Laser processing system and method for array micropores

Abstract

The invention relates to a laser processing system and method for array micropores. The method comprises the following steps: selecting and preparing a chemical solution according to a to-be-processed material; determining the number of laser beams, the size of a galvanometer and machining parameters of each layer; a laser focus is positioned on the upper surface of the to-be-machined material, axial feeding machining is conducted on the first layer according to the determined machining parameters, the micropore morphology is obtained during machining, and machining of the next layer is conducted when set requirements are met; a laser focal plane is positioned to a machining plane after machining of the upper layer is finished, axial feeding machining is carried out on the current layer according to the determined machining parameters, machining of the next layer is carried out during machining when the micropore morphology meets the set requirement, and execution is repeated till the focal plane passes through the lower surface of the material to form a through hole; and the target material is moved to the next machining position, the laser beam is adjusted to the initial machining state, and repeated machining of the micropores is conducted. Through a variable-parameter layer-by-layer girdling technology, a focal plane is flush with the surface of a material to be processed, and light spot dispersion and energy density reduction caused by enlargement of laser light spots are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of laser micro - machining, and specifically to a laser processing system and method for array micro - holes. Background Technique

[0002] The statements in this part merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] Micro - holes are a common machining form in parts, such as the film holes of aero - engine turbine blades, micro - holes on electronic integrated boards, inkjet nozzles of inkjet printers, etc. Laser processing is an important machining method for micro - holes. However, during the process of laser - machining micro - holes, defects such as recast layers, heat - affected zones, and micro - cracks will inevitably occur. At the same time, due to the characteristics of the laser beam itself and defocusing, the phenomena of tapered holes and poor roundness of the hole opening will also occur, which is not conducive to the application of micro - holes.

[0004] Ultrafast lasers, that is, lasers with a pulse width shorter than 10 ps, can obtain extremely high peak power. Due to the short action time and high peak energy, theoretically, the material is directly removed in a plasma state without going through the process of endothermic melting, so that the processed micro - holes have no defects such as heat - affected zones and recast layers, realizing "cold machining".

[0005] However, it is found in the experimental process that when ultrafast lasers are used for multiple machining, the phenomenon of defocusing between the laser focus and the surface of the material to be machined will occur, making the light spot larger and the energy density lower, resulting in defects such as recast layers and heat - affected zones in the micro - holes. At the same time, due to the characteristics of the Gaussian laser beam and the expansion of the laser when it reaches the side wall of the micro - hole under the defocused state, the taper of the micro - hole becomes larger. As a result, the angle between the incident laser and the normal of the side wall of the micro - hole changes, and under the influence of polarization, the roundness of the outlet of the micro - hole is poor, affecting the machining quality.

[0006] Meanwhile, micro - holes do not exist individually in most parts. For example, the film holes of turbine blades have a very large number of micro - holes arranged in a region on the blade surface. When machining micro - holes, if they are machined one by one, the machining efficiency is low. Summary of the Invention

[0007] In order to solve the technical problems existing in the above - mentioned background technique, the present invention provides a laser processing system and method for array micro - holes. By means of a variable - parameter processing method, it is ensured that the laser focus of each layer of machining is flush with the surface of the material to be machined, so as to be able to machine micro - holes with small taper and high roundness, and at the same time, heat accumulation during the machining of a large - area micro - hole array can be reduced.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] The first aspect of the present invention provides a laser processing method for array micro - holes, including the following steps:

[0010] Select a chemical solution according to the material to be processed;

[0011] Determine the number of laser beams and the size of the galvanometer according to the processing requirements, and select the corresponding beam splitter;

[0012] Layer the material to be processed, and determine the processing parameters and the number of layers for each layer;

[0013] Position the laser focus on the upper surface of the material to be processed, and perform axial feed processing on the first layer according to the determined processing parameters. During the processing, obtain the micropore morphology, and perform the next layer processing when the set requirements are met;

[0014] Position the laser focal plane to the processing plane after the end of the upper layer processing, and perform axial feed processing on the current layer according to the determined processing parameters. During the processing, perform the next layer processing when the micropore morphology meets the set requirements, and repeat the execution until the through hole is formed by passing the focal plane through the lower surface of the material;

[0015] Move the material to be processed to the next processing position, adjust the laser beam to the initial processing state, and perform repeated processing of the micropores.

[0016] As a further implementation, the chemical solution does not react with the material to be processed at room temperature and reacts with the material to be processed under conditions higher than the set temperature.

[0017] As a further implementation, a target is provided on the upper surface of the material to be processed.

[0018] As a further implementation, the laser beam is focused on the upper surface of the target, and the set depth is processed layer by layer through nested circular ring cutting scanning and axial feed.

[0019] As a further implementation, during the processing, the liquid level of the chemical solution is flush with the upper surface of the target.

[0020] As a further implementation, the laser spacing after focusing by the beam splitter is at least twice the distance between the centers of adjacent two holes.

[0021] As a further implementation, determine the number of layers according to the thickness of the material to be processed.

[0022] As a further implementation, determine the scanning paths of different layers using drawing software according to the number of layers. The layers in the scanning paths are aligned, and the outer diameters are kept consistent.

[0023] The second aspect of the present invention provides a laser processing system for array micropores, including a target arranged on a processing platform. The target and the material to be processed are immersed in a chemical solution. Above the target, there is a focusing mirror connected to a galvanometer and a CCD camera in the space. The laser generated by the laser passes through the optical path, passes through the galvanometer and the focusing mirror, and reaches the surface of the material to be processed.

[0024] As a further implementation, the laser is sequentially connected to a shutter, a first mirror, a beam expander, a second mirror, a beam splitter, and a galvanometer scanner.

[0025] Compared with the prior art, the above one or more technical solutions have the following beneficial effects:

[0026] 1. By processing layer by layer with variable parameters, the utilization rate of the laser is improved, and the laser energy waste caused by the excessive single-layer processing time, the increase in the material ablation depth, and the insufficient laser energy reaching the material to be processed to remove the material is reduced.

[0027] 2. Aiming at the problems of large micro-hole taper and poor roundness during laser drilling, through the technology of variable-parameter layer-by-layer circumcision, the focal plane can be made flush with the surface of the material to be processed, avoiding the spot dispersion and energy density reduction caused by the enlargement of the laser spot, and micro-holes with small taper and high roundness, as well as large-area micro-hole arrays with less heat accumulation, can be processed.

[0028] 3. Aiming at the problem of the recast layer during the laser drilling process, through chemical solution assistance and improving the divergence of the laser during layer-by-layer processing, the material instantaneously absorbs energy and gasifies to be removed in the form of plasma, reducing the generation of molten matter, and a small amount of molten matter reacts with the chemical solution under the action of the high laser temperature and is removed.

[0029] 4. Aiming at the problem of low efficiency during laser processing of array micro-holes, through the method of laser beam splitting and parallel processing, multiple micro-holes can be processed simultaneously, doubling the processing efficiency. Description of the Drawings

[0030] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0031] Figure 1 is a schematic diagram of material removal in laser layer-by-layer processing provided by one or more embodiments of the present invention;

[0032] Figure 2 is a schematic diagram of the principle of chemical-assisted variable-parameter ultrafast laser beam splitting for processing micro-hole arrays provided by one or more embodiments of the present invention;

[0033] Figure 3 is a flowchart of a method for laser processing array micro-holes provided by one or more embodiments of the present invention;

[0034] Figure 4 is a schematic diagram of a laser scanning path and an axial feed provided by one or more embodiments of the present invention;

[0035] Figure 5It is a schematic diagram of the principle of variable-parameter ultrafast laser layer-by-layer rotary cutting of microholes provided by one or more embodiments of the present invention;

[0036] Figure 6 It is a schematic diagram of chemical-assisted variable-parameter ultrafast laser beam splitting for machining a microhole array provided by one or more embodiments of the present invention;

[0037] Figure 7 It is a schematic diagram of the principle of chemical-assisted variable-parameter ultrafast laser beam splitting for machining a microhole array provided by one or more embodiments of the present invention.

[0038] In the figure: 1 - ultrafast laser, 2 - shutter, 3 - first reflector, 4 - beam expander, 5 - second reflector, 6 - beam splitter, 7 - scanning galvanometer, 8 - focusing lens, 9 - target material, 10 - chemical solution, 11 - processing platform, 12 - CCD camera, 13 - processing control system. Detailed implementation manners

[0039] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0040] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0041] It should be noted that the terms herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0042] With the increasing demand for the quality and efficiency of array microholes, it is more urgent to solve defects such as recast layers and microcracks, achieve parallel machining of multiple holes, and obtain non-tapered holes and holes with high roundness.

[0043] Due to the characteristics of the laser itself, the energy is Gaussian distributed on the focal plane and gradually decreases from the focus to both sides in the Z-axis direction, as Figure 1 shown. Therefore, when machining materials, the material removal area is ellipsoidal, and there are inevitably gaps during layer-by-layer machining. In addition, problems such as plasma shielding and melt blockage are also not conducive to improving the quality of microhole machining. The low efficiency and serious heat accumulation during the machining of array microholes also restrict the development of laser machining of array microholes.

[0044] Therefore, the following embodiments provide a laser processing system and method for array microholes. A chemical solution is selected according to the material to be processed, and the laser beam is split by a beam splitter as required to achieve chemical-assisted laser parallel processing of microholes. Then, layer-by-layer laser processing is performed on the material to be processed. The processing parameters for a single layer are determined and then layer-by-layer processing is carried out. By means of variable parameter processing, it is ensured that the laser focus is flush with the surface of the material to be processed for each layer. In this way, microholes with small taper and high roundness can be processed, and at the same time, heat accumulation during the processing of a large-area microhole array can be reduced. In addition, the assistance of the chemical solution further improves the microhole processing quality to achieve high-quality processing, and the simultaneous processing of multiple laser beams greatly improves the processing efficiency, realizing high-quality and high-efficiency processing of array microholes.

[0045] Embodiment 1:

[0046] As Figure 2 shown, the laser processing system for array microholes includes a target 9 arranged on a processing platform 11. The target 9 is immersed in a chemical solution 10, and above the space of the target 9, there is a focusing lens 8 connected to a scanning galvanometer 7 and a CCD camera 12; an ultrafast laser 1 is sequentially connected to a shutter 2, a first mirror 3, a beam expander 4, a second mirror 5, a beam splitter 6 and a scanning galvanometer 7.

[0047] The ultrafast laser 1 serves as an energy source. In this embodiment, a 30W picosecond laser is selected.

[0048] In this embodiment, the shutter 2 controls the opening and closing of laser processing.

[0049] In this embodiment, the first mirror 3 and the beam expander 4 are used to expand the beam diameter and reduce the beam divergence angle. The second mirror 5 and the beam splitter 6 are used to split the laser beam to achieve parallel processing. In this embodiment, 3 laser beams are split, with an interval of 2 mm. The scanning galvanometer 7 is used to achieve the moving scanning processing of the beam focus.

[0050] In this embodiment, for the target 9, a CMC-SiC ceramic matrix composite material with a thickness of 2 mm is selected in this embodiment.

[0051] For the chemical solution 10, hydrofluoric acid is selected in this embodiment.

[0052] In this embodiment, the CCD camera 12 is used to observe the processing results.

[0053] By adjusting the parameters during the processing of microholes at different depths, microholes with small taper, high roundness and few recast layers can be processed, improving the microhole processing quality while ensuring the dimensional accuracy of the microholes.

[0054] The working principle is as follows:

[0055] The target is placed on a fixture, and the chemical solution is added so that the liquid level is flush with the upper surface of the target;

[0056] The laser is focused on the upper surface of the target material, and through nested circular cutting scanning machining, it is axially fed layer by layer to the set depth;

[0057] Adjust the laser and focus it on the machining plane after the axial feed in the previous step;

[0058] Adjust the laser processing parameters, and through nested circular cutting scanning machining, axially feed layer by layer to the set depth, as Figure 4 shown; Figure 4 (a) is a schematic diagram of the scanning path, Figure 4 (b) is a schematic diagram of the axial feed;

[0059] Repeat adjusting the laser and the laser processing parameters until the laser focal plane after the axial feed machining passes through the lower surface of the target material, and the through-hole machining is completed.

[0060] Aiming at the problems of large micro-hole taper and poor roundness during laser drilling, through the technology of variable parameter layer-by-layer circumferential cutting, the focal plane can be made flat with the surface of the material to be processed, avoiding the spot dispersion and energy density reduction caused by the increase of the laser spot size, and micro-holes with small taper and high roundness, as well as large-area micro-hole arrays with less heat accumulation, can be machined.

[0061] Aiming at the problem of the recast layer during the laser drilling process, through chemical solution assistance and improving the laser divergence during layer-by-layer machining, the material instantaneously absorbs energy and gasifies, and is removed in the form of plasma, reducing the generation of molten matter. A small amount of molten matter reacts with the chemical solution under the action of the high laser temperature and is removed.

[0062] Aiming at the problem of low efficiency when machining array micro-holes by laser, through the method of laser beam splitting and parallel machining, multiple micro-holes can be machined simultaneously, which can double the machining efficiency

[0063] Through variable parameter layer-by-layer machining, the utilization rate of the laser is improved, and the laser energy waste caused by the single-layer machining time being too long, the material ablation depth increasing, and the laser reaching the material to be processed being insufficient to remove the material is reduced.

[0064] Example 2:

[0065] As Figure 3 shown, the method of the laser processing system for array micro-holes includes the following steps:

[0066] S1: Fix the material to be processed on the workbench, add the chemical solution, and adjust the laser focus to the upper surface of the material;

[0067] S2: Determine the processing parameters according to the properties of the material and the processing requirements of the micro-holes;

[0068] S3: Set the feed distance according to the processing parameters set in S2 and the thickness of the processed material, and axially feed layer by layer along the feed direction;

[0069] S4: Detect the error between the machining distance and the actual machining depth, as well as the micro-hole morphology, by means of a machining detection system. Proceed to the next step when the requirements are met.

[0070] S5: Set the laser focus on the machining plane after axial feed machining, as Figure 5 shown, and adjust the laser machining parameters; ( Figure 5 Taking the machining with three sets of parameter settings as an example, Figure 5 (a)- Figure 5 (c) are respectively the schematic diagrams of the principle of laser layer-by-layer spiral cutting of micro-holes under the first group - the third group of machining parameters);

[0071] S6; According to the feed distance set in S3, perform layer-by-layer machining with axial feed;

[0072] S7: Calculate the total axial feed distance of several variable-parameter machining. After axial feed, the laser focal plane passes through the lower surface of the target material, and proceed to the next step;

[0073] S8: Move the target material to the next machining position, and set the laser machining parameters and the focal plane position to the initial positions.

[0074] In this embodiment, according to the properties of the material to be machined, select a laser power of 30 W, a repetition frequency of 500 kHz, a scanning speed of 300 mm / s, a scanning number of 20 times, and a scanning path of nested concentric circles filled from the outside to the inside, with the maximum circle diameter of 0.3 mm. Set the feed number to 10 times and the feed distance to 0.2 mm according to the thickness of the material to be machined, so as to ensure that the material removal depth and the laser focal plane feed depth are consistent after feed machining with appropriate machining parameters, and avoid the material being blocked in a molten state in the micro-holes due to the reduction of energy density, which hinders the next laser machining. As the machining progresses, when machining inside the micro-holes, due to the effect of plasma shielding, there is a certain loss of energy when the laser reaches the surface of the material to be machined. Therefore, increase the scanning number by 5 times for each feed. After machining, three micro-holes with an axial center spacing of 3 mm are obtained, the micro-hole taper reaches 3.2° - 3.5°, the roundness of the micro-hole outlet reaches 94.5% - 94.7%, and there are no phenomena such as recast layer and thermal crack.

[0075] The specific steps are as follows:

[0076] Step 1: (Select a chemical solution) Select a chemical solution according to the material to be machined;

[0077] Step 2: (Laser parallel machining system) Select a beam splitter according to the required number of laser beams and the size of the galvanometer scanner, and install it in the optical path (as Figure 2 shown);

[0078] Step 3: (Determine parameters) Layer and measure the material to be machined to determine the machining parameters and the number of layers for each layer;

[0079] Step 4: (Variable parameter machining) Locate the laser focus on the upper surface of the material to be machined, and perform axial feed machining according to the determined machining parameters. Proceed to the next step when the micropore morphology detected by the real-time monitoring device meets the requirements.

[0080] Step 5: (Variable parameter machining) Locate the laser focal plane on the machining plane after the end of the previous machining step, change the machining parameters and perform axial feed machining until a through hole is formed when the focal plane passes through the lower surface of the material. Proceed to the next step when the machining quality meets the requirements.

[0081] Step 6: Move the target to the next machining position, adjust the laser beam to the initial machining settings, and perform repeated micropore machining.

[0082] As a further implementation, in Step 1, select a chemical solution that does not react with the material at room temperature but reacts at high temperature.

[0083] As a further implementation, in Step 1, place the chemical solution at the position as shown in Figure 2 such that the liquid level is flush with the upper surface of the material to be machined for synchronous machining assistance.

[0084] As a further implementation, in Step 2, the beam splitter can be selectively installed according to the number and arrangement of the array micropores to be machined, as well as the machining efficiency requirements and the size of the galvanometer scanner.

[0085] As a further implementation, in Step 2, the spacing of the split laser beams after focusing should be at least twice the spacing between the axes of adjacent holes to reduce heat accumulation.

[0086] As a further implementation, in Step 3, measure the machining depth of each layer according to the single-layer machining parameters (scanning interval, laser power, number of scans, scanning speed) to determine the feed distance.

[0087] As a further implementation, in Step 3, observe the bottom morphology of the holes after machining each layer according to the single-layer machining parameters to ensure that the laser defocus amount is as small as possible while ensuring machining efficiency, and proceed to the subsequent steps after meeting the bottom size morphology requirements.

[0088] As a further implementation, in Step 3, based on the determination of the single-layer machining parameters, determine the number of layers according to the thickness of the material to be machined.

[0089] As a further implementation method, in step 4, the scanning paths of different layers are drawn using drawing software according to the number of layers. In the drawing software, each layer corresponds to a "layer" to be processed in the material, and accordingly, the setting method of each layer, including the path and processing parameters, corresponds to a "layer" to be processed. The main reason for setting different scanning paths is that with the increase of processing depth, especially micro-hole processing, due to the linear polarization effect of the laser, plasma shielding effect, etc., the material removal ability corresponding to the same processing parameters is different. In addition, the material removed at one time by the laser focal plane mostly depends on the reflection of the laser in the micro-hole. A large number of studies have shown that the scanning path has a considerable influence on this, so accurate material removal can be achieved by reasonably planning the scanning path of each layer to obtain an ideal micro-hole shape.

[0090] As a further implementation, in step 4, the drawn scanning path needs to be aligned in each layer, and the outer circle diameter remains consistent.

[0091] As a further implementation, in step 4, the laser focus is positioned at the surface of the material to be processed before processing. After the processing is completed, the laser focal plane is displaced downward, and the displacement distance is set according to step 1.

[0092] As a further implementation, in step 5, after the laser moves downward, processing is performed according to the scanning trajectory and parameters of the next layer, and this process is performed in sequence until all layers are processed.

[0093] Experimental Example 1: A picosecond laser with a wavelength of 1064nm and a power of 30W was used as the processing source to process micropores of a nickel-based high-temperature alloy (IN718) material with a thickness of 1mm and a pore size of 0.6mm. The chemical solution was a mixed solution of NaNO3 and HCl, and the beam splitter was divided into three laser beams with an interval of 3mm. The material was cleaned by ultrasound, and after drying, it was suspended and fixed on the workbench. The processing parameters were set, and the scanning path was a nested circle (filling from the outside to the inside) as shown in the figure. Figure 4 As shown, the maximum circle diameter is 0.6mm, the minimum circle diameter is 0.06mm, the adjacent circle spacing is 0.02mm, the laser power is 30W, the laser frequency is 500kHz, the scanning speed is 350mm / s, the number of scans is 60 times, the feed distance is 0.06mm, the feed is 6 times, and the laser focus is set on the upper surface of the material, as shown Figure 5 shown.

[0094] After the first set of parameters was processed, the laser focus was positioned at 0.36mm from the upper surface of the material, the laser focus was located inside the microhole, the parameters were changed, the scanning times were 80 times, and the scanning speed was 200mm / s. After the second set of parameters was processed, the laser focus was positioned at 0.72mm from the upper surface of the material, the laser focus was located inside the microhole, the parameters were changed, the scanning times were 100 times, the scanning speed was 200mm / s, the feed distance was 0.03mm, and the feed times were 10 times. After the processing was completed, 3 microholes with an interval of 3mm were obtained, the recast layer was less accumulated, the microhole taper reached 1.3°, and the microhole outlet roundness reached 97%. For difficult-to-process materials, according to the microhole processing quality requirements and material thickness, the number of parameter changes can be increased to accurately control the microhole processing and improve the accuracy of laser processing of microholes.

[0095] Experimental Example 2: A picosecond laser with a wavelength of 1064 nm and a power of 30 W was used as a processing source to process a 9×6 array microhole of a nickel-based high-temperature alloy (IN718) material with a thickness of 0.6 mm and an aperture of 0.3 mm. A mixed solution of NaNO3 and HCl was selected as the chemical solution. The beam splitter was used to divide the laser into three beams with an interval of 4 mm. Figure 6 shown.

[0096] The material was cleaned by ultrasound, and then fixed on the workbench after drying. The processing parameters were set, and the scanning path was nested circles (filling from the outside to the inside), the maximum circle diameter was 0.3 mm, the minimum circle diameter was 0.06 mm, the spacing between adjacent circles was 0.02 mm, the laser power was 15 W, the laser frequency was 500 kHz, the scanning speed was 350 mm / s, the number of scans was 60 times, the feed distance was 0.06 mm, and the feed was 5 times. Figure 7 AA The first set of parameters positions the focus of the three laser beams after splitting to the upper surface of the material at position (1-1) in row 1 labeled 1. After processing, the laser focus is positioned to the upper surface of the material at position (1-2). After processing, the laser focus is positioned to the upper surface of the material at position (1-3). After processing, the laser focus is positioned to the upper surface of the material at position (1-3). Figure 6 The AA (1-1) position is 0.3 mm away from the upper surface of the material, and the laser focus is located inside the microhole. The processing parameters are changed, the scanning number is 80 times, and the scanning speed is 200 mm / s. After the processing, the laser focus is positioned at the (1-2) position at 0.3 mm away from the upper surface of the material, and the laser focus is located inside the microhole. After the processing, the laser focus is positioned at the (1-3) position at 0.3 mm away from the upper surface of the material, and the laser focus is located inside the microhole.

[0097] After the machining is completed, the laser focus is positioned at the row numbered 2, and machining is carried out successively at the positions of (2-1), (2-2), (2-3). After the machining is completed, the laser focus is positioned at the row numbered 3, and machining is carried out successively at the positions of (3-1), (3-2), (3-3). After the machining is completed, the laser focus is positioned at the row numbered 4, and machining is carried out successively at the positions of (4-1), (4-2), (4-3). After the machining is completed, the laser focus is positioned at the row numbered 5, and machining is carried out successively at the positions of (5-1), (5-2), (5-3). After the machining is completed, the laser focus is positioned at the row numbered 6, and machining is carried out successively at the positions of (6-1), (6-2), (6-3). After the machining is completed, an array of holes with small heat accumulation, less stacking of the recast layer, a micro-hole taper of 1.5°, and a roundness of the micro-hole outlet of 95% is obtained.

[0098] In this embodiment, the positioning position of the laser focus is determined by the drawing order of the machining path in the imported layer. When machining multiple array holes, the machining order can be adjusted according to the method of this embodiment.

[0099] Aiming at the problems of large micro-hole taper and poor roundness during laser drilling, through the technology of variable-parameter layer-by-layer circumferential cutting, the focal plane can be made flush with the surface of each layer of the material to be machined, avoiding the spot dispersion and energy density reduction caused by the enlargement of the laser spot, and being able to machine micro-holes with small taper and high roundness, as well as large-area micro-hole arrays with less heat accumulation.

[0100] Specifically: by changing the moving interval between layers (one of the variable parameters), it is ensured that the surface after the laser precisely removes the material coincides with the laser focal plane after moving. Considering that the main reason for the large micro-hole taper is that when removing the material with constant machining parameters, as the removal depth increases, the defocus of the laser amplifies the influence of the Gaussian distribution of the laser energy on the material removal, and the reflection of the laser in the micro-hole exacerbates this phenomenon. Of course, the poor roundness is also related to the linear polarization of the laser. Through the variable-parameter layer-by-layer circumferential cutting technology, the machining parameters can be reasonably planned to precisely correspond to the material removal amount, optimizing the influence of the defocus amount and the linear polarization of the laser.

[0101] Aiming at the problem of the recast layer during the laser drilling process, through chemical solution assistance and improving the divergence of the laser during layer-by-layer machining, the material instantaneously absorbs energy and vaporizes, and is removed in the form of plasma, reducing the generation of molten matter. A small amount of molten matter reacts with the chemical solution under the action of the high temperature of the laser and is removed.

[0102] Aiming at the problem of low efficiency when machining an array of micro-holes by laser, through the method of laser beam splitting and parallel machining, multiple micro-holes can be machined simultaneously, which can multiply the machining efficiency.

[0103] By means of variable-parameter layer-by-layer processing, the utilization rate of the laser is improved, and the laser energy waste caused by the overlong single-layer processing time, the increase in the material ablation depth, and the insufficient laser reaching the material to be processed to remove the material is reduced.

[0104] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A laser processing method for an array of micro-holes, characterized in that, The steps include: Select a chemical solution according to the material to be processed; Determine the number of laser beams and the size of the galvanometer scanner according to the processing requirements, and select the corresponding beam splitter; Layer the material to be processed and determine the processing parameters and the number of layers for each layer; Position the laser focus on the upper surface of the material to be processed, and perform axial feed processing on the first layer according to the determined processing parameters. During processing, obtain the micropore morphology, and proceed to the next layer when the set requirements are met; Position the laser focal plane at the processing plane after the end of the previous layer's processing, and perform axial feed processing on the current layer according to the determined processing parameters. During processing, proceed to the next layer when the micropore morphology meets the set requirements. Repeat until the focal plane passes through the lower surface of the material to form a through hole; Move the material to be processed to the next processing position, adjust the laser beam to the initial processing state, and perform repeated processing of the micropores.

2. The laser processing method of the array of micropores according to claim 1, characterized in that, A target material is provided on the upper surface of the material to be processed.

3. The laser processing method for the array of micro-holes as claimed in claim 2, wherein, The laser beam is focused on the upper surface of the target material, and is processed layer by layer to the set depth through nested circular ring cutting scanning and axial feed.

4. The laser processing method for the array of micro-holes according to claim 2, wherein During processing, the liquid level of the chemical solution is flush with the upper surface of the target material.

5. The laser processing method for the array of micro-holes according to claim 1, characterized in that The chemical solution does not react with the material to be processed at room temperature and reacts with the material to be processed under conditions higher than the set temperature.

6. The laser processing method of the array of micro-holes according to claim 1, characterized in that, The laser spacing after focusing by the beam splitter is at least twice the spacing between the axes of adjacent two holes.

7. The laser processing method for the array of micro-holes according to claim 1, characterized in that, Determine the number of layers according to the thickness of the material to be processed.

8. The laser processing method for the array of micro-holes according to claim 1, characterized in that Use drawing software to determine the scanning paths of different layers according to the number of layers. The layers in the scanning paths are aligned, and the outer diameters are kept consistent.

9. A system for implementing the laser processing method of the array of micro-holes as described in any one of claims 1-8, characterized in that, It includes a target material arranged on the processing platform. The target material and the material to be processed are immersed in the chemical solution. Above the target material, there is a focusing lens and a CCD camera connected to a scanning galvanometer. The laser generated by the laser passes through the optical path, passes through the scanning galvanometer and the focusing lens, and reaches the surface of the material to be processed.

10. The laser processing system for the array of micro-holes according to claim 9, characterized in that, The laser is sequentially connected to a shutter, a first reflector, a beam expander, a second reflector, a beam splitter, and a scanning galvanometer.

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