Dynamic spot control method, system and laser processing equipment for laser processing

Abstract

The present invention relates to the field of laser processing technology and discloses a dynamic spot control method, system, and laser processing equipment for laser processing. The method comprises: modulating the oscillation frequency of a galvanometer and the laser light intensity to generate at least one dynamic light spot on a workpiece, wherein the energy density of the dynamic light spot is optimally distributed along the processing direction. In addition to the existing method of modulating the oscillation frequency of the galvanometer, the process of modulating the laser light intensity is added. By leveraging the high-frequency resources of the laser, the requirements for the galvanometer modulation frequency when generating complex light spots are reduced, thereby solving the bottleneck problem of the response bandwidth of the galvanometer device.

Description

Technical Field

[0001] The present invention relates to the field of laser processing technology, and in particular to a dynamic spot control method and system for laser processing and laser processing equipment. Background Art

[0002] At present, the mainstream laser processing method adopts static processing, which has the following problems: heat distribution is limited by the distribution of light spots, resulting in high difficulty in optimization; the cutting seam of laser processing is limited by the size of the light spot itself; affected by the laser divergence angle, the verticality in the processing depth direction is cracked, and the power density in the processing depth direction is seriously reduced.

[0003] Recently, a new technology has emerged, which is to use a dynamic light spot method to process materials. For example, in patent CN201710568597.3, the basic principle is that during the laser drilling, cutting, welding, etching and thermal cracking separation processes, the laser focus is no longer fixed at a certain position and does not move, but moves downward or upward at a certain speed along the optical axis direction of the thickness of the workpiece to be processed, or moves linearly, oscillatingly or spirally up and down at a certain frequency. The present invention also provides a method and device for realizing the dynamic processing of the laser focus as described above. The method and device of the present invention overcome a series of processing problems caused by the uneven distribution of energy density of the laser optical axis in traditional processing methods. Compared with the static processing method, the dynamic light spot method has the following advantages: the light spot can be gathered smaller to increase the power density, and the spatial distribution of power can be controlled by combining the lateral and longitudinal oscillations of the light spot, breaking through the limitations of the size of the light spot itself and the distribution of light on the processing quality.

[0004] However, theoretical calculations show that the current dynamic spot method has certain requirements for the oscillation frequency of the light source. To maintain a certain processing speed, the oscillation frequency of the light source needs to reach 1-4kHz, which is already very difficult for high-power galvanometer devices. If the processing quality requires a more complex dynamic scanning spot, a higher light source oscillation frequency is required, such as the second harmonic or even higher harmonics of the control signal. This will pose a huge challenge to the response bandwidth of the galvanometer device, and it may even be difficult to achieve. Summary of the Invention

[0005] The embodiments of the present invention aim to provide a dynamic spot control method, system and laser processing equipment for laser processing, so as to solve the technical problem that the processing method of dynamic spot in the prior art has high requirements on the response bandwidth of the galvanometer device.

[0006] The embodiment of the present invention solves the technical problem by adopting the following technical solution: providing a dynamic spot control method for laser processing, the method comprising:

[0007] The oscillation frequency of the galvanometer and the intensity of the laser are modulated so that the laser beam generates at least one dynamic light spot on the workpiece, and the energy density of the dynamic light spot is optimally distributed along the processing direction.

[0008] Furthermore, the galvanometer oscillation frequency modulation signal and the laser light intensity modulation signal maintain a fixed phase relationship, and the dynamic light spot is a repeatable periodic light spot;

[0009] The modulation frequency response range of the laser light intensity is 10Hz-GHz to achieve high-speed image modulation. The laser light intensity modulation signal is a single-frequency sinusoidal signal or a periodic signal containing high-order harmonics, and the initial phase of the laser light intensity modulation signal is adjustable.

[0010] The embodiment of the present invention solves the technical problem by adopting the following technical solution: providing a dynamic spot control method for laser processing, the method comprising:

[0011] Modulating the oscillation frequency of the galvanometer in two dimensions, the two dimensions including an x-direction consistent with the processing direction and a y-direction perpendicular thereto, so that the laser beam generates at least one dynamic light spot on the workpiece, the dynamic light spot being a Lissajous pattern light spot;

[0012] The galvanometer oscillation modulation frequency is a multiple relationship in the x direction and the y direction;

[0013] The laser light intensity is modulated, and the laser light intensity modulation frequency is in a multiple relationship with the oscillation modulation frequency of the galvanometer along the x-direction, so that the energy density of the dynamic light spot is optimally distributed along the x-direction.

[0014] Furthermore, the galvanometer oscillation frequency modulation signal and the laser light intensity modulation signal maintain a fixed phase relationship, and the dynamic light spot is a repeatable periodic light spot;

[0015] The dynamic light spot includes a first area and at least one second area. By adjusting the initial phase and modulation depth of the light intensity modulation signal of the laser, the energy density distribution area and energy density distribution ratio of the dynamic light spot can be changed, so that the energy density of the first area is greater than that of the second area.

[0016] Furthermore, when the modulation frequencies of the galvanometer in the x-direction and the y-direction are equal, the Lissajous pattern light spot is a ring-shaped light spot; and

[0017] When the laser light intensity modulation frequency is equal to the galvanometer oscillation frequency modulation frequency, the energy density of the annular light spot is weakened in the x direction;

[0018] When the laser light intensity modulation frequency is 1 / 2 of the galvanometer oscillation frequency modulation frequency, the energy density of the annular light spot is asymmetrically distributed in the y direction.

[0019] Adjusting the light intensity modulation depth of the laser to achieve a change in the energy density distribution of the annular light spot; and / or,

[0020] The initial phase of the light intensity modulation signal of the laser is adjusted to achieve a 90-degree rotation of the energy density distribution of the annular light spot.

[0021] Furthermore, the modulation frequencies of the galvanometer in the x-direction and the y-direction are a multiple relationship greater than 1, and the light spot is any one of an "8" shape, a horseshoe shape, and a cross shape;

[0022] When the laser light intensity modulation frequency is equal to the oscillation frequency of the galvanometer in the x-direction, the energy density of the dynamic light spot in at least a part of the area is weakened, and the weakened light spot is used for welding preheating of the workpiece.

[0023] The embodiment of the present invention solves the technical problem by adopting the following technical solution: providing a dynamic spot control method for laser processing, the method comprising:

[0024] Modulating the oscillation frequency of the galvanometer in three dimensions, wherein the three dimensions include x, y, and z directions, wherein the x, y, and z directions are perpendicular to each other, the x direction is consistent with the processing direction, and the z direction is consistent with the processing depth direction, so that the laser beam generates at least one dynamic spot on the workpiece;

[0025] The laser light intensity is modulated, and the laser light intensity modulation frequency is equal to the oscillation frequency of the galvanometer in the z direction, so as to change the energy density distribution of the light spot in the z direction.

[0026] Furthermore, the modulation depth of the laser light intensity modulation signal is adjusted to achieve uniform distribution of the energy density of the dynamic light spot along the z direction;

[0027] Adjusting the initial phase of the laser light intensity modulation signal to achieve the upward and downward movement of the highest point of the energy density distribution of the dynamic light spot along the z direction;

[0028] The galvanometer oscillation frequency modulation signal and the laser light intensity modulation signal have a fixed phase relationship, and the dynamic light spot is a repeatable periodic dynamic light spot.

[0029] The embodiment of the present invention solves the technical problem by adopting the following technical solution: providing a dynamic spot control method for laser processing, the method comprising:

[0030] Modulating the oscillation frequency of the galvanometer in three dimensions, where the three dimensions include x, y, and z directions, wherein the x, y, and z directions are perpendicular to each other, and the oscillation frequencies in the x and y directions are 2N times the oscillation frequency in the z direction, where N is an integer, so that the laser beam generates a first light spot and at least one second light spot on the workpiece, wherein the second light spot is located within the first light spot;

[0031] Adjusting the initial phase relationship of the oscillation frequency modulation signals in the x-direction, y-direction, and z-direction to achieve a change in the relative position of the first light spot and the second light spot;

[0032] Modulating the laser light intensity to adjust the energy density distribution area and energy density ratio of the first light spot and the second light spot;

[0033] The galvanometer oscillation frequency modulation signal and the laser light intensity modulation signal have a fixed phase relationship, and the dynamic light spot is a repeatable periodic dynamic light spot.

[0034] The embodiment of the present invention solves the technical problem by adopting the following technical solution: providing a dynamic spot control system for laser processing, including a laser control module, a galvanometer control module and a modulation module; wherein,

[0035] The modulation module is used to send an oscillation frequency modulation signal to the galvanometer control module, so that the laser beam generates at least one light spot on the workpiece;

[0036] The modulation module is used to send a light intensity modulation signal to the laser control module so that the energy density of the light spot is optimally distributed along the processing direction;

[0037] The modulation module is used to adjust and lock the phase difference between the galvanometer oscillation frequency modulation signal and the laser light intensity modulation signal, so that the light spot can be periodically and repeatedly generated.

[0038] The embodiment of the present invention solves the technical problem by adopting the following technical solution: providing a laser processing device, comprising:

[0039] Fiber lasers;

[0040] a laser processing head connected to the fiber laser; and

[0041] The control system as described above is used to control the fiber laser and the laser processing head.

[0042] Compared with the existing technology, in the spot control method, control system and laser processing equipment for laser processing provided in the embodiments of the present invention, on the basis of the existing modulation of the oscillation frequency of the galvanometer, a process of modulating the light intensity of the laser is added. By leveraging the high-frequency resources of the laser, the requirements for the modulation frequency of the galvanometer when generating complex spots are reduced, thereby solving the bottleneck problem of the response bandwidth of the galvanometer device. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0044] Figure 1a This is a schematic diagram of determining the dynamic cutting frequency resource only through the oscillation frequency resource of the galvanometer;

[0045] Figure 1b This is a schematic diagram of the dynamic cutting frequency resource being determined by the oscillation modulation frequency of the galvanometer and the light intensity modulation frequency of the laser;

[0046] Figure 2 This is a schematic diagram of the relationship between the Lissajous pattern spot modulation frequency and initial phase;

[0047] Figure 3a is a schematic diagram of an annular light spot formed without light intensity modulation in Example 1;

[0048] Figure 3b and Figure 3c is a schematic diagram of the annular light spot formed by the light intensity modulation in the first embodiment, wherein the Figure 3b 、 Figure 3c The annular light spots shown require different light intensity modulation frequencies to be set;

[0049] Figure 4a 、 Figure 4b 、 Figure 4c They are schematic diagrams of the "8"-shaped, horseshoe-shaped, and cross-shaped light spots formed in Example 1 without light intensity modulation;

[0050] Figure 5a 、 Figure 5b 、 Figure 5c They are schematic diagrams of the "8"-shaped, horseshoe-shaped, and cross-shaped light spots formed after the light intensity modulation in Example 1;

[0051] Figure 6a is a schematic diagram of a light spot formed without light intensity modulation in Example 2;

[0052] Figure 6band Figure 6c is a schematic diagram of the light spot after light intensity modulation in Example 2;

[0053] Figure 7a is a schematic diagram of a light spot formed without light intensity modulation in Example 3;

[0054] Figure 7b is a schematic diagram of the light spot after light intensity modulation in Example 3;

[0055] Figure 8 Schematic diagram of the laser processing equipment in the fifth embodiment, which includes the dynamic spot control system in the fourth embodiment. DETAILED DESCRIPTION

[0056] For ease of understanding of the present invention, the present invention will be described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "connected" to another element, it can be directly on another element, or there can be one or more centered elements therebetween. The orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "upper end", "lower end", "top" and "bottom" used in this specification is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0057] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0058] See also Figure 1a In the existing dynamic spot processing system, the calculation formula of the oscillation modulation signal of the galvanometer is as follows:

[0059] C(t)=cos(ωt+φ)

[0060] The upper limit of dynamic cutting frequency is calculated as follows:

[0061]

[0062] It can be seen from this that the dynamic cutting frequency resource is only determined by the oscillation modulation frequency resource of the galvanometer, and the requirement for the galvanometer response bandwidth is relatively high.

[0063] See also Figure 1bThe present invention provides a spot control method for laser processing. On the basis of the existing dynamic spot processing system, the light intensity modulation frequency of the laser is controlled to jointly determine the dynamic cutting frequency of the dynamic spot processing system by the oscillation modulation frequency and the light intensity modulation frequency.

[0064] The calculation formula of the oscillation frequency modulation signal is as follows:

[0065] C(t)=cos(ω1t+φ)

[0066] The calculation formula of the light intensity modulation signal is as follows:

[0067]

[0068] The upper limit of dynamic cutting frequency is calculated as follows:

[0069]

[0070] Among them, the initial phase of the oscillation modulation frequency and the initial phase of the light intensity modulation frequency should meet the following conditions:

[0071]

[0072] Correspondingly, the dynamic spot control method in laser processing is as follows:

[0073] The oscillation frequency of the galvanometer and the laser light intensity are modulated so that the laser beam generates at least one dynamic light spot on the workpiece. The energy density of the dynamic light spot is optimally distributed along the processing direction. The optimal distribution refers to the light spot energy density distribution that can achieve the expected processing effect during processing.

[0074] Furthermore, the galvanometer oscillation frequency modulation signal maintains a fixed phase relationship with the laser light intensity modulation signal, and the light spot is a repeatable periodic light spot; wherein, the modulation frequency response range of the laser light intensity is 10Hz-GHz to achieve high-speed image modulation, the laser light intensity modulation signal is a single-frequency sinusoidal signal or a periodic signal containing high-order harmonics, and the initial phase of the laser light intensity modulation signal is adjustable.

[0075] In the spot control method provided in the embodiment of the present invention, by adding a step of modulating the laser light intensity, the high-frequency resources of the laser, which can reach MHz or even GHz, are utilized, thereby reducing the modulation frequency requirements of the galvanometer for complex dynamic spot processing. This helps fill the gap in traditional dynamic spot processing systems for control signals such as sawtooth waves and triangle waves that are non-conductive and have rich high-order harmonics.

[0076] At the same time, by maintaining a fixed phase relationship between the light intensity modulation signal and the oscillation modulation signal (that is, the initial phase difference between the light intensity modulation signal and the oscillation modulation signal is a fixed constant and does not change with time), a richer oscillation spot distribution can be achieved under the same galvanometer response bandwidth resources. The phase locking between the light intensity modulation signal and the oscillation modulation signal can ensure the periodicity of the synthetic light spot and eliminate the pattern evolution (commonly known as beat length) caused by the lack of synchronization between the light intensity modulation signal and the oscillation modulation signal.

[0077] It should be noted that since the laser processing effect is affected by multiple factors such as laser type, auxiliary gas, workpiece material, processing speed, processing path, etc., the light spot needs to be adjusted in each processing to achieve the expected processing effect.

[0078] The following describes specific implementations of various light spot control methods, including different light spots generated by two-dimensional and three-dimensional modulation of the scanning galvanometer in a dynamic light spot device. It should be noted that the following are merely illustrative, and any method that meets the above requirements is within the scope of protection of this invention.

[0079] Example 1

[0080] When the oscillation frequency of the galvanometer is modulated in two dimensions, the two dimensions are defined as including an x-direction consistent with the processing direction and a y-direction perpendicular to the processing direction, so that the laser beam generates at least one dynamic spot on the workpiece, and the dynamic spot is a Lissajous pattern spot;

[0081] The oscillation modulation frequency of the galvanometer is a multiple relationship in the x-direction and the y-direction (the multiple can be a non-integer). When the modulation frequency is in different ratios and different phase differences in the x-direction and the y-direction, different types of Lissajous patterns can be generated, such as Figure 2 shown.

[0082] When the light intensity modulation frequency is a multiple of the oscillation modulation frequency of the galvanometer along the x-direction, the energy density of the light spot is optimally distributed along the x-direction. The optimal distribution refers to the light spot energy density distribution that can achieve the expected processing effect during processing.

[0083] The initial phase difference between the oscillation frequency modulation signal of the galvanometer and the light intensity modulation signal of the laser is adjusted and locked. The oscillation frequency modulation signal of the galvanometer and the light intensity modulation signal of the laser maintain a fixed phase relationship, so that the generated dynamic light spot is a periodic light spot, ensuring the repeatability of the dynamic light spot.

[0084] The dynamic light spot includes a first area and at least one second area. By adjusting the initial phase and modulation depth of the light intensity modulation signal of the laser, the energy density distribution area and energy density distribution ratio of the dynamic light spot can be changed, so that the energy density of the first area is greater than that of the second area.

[0085] When the coordinate oscillation signal of the galvanometer is:

[0086] x(t)=cos(2πf x t+π / 2);

[0087] y(t)=cos(2πf y t);

[0088] f x =f y .

[0089] Generate as Figure 3a The Lissajous pattern light spot shown in the figure is a ring-shaped light spot pattern.

[0090] That is, when the modulation frequencies in the x-direction and the y-direction are equal and no laser intensity modulation is performed, that is, I(t) = constant, the laser processing at this time is a conventional dynamic cutting or dynamic welding state.

[0091] When the laser light intensity is modulated, that is, when I(t) is not constant, the pattern will be modified based on the original one.

[0092] In some embodiments, when the light intensity modulation frequency of the laser is equal to the oscillation frequency modulation frequency of the galvanometer, the optimized initial phase difference between the control signal and the light intensity modulation signal is adjusted and locked, so as to reduce the energy density of the annular light spot along the x direction (i.e., the center area of ​​the annular light spot), that is, the energy density of the annular light spot is weakened in the x direction (i.e., the center area of ​​the annular light spot), and the energy density of the light spot in the y direction is enhanced, as shown in FIG. Figure 3b shown.

[0093] Furthermore, the energy density distribution of the annular light spot can be changed by adjusting the light intensity modulation depth of the laser.

[0094] It should be noted that Taking the light intensity modulation signal as an example, the light intensity modulation depth is the value of A. When the light intensity modulation depth of the laser is not adjusted, A=0.

[0095] Furthermore, the initial phase of the light intensity modulation signal of the laser is adjusted to achieve a 90-degree rotation of the energy density distribution of the annular light spot.

[0096] For example, when serving laser cutting processing, the concave direction of the light spot is rotated 90 degrees to achieve the effect of enhancing the light intensity gradient along the cutting direction.

[0097] In some embodiments, when the light intensity modulation frequency is 1 / 2 of the oscillation frequency modulation frequency, the optimized initial phase difference between the control signal and the light intensity modulation signal is adjusted and locked to achieve an asymmetrically distributed light spot, such as Figure 3c As shown, the energy density of the annular spot is weakened in the x-direction, resulting in an asymmetric distribution in the y-direction.

[0098] Furthermore, the laser's light intensity modulation depth is adjusted to achieve a change in the energy density distribution of the dynamic spot, thereby varying the asymmetry of the annular spot. For example, when serving laser welding processes with varying melting points, by adjusting the laser's light intensity modulation depth to change the asymmetry of the annular spot, the energy density distribution of the annular spot falling on a material with a relatively low melting point can be weakened, thereby reducing the risk of overburning the material during the welding process.

[0099] Furthermore, the initial phase of the laser's light intensity modulation signal is adjusted to rotate the annular spot pattern. For example, by adjusting the initial phase of the light intensity modulation signal, the annular spot can be rotated 90 degrees clockwise or counterclockwise, thereby achieving an asymmetric distribution of the annular spot along the cutting direction (X direction). This enhances the edge energy distribution intensity, improves the kerf formation of laser cutting sheet metal, and facilitates the increase in the intake of cutting gas or auxiliary gas, thereby improving the cutting thickness and speed while also improving the quality of the cut section.

[0100] In some embodiments, when the modulation frequencies in the x-direction and the y-direction are a multiple greater than 1 (the multiple can be an integer or a non-integer), the light intensity of the laser is modulated, and the modulation frequency is equal to the oscillation frequency of the galvanometer along the processing direction (x-direction). The initial phase difference between the control signal and the light intensity modulation signal is adjusted and locked to optimize the initial phase, so as to achieve modulation of more complex Lissajous figures.

[0101] Figure 4a 、 Figure 4b as well as Figure 4c Three types of "8"-shaped, horseshoe-shaped, and cross-shaped light spots are listed. These three types of graphic spots have better processing effects in welding processing. The first area of ​​the "8"-shaped light spot is the central area, and the second area is the surrounding area. The second area of ​​the horseshoe-shaped light spot is located on one side of the processing direction (x direction) of the first area, and the second area of ​​the cross-shaped light spot is located on one side of the processing direction (x direction) of the first area.

[0102] When the laser light intensity is not modulated, the "8" shaped, horseshoe shaped, and cross shaped light spots are formed as follows: Figure 4a、 Figure 4b 、 Figure 4c shown.

[0103] By modulating the laser light intensity, the patterns of the “8”-shaped, horseshoe-shaped, and cross-shaped spots change, as shown in the following example. Figure 5a 、 Figure 5b 、 Figure 5c As shown, the energy density of the first area (corresponding to the welding area) in the dynamic spot is enhanced, and the energy density of the second area (corresponding to the preheating area) is weakened.

[0104] Furthermore, the initial phase and modulation depth of the laser's light intensity modulation signal are adjusted to alter the energy density distribution area and energy density distribution ratio of the light spot, so that the energy density distribution in the first area is greater than that in the second area. The dynamic light spot in the second area is used to preheat the workpiece for welding. When laser welding materials with a certain hardness, the same heat source is used to simultaneously achieve preheating and welding operations. The structure is simple and easy to control, effectively eliminating thermal stress generated by welding.

[0105] Example 2

[0106] An embodiment of the present invention provides a spot control method for laser cutting applications. By combining light intensity modulation along the cutting thickness direction with oscillation frequency modulation, a richer energy distribution in the optical axis direction can be formed, further expanding the parameter space for optimizing the verticality of the processed material.

[0107] The oscillation frequency of the galvanometer is modulated in three dimensions, including the x, y, and z directions, wherein the x, y, and z directions are perpendicular to each other, the x direction is consistent with the processing direction, and the z direction is consistent with the processing depth direction.

[0108] When the laser intensity is not modulated, the pattern of the dynamic spot on the yoz plane, i.e. the cutting section, is as follows: Figure 6a shown.

[0109] The laser light intensity is modulated, and the laser light intensity modulation frequency is equal to the oscillation frequency of the galvanometer in the z direction, that is, the processing depth direction, so as to change the energy density distribution of the dynamic light spot along the z direction, that is, the cutting thickness, and improve the verticality of the cut product.

[0110] In some embodiments, by adjusting the initial phase of the laser light intensity modulation signal, the highest point (i.e., the maximum value) of the dynamic spot energy density distribution is moved up and down along the z direction. The pattern of the dynamic spot on the yoz plane is as follows: Figure 6b shown.

[0111] In some embodiments, the modulation depth of the laser light intensity modulation signal is adjusted to achieve a more uniform distribution of the energy density of the dynamic light spot along the z direction, thereby generating a dynamic light spot such as Figure 6c shown.

[0112] Example 3

[0113] An embodiment of the present invention provides a method for controlling a spot in a laser welding process, comprising:

[0114] The oscillation frequency of the galvanometer is modulated in three directions, wherein the three directions include x, y, and z directions, wherein the x, y, and z directions are perpendicular to each other, and the oscillation frequency in the x and y directions is 2N times (N is an integer) the oscillation frequency in the z direction, such as Figure 7a As shown, a spot-in-spot type of light spot distribution can be achieved, namely a first light spot and at least one second light spot, with the second light spot located inside the first light spot. By adjusting the initial phase relationship of the x, y, and z oscillation direction signals, the relative positions of the first and second light spots will also change, that is, the outer periphery of the light spot can be moved relative to the inner central light spot.

[0115] By adjusting the initial phase and modulation depth of the laser light intensity modulation signal, the energy density distribution area and energy density ratio of the first light spot and the second light spot (inner and outer light spot patterns) can be adjusted, such as Figure 7b shown.

[0116] By modulating the light intensity of the laser to adjust the energy density distribution area and energy density ratio of the first light spot and the second light spot, the energy density of the second light spot can be weakened, so that the energy density ratio of the second light spot to the first light spot is closer. Combined with more complex light intensity modulation and optimization algorithms, a richer distribution of internal and external light spots can be generated, which is expected to have better processing effects on asymmetric welds and large welds.

[0117] Example 4

[0118] like Figure 8 As shown, this embodiment provides a control system for laser processing, comprising a laser control module, a galvanometer control module, and a modulation module. The modulation module is configured to send an oscillation frequency modulation signal to the galvanometer control module, causing the laser beam to generate at least one light spot on the workpiece; the modulation module is configured to send a light intensity modulation signal to the laser control module, optimizing the energy density of the light spot along the processing direction; and the modulation module is configured to adjust and lock the phase difference between the galvanometer oscillation frequency modulation signal and the laser light intensity modulation signal, enabling the light spot to be periodically and repeatedly generated.

[0119] Example 5

[0120] like Figure 8 As shown, another embodiment of the present invention provides a laser processing device, including a fiber laser, which can be connected to a laser processing head of the fiber laser through an energy transmission fiber and a control system, wherein the control system is used to control the fiber laser and the laser processing head.

[0121] The spot control method, control system, and laser processing equipment for laser processing provided in the embodiments of the present invention can improve the intensity distribution of the laser in the processing plane and the processing depth direction, and on this basis, the dynamic scanning spot pattern of the laser in the processing plane is richer, that is, on the basis of the conventional spot pattern, it presents a larger gradient distribution and asymmetric intensity distribution, thereby expanding the application field of dynamic spot processing. In addition, in the application of laser welding, by increasing the modulation of the laser light intensity on the basis of modulating the oscillation frequency of the galvanometer, it is possible to achieve arbitrary adjustment of the intensity ratio of the center and periphery of the spot, realizing a welding scheme similar to the inner and outer ring spots, which helps to achieve anti-spatter welding. Moreover, by modulating the light intensity of the laser, the high frequency resources of the laser in MHz or even GHz are utilized, which reduces the modulation frequency requirements of the galvanometer for complex dynamic spots, helping to fill the gap in traditional dynamic spot processing systems for control signals such as sawtooth waves and triangle waves that are non-conductive and have rich high-order harmonics.

[0122] In addition, the method and system provided by the embodiments of the present invention can form an asymmetric spot distribution. When the asymmetric direction is perpendicular to the processing direction, it is possible to weld two or more materials with different melting points, which helps to reduce the risk of overburning of a certain material during processing.

[0123] In addition, the Lissajous pattern light spots generated based on dynamic scanning, such as the "8"-shaped, horseshoe-shaped, and cross-shaped light spots, can achieve a combination similar to the preheating area and the welding area. Combined with the light intensity modulation, the energy ratio of the preheating area and the welding area can be arbitrarily changed, greatly improving the optimization freedom.

[0124] In addition, by combining light intensity modulation along the cutting thickness direction with oscillation frequency modulation, a richer energy distribution in the optical axis direction can be formed, further expanding the parameter space for verticality optimization of the processed material.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Under the idea of ​​the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the present invention as above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dynamic spot control method for laser processing, characterized in that: The method comprises: Modulating the oscillation frequency of the galvanometer in three dimensions, where the three dimensions include x, y, and z directions, wherein the x, y, and z directions are perpendicular to each other, and the oscillation frequencies in the x and y directions are 2N times the oscillation frequency in the z direction, where N is an integer, so that the laser beam generates a first light spot and at least one second light spot on the workpiece, wherein the second light spot is located within the first light spot; Adjusting the initial phase relationship of the oscillation frequency modulation signals in the x-direction, y-direction, and z-direction to achieve a change in the relative position of the first light spot and the second light spot; Modulating the laser light intensity to adjust the energy density distribution area and energy density ratio of the first light spot and the second light spot; The galvanometer oscillation frequency modulation signal and the laser light intensity modulation signal have a fixed phase relationship, and the light spot is a repeatable periodic dynamic light spot.

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