A laser processing system

Abstract

This application provides a laser processing system, including a laser source, a collimator, a beam splitter, a beam combiner, a first directional mirror, a first dimmer, a second directional mirror, a focusing lens, a workpiece, and a moving stage. The laser source generates a linearly polarized laser beam. The collimator adjusts the laser emitted from the laser source into a collimated beam. The beam splitter splits the collimated beam output from the collimator, allowing light polarized along the horizontal axis to pass through as the first beam, and reflecting light polarized along the vertical axis as the second beam. The first and second directional mirrors reflect the second beam, which then reaches the beam combiner, causing the output directions of the first and second beams to converge and combine. The first dimmer separates the focal points of the first and second beams, allowing one beam to be used for laser processing and the other for auxiliary heating, thereby mitigating problems such as spatter, bubbles, and cracks in the laser processing system.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and more specifically, to a laser processing system. Background Technology

[0002] In recent years, with the continuous development of laser processing technology, laser processing has been increasingly widely used in the field of industrial processing. At the same time, higher requirements are constantly being put forward for laser processing technology.

[0003] Traditional laser processing typically uses a Gaussian laser beam distribution. When the laser beam is Gaussian, the temperature at the processing center becomes too high, which can cause splashing during processing and damage the electronic components around the workpiece. At the same time, due to the large temperature difference between the processing center and the surrounding area, a temperature gradient is formed, resulting in uneven heating of the workpiece, which can easily lead to various problems such as deformation, bubbles, and cracks.

[0004] To address these issues, laser manufacturers typically require an additional ring-shaped light-assisted processing system to complement the existing laser. This system creates a ring-shaped heating field around the original processing location to reduce the temperature gradient and mitigate problems such as splashing, bubbles, and cracks.

[0005] Currently, there are two common types of ring-beam assisted processing systems. One type directly uses a separate ring laser to form a ring-shaped spot for auxiliary processing. The other type is a laser processing system with a ring fiber, developed by IPG. Specifically, the laser's fiber structure includes a central fiber and a ring fiber. The laser controls the central fiber and the ring fiber to form a central beam and a ring beam, respectively. The central beam performs laser processing, while the ring beam provides auxiliary processing. Both of these common laser processing systems are relatively complex and have high production costs.

[0006] To reduce production costs, the industry has adopted solutions that split a single laser light source into multiple beams for laser processing and auxiliary heating. However, splitting and recombining a single laser beam often leads to various optical problems such as interference and diffraction, resulting in deterioration of the spot quality on the workpiece. Specifically, when there is only one laser source, beam splitting typically requires a lens with an annular aperture. When the laser beam passes through this lens, diffraction easily occurs. Simultaneously, beam combining results in beam superposition, producing interference fringes. To achieve superposition of two or more beams without interference fringes, the superimposed beams generally need to originate from two or more independent laser sources.

[0007] Therefore, it is necessary to invent a laser processing system that is simple in structure, low in cost, easy to operate, and has excellent spot quality, which can also reduce problems such as workpiece curling, splashing, bubbles and cracks that occur during laser processing. Summary of the Invention

[0008] The purpose of this application is to provide a laser processing system to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, this application provides the following technical solution: This application provides a laser processing system, which includes a laser source, a collimator, a beam splitter, a beam combiner, a first directional mirror, a first dimmer, a second directional mirror, a focusing lens, a workpiece, and a moving stage.

[0010] The laser source generates a linearly polarized laser beam whose vibration direction is neither horizontal nor perpendicular to the beam output direction. Therefore, the laser beam has horizontal and vertical components.

[0011] The collimator is disposed in the output optical path of the laser source. The collimator is used to adjust the laser emitted by the laser source into a collimated beam. It is assumed that the beam propagates along the X direction and has a vertical axis component in the Z direction and a horizontal axis polarization component in the Y direction.

[0012] The beam splitter is disposed on the output optical path of the collimator. The beam splitter is used to split the collimated beam output by the collimator. When the collimated beam is incident on the beam splitter, the beam splitter allows light polarized along the horizontal axis to pass through, becoming the first beam, and reflects light polarized along the vertical axis to another direction, becoming the second beam.

[0013] The beam combiner is positioned on the output optical path of the first beam generated by the beam splitter, and the orientation direction of the beam combiner is the same as that of the beam splitter.

[0014] The first direction-changing mirror is set in the output direction of the second beam generated by the beam splitter being reflected for the first time. The second beam is reflected for the second time by the first direction-changing mirror. Then, a second direction-changing mirror is set in the output direction of the second beam being reflected for the second time. The second beam is reflected for the third time by the second direction-changing mirror. Then, the second beam reaches the beam combiner and is reflected by the beam combiner again. The output directions of the first beam and the second beam converge again.

[0015] The focusing lens is disposed in the output optical path of the beam combiner. The focusing lens is used to focus the first beam and the second beam, and then use the focused beam to process the workpiece.

[0016] The moving stage is used to move the second beam, the first beam, and the workpiece relative to each other on at least two different axes.

[0017] To achieve the effect of composite laser processing using only a single laser source, the laser processing system of this application includes a first dimmer located between the first and second dimmer mirrors. This first dimmer controls the focal point of the second beam and the size of the spot on the workpiece. This allows the first focal point of the first beam and the second focal point of the second beam to be separated, resulting in spots of different sizes on the workpiece.

[0018] The working principle of the laser processing system of this application is as follows: after the first beam and the second beam are separated, one beam is used for laser processing, and the other beam is used for auxiliary heating. Laser processing here can cause the workpiece to reach a molten state, while auxiliary heating cannot, but it can modify the workpiece to a certain extent, thereby reducing the temperature gradient at and near the laser processing location on the workpiece, thus mitigating problems such as spatter, bubbles, and cracks. Since the laser processing system of this application uses only one laser source, the overall system structure is relatively simple, and the production cost is lower. Furthermore, because the first beam and the second beam of the laser processing system of this application are orthogonally polarized, there is no beam interference problem when the beams are combined. When a ring lens is not used for beam splitting, no diffraction problem occurs, resulting in a high-quality beam spot. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a first structural schematic diagram of the laser processing system provided in this application;

[0021] Figure 2 This is a second structural schematic diagram of the laser processing system provided in this application;

[0022] Figure 3 This is a schematic diagram of the third structure of the laser processing system provided in this application;

[0023] Figure 4 This is a fourth structural schematic diagram of the laser processing system provided in this application;

[0024] Figure 5 A schematic diagram of the structure of an embodiment of the third dimmer of the laser processing system provided in this application;

[0025] Figure 6 The fifth structural schematic diagram of the laser processing system provided in this application.

[0026] Reference numerals: 11, laser source; 21, collimator; 31, beam splitter; 32, beam combiner; 33, second dimmer; 41, first directional mirror; 42, second directional mirror; 43, first dimmer; 51, focusing lens; 52, third dimmer; 61, workpiece; 53, third directional mirror; 54, fourth directional mirror; L, collimated beam; L1, first beam; L2, second beam; f1, first focal point; f2, second focal point. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present application and are not intended to limit the scope of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort are within the scope of protection of the present application.

[0028] Please see Figure 1 , Figure 1 This is a first structural schematic diagram of the laser processing system provided in this application.

[0029] The laser processing system includes a laser source 11, a collimator 21, a beam splitter 31, a beam combiner 32, a first directional mirror 41, a first dimmer 43, a second directional mirror 42, a focusing lens 51, a workpiece 61, and a moving stage (not shown in the figure). The laser source 11 generates a linearly polarized laser beam whose vibration direction is neither horizontal nor perpendicular to the beam output direction (for example, forming an angle between 30° and 75°). Therefore, the laser beam has horizontal and vertical components.

[0030] The collimator 21 is disposed on the output optical path of the laser source 11. The collimator 21 is used to adjust the laser emitted by the laser source 11 into a collimated beam L, which is transmitted along the X direction and has a vertical axis component in the Z direction and a horizontal axis polarization component in the Y direction.

[0031] The beam splitter 31 is disposed in the output optical path of the collimator 21. The beam splitter 31 is used to split the collimated beam L output by the collimator 21. When the collimated beam L is incident on the beam splitter 31, the beam splitter 31 allows light polarized along the horizontal axis in the Y direction to pass through, becoming the first beam L1, and reflects light polarized along the vertical axis in the Z direction to another direction, becoming the second beam L2. That is, the beam splitter 31 reflects the beam L2 polarized along the vertical axis and allows the beam L1 polarized along the horizontal axis to pass through.

[0032] The beam combiner 32 is disposed on the output optical path of the first beam L1 generated by the beam splitter 31. The orientation direction of the beam combiner 32 is the same as that of the beam splitter 31, that is, the beam combiner 32 allows the first beam L1 to pass through.

[0033] The first direction-changing mirror 41 is set in the output direction of the second beam L2 generated by the beam splitter 31 being reflected for the first time. The second beam L2 is reflected for the second time by the first direction-changing mirror 41. Then, a second direction-changing mirror 42 is set in the output direction of the second beam L2 being reflected for the second time. The second beam L2 is reflected for the third time by the second direction-changing mirror 42. Then, the second beam L2 reaches the beam combiner 32 and is reflected again by the beam combiner 32. The output directions of the first beam L1 and the second beam L2 converge again.

[0034] The focusing lens 51 is disposed on the output optical path of the beam combiner 32. The focusing lens 51 is used to focus the first beam L1 and the second beam L2, and then use the focused beam to process the workpiece 61.

[0035] The moving stage is used to move the second beam L2, the first beam L1, and the workpiece 61 relative to each other on at least two different axes.

[0036] The first dimmer 43 of the laser processing system of this application is located between the first diverter mirror 41 and the second diverter mirror 42, and is used to control the focal point of the second beam L2 and the size of the spot on the workpiece 61. Thus, the second beam L2 can be formed into a defocused beam, thereby separating the first focal point f1 of the first beam L1 and the second focal point f2 of the second beam L2, and forming spots of different sizes on the workpiece 61.

[0037] Specifically, the laser processing system of this application can split a laser beam generated by a laser source 11 into two parts, a first beam L1 and a second beam L2, by beam splitting. The first beam L1 passes through a beam splitter 31, while the second beam L2 is reflected by a first diverter mirror 41 and a second diverter mirror 42, and its focus is controlled by a first dimmer 43, thus separating the focal points of the first beam L1 and the second beam L2. One beam of the first beam L1 and the second beam L2 is used for laser processing, while the other beam is used for auxiliary heating. Here, laser processing can cause the workpiece 61 to reach a molten state, while auxiliary heating cannot cause the workpiece 61 to reach a molten state, but it can still modify the material of the workpiece 61 to a certain extent, thereby reducing the temperature gradient at and around the laser processing location on the workpiece 61, and mitigating problems such as spatter, bubbles, and cracks.

[0038] In an optional configuration, the first dimmer 43 can be a concave lens or a convex lens, as long as it can change the divergence angle of the second beam L2.

[0039] In a preferred embodiment, the first beam L1 of the laser processing system is used for laser processing, and the second beam L2 is used for auxiliary heating. Since the second focal point f2 of the second beam L2 and the spot size on the workpiece 61 are flexibly adjustable, the laser processing system of this application can be applied to more application scenarios.

[0040] In a preferred embodiment, the first focal point f1 of the first beam L1 of the laser processing system acts on the workpiece 61 to achieve the optimal processing effect, while the second focal point f2 of the second beam L2 may not act on the workpiece 61. Optionally, when the workpiece 61 is a thin layer of metal material, the second focal point f2 is located between the focusing lens 51 and the workpiece 61, which will produce a better processing effect; when the workpiece 61 is a thick layer of metal material, the second focal point f2 is located on the side of the workpiece 61 away from the focusing lens 51, which will also produce a better processing effect.

[0041] Please see Figure 2 , Figure 2 This is a second structural schematic diagram of the laser processing system provided in this application.

[0042] like Figure 2 As shown, in other embodiments, a second dimmer 33 may be provided between the beam splitter 31 and the beam combiner 32. That is, the first focal point f1 of the first beam L1 and the size of the spot acting on the workpiece 61 can be controlled by the second dimmer 33. This design will make it difficult for the first beam L1 to pass through the beam combiner 32. In order to make the first beam L1 pass through the beam combiner 32 smoothly, special rotation design and other deflection design of the beam combiner 32 will be required, which makes the overall structure of the system complex and difficult to control, and may not even guarantee the realization of beam splitting and beam combining. This embodiment is not a preferred solution, nor is it the solution to be protected in this application. It is only proposed as a possible solution.

[0043] Furthermore, in order to change the beam ratio between the first beam L1 and the second beam L2, the angle between the vibration direction of the collimated beam L and the surface of the beam splitter 31 can be changed by rotation (rotating the laser source 11 or the beam splitter 31) or other means. As the angle changes, the horizontal and vertical components will change, and thus the beam ratio between the first beam L1 and the second beam L2 will change accordingly.

[0044] In the preferred embodiment, the first beam L1 has a larger proportion of the total beam than the second beam L2. To improve the processing capability of the first beam L1, it is necessary to at least ensure that the first beam L1 melts the workpiece 61. At the same time, the auxiliary temperature formed by the second beam L2 near the processing position of the workpiece 61 is not too high, meaning that the second beam L2 cannot melt the workpiece 61.

[0045] In a more preferred embodiment, the proportion of the first beam L1 in the total beam is more than twice the proportion of the second beam L2 in the total beam.

[0046] Furthermore, the output direction of the second beam L2 after being reflected by the first direction-changing mirror 41 is parallel to the output direction of the first beam L1 transmitted through the beam splitter 31. This design facilitates control over the second beam L2 to ensure that its output direction is the same as that of the first beam L1 after subsequent dimming and reflection. That is, it facilitates maintaining the same output direction for the first beam L1 and the second beam L2 after beam combining.

[0047] Furthermore, the first dimmer 43 can move back and forth in the output direction of the second beam L2 to further flexibly control the second focal point f2 of the second beam L2 and the size of the light spot acting on the workpiece 61.

[0048] Please see Figure 3 , Figure 3 This is a schematic diagram of the third structure of the laser processing system provided in this application.

[0049] like Figure 3 As shown, the laser processing system of this embodiment also includes a third dimmer 52, which is a concave lens located between the beam combiner 32 and the focusing lens 51. It can move back and forth in the optical path output direction of the first beam L1 and the second beam L2, thereby flexibly changing the second focal point f2 of the first beam L1 and the second beam L2 and the size of the spot acting on the workpiece 61, so as to more flexibly control the second focal point f2 of the first beam L1 and the second beam L2 and the spot size to meet the processing requirements of the workpiece 61 in actual production.

[0050] In the optional scheme, the diameter of the laser beam spot on the workpiece 61 for laser processing is d, and the diameter of the laser beam spot on the workpiece 61 for auxiliary heating is D. To obtain a better auxiliary heating field, 2d ≤ D ≤ 10d must be satisfied. It should be noted that if the laser beam spot on the workpiece 61 is elliptical or approximately elliptical, D and / or d here can be understood to include the major axis diameters D1 and / or d1 and the minor axis diameters D2 and / or d2.

[0051] Please see Figure 4 , Figure 4 This is a schematic diagram of the fourth structure of the laser processing system provided in this application.

[0052] Please see Figure 5 , Figure 5 A schematic diagram of an embodiment of the third dimmer of the laser processing system provided in this application.

[0053] like Figure 4and Figure 5 As shown, the third dimmer 52 is a lens structure that gradually thickens (h1) from the center outwards (h2), and the thickness of the third dimmer 52 is not exactly the same at different positions on the outer side. Figure 5 As shown, the thickness of the outer side of the third dimmer 52 can vary from thin (h4) to thick (h3) and then from thick (h3) to thin (h4). This structural design can control the position and shape of the light spots of the first beam L1 and the second beam L2 on the workpiece 61. The third dimmer 52 can move back and forth in the optical path output direction and can rotate about the output direction of the first beam L1 and the second beam L2 as the rotation axis. During the rotation, the center of the light spot of the second beam L2 on the workpiece 61 can deviate from the center of the light spot of the first beam L1 on the workpiece 61, that is, the light spots of the first beam L1 and the second beam L2 on the workpiece 61 are not concentric, so that the auxiliary heating can be preheating or postheating.

[0054] In practical applications, the center of the auxiliary heating beam applied to the workpiece 61 can be closer to the workpiece position on the pre-processing direction than the center of the processing laser beam applied to the workpiece 61. This means that laser processing is carried out by pre-heating, which can better reduce problems such as workpiece curling, splashing, bubbles and cracks that occur during laser processing.

[0055] With the increasing prevalence of non-linear laser processing, requiring workpieces to follow curved or irregular complex paths (e.g., "8" or "S"), the third dimmer 52 in this embodiment can be flexibly controlled by the laser processing system's control system to adjust its clockwise or counterclockwise rotation and angle to match the processing path. The thickness on the side closer to the pre-processing direction can be adjusted, allowing the second beam L2 to preheat the workpiece 61, thus mitigating issues like workpiece curling, spattering, bubbles, and cracks during laser processing. The thickness values ​​of h1, h2, h3, and h4 can be specifically designed based on the actual production requirements regarding the deviation between the center of the second beam L2's spot on the workpiece 61 and the center of the first beam L1's spot.

[0056] Please see Figure 6 , Figure 6 This is a fifth structural schematic diagram of the laser processing system provided in this application. This laser processing system, in... Figure 1Based on the laser processing system, it also includes a third directional mirror 53 and a fourth directional mirror 54. The third directional mirror 53 and the fourth directional mirror 54 are located between the focusing lens 51 and the workpiece 61, and the second beam L2 and the first beam L1 can be controlled to move on at least two different axes on the workpiece 61 by swinging or moving the third directional mirror 53 and the fourth directional mirror 54.

[0057] In a preferred embodiment, the axes by which the third directional mirror 53 and the fourth directional mirror 54 control the movement of the second beam L2 and the first beam L1 are perpendicular to each other.

[0058] In a preferred embodiment, the third and fourth directional mirrors 53 and 54 only control the second beam L2 and the first beam L1 to oscillate or move within a small angle range, such as 2 to 5 degrees. The moving stage, however, can control the second beam L2, the first beam L1, and the workpiece 61 to move over a wide range relative to each other on at least two different axes. This is because controlling the second beam L2 and the first beam L1 to oscillate or move over a wide range with the third and fourth directional mirrors 53 and 54 would significantly increase the overall size and weight of the laser, thus increasing production and usage costs.

[0059] In an optional embodiment, the laser processing system provided in this application also includes a temperature feedback adjustment mechanism (not shown in the figure). This temperature feedback adjustment mechanism can detect the temperature of the processing position and the temperature auxiliary field position of the workpiece 61 by infrared detection, and can adjust the second beam L2 and the first beam L1 according to the real-time temperature feedback to the control mechanism to meet the good processing requirements of the workpiece 61.

[0060] In alternative solutions, the laser processing system described in this application can be used in various laser processing applications such as laser cutting, laser welding, laser engraving, laser cleaning, and laser additive manufacturing.

[0061] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that the elements inherent in a process, method, article, or apparatus that includes a list of elements are included. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Additionally, portions of the technical solutions provided in the embodiments of this application that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0062] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made to this application, as well as combinations of the various embodiments in this application, without departing from the principles of this application. These improvements, modifications, and combinations also fall within the protection scope of the claims of this application.

Claims

1. A laser processing system, characterized in that, It includes a laser source (11), a collimator (21), a beam splitter (31), a beam combiner (32), a first directional mirror (41), a first dimmer (43), a second directional mirror (42), a focusing lens (51), a workpiece (61), and a moving stage; The laser source (11) generates a linearly polarized laser beam whose vibration direction is neither horizontal nor perpendicular to the beam output direction. The collimator (21) is disposed on the output optical path of the laser source (11) and is used to adjust the laser emitted by the laser source (11) into a collimated beam (L). The beam is transmitted along the X direction and has a vertical axis component in the Z direction and a horizontal axis polarization component in the Y direction. The beam splitter (31) is located on the output optical path of the collimator (21). When the collimated beam (L) is incident on the beam splitter (31), the light polarized along the horizontal axis passes through and becomes the first beam (L1), while the light polarized along the vertical axis is reflected to another direction and becomes the second beam (L2). The beam combiner (32) is disposed on the output optical path of the first beam (L1) generated by the beam splitter (31), and the orientation direction of the beam combiner (32) is the same as that of the beam splitter (31). The first direction-changing mirror (41) is set in the output direction of the second beam (L2) generated by the beam splitter (31) being reflected for the first time, and performs a second reflection on the second beam (L2); The second direction-changing mirror (42) is in the output direction of the second beam (L2) being reflected for the second time, so that the second beam (L2) is reflected for the third time by the second direction-changing mirror (42); The second beam (L2) reaches the beam combiner (32), and after being reflected by the beam combiner (32) again, the output directions of the first beam (L1) and the second beam (L2) converge again; The focusing lens (51) is disposed in the output optical path of the beam combiner (32), and the focusing lens (51) is used to focus the first beam (L1) and the second beam (L2); The moving stage is used to move the second beam (L2), the first beam (L1), and the workpiece (61) relative to each other on at least two different axes; The first dimmer (43) is located between the first diverter (41) and the second diverter (42) to control the focal point of the second beam (L2) and the size of the light spot acting on the workpiece (61), thereby separating the first focal point (f1) of the first beam (L1) and the second focal point (f2) of the second beam (L2) and forming light spots of different sizes on the workpiece (61); The first beam (L1) is used for laser processing, and the second beam (L2) is used for auxiliary heating; It also includes a third dimmer (52), which is a concave lens located between the beam combiner (32) and the focusing lens (51), and can move back and forth in the optical path output direction of the first beam (L1) and the second beam (L2); The third dimmer (52) is a lens structure that gradually thickens from the center outwards. The thickness of the third dimmer (52) is not exactly the same at different positions on the outside, and it is a structure that changes from thin to thick and then from thick to thin.

2. The laser processing system according to claim 1, characterized in that, By controlling the angle between the vibration direction of the collimated beam (L) and the surface of the beam splitter (31) through rotation, the beam ratio between the first beam (L1) and the second beam (L2) is changed.

3. The laser processing system according to claim 2, characterized in that, The first beam (L1) has a greater proportion of the total beam than the second beam (L2).

4. The laser processing system according to claim 1, characterized in that, The output direction of the second beam (L2) after being reflected by the first direction-changing mirror (41) is parallel to the output direction of the first beam (L1) of the beam splitter (31).

5. The laser processing system according to claim 1, characterized in that, The diameter of the laser beam spot on the workpiece (61) during laser processing is d, and the diameter of the laser beam spot on the workpiece (61) during auxiliary heating is D. The relationship between D and d is: 2d≤D≤10d.

6. The laser processing system according to claim 1, characterized in that, It also includes a third directional mirror (53) and a fourth directional mirror (54), which are located between the focusing lens (51) and the workpiece (61), and the second beam (L2) and the first beam (L1) are controlled to move on at least two different axes on the workpiece (61) by the swinging or moving of the third directional mirror (53) and the fourth directional mirror (54).

7. The laser processing system as described in claim 1, characterized in that, It also includes a temperature feedback adjustment mechanism that detects the temperature of the processing position of the workpiece (61) and the temperature auxiliary field position by infrared detection, and adjusts the second beam (L2) and the first beam (L1) according to the real-time temperature feedback.

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