting plate is a screw hole plate with multiple adjusting screw holes, and the fixing structure is a combination of multiple screws or bolts, the screws or bolts passing through the adjusting screw holes to fix the screw hole plate to the fixing plate, thereby fixing the universal adjustment structure to the fixing plate above the beam combining module, and adjusting the height of the screws or bolts to adjust the direction of the output beam of the composite light source in the sphere.

2. The multi-wavelength galvanometer according to claim 1, characterized in that, The connecting part is used to fix the universal adjustment structure and the beam combining module to each other.

3. The multi-wavelength galvanometer according to claim 1 or 2, characterized in that, The composite light source includes one or more of a cleaning light source, a preheating light source, and a thermal stress relief light source, wherein the cleaning light source is a purple light source, the preheating light source is a green light source, and the thermal stress relief light source is a red light source.

4. An optical system for laser processing, characterized in that, It includes a control system and, arranged in the optical path sequence, a laser, a laser output head, a collimating lens, and a multi-wavelength galvanometer as described in claim 3. The laser beam emitted from the collimating lens and the emitted light from the composite light source are both projected onto the beam combining module and, after being adjusted by the beam combining module, emitted to the oscillating reflector.

5. A laser welding method using the optical system for laser processing as described in claim 4, characterized in that, include: Cleaning: The cleaning light source in the composite light source is turned on by the control system. The cleaning light source is a purple light source and is used to clean the substances and dirt on the welding path. After the cleaning light source is turned on for a period of time, the laser is turned on by the control system. The main welding beam emitted by the laser, i.e., the yellow beam, welds the surface to be welded. At the same time, the purple light continues to clean until the welding work of the main welding beam is completed or after a period of time, the cleaning light source is turned off. And / or, Preheating: The preheating light source in the composite light source is turned on by the control system. The preheating light source is a green light source. The preheating beam preheats the surface to be welded. When the surface to be welded reaches the predetermined temperature, the main welding beam of the laser is turned on by the control system. The preheating light source continues to work until the main welding beam finishes welding or is turned off after the welding ends. And / or, Thermal stress relief: After the main welding beam of the laser has been working for a period of time, the red light source in the composite light source used to relieve thermal stress at the weld is turned on by the control system. The red beam continues to work until the main welding beam and other lasers in the composite light source are all turned off.

6. The laser welding method according to claim 5, characterized in that, in, The beams of the preheating light source, the main welding beam, the thermal stress relief light source, and / or the cleaning light source have increased time-modulated pulse output power.

7. The laser welding method according to claim 5, characterized in that, The light beam of the thermal stress relief light source is a power-dithered beam, which releases stress through high and low temperature changes.

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