Laser processing method, system and storage medium

Abstract

The invention provides a laser processing method and a laser processing system, and according to the technical scheme, through the modes of parameter setting optimization, light beam polarization state selection, processing path optimization and protective gas addition of a galvanometer type laser processing system, the outlet diameter of a hole formed by using a laser thick material can keep better outlet roundness (greater than 98.5%) under the precise size (about 1-100 microns); the problems that a drill bit is prone to damage and low in efficiency by means of traditional machining, ultrasonic machining and other machining means and the difficult problem that laser machining outlet roundness is poor are solved.

Description

Technical Field

[0001] The present invention relates to the field of laser processing technology, and in particular to a laser processing method, system, and storage medium. Background Art

[0002] Laser processing technology is widely used in material processing in various scenarios, such as cutting, welding, drilling, surface modification, etc., due to its high efficiency, high aspect ratio, non-contact processing, high precision and high quality. Micropores, as a common microstructure, are often used in aerospace, vehicle and shipbuilding, medical, electronic packaging, new energy, fiber optic sensors and other fields. For example, high-quality tiny holes are used as film cooling holes for aircraft engine turbine blades, nozzles for automobile engine fuel injectors, and small holes in gas turbine combustion chambers. At present, the highly advanced social production process has put forward more stringent requirements on the geometric hole type and performance indicators of micropore structures. This trend is reflected in the demand for micropore processing efficiency, microscale, aspect ratio characteristics, surface quality, processing precision and hole roundness.

[0003] The current laser micro-hole processing scheme is more inclined to control the quality of the hole making entrance, and the optimization of the roundness of the outlet end has not received sufficient attention, which leads to the widespread phenomenon of poor roundness at the micro-hole outlet. Due to the influence of various complex factors involved in the laser hole making process, including material properties, processing equipment accuracy and processing parameter settings, the problem of poor roundness of the micro-hole outlet has not been effectively solved. Poor outlet roundness may lead to a decrease in the functional performance of the hole, such as reducing the flow performance of liquid or gas, affecting the heat dissipation effect, and may even cause device failure. Therefore, solving the problem of poor outlet roundness is of decisive significance for comprehensively improving the overall quality and practical efficiency of micro-hole processing. Summary of the invention

[0004] In order to at least overcome the above-mentioned deficiencies in the prior art, the present application provides a laser processing method, system, and storage medium.

[0005] In one aspect, the present application provides a laser processing method, comprising the following steps:

[0006] Provide parts to be processed;

[0007] Providing a first processing component, wherein the first processing component includes processing control software;

[0008] The first processing component can output a processing laser and form a first processing path and a second processing path;

[0009] The first processing path can form a plurality of concentric circles with different polarization angles on the surface and inside of the workpiece to be processed;

[0010] The second processing path can form a plurality of concentric ellipse arrays on the surface and inside of the workpiece to be processed, wherein the concentric ellipse array includes a plurality of concentric ellipses of the same size, the major axis length of the concentric ellipse is the same as the maximum diameter of the concentric circle, and the concentric ellipse is concentric with the concentric circle;

[0011] The processing laser is controlled to first process the workpiece along a first processing path to form a penetrating exit circular hole, and then to process the workpiece along a second processing path to obtain a through hole with a desired exit roundness.

[0012] Preferably, the number of times of repeating the processing along the second processing path is 4 to 6 times, and the second processing path is a further improvement of the hole roundness of the first processing path.

[0013] In a possible implementation, both the first processing path and the second processing path are multi-polarization angle laser processing.

[0014] In a possible implementation manner, the number of ellipses in the second processing path is 20 to 60.

[0015] Preferably, the number of ellipses in the second processing path is 20.

[0016] In a possible implementation, the number of the concentric circles is 500um / (processing line width*3).

[0017] Furthermore, the forming of the first processing path comprises the following steps:

[0018] Drawing a plurality of layers in the processing control software, each layer is set with a different polarization angle, and the layers with different polarization angles together form a first layer group;

[0019] Concentric circles with diameters greater than or equal to the diameter of the target circular hole outlet are drawn in each layer of the first layer group, and the diameters of the concentric circles decrease in sequence.

[0020] Furthermore, the spacing between the concentric circles is 1 to 3 times the laser processing line width.

[0021] Furthermore, the first layer group includes 4N layers, where N is a natural number ≥ 1. The processing control software is used to set different linear polarization angles for each layer in the first layer group, and the linear polarization angle of each layer in the first layer group is 0 to 90°, and the specific angle interval is 90° / 4N.

[0022] Preferably, the first layer group includes 4 layers.

[0023] In a possible implementation, forming the second processing path includes the following steps:

[0024] On the basis of the 4N layers, concentric ellipse graphics of the same size are drawn in the layers respectively using processing control software, and the angle between the ellipses is 180° / the number of ellipses, and the layers together form a second layer group.

[0025] In a possible implementation manner, the linear polarization angle of each layer in the first layer group is 0° to 90°.

[0026] Furthermore, the linear polarization angles are 0°, 22.5°, 45° and 67.5°.

[0027] In a possible implementation, it also includes setting layer parameters for each layer in the first layer group and the second layer group, and the layer parameters include element number, layer number, power angle, defocus distance, feed distance, scanning speed and jump speed, etc.

[0028] In a possible implementation, when the processing laser performs processing along the first processing path and the second processing path on the workpiece, processing laser parameters are different.

[0029] Preferably, the laser parameters of the processing laser include central wavelength, laser pulse width, laser frequency, spot diameter and laser power.

[0030] In a possible implementation, the laser processing method further includes the following step: before performing processing along the first processing path, the processing laser draws a circle on the surface of the workpiece to be processed to determine the processing roundness error and line width of the first processing component.

[0031] In a possible implementation, the laser processing method further includes a gas purging step, and when the processing laser is performing processing, the processing position of the workpiece to be processed is purged synchronously with gas.

[0032] Preferably, the gas is one or more of air, nitrogen and argon.

[0033] In a second aspect, the present application further provides a laser processing system. In a possible implementation, the laser processing system includes a first processing component and a working platform.

[0034] The first processing assembly includes a laser, an optical path system and a galvanometer scanning system arranged in sequence along the transmission direction of the processing laser, and the processing laser is focused onto the working platform by the galvanometer scanning system;

[0035] The optical path system can modulate the processing laser into circularly polarized light;

[0036] The workpiece to be processed is placed on a working platform;

[0037] The first processing component also includes processing control software, which can set processing parameters and draw processing paths. The laser control software can control the processing path of the processing laser and control the component parameters of the first processing component.

[0038] Preferably, the above-mentioned processing control software includes CAD drawing software and / or laser control software.

[0039] Preferably, the above-mentioned processing path can be drawn by CAD drawing software.

[0040] In a possible implementation manner, the distance between the workpiece to be processed and the working platform is the focal length of the field mirror in the galvanometer system.

[0041] Preferably, the specific focal length is determined according to the spot size required for processing.

[0042] In a possible implementation, the laser is an ultraviolet picosecond laser.

[0043] Preferably, the laser parameters output by the ultraviolet picosecond laser are: the picosecond laser is linearly polarized light, the central wavelength is 355nm, the pulse width is less than 15ps, the frequency is 1Hz-2MHz, the spot diameter is 2mm, and the maximum power is 60W.

[0044] In a possible implementation, the optical path system includes a beam expander and a quarter-wave plate that are sequentially arranged along a transmission direction of the processing laser.

[0045] In a possible implementation, the galvanometer scanning system includes a galvanometer and a field mirror sequentially arranged along a transmission direction of the processing laser.

[0046] Preferably, the parameters of the field lens are: format>45*45mm, focal length is 100mm.

[0047] In a possible implementation, the laser processing system further includes a purge device.

[0048] The purging equipment can provide a gas flow rate of >5 m / s to purge the workpiece to be processed on the working platform.

[0049] In a possible implementation, the laser processing system further includes a refrigeration system.

[0050] The refrigeration system adopts water cooling and is maintained at 15-29° C. The refrigeration system is used to ensure the stable operation of the laser and the galvanometer scanning system during the processing.

[0051] In a possible implementation, the laser processing system further includes an electrical control system.

[0052] The electrical control system controls the movement of the working platform, CCD camera and galvanometer, including but not limited to moving the workpiece to be processed, adjusting the focal length and CCD imaging.

[0053] In a third aspect, the present application provides a computer-readable storage medium storing computer-executable instructions, wherein the computer-executable instructions are configured to execute the above-mentioned laser processing method.

[0054] Technical advantages of this application:

[0055] 1. This application uses multiple polarization angles and elliptical array layers to correct the geometric roundness of through holes with poor exit roundness during processing, thereby effectively improving the exit roundness of laser hole making;

[0056] 2. The technical solution of the present application optimizes the parameter settings of the galvanometer laser processing system, selects the beam polarization state, optimizes the processing path, and adds protective gas, so that the exit diameter of the laser hole in thick materials can maintain a good exit roundness (>98.5%) under the condition of precise size (about 1 to 100 um), thus solving the pain points of drill bit fragility and low efficiency of traditional mechanical processing, ultrasonic processing and other processing methods, as well as the difficulty of poor exit roundness of laser processing;

[0057] 3. The technical solution of this application can also reduce energy consumption and costs, reduce environmental pollution, and improve processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0059] Figure 1 A flowchart of a laser processing method provided in one embodiment of the present application;

[0060] Figure 2 This is a schematic diagram of the principle of adding an elliptical array to correct the outlet roundness in one embodiment of the present application;

[0061] Figure 3 A schematic diagram of the structure of a laser processing system provided in one embodiment of the present application;

[0062] Figure 4 A schematic diagram of the structure of a laser processing system provided in one embodiment of the present application;

[0063] Figure 5A schematic diagram of a first processing route provided in one embodiment of the present application;

[0064] Figure 6 A schematic diagram of a first type of second processing route provided in one embodiment of the present application;

[0065] Figure 7 A schematic diagram of a second type of second processing route provided in one embodiment of the present application;

[0066] Figure 8 Schematic diagram of the roundness of the laser hole exit without adding the elliptical array and polarization angle in the comparative example;

[0067] Fig. 9 Schematic diagram of the roundness of the laser hole making outlet with the addition of an elliptical array and polarization angle in the embodiment.

[0068] In the figure: 10 - first processing component; 20 - working platform; 101 - laser; 102 - optical path system; 103 - galvanometer scanning system; 104 - processing control software. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0070] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0071] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0072] In the description of this application, it should be noted that the terms "upper", "lower", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply 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 a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0073] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0074] It should be noted that, in the absence of conflict, different features in the embodiments of the present application may be combined with each other.

[0075] Laser processing is a rapidly developing processing technology. It is to irradiate the surface of the workpiece with a laser beam, and use the high energy of the laser to cut, melt the material and change the surface properties of the object. Since laser processing is a non-contact processing, the tool will not directly rub against the surface of the workpiece to produce resistance, so the speed of laser processing is extremely fast, the range of the processing object affected by heat is small, and no noise is generated. Since the energy of the laser beam and the moving speed of the beam can be adjusted, laser processing can be applied to different levels and ranges. At present, laser processing can be used for drilling holes, especially for drilling microholes and special-shaped holes. Laser drilling has been widely used in the processing of workpieces such as gem bearings, air film cooling holes, engine fuel injectors (holes), diamond wire drawing dies, and chemical fiber spinnerets for watches and instruments. However, the current laser processing drilling scheme focuses more on the entrance quality of the hole, such as the roundness of the round hole, and ignores the importance of the exit quality, resulting in the problem of poor exit roundness of the hole, which still exists, affecting the performance of the device and subsequent use.

[0076] In order to solve the problems in the prior art, the present application provides a laser processing method, see Figure 1 As shown, the following steps are included:

[0077] Provide parts to be processed;

[0078] In this step, the workpiece to be processed is a component to be prepared with a through hole. In this application, there are no requirements for the shape, thickness and material of the workpiece to be processed. When the material and thickness of the workpiece to be processed change, the purpose of processing the circular hole can be achieved by adjusting the corresponding processing laser parameters. The material selection of the workpiece to be processed is also relatively wide. Most metal and non-metal materials that can be used for laser processing can be used as the workpiece to be processed in this application. For example, the material of the workpiece to be processed can be selected from one or more of metal, plastic film, semiconductor, metal film, glass, zirconium oxide, and sapphire. Exemplarily, the workpiece to be processed can be various shapes such as round, rectangular, polygonal, square, irregular, etc.

[0079] providing a first processing component, the first processing component including processing control software;

[0080] The first processing component can output a processing laser and form a first processing path and a second processing path.

[0081] In this step, the first processing component can output a processing laser. Exemplarily, the processing laser can include a laser, such as a laser selected from a solid laser, a gas laser, a liquid dye laser, a semiconductor laser and a fiber laser.

[0082] The first processing path and the second processing path are generated by processing control software. Specifically, the processing control software has functions such as controlling processing parameters and drawing processing patterns.

[0083] Processing control software is a general term, which can include a variety of software, such as common mapping software, laser control software, etc., or mature CAM (Computer Aided Manufacturing) software can be directly used to achieve technical effects. Processing control software can set processing parameters and control processing. For example, the processing parameters that can be set and controlled by the processing control software include: processing times, defocus distance, feed distance, scanning speed, jump speed, laser frequency and laser power, etc.

[0084] Specifically, the first processing path and the second processing path can be obtained by the following steps: confirming the size of the circular hole outlet to be processed, making a corresponding processing pattern in the processing control software and outputting a storage file, importing the storage file storing the processing pattern into the control system, and the processing control software reads the processing pattern in the storage file again, and selects and sets the laser processing parameters according to the thickness, material and other characteristics of the workpiece to be processed, and controls the processing laser to perform processing along the first processing path and the second processing path. Specifically, the drawing software part in the processing control software can be common drawing software such as AUTOCAD, Solidworks, UG, and Unigraphics NX.

[0085] The first processing path can form a plurality of concentric circles on the surface and inside of the workpiece to be processed;

[0086] In this step, the first processing path drawn in the processing control software is a plurality of concentric circles with different polarization angles. By adjusting the parameters of the processing laser, when the processing laser processes along the first processing path, the workpiece to be processed can be directly ablated to preliminarily form a through hole penetrating the workpiece to be processed;

[0087] Theoretically, the shape of the circular hole at the exit should be the same as that of the first path, which is a standard circle. However, in reality, there is always an error in the roundness at the exit. This result is related to the interaction between the laser and the material. The reason is that when the laser processes the material, the high-density plasma generated by the ionization of the material forms a shielding effect on the laser, resulting in energy attenuation and uneven distribution, which affects the roundness of the processed micro-hole exit. On the other hand, different materials have different absorption rates and thermal conductivity of lasers. Changes in material thickness or uneven release of internal stress may also lead to poor hole exit shape. In addition, the poor hole exit shape may also be affected by the state of the optical system, software control and programming, and mechanical system factors.

[0088] The second processing path can form a plurality of concentric ellipse arrays on the surface of the workpiece to be processed, wherein the concentric ellipse arrays include a plurality of concentric ellipses of the same size, the major axis length of the concentric ellipse is the same as the maximum diameter of the concentric circle, and the concentric ellipse is concentric with the concentric circle;

[0089] See also Figure 5 , Figure 6 and Figure 7 , Figure 5 , Figure 6 , Figure 7 The shapes of a first processing path and a second processing path are schematically given. In this embodiment, the first processing path is concentric circles with different polarization angles, and the second processing path is a plurality of concentric ellipses of the same size, the major axis length of the concentric ellipses is the same as the maximum diameter of the concentric circles, and the concentric ellipses are concentric with the concentric circles.

[0090] In this step, as described above, when the first processing path is executed, the roundness of the circular hole at the exit is poor. Therefore, in this embodiment, laser multilayer processing with different polarization angles is used again, and the short axis part of the exit circular hole is compensated by the elliptical array of the second processing path to achieve high-quality exit roundness. During the processing, circularly polarized light has better exit roundness than linearly polarized light, so the exit morphology of the through hole processed by concentric circles with circularly polarized light and the same polarization angle is as follows: Figure 3As shown in the figure, it can be seen that the actual processed through-hole outlet is not a regular circle but an ellipse. When the polarization angle is changed, the long axis of the outlet ellipse will also change at a fixed angle. Therefore, multi-layer and multi-polarization angle laser processing is used to improve the outlet roundness. Although this method can further improve the outlet roundness, the roundness still cannot reach the expected roundness of 90%. In order to further optimize the outlet roundness, an elliptical array is added to the layer to correct the short axis of the ellipse, and finally a through-hole outlet roundness better than 98% is obtained, as shown in the figure. Figure 4 shown.

[0091] Specifically, the number of ellipses in the concentric ellipses and the number of circles in the concentric circles can be the same or different; the ellipse array can be directly added to the concentric circle layer, that is, the ellipse graphic is directly added to the original layer; the ellipse array can also create a new layer to draw the ellipse array.

[0092] The processing laser is controlled to first process the workpiece along a first processing path to form a penetrating circular hole, and then to process the workpiece along a second processing path to obtain a through hole with a desired exit roundness. Generally speaking, the desired exit circular hole roundness is above 98.3%.

[0093] Specifically, the method of controlling the processing laser can be to control the direction of the laser beam by adding a galvanometer scanning system, or to control the direction of the laser beam by processing control software. For example, as an embodiment, the workpiece to be processed can be placed on a work platform, and the work platform can be controlled to move along the processing path, thereby achieving the purpose of controlling the laser processing path.

[0094] In the present application, the processing laser is first controlled to perform processing and drilling along the concentric circles of the first path, and a penetrating circular hole is directly and initially formed on the workpiece to be processed. At this time, as mentioned above, the outlet roundness is not good; at this time, the processing laser is controlled to perform processing along the concentric elliptical array of the second path, and the concentric elliptical array can be processed again on the basis of the penetrating circular hole, so as to correct the roundness of the circular hole outlet.

[0095] In one possible implementation, the number of times the entire processing flow is repeated to achieve the desired roundness is 4 to 6 times. The purpose of controlling the laser processing path is achieved by controlling the work platform to move along the processing path. In this embodiment, the addition of a layer of elliptical array cannot meet the requirements of roundness correction, and multi-layer processing can be performed. Specifically, in the process of multi-layer processing along the second processing path, the processing control software can be used to flexibly adjust the polarization angles of the concentric ellipses in the second processing path. For example, when the first layer is processed along the second processing path, the polarization angle of the selected ellipse is only corrected for the roundness on the right side of the exit hole. At this time, when the second layer is processed, the polarization angle of the concentric ellipse can be adjusted to correct the roundness on the left side of the exit hole. Through multiple processing, the technical effect of further correcting the exit roundness can be achieved. In addition, during multiple processing, the processing control software can also control the changes in processing parameters to achieve better processing effects.

[0096] In a possible implementation, the whole processing flow to achieve the desired roundness is repeated 4 times. 4 repetitions of processing along the first and second processing paths can basically meet the roundness requirement.

[0097] In a possible implementation, the number of concentric circles is the same as the number of concentric ellipses. That is, the number of circles in the concentric circles is the same as the number of ellipses in the concentric ellipse array. The ellipse array can be directly drawn again in the concentric circle layer, which is easy to process.

[0098] In a possible implementation, each layer is set with a different polarization angle, and the layers with different polarization angles together form a first layer group, and forming the first processing path includes the following steps:

[0099] Drawing a plurality of layers in the processing control software, wherein the layers together form a first layer group;

[0100] Concentric circles with diameters equal to the diameter of the exit circular hole are drawn in each layer of the first layer group, and the diameters of the concentric circles decrease in sequence. Specifically, several layers are first drawn using the drawing function of the processing control software, and then circular patterns are drawn in the layers. The layers can also draw other patterns, such as concentric ellipse arrays.

[0101] In a possible implementation, the spacing between the concentric circles is three times the processing line width.

[0102] In a possible implementation, it is recommended that the first layer group includes 4N layers, where N is a natural number ≥ 1, and may also be any number of layers ≥ 4. Exemplarily, it may be 4 layers, 8 layers, or 12 layers.

[0103] Preferably, the first layer group includes 4 layers.

[0104] In a possible implementation, forming the second processing path includes the following steps:

[0105] Using the processing control software, add an elliptical array to each layer in the first layer group, or create a new layer to add an elliptical array and set the polarization angle;

[0106] Draw concentric ellipse array graphics of the same size in each layer of the second layer group.

[0107] In this embodiment, when forming the first processing path, the first layer group is a layer group for drawing a concentric circle array, and each layer needs to set a polarization angle; when forming the second processing path, the concentric ellipse array layer can set a polarization angle or not add it.

[0108] Here, the first layer group and the second layer group can be the same layer group, that is, on the basis of the first layer group, a concentric ellipse array is added to form the second layer group; the first layer group and the second layer group can also be different layer groups, that is, a new concentric ellipse array layer group is created to form the second layer group, so the number of layers in the first layer group and the second layer group can be the same or different. Regardless of whether the second layer group is a newly created layer group, concentric ellipse graphics of the same size can be drawn in each layer of the second layer group, and the concentric ellipse graphics form a concentric ellipse array, which is the second processing path.

[0109] In a possible implementation, the linear polarization angle of each layer in the first layer group is 0 to 90°. The specific layer polarization angle interval is 90° / number of layers. For example, 0°, 18°, 36°, 54°, and 72° can be selected. By setting different linear polarization angles for each layer, a perforation with better exit roundness can be obtained. The layer polarization angle is selected according to actual conditions. Furthermore, the linear polarization angles are 0°, 22.5°, 45°, and 67.5°, and the desired exit roundness can be achieved by correction using a concentric elliptical array.

[0110] In a possible implementation, the processing software is further used to set layer parameters for each layer in the first layer group and the second layer group, and the layer parameters include processing times, defocus distance, feed distance, scanning speed, jump speed and polarization angle, etc. In this embodiment, the processing control software can be used to control the above layer parameters, and the processing times are the times that the processing laser repeats along the processing path; specifically, the defocus distance affects the size of the processing outlet, the feed distance affects the processing quality, the scanning speed affects the processing quality and efficiency, and the jump speed affects the roundness of the inlet and outlet.

[0111] In a possible implementation, when the processing laser performs processing along the first processing path and the second processing path on the workpiece to be processed, the processing laser parameters are different. When the processing laser performs processing along the first processing path and the second processing path on the workpiece to be processed, the processing laser parameters can be the same or different. In this embodiment, the processing parameters are different. Further, the laser parameters of the processing laser include central wavelength, laser pulse width, laser frequency, spot diameter and laser power.

[0112] In a possible implementation, the laser processing method further includes the following steps: before performing processing along the first processing path, the processing laser draws a circle on the surface of the workpiece to be processed, and determines the system processing roundness error and line width based on the morphological characteristics after processing.

[0113] In a possible implementation, the laser processing method further includes a gas purging step, and when the processing laser is performing processing, the processing area of ​​the workpiece to be processed is purged synchronously with gas. In this embodiment, the addition of a gas purging step can effectively purge the debris generated during the processing process to avoid the influence of the debris on the subsequent processing process and further improve the roundness of the processing outlet. When purging, the direction of the purge gas is not fixed, and it can be purged from the top or from the side; the purge gas flow should not be too large, otherwise it will cause the workpiece to be processed to shift; the purge gas flow should not be too small, otherwise it will not achieve the technical effect of purging the debris. The specific purge speed varies according to factors such as the specific laser processing technology, material type, laser power, and processing accuracy.

[0114] Furthermore, the gas is one or more of air, nitrogen, and argon. Any gas that does not react with the workpiece can be used as the purge gas flow. For example, the purge gas flow can be one of air, nitrogen, and argon. These three types of gases are widely available and have low costs.

[0115] In one embodiment of the present application, a laser processing system is also provided. Figure 3 In a possible implementation, the laser processing system includes a first processing component and a working platform,

[0116] The first processing assembly includes a laser, an optical path system and a galvanometer scanning system arranged in sequence along the transmission direction of the processing laser, and the processing laser is focused on the working platform from the galvanometer scanning system;

[0117] In this embodiment, a laser is used to emit a processing laser, and the laser can be selected from a solid laser, a gas laser, a liquid dye laser, a semiconductor laser and a fiber laser;

[0118] The optical path system is used to accurately and efficiently transmit the laser beam generated by the laser generator to the processing position. The laser beam is first emitted from the laser, passes through components such as reflectors (such as plane mirrors or curved mirrors) and beam expanders to control the transmission direction and increase the energy density at the focus, and finally reaches the focusing lens to achieve long-distance lossless transmission of energy.

[0119] The galvanometer scanning system converges parallel laser beams to one point, forming a very small high-energy focus, thereby generating high temperature on the material to achieve processing processes such as cutting, welding and marking. The spot size and energy density after focusing directly affect the processing efficiency and quality. At the same time, the focus position can be changed quickly to achieve special-shaped processing and large-format processing. The optical path system can modulate the processing laser into circularly polarized light;

[0120] The workpiece to be processed is placed on a working platform;

[0121] The first processing component also includes processing control software, which can set processing parameters and draw processing paths, control the processing path of the processing laser, and control the parameters of the first processing component.

[0122] In this embodiment, the processing control software and the laser, optical path system, galvanometer scanning system, and work platform are electrically coupled and can be used to set and control processing parameters. For example, the central wavelength, laser pulse width, laser frequency, spot diameter, and laser power of the laser can be controlled; the number of processing times, defocus distance, feed distance, scanning speed, and jump speed of the processing path can also be controlled, and the processing path can also be drawn.

[0123] In another feasible method, the working parameters of the laser, the optical path system, the galvanometer scanning system, and the working platform can also be manually adjusted.

[0124] In one possible implementation, the distance between the workpiece to be processed and the work platform is selected based on the actual processing content. The workpiece can be adsorbed on the work platform. However, for processing that requires penetration, such as drilling, a certain distance is required between the workpiece and the work platform to ensure that the processing is not affected by the work platform or damage the work platform.

[0125] In a possible implementation, the laser is an ultraviolet picosecond laser. Exemplarily, the parameters of the picosecond laser emitted by the ultraviolet picosecond laser are: the picosecond laser is linearly polarized light, the central wavelength is 355nm, the pulse width is less than 15ps, the frequency is 1Hz to 2MHz, the spot diameter is 2mm, and the maximum power is 60W.

[0126] Due to the long pulse width and low laser intensity of the laser, the material will melt and continue to evaporate. Although the laser beam can be focused into a very small spot, the thermal shock to the material is still very large, limiting the processing accuracy. Therefore, reducing thermal effects is the way to improve processing quality.

[0127] When the laser acts on the material with a pulse time of picoseconds, the processing effect will change significantly. As the pulse energy rises sharply, the high power density is sufficient to strip the outer electrons. Since the time for the laser to interact with the material is very short, the ions are ablated from the surface of the material before transferring the energy to the surrounding materials, and will not cause thermal effects on the surrounding materials. Therefore, the use of ultraviolet picosecond lasers in this embodiment can achieve better technical effects, and the laser parameters used are optimized laser parameters.

[0128] In a possible implementation, the optical path system includes a beam expander and a quarter wave plate arranged in sequence along the direction of the processing laser emission. In this embodiment, the beam expander serves to expand the laser spot size so as not to damage subsequent components when the power is increased, and the quarter wave plate can modulate the linear polarized light into circular polarized light with better processing effect.

[0129] In a possible implementation, the galvanometer scanning system includes a galvanometer and a field lens sequentially arranged along the emitting direction of the processing laser. Preferably, the parameters of the field lens are: format>45*45mm, focal length is 100mm.

[0130] In a possible implementation, the laser processing system further includes a purge device, which can spray gas to purge the work platform. In this embodiment, the purge device can be a hair dryer.

[0131] In a possible implementation, the laser processing system also includes a refrigeration system, which absorbs and removes a large amount of heat generated by the laser during operation through circulating cooling water, ensuring that the core components of the laser are maintained within a safe operating temperature range to prevent device damage or performance degradation caused by overheating. At the same time, the galvanometer scanning system is cooled to suppress temperature drift and improve processing accuracy.

[0132] In a possible implementation, the laser processing system also includes an electrical control system, which ensures that the processing process is carried out in accordance with the preset process requirements by accurately controlling the output power, pulse width, frequency and other parameters of the laser. It is the core of human-computer interaction, enabling the operator to easily input processing instructions, monitor processing status, adjust parameter settings, etc. The electrical control system also needs to coordinate with other subsystems in the laser processing system (such as cooling systems, etc.) to ensure the stability and safety of the entire processing environment and process. It also has fault detection and alarm functions. When the system detects abnormal conditions (such as overheating, abnormal current and voltage, laser failure, etc.), it can take protective measures in time to avoid equipment damage and send an alarm to the operator.

[0133] See also Figure 4 , Figure 4 The structure of a laser processing system is given as an example.

[0134] The laser processing method of the present invention is further described below with an embodiment, which specifically includes the following steps:

[0135] Step 1: Install and debug the UV picosecond laser, cooling system, power supply, electrical control system, optical path system, galvanometer scanning system and processing control software;

[0136] Step 2: Start the refrigeration system, UV picosecond laser, galvanometer scanning system, electrical control system and processing control software;

[0137] Step 3: Adjust the parameters of the ultraviolet picosecond laser. The laser parameters output by the ultraviolet picosecond laser are: central wavelength of 355nm, pulse width <15ps, frequency of 1Hz~2MHz, linear polarized light with a spot diameter of 2mm, and maximum power of 60W;

[0138] Step 4: Use a beam expander to expand the spot size of the picosecond laser in step 3 to 10 mm, and place a quarter-wave plate behind it to obtain circularly polarized light, which is then incident on the galvanometer;

[0139] Step 5: Use a field lens with a format of >45*45mm and a focal length of 100mm to focus the laser spot in step 4 to ≤8um;

[0140] Step 6: In the processing control software, adjust the scanning speed of the galvanometer to less than 100 mm / s, and draw a circle on the surface of the material to determine the processing roundness error and line width of the galvanometer;

[0141] Step 7: Create 4 new layers in the CAD software, and draw concentric circles with a diameter larger than the target outlet size on each layer. The diameters decrease in sequence, and the spacing is kept at about 3 times the processing line width;

[0142] Step 8: Import the processing path CAD file drawn in step 7 into the processing control software. The processing control software sets different linear polarization angles for the four layers in step 7, which are 0°, 22.5°, 45° and 67.5° respectively;

[0143] Step 9: Further using the processing control software, set the processing times of the four layers in step 8 to 4 times, the defocus distance to 6 μm, the feed distance to 10 μm, the scanning speed to 90 mm / s, the jump speed to 5000 mm / s, the laser power, and the laser frequency to 300 KHz;

[0144] Step 10: Place the sample to be processed on the working platform. To prevent the sample from being too close to the platform and affecting the processing quality, suspend the sample in the air with a distance of 3mm from the working platform.

[0145] Step 11: Purge the work platform with nitrogen and start laser processing;

[0146] Step 12: If the processing roundness is greater than 80%, proceed to the next step, otherwise repeat step 9 to adjust the processing parameters and reprocess;

[0147] Step 13: Based on step 7, add an ellipse array to each layer. The major axis of the ellipse is equal to the maximum radius of the concentric circle, and the center of the ellipse coincides with the center of the concentric circle.

[0148] Step 14: Repeat steps 8 to 13 again, reduce the laser power and perform hole making processing until the roundness at the exit reaches more than 98.5%.

[0149] At the same time, the present application also provides a comparative example. Compared with the embodiment, the comparative example does not include the step of adding an elliptical array and step 13, that is, the ellipse is not used to correct the roundness of the outlet, and the circular hole is directly opened.

[0150] See also Figure 8 , Fig. 9 , Figure 8 This is the exit circular hole without adding the elliptical array. Fig. 9 The exit circular hole with the ellipse array added, it can be seen that Fig. 9 Has better roundness.

[0151] In summary, this technical solution uses picosecond lasers to change beam polarization, optimize control software parameter settings, optimize processing paths, and add processing protective gases to successfully achieve 300μm thick metal molybdenum processing parts, with a precision round hole at the 100μm level at the exit, and the roundness is maintained above 98.5%, and the major axis and minor axis difference is less than 1.5μm. This solution has the advantages of high exit roundness, high precision, high efficiency, non-contact processing, small heat-affected zone, and is suitable for various difficult-to-process materials.

[0152] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A laser processing method, characterized in that: The steps include: Provide parts to be processed; Providing a first processing component, wherein the first processing component includes processing control software; The first processing component can output a processing laser and form a first processing path and a second processing path; The first processing path can form a plurality of concentric circles with different polarization angles on the surface and inside of the workpiece to be processed; The second processing path can form a plurality of concentric ellipse arrays on the surface and inside of the workpiece to be processed, wherein the concentric ellipse array includes a plurality of concentric ellipses of the same size, the major axis length of the concentric ellipse is the same as the maximum diameter of the concentric circle, and the concentric ellipse is concentric with the concentric circle; The processing laser first processes the workpiece along a first processing path to form a penetrating circular hole, and then processes the workpiece along a second processing path to obtain a through hole with a desired exit roundness.

2. The laser processing method according to claim 1, characterized in that: The first processing path and the second processing path are both multi-polarization angle laser processing.

3. The laser processing method according to claim 1, characterized in that: The forming of the first processing path comprises the following steps: Drawing a plurality of layers in the processing control software, each layer is set with a different polarization angle, and the layers with different polarization angles together form a first layer group; Concentric circles with diameters greater than or equal to the diameter of the target circular hole outlet are drawn in each layer of the first layer group, and the diameters of the concentric circles decrease in sequence.

4. The laser processing method according to claim 3, characterized in that: The spacing between the concentric circles is 1 to 3 times the laser processing line width.

5. The laser processing method according to claim 4, characterized in that: The first layer group includes 4N layers, where N is a natural number ≥1, and the linear polarization angle of each layer in the first layer group is 0-90°.

6. The laser processing method according to claim 3, characterized in that: The forming of the second processing path comprises the following steps: Concentric elliptical figures of the same size are drawn in the layers respectively based on the multiple layers by using the processing control software, and the multiple layers together form a second layer group.

7. The laser processing method according to claim 6, characterized in that: The number of ellipses in the second layer group is 20 to 60, and the angle between the ellipses is 180° / the number of ellipses.

8. The laser processing method according to claim 6, characterized in that: The laser processing method also includes setting processing parameters for each layer in the first layer group and the second layer group, and the layer parameters include but are not limited to the number of elements, the number of layers, the power angle, the defocus distance, the feed distance, the scanning speed and the jump speed.

9. The laser processing method according to claim 1, characterized in that: When the processing laser performs processing along the first processing path and the second processing path on the workpiece, different processing parameters are set.

10. The laser processing method according to claim 1, characterized in that: The laser processing method further comprises the following steps: before processing is performed along the first processing path, the processing laser draws a circle on the surface of the workpiece to be processed to determine the roundness error and line width of the first processing component processing.

11. The laser processing method according to claim 1, characterized in that: The laser processing method further comprises a gas purging step, wherein when the processing laser is performing processing, the processing position of the workpiece to be processed is purged synchronously with gas.

12. A laser processing system capable of executing the laser processing method according to any one of claims 1 to 11, characterized in that: The laser processing system includes a first processing component and a working platform. The first processing assembly includes a laser, an optical path system and a galvanometer scanning system arranged in sequence along the transmission direction of the processing laser, and the processing laser is focused onto the working platform by the galvanometer scanning system; The optical path system can modulate the processing laser into circularly polarized light; The workpiece to be processed is placed on a working platform; The first processing component also includes processing control software, which can set processing parameters and draw processing paths. The laser control software is used to control the processing path of the processing laser and control the component parameters of the first processing component.

13. The laser processing system according to claim 12, characterized in that: The laser is an ultraviolet picosecond laser.

14. The laser processing system according to claim 12, characterized in that: The optical path system comprises a beam expander and a quarter wave plate which are sequentially arranged along the transmission direction of the processing laser.

15. The laser processing system according to claim 12, characterized in that: The galvanometer scanning system comprises a galvanometer and a field mirror which are sequentially arranged along the transmission direction of the processing laser.

16. The laser processing system according to claim 12, characterized in that: The laser processing system further comprises a purging device, which can provide a gas flow rate of >5 m / s to purge the workpiece to be processed on the working platform.

17. The laser processing system according to claim 12, characterized in that: The laser processing system also includes a refrigeration system, which is maintained at 15-29° C. The refrigeration system is used to ensure the stable operation of the laser and the galvanometer scanning system during the processing.

18. The laser processing system according to claim 12, characterized in that: The laser processing system also includes an electrical control system, which controls the movement of the working platform, the CCD camera and the galvanometer.

19. A computer-readable storage medium, characterized in that: It stores computer executable instructions, and the computer executable instructions are configured to execute the laser processing method according to any one of claims 1 to 11.

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