Laser cutting system and laser cutting method

Abstract

The invention provides a laser cutting system and a laser cutting method.The laser cutting system comprises a first laser system and a second laser system, the first laser system generates a first laser beam, and the second laser system generates a second laser beam; the projection point of the first laser beam on the cut object and the projection point of the second laser beam on the cut object are located on the opposite sides of the cut object; the first laser system comprises a first laser, a first PBS (Phosphate Buffer Solution) prism, a half-wave plate, a first beam expander, a first galvanometer reflector and a first field lens which are sequentially arranged along the laser transmission direction; the second laser system comprises a second laser, a second PBS (Phosphate Buffer Solution) prism, a second beam expander, a second galvanometer reflector and a second field lens which are sequentially arranged along the laser transmission direction; the first laser and the second laser both generate S-polarized laser beams. The double-sided cutting device can realize double-sided cutting of a cut object, can effectively improve the cutting efficiency and quality, and can prevent the laser from being damaged.

Description

Technical Field

[0001] This invention relates to the field of laser cutting technology, and in particular to a laser cutting system and a laser cutting method. Background Technology

[0002] Laser cutting, as a novel cutting technology, is widely used in manufacturing due to its advantages of high efficiency, high flexibility, and no consumables. It uses a high-energy-density laser beam to instantly melt and vaporize materials, achieving cutting speeds far exceeding traditional processes. Furthermore, it involves no mechanical contact, allowing for precise machining of complex contours without frequent tool changes, significantly reducing costs.

[0003] However, existing processes still have shortcomings. For example, thicker materials such as lithium battery electrodes require multiple cuts or layered cuts, which affects processing efficiency. Furthermore, prolonged laser exposure can cause thermal effects on the materials and create burrs, affecting product quality. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the first objective of the present invention is to provide a laser cutting system that improves cutting efficiency and quality and avoids damage to the laser.

[0005] The second objective of this invention is to provide a laser cutting method that can effectively improve laser cutting efficiency and quality.

[0006] The embodiments of the present invention are achieved through the following technical solutions: A laser cutting system includes a first laser system and a second laser system. The first laser system generates a first laser beam, and the second laser system generates a second laser beam. The projection points of the first laser beam and the second laser beam on the workpiece are located on opposite sides of the workpiece. The first laser system includes a first laser, a first PBS beam splitter, a half-wave plate, a first beam expander, a first galvanometer mirror, and a first field mirror, arranged sequentially along the laser transmission direction. The second laser system includes a second laser, a second PBS beam splitter, a second beam expander, a second galvanometer mirror, and a second field mirror, arranged sequentially along the laser transmission direction. Both the first and second lasers generate S-polarized laser beams.

[0007] With this configuration, the first laser beam cuts through half the thickness of the object being cut, while the second laser beam cuts through the other half. Compared to the traditional single-sided cutting method, this double-sided cutting method can reduce the depth of single-sided cutting, reduce the heat impact and burr problems caused by prolonged laser action on the object being cut, and improve cutting efficiency and product quality. When the first and second laser beams on the upper and lower sides of the object being cut coincide on the cutting trajectory, the lower S-polarized laser second laser beam enters the first laser system and is converted into a P-polarized laser at the half-wave plate, and is transmitted at the first PBS beam splitter, which can prevent damage to the first laser. Correspondingly, the upper P-polarized laser first laser beam enters the second laser system and is transmitted after passing through the second PBS beam splitter, which can prevent damage to the second laser.

[0008] According to a preferred embodiment, the first laser and the second laser are lasers of the same polarization.

[0009] According to a preferred embodiment, the first laser and the second laser are S-polarized picosecond ultrafast lasers or S-polarized femtosecond ultrafast lasers.

[0010] According to a preferred embodiment, the wavelengths of the first laser beam and the second laser beam are 355nm-1064nm, and the power is 3W-500W.

[0011] According to a preferred embodiment, the first laser beam is a P-polarized laser, and the second laser beam is an S-polarized laser.

[0012] A laser cutting method, applied to the aforementioned laser cutting system, includes the following steps: Step S1: Configure the object to be cut, which has opposing first and second sides; Step S2: Project the first laser beam onto the first side of the object being cut and travel along the cutting trajectory; project the second laser beam onto the second side of the object being cut and travel along the cutting trajectory. The first laser beam is a P-polarized laser, and the second laser beam is an S-polarized laser. The first PBS beam splitter prism, located in the transmission path of the first laser beam, is used to reflect the S-polarized laser and can transmit the P-polarized laser. The half-wave plate is used to convert the S-polarized laser into a P-polarized laser. The second PBS beam splitter prism, located in the transmission path of the second laser beam, is used to reflect the S-polarized laser and can transmit the P-polarized laser.

[0013] Based on the aforementioned laser cutting system, this laser cutting method can effectively improve laser cutting efficiency and quality, while avoiding damage to the laser.

[0014] According to a preferred embodiment, in step S2, the thickness of the object being cut is defined as D, then the cutting depth of the first laser beam is greater than or equal to 0.5D, and the cutting depth of the second laser beam is greater than or equal to 0.5D.

[0015] According to a preferred embodiment, during the movement along the cutting trajectory on the object being cut, the projection point of the first laser beam on the object being cut and the projection point of the second laser beam on the object being cut may be asynchronous.

[0016] According to a preferred embodiment, a cutting plane is defined as the bisecting plane of the thickness direction of the object being cut; the projection point of the first laser beam on the cutting plane is defined as the first spot, and the projection point of the second laser beam on the cutting plane is defined as the second spot; in the cutting plane and in a direction perpendicular to the cutting trajectory, the distance between the center point of the first spot and the center point of the second spot is L, and the diameter of the smaller of the first spot and the second spot is N, then L < 0.3N. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a laser cutting system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure in which the first laser beam and the second laser beam are staggered on the cutting trajectory in an embodiment of the present invention; Figure 3 for Figure 2 A top view of the structure shown in the cutting plane; Figure 4 This is a schematic diagram showing the staggered distribution of the first and second light spots in the cutting plane perpendicular to the cutting trajectory direction in some embodiments.

[0019] Icons: 1. First laser; 2. First S-polarized laser beam; 3. Half-wave plate; 4. First PBS beam splitter prism; 5. P-polarized laser beam; 6. First beam expander; 7. First galvanometer mirror; 8. First galvanometer system; 9. First field mirror; 10. First laser beam; 100. First spot; 11. Object to be cut; 110. Cutting plane; 111. First side surface; 112. Second side surface; 113. Cutting trajectory; 12. Second laser beam; 120. Second spot; 13. Second field mirror; 14. Second galvanometer system; 15. Second galvanometer mirror; 16. Second beam expander; 17. Third S-polarized laser beam; 18. Second PBS beam splitter prism; 19. Second S-polarized laser beam; 20. Second laser. Detailed Implementation

[0020] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0021] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0023] Please refer to Figures 1 to 4A laser cutting system includes a first laser system and a second laser system. The first laser system generates a first laser beam 10, and the second laser system generates a second laser beam 12. The projection points of the first laser beam 10 and the second laser beam 12 on the workpiece 11 are located on opposite sides of the workpiece 11. The first laser system includes a first laser 1, a first PBS beam splitter 4, a half-wave plate 3, a first beam expander 6, a first galvanometer reflector 7, and a first field mirror 9 arranged sequentially along the laser transmission direction. The second laser system includes a second laser 20, a second PBS beam splitter 18, a second beam expander 16, a second galvanometer reflector 15, and a second field mirror 13 arranged sequentially along the laser transmission direction. In this embodiment, the first laser beam 10 cuts the object 11 from top to bottom, and the second laser beam 12 cuts the object 11 from bottom to top. Specifically, the first laser beam 10 cuts through half the thickness of the object 11, while the second laser beam 12 cuts through the other half of the thickness of the object 11. Compared with the traditional single-sided cutting method, the double-sided cutting method of this embodiment can reduce the depth of single-sided cutting, reduce the heat effect and burr problems caused by the laser acting on the object 11 for a long time, and help improve cutting efficiency and product quality.

[0024] In this embodiment, both the first PBS beam splitter 4 and the second PBS beam splitter 18 are used to reflect S-polarized laser light and transmit P-polarized laser light. During use, both the first laser 1 and the second laser 20 generate S-polarized laser beams. In the first laser system, the S-polarized laser beam is converted into a P-polarized laser beam 5 by a half-wave plate 3, so that the first laser beam 10 is P-polarized and the second laser beam 12 is S-polarized. Thus, during the cutting process, when the first laser beam 10 and the second laser beam 12, located on the upper and lower sides of the workpiece 11, coincide on the cutting trajectory 113, the lower S-polarized second laser beam 12 enters the first laser system, is transmitted to the half-wave plate 3, is converted into P-polarized laser light, and is transmitted through the first PBS beam splitter 4, preventing damage to the first laser 1. Correspondingly, the upper P-polarized first laser beam 10 enters the second laser system, is transmitted to the second PBS beam splitter 18, and is transmitted, preventing damage to the second laser 20. This laser cutting system improves cutting efficiency and quality while effectively preventing laser damage.

[0025] In this embodiment, the first laser 1 and the second laser 20 are lasers of the same polarization. Further, the first laser 1 and the second laser 20 are S-polarized picosecond ultrafast lasers or S-polarized femtosecond ultrafast lasers. The first laser system and the second laser system can have their parameters set independently, increasing the flexibility of process debugging. In this embodiment, the first laser 1 and the second laser 20 can be infrared lasers with a wavelength of 1064nm, green lasers with a wavelength of 532nm, or ultraviolet lasers with a wavelength of 3W-500W. In this embodiment, preferably, the first laser 1 and the second laser 20 have equal power, the same wavelength, and the same polarization direction. In another embodiment, the first laser 1 and the second laser 20 can also be extended to use two sets of lasers with different laser powers and wavelengths.

[0026] like Figure 1 As shown, the same first laser 1 and second laser 20 are used. The first laser 1 generates a first S-polarized laser beam 2. The first S-polarized laser beam 2 is reflected by the first PBS beam splitter 4 and then passes through the half-wave plate 3 to form a P-polarized laser beam 5. The P-polarized laser beam 5 is expanded at the first beam expander 6 and reflected at the first galvanometer reflector 7 before being focused by the first field mirror 9 to form a first laser beam 10, which is a P-polarized laser. The first galvanometer reflector 7 belongs to the first galvanometer system 8. By adjusting the first galvanometer reflector 7, the projection point of the first laser beam 10 on the workpiece 11 can be moved along the cutting trajectory 113. Correspondingly, the second laser 20 generates a second S-polarized laser beam 19. The second S-polarized laser beam 19 is reflected by the second PBS beam splitter 18 to form a third S-polarized laser beam 17. The third S-polarized laser beam 17 is projected to the second beam expander 16, expanded, and then projected to the second galvanometer reflector 15 for reflection. It is then focused by the second field mirror 13 to form a second laser beam 12, which is an S-polarized laser. In this embodiment, the second galvanometer reflector 15 belongs to the second galvanometer system 14. By adjusting the second galvanometer reflector 15, the projection point of the second laser beam 12 on the object being cut 11 can be moved along the cutting trajectory 113. The first galvanometer system 8 and the second galvanometer system 14 are existing technologies, and the method of adjusting the galvanometer reflector to achieve the position of the light spot, i.e., the projection point of the laser beam on the object being cut 11, is also existing technology and will not be described in detail here.

[0027] In this embodiment, a laser cutting method is also provided, applied to the aforementioned laser cutting system, comprising the following steps: Step S1: Configure the object to be cut 11, which has opposing first side surface 111 and second side surface 112; Step S2: Project the first laser beam 10 onto the first side 111 of the object to be cut 11 and travel along the cutting trajectory 113; project the second laser beam 12 onto the second side 112 of the object to be cut 11 and travel along the cutting trajectory 113. In this design, the first laser beam 10 is a P-polarized laser, and the second laser beam 12 is an S-polarized laser. A first PBS beam splitter 4, located in the transmission path of the first laser beam 10, reflects the S-polarized laser and transmits the P-polarized laser. A half-wave plate 3 converts the S-polarized laser into a P-polarized laser. A second PBS beam splitter 18, located in the transmission path of the second laser beam 12, reflects the S-polarized laser and transmits the P-polarized laser. Figure 2 and Figure 3 As shown, after the object to be cut 11 is fixed, the first side 111 is on the upper side and the second side 112 is on the lower side. The projection point of the first laser beam 10 on the object to be cut 11 forms a first spot 100, and the projection point of the second laser beam 12 on the object to be cut 11 forms a second spot 120. The first spot 100 and the second spot 120 travel along the cutting trajectory 113, which helps to improve the cutting efficiency. At the same time, when the first spot 100 and the second spot 120 overlap or partially overlap on the cutting trajectory 113 during the cutting process, the second laser beam 12 of the S-polarized laser on the lower side enters the first laser system and is transmitted to the half-wave plate 3, where it is converted into a P-polarized laser and transmitted through the first PBS beam splitter 4, which can prevent damage to the first laser 1. Correspondingly, the first laser beam 10 of the P-polarized laser on the upper side enters the second laser system and is transmitted through the second PBS beam splitter 18, which can prevent damage to the second laser 20.

[0028] Further, in step S2, the thickness of the object 11 to be cut is defined as D. Then, the cutting depth of the first laser beam 10 is greater than or equal to 0.5D, and the cutting depth of the second laser beam 12 is greater than or equal to 0.5D. For example... Figure 2 As shown, the first laser beam 10 cuts from top to bottom at least to the cutting plane 110, and the second laser beam 12 cuts from bottom to top at least to the cutting plane 110. This reduces the depth of single-sided cutting, minimizing heat effects and burr problems caused by prolonged laser exposure to the workpiece 11, thus improving cutting efficiency and product quality. It should be noted that the cutting plane 110 is the bisecting plane of the thickness direction of the workpiece 11, and it is parallel to both the first side surface 111 and the second side surface 112.

[0029] In use, preferably, during the movement along the cutting trajectory 113 on the object being cut 11, the projection points of the first laser beam 10 and the second laser beam 12 on the object being cut 11 may be asynchronous. That is, as... Figure 3As shown, on the cutting trajectory 113, the first spot 100 and the second spot 120 may not overlap, i.e., they may be misaligned. This prevents the first laser beam 10 from entering the second laser system and also prevents the second laser beam 12 from entering the first laser system. Based on the foregoing, even if the first spot 100 and the second spot 120 overlap or partially overlap during use, since the first laser beam 10 is a P-polarized laser and the second laser beam 12 is an S-polarized laser, i.e., the first laser beam 10 and the second laser beam 12 are distributed with a polarization direction of 90°, the first laser 1 and the second laser 20 can be prevented from being damaged by the first PBS beam splitter prism 4 and the half-wave plate 3 set in the first laser system and the second PBS beam splitter prism 18 set in the second laser system.

[0030] In some embodiments, such as Figure 4 As shown, the projection point of the first laser beam 10 on the cutting plane 110 is defined as the first spot 100, and the projection point of the second laser beam 12 on the cutting plane 110 is defined as the second spot 120. Within the cutting plane 110 and in a direction perpendicular to the cutting trajectory 113, the distance between the center point of the first spot 100 and the center point of the second spot 120 is L, and the diameter of the smaller of the first spot 100 and the second spot 120 is N, where L < 0.3N. This prevents the first laser beam 10 and the second laser beam 12 from causing a break in the double-sided cutting of the workpiece 11, ensuring a good cutting effect.

[0031] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A laser cutting system, characterized in that, It includes a first laser system and a second laser system, wherein the first laser system generates a first laser beam and the second laser system generates a second laser beam, and the projection points of the first laser beam and the second laser beam on the object being cut are located on opposite sides of the object being cut. The first laser system includes a first laser, a first PBS beam splitter, a half-wave plate, a first beam expander, a first galvanometer mirror, and a first field mirror arranged sequentially along the laser transmission direction; The second laser system includes a second laser, a second PBS beam splitter, a second beam expander, a second galvanometer mirror, and a second field mirror arranged sequentially along the laser transmission direction; Both the first laser and the second laser generate S-polarized laser beams.

2. The laser cutting system according to claim 1, characterized in that, The first laser and the second laser are lasers of the same polarization.

3. The laser cutting system according to claim 1, characterized in that, The first laser and the second laser are S-polarized picosecond ultrafast lasers or S-polarized femtosecond ultrafast lasers.

4. The laser cutting system according to claim 1, characterized in that, The wavelengths of the first laser beam and the second laser beam are 355nm-1064nm, and the power is 3W-500W.

5. The laser cutting system according to claim 1, characterized in that, The first laser beam is a P-polarized laser, and the second laser beam is an S-polarized laser.

6. A laser cutting method, applied to the laser cutting system as described in any one of claims 1-5, characterized in that, Includes the following steps: Step S1: Configure the object to be cut, which has opposing first and second sides; Step S2: Project the first laser beam onto the first side of the object being cut and travel along the cutting trajectory; project the second laser beam onto the second side of the object being cut and travel along the cutting trajectory. The first laser beam is a P-polarized laser, and the second laser beam is an S-polarized laser. The first PBS beam splitter prism, located in the transmission path of the first laser beam, is used to reflect the S-polarized laser and can transmit the P-polarized laser. The half-wave plate is used to convert the S-polarized laser into a P-polarized laser. The second PBS beam splitter prism, located in the transmission path of the second laser beam, is used to reflect the S-polarized laser and can transmit the P-polarized laser.

7. The laser cutting method according to claim 6, characterized in that, In step S2, the thickness of the object being cut is defined as D. Then the cutting depth of the first laser beam is greater than or equal to 0.5D, and the cutting depth of the second laser beam is greater than or equal to 0.5D.

8. The laser cutting method according to claim 7, characterized in that, During the movement along the cutting trajectory on the object being cut, the projection point of the first laser beam on the object being cut and the projection point of the second laser beam on the object being cut may be asynchronous.

9. The laser cutting method according to claim 6, characterized in that, Define a cutting plane, which is the half-bisector of the thickness direction of the object being cut; define the projection point of the first laser beam on the cutting plane as the first spot, and the projection point of the second laser beam on the cutting plane as the second spot; In the cutting plane and in a direction perpendicular to the cutting trajectory, the distance between the center point of the first light spot and the center point of the second light spot is L, and the diameter of the smaller of the first light spot and the second light spot is N, then L < 0.3N.

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