Machining apparatus and method for water-jet guided laser micro-hole with high surface quality

Abstract

The present invention belongs to the field of water-jet guided laser micro-hole machining. Specifically, provided is a machining apparatus for a water-jet guided laser micro-hole with a high surface quality, the apparatus comprising: a nanosecond laser device, which is turned on on the basis of a control instruction of a machining control system and refracts an incident laser into a laser water-jet coupling head by means of an optical path transmission unit; a CCD camera, which is arranged above the optical path transmission unit, wherein the laser enters a detection optical path by means of the optical path transmission unit and images on the CCD camera, so as to detect the position of a laser spot diameter at a nozzle of the laser water-jet coupling head in real time, and to complete the coupling of the laser and a water jet; and the laser water-jet coupling head, which is used for coupling the laser, which is focused in the coupling head, and a high-pressure water flow, which enters a coupling cavity through a pipe of a water cavity sidewall, at small holes of the nozzle, so as to perform micro-hole machining on a workpiece. By means of the present invention, interference with a stable jet is reduced, and a micro-hole with a high roundness, a low taper and a good outlet / inlet morphology can be machined, thereby improving the machining efficiency, while also ensuring the precision and quality of micro-hole machining.

Description

A water-guided laser micro-hole processing device and method with high surface quality Technical Field

[0001] The invention belongs to the field of water-guided laser micro-hole processing, in particular to a water-guided laser micro-hole processing device and method with high surface quality. Background Art

[0002] In water-guided laser processing of micro-hole structures such as turbine blade film holes, fuel injectors, and jewel bearing holes, designing an appropriate coupled energy beam scanning method is paramount to achieving the desired process and ensuring both precision and quality. Currently, water-guided laser micro-hole processing generally utilizes a single-step rotary cutting process, where the scanning trajectory forms equally spaced concentric circles or an equally pitched Archimedean spiral. However, with this hole-making method, the spatter and plasma generated by the ablation process interfere with the laminar jet flow and create a plasma shielding effect. This results in difficulties in processing the micro-hole bottom, poor entrance and exit morphology, and large taper. The resulting processing fails to meet the metallurgical quality requirements for high-quality and precise micro-hole structures.

[0003] Summary of the Invention

[0004] The present invention aims to provide a high-surface-quality water-guided laser micro-hole processing method. The method first punctures the material to form a prefabricated central hole, then widens the aperture and modifies the hole shape. This method can reduce the micro-hole taper and improve the entrance and exit morphology. While ensuring the micro-hole processing accuracy and quality, it also improves the processing efficiency, thereby overcoming the defects of the processing hole-making process.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned object is: a high-surface-quality water-guided laser micro-hole processing device, comprising: a processing control system and a nanosecond laser controlled by the processing control system, an optical transmission unit, a laser-water jet coupling head, a CNC workbench, and a CCD camera;

[0006] The processing control system is used to send control instructions for opening the nanosecond laser, CCD camera, and ultrapure water circulation system, and also sends motion control instructions to the optical transmission unit, the laser-water jet coupling head, and the CNC workbench, so as to change the angle of the scanning galvanometer in the optical transmission unit, and cause the laser-water jet coupling head and the CNC workbench to move according to the motion control instructions;

[0007] The emission end of the nanosecond laser is arranged opposite to the incident end of the optical transmission unit, so as to be turned on according to the control instruction of the processing control system and refract the incident laser into the laser water jet coupling head through the optical transmission unit;

[0008] The CCD camera is located above the optical transmission unit, and the laser enters the detection optical path through the optical transmission unit and forms an image on the CCD camera, so as to detect the position of the laser focus at the nozzle of the laser water jet coupling head in real time, and adjust the scanning galvanometer angle through the processing control system to complete the coupling of the laser and the water jet;

[0009] The laser water jet coupling head is used to couple the laser light transmitted into the coupling head and the high-pressure water entering the coupling chamber through the pipe on the side wall of the water chamber at the nozzle orifice, and eject the coupled energy beam from the nozzle to perform micro-hole processing on the workpiece;

[0010] Ultrapure water circulation system, used for multi-stage purification of waste liquid, and delivering high-pressure ultrapure water jet with stable pressure to the laser water jet coupling head through a high-pressure water pump;

[0011] The CNC workbench is used to place the workpiece and adjust the position of the workpiece according to the control instructions of the machining control system.

[0012] The optical transmission unit includes: a beam expander, a scanning galvanometer, and a focusing mirror connected in sequence;

[0013] The beam expander, scanning galvanometer and nanosecond laser are arranged on the same horizontal line; the focusing mirror and scanning galvanometer are arranged coaxially;

[0014] The focusing mirror is an F-theta focusing mirror, which is used to focus the laser beam refracted by the scanning galvanometer;

[0015] The scanning galvanometer is connected to the processing control system and is used to control the scanning galvanometer angle through the processing control system according to the laser focus position on the CCD camera imaging, thereby achieving the deflection of the laser beam, so that the laser focus point with a certain power density can be located at the center position of the upper surface of the nozzle hole and coupled with the water jet.

[0016] The laser water jet coupling head comprises: a coupling head housing and an optical window, a sealing ring, a nozzle, a hydraulic chamber, a spiral airflow generating chamber, an air inlet and a water inlet arranged on the coupling head housing;

[0017] The upper end of the coupling head housing is provided with an inlet, and an optical window is provided in the inlet. The lower end of the housing is provided with a nozzle, and the laser is focused on the nozzle through a focusing lens. A hydraulic chamber is formed between the upper and lower ends of the housing, and the liquid in the hydraulic chamber forms a water jet through the nozzle;

[0018] The nozzle is arranged at the bottom outlet of the hydraulic chamber and is coaxial with the optical window; the junction between the nozzle and the bottom surface of the coupling chamber is sealed by a sealing ring;

[0019] The lower part of the nozzle is a spiral airflow generating chamber. The auxiliary gas provided by the auxiliary gas supply device enters the spiral airflow generating chamber through the air inlet to form a spiral auxiliary airflow surrounding the water jet.

[0020] The ultrapure water circulation system is provided with a high-pressure laminar water jet ejected from a nozzle, which guides the laser through total internal reflection and transmits it to the surface of the workpiece; the hydraulic cavity is connected to the ultrapure water circulation system to receive the high-pressure water flow from the ultrapure water circulation system into the hydraulic cavity, and the high-pressure water flow is ejected through the nozzle to form a high-pressure laminar water jet.

[0021] A method for processing a water-guided laser micro-hole processing device with high surface quality, comprising the following steps:

[0022] 1) Turn on the nanosecond laser. After being transmitted through the optical transmission unit, the laser is focused by a focusing lens at the center of the upper surface of the nozzle hole in the laser water jet coupling head and coupled with the water jet. The laser propagates along the water jet through total internal reflection to form a coupled energy beam acting on the workpiece, and micro-hole processing is performed on the workpiece.

[0023] 2) Prefabricate the center hole of the workpiece: The coupled energy beam acts on the upper surface of the workpiece, and penetrates the workpiece at the center by rotary cutting scanning to form a prefabricated hole;

[0024] 3) Widening the aperture: Adjust the coupled energy beam to the boundary point of the prefabricated central hole, widen the aperture by rotary cutting and scanning, and the micropore is initially formed;

[0025] 4) Modify the hole shape: The bottom area and outlet area of ​​the micropore are processed by rotary cutting scanning to modify the morphology and size of the micropore inlet and outlet, so that the micropore surface morphology, hole wall roughness and taper meet the set requirements;

[0026] 5) After one micro-hole machining modification is completed, move the CNC workbench to the next micro-hole machining position and repeat steps 2) to 4).

[0027] The rotary cutting scanning method is: a nested equidistant concentric circle method or an equal pitch Archimedean spiral rotary cutting scanning method.

[0028] In steps 2) to 4), the diameter of the coupled energy beam scanning area is adjusted as follows:

[0029] a. During the prefabrication of the center hole, the inner diameter of the coupled energy beam scanning area is larger than the water jet diameter, and the outer diameter is smaller than the set diameter of the microhole, to ensure the prefabrication of the center hole and the subsequent expansion and repair processes.

[0030] b. During the aperture widening stage, the inner diameter of the coupled energy beam scanning area is equal to the diameter of the prefabricated center hole to avoid empty scanning of the coupled energy beam and waste of laser energy;

[0031] c. During the hole shape modification stage, the inner diameter of the coupled energy beam scanning area is larger than the inner diameter of the coupled energy beam scanning area during the aperture widening stage, so as to reduce the number of rotary cutting scanning circles during the hole shape modification stage;

[0032] d. In the aperture widening stage and the aperture shape modification stage, the outer diameter of the coupled energy beam scanning area is equal, and is equal to the diameter set for the micropore.

[0033] In step 3), perform the following steps:

[0034] Increase the number of single-layer scans and the spot overlap rate to modify the micropore morphology, reduce the hole wall roughness and micropore taper.

[0035] In the steps 2) to 4), during the stages of prefabricating the center hole, widening the aperture, and modifying the hole shape, the workpiece (10) is axially fed by a coupled energy beam, so that the coupled energy beam performs rotary cutting scanning layer by layer, and after completing the axial rotary cutting scanning of one layer, the rotary cutting scanning of the next layer is performed.

[0036] The preparation before micro-hole processing also includes the following steps:

[0037] 1-1) After the workpiece (10) is immersed in an ethanol solution for ultrasonic cleaning and drying, the workpiece (10) is fixed on a CNC workbench (7), and after positioning by a trial cutting method, the working distance of the Z-axis position of the laser water jet coupling head (5) is adjusted to a set value;

[0038] 1-2) setting the water-guided laser peeling scanning process parameters according to the processing requirements of the workpiece (10);

[0039] 1-3) The ultrapure water circulation system (6) is turned on, and tap water is transported into the hydraulic chamber through a high-pressure water pump after multi-stage purification, and then ejected through the nozzle to form a stable laminar water jet;

[0040] 1-4) Turn on the auxiliary gas supply device, and the auxiliary gas enters the spiral airflow generating chamber from the air inlet to form a spiral auxiliary airflow surrounding the water jet, thereby reducing the interference of the ambient air on the water jet, reducing the momentum loss of the water jet, and improving the stability of the water jet during the processing.

[0041] The water-guided laser peeling scanning process parameters include: laser single pulse energy, pulse repetition frequency, scanning inner circle diameter, scanning outer circle diameter, scanning spacing, scanning speed, number of scans, water jet pressure, nozzle diameter, auxiliary gas type and flow rate.

[0042] The present invention has the following beneficial effects and advantages:

[0043] 1. The prefabricated center hole of the present invention allows most of the spatter, slag and liquid flow generated during the drilling process to be discharged through the bottom of the center hole, thereby reducing interference with the water jet, enhancing the stability of the processing process, improving the outlet morphology of the micropore, and reducing the micropore taper and hole wall roughness.

[0044] 2. The present invention does not require replacement of the processing platform and lifting of the Z axis. It can be achieved by optimizing the process flow and parameters, avoiding secondary positioning and repeated operations. The operation is simple and the punching efficiency and quality are improved.

[0045] 3. The hole shape modification stage of the present invention mainly modifies the edge of the microhole, and initially forms the hole through the aperture widening stage. The appropriate nested concentric circle scanning inner ring diameter is selected according to the size of the outlet to obtain the maximum energy utilization rate, which has a significant effect on reducing the microhole taper, hole outlet roundness, hole inner wall roughness and improving microhole processing efficiency.

[0046] 4. The reduction in the number of scanning circles during the hole shape modification stage of the present invention avoids repeated empty scanning and excessive ablation of the processed area by the coupled energy beam, effectively improving the utilization rate of laser energy and the efficiency of water-guided laser micro-hole processing, and provides a technical reference for the application of water-guided laser in high-surface-quality micro-hole processing.

[0047] 5. The present invention reduces the interference to the stable jet, and can process microholes with high roundness, small taper and good entrance and exit morphology, thereby improving the processing efficiency while ensuring the microhole processing accuracy and quality.

[0048] 6. The laser-water jet coupling head of this invention couples the laser light transmitted into the coupling head with the high-pressure water entering the coupling chamber through a pipe in the water chamber's sidewall. The water jet is then ejected from the nozzle through a small orifice. Simultaneously, an auxiliary air chamber ejects a spiral airflow around the coupled jet, reducing momentum loss in the water jet and enhancing machining stability.

[0049] 7. The lower part of the nozzle of the present invention is a spiral airflow generating chamber. The auxiliary gas provided by the auxiliary gas supply device enters the spiral airflow generating chamber from the air inlet to form a spiral auxiliary airflow surrounding the water jet, thereby reducing the interference of the ambient air on the water jet, reducing the momentum loss of the water jet, and improving the stability of the water jet during the processing process.

[0050] 8. The ultrapure water circulation system of the present invention can purify the waste liquid generated during the processing in multiple stages, so that the water flow can be recycled, which is green and pollution-free and saves resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG1 is a schematic flow chart of a method for processing micro-holes with high surface quality using water-guided lasers according to the present invention;

[0052] FIG2 is a schematic diagram of a device for realizing water-guided laser micro-hole processing in the present invention;

[0053] FIG3 is a schematic diagram of the processing principle of the prefabricated center hole stage in the present invention;

[0054] FIG4 is a schematic diagram of the processing principle of the aperture widening stage in the present invention;

[0055] FIG5 is a schematic diagram of the processing principle of the hole shape modification stage in the present invention;

[0056] FIG6 is a schematic diagram of a single-layer scanning path of a coupled energy beam during the prefabrication of a central hole in the present invention;

[0057] FIG7 is a schematic diagram of a single-layer scanning path of a coupled energy beam during the aperture widening stage of the present invention;

[0058] FIG8 is a schematic diagram of a single-layer scanning path of a coupled energy beam during the aperture shape modification stage of the present invention;

[0059] Among them, 1 is a nanosecond laser, 2 is a beam expander, 3 is a scanning galvanometer, 4 is a focusing lens, 5 is a laser-water jet coupling head, 6 is an ultrapure water circulation system, 7 is a CNC workbench, 8 is a processing control system, 9 is a CCD camera, and 10 is a workpiece. DETAILED DESCRIPTION

[0060] To further clarify the objectives, technical solutions, and advantages of the embodiments of the present invention, the following will provide a clear and complete description of the high-surface-quality water-conducting laser micro-hole machining method according to the present invention, in conjunction with the accompanying drawings. Obviously, the described embodiments are only a portion of the embodiments of the present invention, not all of them. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

[0061] FIG2 is a schematic diagram of a device for performing water-guided laser micro-hole processing according to the present invention. The device for performing water-guided laser micro-hole processing according to the present invention, which provides high surface quality, includes: a processing control system 8 and a nanosecond laser 1 controlled by the control system, an optical transmission unit, a laser-water jet coupling head 5, a CNC workbench 7, and a CCD camera 9.

[0062] The processing control system 8 is used to send control instructions for opening the nanosecond laser 1, the CCD camera 9, and the ultrapure water circulation system 6, and also sends motion control instructions to the optical transmission unit, the laser-water jet coupling head 5, and the CNC workbench 7, so as to change the angle of the scanning galvanometer 3 in the optical transmission unit, and to cause the laser-water jet coupling head 5 and the CNC workbench 7 to move according to the motion control instructions;

[0063] The emission end of the nanosecond laser 1 is arranged opposite to the incident end of the optical transmission unit, so as to be turned on according to the control instruction of the processing control system 8 and refract the incident laser into the laser water jet coupling head 5 through the optical transmission unit;

[0064] The CCD camera 9 is located above the optical transmission unit, and the laser enters the detection optical path through the optical transmission unit and forms an image on the CCD camera 9, so as to detect the position of the laser spot diameter at the nozzle of the laser-water jet coupling head 5 in real time, and adjust the angle of the scanning galvanometer 3 through the processing control system 8 to complete the coupling between the laser and the water jet;

[0065] The laser water jet coupling head 5 is used to couple the laser focused in the coupling head with the high-pressure water flow entering the coupling chamber through the pipe on the side wall of the water chamber at the nozzle orifice, and eject the coupled energy beam from the nozzle to perform micro-hole processing on the workpiece 10;

[0066] The ultrapure water circulation system 6 is used to perform multi-stage purification of the waste liquid, including reverse osmosis, exhaust gas removal, deionization and submicron particle filtration, ultraviolet irradiation and other composite filtration, and delivers a high-pressure ultrapure water jet with stable pressure to the laser water jet coupling head 5 through a high-pressure water pump.

[0067] The numerical control workbench 7 is used to place the workpiece 10 and adjust the position of the workpiece 10 according to the control instructions of the machining control system 8 .

[0068] The optical transmission unit includes: a beam expander 2, a scanning galvanometer 3, and a focusing mirror 4 connected in sequence;

[0069] The beam expander 2, the scanning galvanometer 3 and the nanosecond laser 1 are arranged on the same horizontal line; the focusing mirror 4 and the scanning galvanometer 3 are arranged coaxially;

[0070] The focusing mirror 4 is an F-theta focusing mirror, which is used to focus the laser beam refracted by the scanning galvanometer 3;

[0071] The scanning galvanometer 3 is connected to the processing control system 8 and is used to control the angle of the scanning galvanometer through the processing control system 8 according to the laser focus position on the CCD camera 9 image, thereby achieving the deflection of the laser beam so that the laser focus point with a certain power density can be located at the center position of the upper surface of the nozzle hole and coupled with the water jet.

[0072] The laser water jet coupling head 5 comprises: a coupling head housing and an optical window, a sealing ring, a nozzle, a hydraulic chamber, a spiral airflow generating chamber, an air inlet and a water inlet provided on the coupling head housing;

[0073] An inlet is provided at the upper end of the coupling head housing, and an optical window is provided in the inlet. A nozzle is provided at the lower end of the housing, and the laser is focused on the nozzle through a focusing lens 4. A hydraulic chamber is formed between the upper and lower ends of the housing, and the liquid in the hydraulic chamber forms a water jet through the nozzle.

[0074] The nozzle is arranged at the bottom outlet of the hydraulic chamber and is coaxial with the optical window; the junction between the nozzle and the bottom surface of the coupling chamber is sealed by a sealing ring;

[0075] The lower part of the nozzle is a spiral airflow generating chamber. The auxiliary gas provided by the auxiliary gas supply device enters the spiral airflow generating chamber through the air inlet to form a spiral auxiliary airflow surrounding the water jet.

[0076] The ultrapure water circulation system 6 is equipped with a high-pressure laminar water jet ejected from a nozzle to guide the laser through total internal reflection, so that it is transmitted to the surface of the workpiece; the hydraulic cavity is connected to the ultrapure water circulation system 6 to receive the high-pressure water flow of the ultrapure water circulation system 6 into the hydraulic cavity, and the high-pressure water flow is ejected through the nozzle to form a high-pressure laminar water jet.

[0077] FIG1 is a schematic diagram of a process flow of a high-surface-quality water-guided laser micro-hole machining method according to the present invention. The process flow of a high-surface-quality water-guided laser micro-hole machining method according to the present invention comprises the following steps:

[0078] 1-1) After the workpiece 10 is immersed in an ethanol solution for ultrasonic cleaning and drying, the workpiece 10 is fixed on the CNC workbench 7, and the workpiece 10 is positioned by a trial cutting method, and then the working distance of the Z-axis position of the laser water jet coupling head 5 is adjusted to the set value;

[0079] 1-2) Setting the water-guided laser peeling scanning process parameters according to the processing requirements of the workpiece 10;

[0080] The water-guided laser peeling scanning process parameters include: laser single pulse energy, pulse repetition frequency, scanning inner circle diameter, scanning outer circle diameter, scanning spacing, scanning speed, number of scans, water jet pressure, nozzle diameter, auxiliary gas type and flow rate.

[0081] 1-3) The ultrapure water circulation system 6 is turned on. Tap water undergoes multi-stage purification and is delivered to the hydraulic chamber by a high-pressure water pump. The water is then ejected through a nozzle to form a stable laminar water jet.

[0082] 1-4) Turn on the auxiliary gas supply device, and the auxiliary gas enters the spiral airflow generating chamber from the air inlet to form a spiral auxiliary airflow surrounding the water jet, thereby reducing the interference of the ambient air on the water jet, reducing the momentum loss of the water jet, and improving the stability of the water jet during the processing.

[0083] 1-5) Turning on the nanosecond laser 1, after being transmitted through the optical transmission unit, the laser is focused by a focusing lens onto the center of the upper surface of the nozzle orifice in the laser water jet coupling head 5, coupling with the water jet. The laser propagates along the water jet through total internal reflection to form a coupled energy beam acting on the workpiece 10, thereby performing micro-hole machining on the workpiece 10;

[0084] 2) FIG3 is a schematic diagram of the processing principle of the prefabricated center hole stage in the present invention. A prefabricated center hole is formed in a workpiece 10 by applying a coupled energy beam to the upper surface of the workpiece 10 and penetrating the workpiece 10 at the center by rotary cutting scanning, thereby forming a prefabricated hole. The scanning path is shown in FIG6 ;

[0085] During the prefabrication of the center hole, the inner diameter of the coupled energy beam scanning area is larger than the water jet diameter, and the outer diameter is smaller than the set diameter of the microhole, to ensure the prefabrication of the center hole and the subsequent expansion and repair processes.

[0086] 3) As shown in FIG4 , a schematic diagram of the processing principle of the aperture widening stage in the present invention is shown. Aperture widening: the coupled energy beam is adjusted to the boundary point of the prefabricated central hole, and the aperture is widened by rotary cutting scanning. The micropore is initially formed. The scanning path is shown in FIG7 ;

[0087] During the aperture widening stage, the inner diameter of the coupled energy beam scanning area is equal to the diameter of the prefabricated central hole to avoid empty scanning of the coupled energy beam and waste of laser energy.

[0088] In this step, the number of single-layer scans and the spot overlap rate are increased to modify the micropore morphology, reduce the pore wall roughness and the micropore taper.

[0089] 4) As shown in FIG5 , a schematic diagram of the processing principle of the hole shape modification stage in the present invention, hole shape modification: the bottom area and the outlet area of ​​the micropore are processed by rotary cutting scanning to modify the morphology and size of the micropore inlet and outlet, so that the micropore surface morphology, hole wall roughness and taper meet the set requirements. The scanning path is shown in FIG8 ;

[0090] In the hole shape modification stage, the inner circle diameter of the coupling energy beam scanning area is larger than the inner circle diameter of the coupling energy beam scanning area in the aperture widening stage, so as to reduce the number of rotary cutting scanning circles in the hole shape modification stage.

[0091] In the aperture widening stage and the aperture shape modification stage, the outer diameters of the coupled energy beam scanning area are equal, and are both equal to the diameter set for the micropore.

[0092] During the above-mentioned stages of prefabricating the center hole, widening the aperture, and modifying the hole shape, the workpiece 10 is axially fed by the coupled energy beam, so that the coupled energy beam performs rotary cutting scanning layer by layer, and after completing the axial rotary cutting scanning of one layer, the rotary cutting scanning of the next layer is performed.

[0093] The present invention does not require moving the workbench. It is just that the laser single-layer action depth is limited and cannot penetrate the workpiece in one go, so the workpiece 10 needs to be fed multiple times. The water-guided laser does not need to be focused and has a long working distance, so the position of the coupling head does not need to be changed.

[0094] 5) After one micro-hole machining modification is completed, move the CNC workbench to the next micro-hole machining position and repeat steps 2) to 4).

[0095] Among them, in the above operation, the rotary cutting scanning method is: using a nested equally spaced concentric circle method or an equal pitch Archimedean spiral rotary cutting scanning method.

[0096] Example 1:

[0097] 1. Fix the workpiece to be processed and adjust the working distance after positioning.

[0098] As shown in FIG2 , the nickel-based single crystal high-temperature alloy workpiece 10 is immersed in an ethanol solution for ultrasonic cleaning and drying, and then fixed on a workbench 9 . After positioning by trial cutting and tool alignment, the Z-axis position of the laser-water jet coupling head is adjusted so that it is 10 mm away from the upper surface of the workpiece.

[0099] 2. According to the properties, thickness and micropore processing requirements of the material to be processed, set the water-guided laser processing parameters, and start the ultrapure water supply device and auxiliary atmosphere device at the same time.

[0100] This example uses an LD-pumped fiber laser with a central wavelength of 532 nm and a pulse width of 100 ns as laser source 1 to process microholes in a nickel-based single-crystal superalloy with a thickness of 2 mm and a diameter of 0.7 mm. The water-guided laser processing parameters are: a pulse repetition frequency of 10 kHz, a single pulse energy of 5 mJ, a scanning speed of 3 mm / s, a water jet pressure of 20 MPa, a water jet diameter of 60 μm, auxiliary gases of helium and argon at a gas flow rate of 2 L / min, and no Z-axis lift.

[0101] 3. Prefabricated center hole

[0102] A nested equidistant concentric circle rotary cutting scanning method is adopted. The inner circle diameter of the nested concentric circle scanning is 0.61mm, the outer circle diameter is 0.64mm, the scanning interval is 30μm, and the number of concentric circles is 2, as shown in Figure 6. The coupled energy beam starts from the starting point and scans progressively from the inside to the outside in a clockwise direction, and then jumps to the direction and repeats the scanning from the outside to the inside for 6 times to obtain a central hole with a diameter of 0.64mm, as shown in Figure 3.

[0103] 4. Widen the aperture

[0104] The inner diameter of the nested concentric circle scanning is set to 0.64 mm, the outer diameter is 0.7 mm, and the number of concentric circles is 3. Other parameters remain unchanged, as shown in Figure 7. The coupled energy beam repeats the scanning path 6 times to obtain a prototype hole with a taper of about 2.38° and an entrance roundness greater than 99%. At this time, the exit roundness is about 85%, as shown in Figure 4.

[0105] 5. Modify hole shape

[0106] Focusing on scanning the microhole edges and exits, the entrance and exit morphology was improved and the taper was reduced, as shown in Figure 5. To improve processing efficiency, the inner diameter of the nested concentric circle scanning was set to 0.67m, and the number of concentric circles was 2. As shown in Figure 8, the number of coupled energy beam scans was increased to 10, while other parameters remained unchanged. After completion of the processing, high-quality nickel-based single crystal superalloy microholes with entrance and exit roundness exceeding 99.8% and a taper of 0.08-0.14° were obtained, free of defects such as thermal damage, recast layers, microcracks, and spatter accumulation, as shown in Figure 5. Compared with the single-step rotary cutting drilling method, the microholes processed by the method of the present invention can improve the microhole roundness by 17%, reduce the taper by approximately 2.3°, and improve efficiency by 40%.

[0107] 6. After the micro-hole processing and modification are completed, move the CNC workbench to the next micro-hole processing position and repeat the micro-hole processing and modification.

[0108] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A water-guided laser micro-hole processing device with high surface quality, characterized in that: include: A processing control system (8) and a nanosecond laser (1), an optical path transmission unit, a laser water jet coupling head (5), a numerical control workbench (7) and a CCD camera (9) controlled by the processing control system; A processing control system (8) is used to send a start control instruction to the nanosecond laser (1), the CCD camera (9) and the ultrapure water circulation system (6), and also to send an action control instruction to the optical transmission unit, the laser water jet coupling head (5) and the numerical control workbench (7), so that the angle of the scanning galvanometer (3) in the optical transmission unit changes, and the laser water jet coupling head (5) and the numerical control workbench (7) move according to the action control instruction; The emission end of the nanosecond laser (1) is arranged opposite to the incident end of the optical path transmission unit so as to be turned on according to a control instruction of a processing control system (8) and refract the incident laser into the laser water jet coupling head (5) through the optical path transmission unit; The CCD camera (9) is arranged above the optical path transmission unit, and the laser enters the detection optical path through the optical path transmission unit and forms an image on the CCD camera (9), so as to detect the position of the laser focus at the nozzle of the laser water jet coupling head (5) in real time, and adjust the angle of the scanning galvanometer (3) through the processing control system (8) to complete the coupling of the laser and the water jet; A laser water jet coupling head (5) is used to couple the laser focused in the coupling head and the high-pressure water flow entering the coupling chamber through the pipeline on the side wall of the water chamber at the nozzle orifice, and eject the coupled energy beam from the nozzle to perform micro-hole processing on the workpiece (10); An ultrapure water circulation system (6) is used to perform multi-stage purification on the waste liquid and to deliver a high-pressure ultrapure water jet with stable pressure to the laser water jet coupling head (5) through a high-pressure water pump; The numerical control workbench (7) is used to place a workpiece (10) and adjust the position of the workpiece (10) according to control instructions of a processing control system (8).

2. The water-guided laser micro-hole processing device with high surface quality according to claim 1 is characterized in that: The optical path transmission unit comprises: a beam expander (2), a scanning galvanometer (3), and a focusing mirror (4) connected in sequence; The beam expander (2), the scanning galvanometer (3) and the nanosecond laser (1) are arranged on the same horizontal line; the focusing mirror (4) and the scanning galvanometer (3) are arranged coaxially; The focusing mirror (4) is an F-theta focusing mirror, which is used to focus the laser beam refracted by the scanning galvanometer (3); The scanning galvanometer (3) is connected to a processing control system (8) and is used to control the angle of the scanning galvanometer through the processing control system (8) according to the laser focus position on the CCD camera (9) image, thereby achieving deflection of the laser beam, so that the laser focus point with a certain power density can be located at the center position of the upper surface of the nozzle hole and coupled with the water jet.

3. The high surface quality water-conducting laser micro-hole processing device according to claim 1, characterized in that: The laser water jet coupling head (5) comprises: a coupling head housing and an optical window, a sealing ring, a nozzle, a hydraulic chamber, a spiral airflow generating chamber, an air inlet and a water inlet arranged on the coupling head housing; The upper end of the coupling head shell is provided with an inlet, and an optical window is provided in the inlet. The lower end of the shell is provided with a nozzle, and the laser is focused on the nozzle through a focusing lens (4). A hydraulic chamber is formed between the upper and lower ends of the shell, and the liquid in the hydraulic chamber forms a water jet through the nozzle. The nozzle is arranged at the bottom outlet of the hydraulic chamber and is coaxially arranged with the optical window; the nozzle and the coupling chamber The joint of the bottom surface is sealed by a sealing ring; The lower part of the nozzle is a spiral airflow generating chamber, and the auxiliary gas provided by the auxiliary gas supply device enters the spiral airflow generating chamber from the air inlet to form a spiral auxiliary airflow surrounding the water jet; The ultrapure water circulation system (6) is provided with a high-pressure laminar water jet ejected from a nozzle to guide the laser through total internal reflection so that it is transmitted to the surface of the workpiece; the hydraulic chamber is connected to the ultrapure water circulation system (6) to receive the high-pressure water flow of the ultrapure water circulation system (6) into the hydraulic chamber, and the high-pressure water flow is ejected through the nozzle to form a high-pressure laminar water jet.

4. The method for processing a water-guided laser micro-hole processing device with high surface quality according to claim 1, characterized in that: The following steps are involved: 1) Turning on the nanosecond laser (1), after being transmitted through the optical path transmission unit, the laser is focused by a focusing lens at the center position of the upper surface of the nozzle hole in the laser water jet coupling head (5) to couple with the water jet, propagating along the water jet through total internal reflection to form a coupled energy beam acting on the workpiece (10), and performing micro-hole processing on the workpiece (10); 2) Prefabricating a center hole on the workpiece (10): coupling an energy beam to act on the upper surface of the workpiece (10), and piercing the workpiece (10) at the center by a rotary cutting scanning method to form a prefabricated hole; 3) Widening the aperture: Adjust the coupling energy beam to the boundary point of the prefabricated central hole, widen the aperture by rotary cutting scanning, and the micropore is initially formed; 4) Modify the hole shape: The bottom area and the outlet area of ​​the micropore are processed by rotary cutting scanning to modify the morphology and size of the micropore inlet and outlet, so that the micropore surface morphology, hole wall roughness and taper meet the set requirements; 5) After one micro-hole processing modification is completed, move the CNC workbench to the next micro-hole processing position and repeat steps 2) to 4).

5. The method for processing a water-guided laser micro-hole processing device with high surface quality according to claim 4, characterized in that: The rotary cutting scanning method is: using a nested equidistant concentric circle method or an equi-pitch Archimedean spiral rotary cutting scanning method.

6. The method for processing a water-guided laser micro-hole processing device with high surface quality according to claim 4, characterized in that: In step 2) to step 4), the diameter size of the coupled energy beam scanning area is adjusted as follows: a. In the stage of prefabricating the center hole, the inner diameter of the coupled energy beam scanning area is larger than the water jet diameter, and the outer diameter is smaller than the set diameter of the microhole, so as to ensure the prefabrication of the center hole and the subsequent hole expansion and repairing processes; b. During the aperture widening stage, the inner diameter of the coupled energy beam scanning area is equal to the diameter of the prefabricated center hole to avoid empty scanning of the coupled energy beam and waste of laser energy; c. In the hole shape modification stage, the inner circle diameter of the coupled energy beam scanning area is larger than the inner circle diameter of the coupled energy beam scanning area in the aperture widening stage, so as to reduce the number of rotary cutting scanning circles in the hole shape modification stage; d. In the stage of widening the aperture and modifying the aperture shape, the outer diameter of the coupled energy beam scanning area is equal, which is equal to the diameter set for the microhole.

7. The method for processing a water-guided laser micro-hole processing device with high surface quality according to claim 4, characterized in that: In step 3), the following steps are performed: Increase the number of single-layer scans and the spot overlap rate to modify the micropore morphology, reduce the hole wall roughness and micropore taper.

8. The method for processing a water-guided laser micro-hole processing device with high surface quality according to claim 4, characterized in that: In the steps 2) to 4), during the stages of prefabricating the center hole, widening the aperture, and modifying the hole shape, the workpiece (10) is axially fed by a coupled energy beam so that the coupled energy beam performs rotary cutting scanning layer by layer, and after completing the axial rotary cutting scanning of one layer, the rotary cutting scanning of the next layer is performed.

9. The method for processing a water-guided laser micro-hole processing device with high surface quality according to claim 4, characterized in that: The preparation before micro-hole processing also includes the following steps: 1-1) After the workpiece (10) is immersed in an ethanol solution for ultrasonic cleaning and drying, the workpiece (10) is fixed on a CNC workbench (7), and after positioning by a trial cutting method, the working distance of the Z-axis position of the laser water jet coupling head (5) is adjusted to a set value; 1-2) setting the water-guided laser peeling scanning process parameters according to the processing requirements of the workpiece (10); 1-3) The ultrapure water circulation system (6) is turned on, and the tap water is transported into the hydraulic chamber through a high-pressure water pump after multi-stage purification, and then sprayed out through a nozzle to form a stable laminar water jet; 1-4) Turn on the auxiliary gas supply device, and the auxiliary gas enters the spiral airflow generating chamber from the air inlet to form a spiral auxiliary airflow surrounding the water jet, thereby reducing the interference of ambient air on the water jet, reducing the momentum loss of the water jet, and improving the stability of the water jet during the processing.

10. The method for processing a water-guided laser micro-hole processing device with high surface quality according to claim 9, characterized in that: The water-guided laser peeling scanning process parameters include: laser single pulse energy, pulse repetition frequency, scanning inner circle diameter, scanning outer circle diameter, scanning spacing, scanning speed, scanning times, water jet pressure, nozzle diameter, auxiliary gas type and flow rate.

Images