Water jet assisted millisecond laser-femtosecond laser secondary composite hole making method

Abstract

The invention discloses a water jet assisted millisecond laser-femtosecond laser secondary composite hole making method. The method comprises the steps that S1, an iron-based high-temperature alloy material is pretreated; s2, preliminarily processing the iron-based high-temperature alloy material through millisecond laser assisted by water jet, and punching for the first time; s3, the transferred iron-based high-temperature alloy material is subjected to finish machining under femtosecond laser, and second-time punching is conducted in combination with ultrasonic vibration; and S4, after punching is completed, the iron-based high-temperature alloy material is cooled, and the quality and precision of machined holes are checked. According to the method, water jet is used for assisting millisecond laser to conduct preliminary punching, heat affected zones are reduced, a good hole shape foundation is laid, fine machining is conducted in combination with ultrasonic vibration assisted femtosecond laser, the roundness and surface quality of holes are further improved, and the machining precision is improved. The problems of poor hole roundness and low machining precision caused by high thermal conductivity of the iron-based high-temperature alloy in femtosecond laser drilling are effectively solved, and the machining quality and precision are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of laser drilling, and in particular to a water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method. Background Art

[0002] Water jet assisted laser processing technology is an advanced processing method that combines water jet and laser energy. During the processing, the water jet not only plays a cooling role, reducing the accumulation of laser heat in the processing area, but also accelerates the discharge of molten materials through impact, and promptly removes them from the processing area, thereby improving the removal efficiency of laser drilling and helping to obtain micro-holes with deeper holes and smoother hole surfaces; in addition, the presence of the water jet can effectively prevent the secondary adhesion of the etched material, help eliminate the recast layer, and improve the processing quality.

[0003] Millisecond laser refers to a laser with a pulse width of milliseconds. It has high energy and fast processing speed and is suitable for occasions with high requirements for processing efficiency. However, due to its relatively large thermal effect, it may cause thermal damage or recasting during the processing. Femtosecond laser refers to a laser with a pulse width of 10 femtoseconds. -15 The biggest feature of femtosecond laser is its extremely short pulse time and very high peak power, which enables it to accurately remove materials with almost no thermal effects, making it very suitable for micro-machining and high-precision application scenarios.

[0004] Secondary composite refers to the process of processing the same position again by adjusting parameters or using different types of lasers on the basis of primary laser processing to achieve a more refined processing effect; the water jet-assisted millisecond laser-femtosecond secondary composite hole-making method has broad application prospects, which can not only improve processing efficiency and accuracy, but also effectively reduce quality problems such as thermal damage and recasting layer.

[0005] Therefore, it is necessary to improve the water jet-assisted millisecond laser-femtosecond secondary composite hole making method in the prior art. Summary of the invention

[0006] The present invention overcomes the shortcomings of the prior art and provides a water jet-assisted millisecond laser-femtosecond laser secondary composite hole-making method, which aims to solve the problems of poor hole roundness and low processing accuracy caused by high thermal conductivity of iron-based high-temperature alloys in femtosecond laser drilling in the prior art.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, comprising:

[0008] S1. Pretreating the iron-based high-temperature alloy material;

[0009] S2, preliminary processing of the iron-based high-temperature alloy material by water jet-assisted millisecond laser to perform the first drilling;

[0010] S3, transferring the iron-based high-temperature alloy material to be finely processed under femtosecond laser, and performing a second drilling in combination with ultrasonic vibration;

[0011] S4. After the drilling is completed, the iron-based high-temperature alloy material is cooled and the quality and accuracy of the processed holes are checked.

[0012] In a preferred embodiment of the present invention, in step S2, the step of water jet assisted millisecond laser processing includes:

[0013] S21, fixing the iron-based high-temperature alloy material on the millisecond laser processing platform and determining the punching position;

[0014] S22, calibrating laser parameters of the water jet assisted laser;

[0015] S23, water jet assisted millisecond laser processing, the punching position is processed layer by layer from the outside to the inside.

[0016] In a preferred embodiment of the present invention, in step S22, the water jet-assisted laser uses a sapphire nozzle with a diameter of 30-50 μm;

[0017] Water jet parameters: water jet pressure is 250-300bar, auxiliary gas flow rate is 1.5-3Nl / min;

[0018] Millisecond laser parameters: laser power is 16-20W, pulse width is 200-250μs, repetition frequency is 0.8-1kHz, and focused spot diameter is 45-55μm.

[0019] In a preferred embodiment of the present invention, in step S23, a spiral feeding method is used to process layer by layer from the outside to the inside to perform the first punching operation, the scanning speed is 10-15 mm / s, the jet height is 7-13 mm; the number of processing times is 2-3 iterative scans.

[0020] In a preferred embodiment of the present invention, in step S3, the step of combining ultrasonic vibration with femtosecond laser processing includes:

[0021] S31, repositioning and fixing the iron-based high-temperature alloy material that has been preliminarily processed by the millisecond laser on the femtosecond laser processing platform to ensure accurate alignment with the initial drilling position;

[0022] S32, calibrating the processing parameters of ultrasonic vibration-assisted femtosecond laser;

[0023] S33, turning on the ultrasonic vibration device and simultaneously starting the femtosecond laser to perform fine processing on the position of the initial punching, scanning processing from the inside to the outside, and performing a second punching.

[0024] In a preferred embodiment of the present invention, in step S32, the ultrasonic vibration parameters are set to: vibration frequency of 20-40kHz, amplitude of 5-15μm; femtosecond laser parameters are set to: laser power of 1-3W, pulse width of 100-200fs, repetition frequency of 1-5MHz, and the focused spot diameter is adjusted to 20-30μm.

[0025] In a preferred embodiment of the present invention, in step S33, ultrasonic vibration-assisted femtosecond laser is used for processing in a low-speed, high-precision mode, the scanning speed is controlled at 1-3 mm / s, the jet height is 5-10 mm, and a spiral feeding method is used to process layer by layer from the outside to the inside.

[0026] In a preferred embodiment of the present invention, a combination of natural cooling and forced cooling is adopted, and the material is naturally cooled on the femtosecond laser processing platform for 10 minutes, and then forced cooling is performed until it cools to room temperature.

[0027] In a preferred embodiment of the present invention, in step S1, the iron-based high-temperature alloy material is cut and polished to a size of 150 mm*150 mm*4 mm.

[0028] In a preferred embodiment of the present invention, in step S1, the surface of the iron-based high-temperature alloy material is cleaned with an organic solvent to remove grease, dust and other pollutants on the surface; the organic solvent is one of acetone and alcohol; after cleaning, it is blown dry with compressed air or dried naturally.

[0029] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0030] (1) The present invention proposes a water jet-assisted millisecond laser-femtosecond laser secondary composite hole-making method. The method first uses a water jet to assist the millisecond laser for preliminary drilling to reduce the heat-affected zone and lay a good foundation for the hole shape, and then combines it with ultrasonic vibration-assisted femtosecond laser for fine processing to further improve the roundness and surface quality of the hole. This effectively solves the problems of poor hole roundness and low processing accuracy caused by high thermal conductivity of iron-based high-temperature alloys in femtosecond laser drilling, and significantly improves the processing quality and accuracy.

[0031] (2) The present invention combines water jet-assisted millisecond laser processing with femtosecond laser finishing, and uses water jet-assisted millisecond laser to perform preliminary drilling of iron-based high-temperature alloy materials, thereby effectively reducing the heat-affected zone, reducing thermal deformation and thermal damage of the material, and laying a good foundation for subsequent femtosecond laser finishing; the high-precision processing capability of the femtosecond laser further improves the roundness and surface quality of the hole. Compared with the existing technology, this secondary composite hole-making method significantly improves the processing accuracy and hole quality, and further achieves the effect of high-precision processing of iron-based high-temperature alloy materials.

[0032] (3) The present invention uses the millisecond laser coupled with the water jet. During the millisecond laser processing, the water jet serves as the transmission medium and cooling medium of the laser, effectively improving the processing accuracy and quality. The cooling effect of the water jet reduces heat accumulation, while the precise control of the laser energy ensures the accuracy and stability of the initial drilling. Compared with the use of the millisecond laser alone, this combination makes the initial hole shape more regular, providing a better foundation for subsequent fine processing, and further achieving the effect of improving processing efficiency and hole roundness.

[0033] (4) The present invention introduces ultrasonic vibration during the femtosecond laser finishing process. The high-frequency vibration of ultrasonic vibration further improves the roundness of the microhole and reduces the taper. Ultrasonic vibration not only enhances the material removal efficiency, but also helps the laser energy to remove the material more effectively through the tiny impact force generated by the vibration, making the inner wall of the hole more uniform and smooth. Compared with the use of femtosecond laser alone, this combination significantly improves the overall processing quality of the hole, and further achieves the effect of optimizing the hole shape and surface quality.

[0034] (5) The present invention effectively avoids the focus drift phenomenon by precisely adjusting the vertical distance between the convex lens inside the laser and the coupling nozzle, ensuring that the laser focus can be accurately positioned at the center of the nozzle hole. This adjustment makes the laser energy evenly distributed in the water jet, improving the processing quality and accuracy. Compared with the case without precise adjustment, this combination significantly reduces the increase in spot diameter and energy loss, further achieving the effect of improving processing accuracy and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 is a flow chart of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0039] Application Overview:

[0040] In the current manufacturing field, water jet-assisted laser processing technology is widely used in micro-processing of various materials due to its unique advantages. However, there is a significant technical difficulty in performing femtosecond laser drilling on materials with high thermal conductivity such as iron-based high-temperature alloys: due to the high thermal conductivity of iron-based alloys, the laser energy is rapidly dispersed inside the material, making it difficult for the laser to form a concentrated and stable heat-affected zone, which makes it difficult to control the quality and roundness of the holes during the drilling process, especially when using ultrashort pulse lasers such as femtosecond lasers, the hole roundness reaches the worst.

[0041] Hole roundness refers to the roundness error of the inner diameter of the hole in each cross section, that is, the variation of the actual circle relative to the ideal circle. The defect of poor hole roundness affects the overall quality and performance of the machined part. Once the roundness of the machined hole deteriorates, the fitting process will fail, resulting in reduced hole machining accuracy. In addition, during deep hole machining, the roundness of the hole will affect the machining of the next step, ultimately causing the machined parts to become scrap.

[0042] In view of the defects in the above-mentioned prior art, the present invention proposes a water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method. The method aims to achieve more precise control and dispersion of laser energy by optimizing laser parameters and processing strategies, especially in the composite use of millisecond laser and femtosecond laser, thereby significantly improving the drilling quality and hole roundness.

[0043] Exemplary methods:

[0044] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, comprising the steps of:

[0045] S1. Pretreating the iron-based high-temperature alloy material;

[0046] S2, preliminary processing of the iron-based high-temperature alloy material by water jet-assisted millisecond laser to perform the first drilling;

[0047] S3, transferring the iron-based high-temperature alloy material to be finely processed under femtosecond laser, and performing a second drilling in combination with ultrasonic vibration;

[0048] S4. After the drilling is completed, the iron-based high-temperature alloy material is cooled and the quality and accuracy of the processed holes are checked.

[0049] Iron-based high-temperature alloy is an alloy with iron as the main component, containing chromium, nickel, molybdenum, cobalt, tungsten and other elements. It has excellent high-temperature strength, corrosion resistance and oxidation resistance. Iron-based high-temperature alloy has high thermal conductivity and can quickly transfer heat from one area to another. During the laser processing, the laser energy is absorbed by the material and then diffuses rapidly to the surrounding area, resulting in a decrease in local heat concentration. This makes it difficult for the laser to form a stable heat-affected zone inside the iron-based high-temperature alloy material, affecting the processing accuracy and quality.

[0050] In step S1, the iron-based high-temperature alloy material is cut and polished into a suitable size; specifically, the size of the iron-based high-temperature alloy material is 150mm*150mm*4mm;

[0051] Clean the surface of the iron-based high-temperature alloy material with an organic solvent to remove grease, dust and other pollutants on the surface; the organic solvent is one of acetone and alcohol; after cleaning, use compressed air to blow dry or dry naturally to ensure that the surface of the material is completely dry;

[0052] A clean surface can reduce the impact of contaminants on laser absorption during processing, ensure the effective use of laser energy, and improve processing accuracy and quality.

[0053] During the femtosecond laser drilling process, high thermal conductivity causes the laser energy to disperse rapidly inside the material, making the shape of the hole difficult to control, and affecting the roundness and surface quality of the hole. Especially for deep hole processing, the roundness and taper of the hole are more prominent.

[0054] To solve the above problems, it is proposed to use water jet assisted millisecond laser processing to perform preliminary processing first; the principle of water jet assisted millisecond laser processing is to use water jet as the transmission medium and cooling medium of the laser to improve the processing accuracy and quality. During the processing, the laser beam is transmitted to the workpiece surface through the water jet. The cooling effect of the water jet can effectively reduce the heat affected zone and reduce the thermal deformation and thermal damage of the material, so that a more regular initial shape of the hole can be formed during the initial drilling, laying a good foundation for the roundness and surface quality of the hole.

[0055] In step S2, the steps of water jet assisted millisecond laser processing include:

[0056] S21, fixing the iron-based high-temperature alloy material on the millisecond laser processing platform and determining the punching position;

[0057] S22, calibrating laser parameters of the water jet assisted laser;

[0058] S23, water jet assisted millisecond laser processing processes the punching position layer by layer from the outside to the inside;

[0059] In step S21, the iron-based high-temperature alloy material is firmly fixed by using a clamp or vacuum adsorption to ensure that the material does not move or deform during the processing;

[0060] The laser positioning system is used to accurately determine the punching position, mark the punching position on the material surface, and record the coordinates of each punching position for precise alignment during subsequent processing.

[0061] In step S22, the water jet assisted laser uses a sapphire nozzle with a diameter of 30-50 μm;

[0062] Water jet parameters: water jet pressure is 250-300bar, auxiliary gas flow rate is 1.5-3Nl / min;

[0063] Millisecond laser parameters: laser power is 16-20W, pulse width is 200-250μs, repetition frequency is 0.8-1kHz, and focus spot diameter is 45-55μm;

[0064] Couple the millisecond laser and the water jet, adjust the alignment of the laser beam and the water jet, ensure that the laser energy is evenly distributed in the water jet, and the laser focus is located in the center of the water jet;

[0065] In laser processing, water jet assistance will cause the laser focus to move downward and produce focus drift. This phenomenon makes it impossible for the laser beam to be accurately focused into a small spot, but instead forms a larger circular or elliptical spot, which increases the spot diameter and causes increased energy loss. To ensure good processing results, it is necessary to accurately adjust the vertical distance between the convex lens inside the laser and the coupling nozzle so that the laser focus is accurately positioned at the center of the nozzle hole. This can effectively avoid focus drift and improve processing quality and accuracy. Specifically, the vertical distance between the convex lens inside the laser and the coupling nozzle is 3-10mm.

[0066] In step S23, a spiral feeding method is used to process layer by layer from the outside to the inside to perform the first punching operation, the scanning speed is 10-15 mm / s, the jet height is 7-13 mm; the number of processing times is 2-3 iterative scanning;

[0067] After processing, the processed iron-based high-temperature alloy material is cooled and cleaned by water jet to remove the residue generated during the processing.

[0068] The first drilling is done based on water jet-assisted millisecond laser to lay a good foundation for the roundness and surface quality of the hole. Then, a femtosecond laser with ultrasonic vibration is used. Ultrasonic vibration can further improve the roundness of the microhole and reduce the taper. Ultrasonic vibration is a high-frequency vibration technology that can enhance the material removal efficiency. The tiny impact force generated by vibration helps the laser energy to remove the material more effectively, which has a better effect on further finishing. Ultrasonic vibration can reduce heat accumulation during laser processing and reduce the size of the heat-affected zone, thereby further reducing thermal damage to the material.

[0069] In step S3, the steps of combining ultrasonic vibration with femtosecond laser processing include:

[0070] S31, repositioning and fixing the iron-based high-temperature alloy material that has been preliminarily processed by the millisecond laser on the femtosecond laser processing platform to ensure accurate alignment with the initial drilling position;

[0071] S32, calibrating the processing parameters of ultrasonic vibration-assisted femtosecond laser;

[0072] S33, turning on the ultrasonic vibration device and simultaneously starting the femtosecond laser to perform fine processing on the position of the initial punching, scanning processing from the inside to the outside, and performing a second punching;

[0073] In step S31, the previously recorded drilling position coordinates are used to ensure accurate material positioning through a positioning system to avoid processing errors caused by position deviations;

[0074] In step S32, the ultrasonic vibration parameters are set to: vibration frequency of 20-40kHz, amplitude of 5-15μm; the femtosecond laser parameters are set to: laser power of 1-3W, pulse width of 100-200fs, repetition frequency of 1-5MHz, and the focus spot diameter is adjusted to 20-30μm; ensure that the femtosecond laser and the ultrasonic vibration device work synchronously, adjust the laser focus to the optimal processing position, and consider the possible slight displacement caused by ultrasonic vibration, and fine-tune the laser focus position to ensure the processing accuracy;

[0075] In step S33, ultrasonic vibration-assisted femtosecond laser is used for processing in a low-speed, high-precision mode. The scanning speed is controlled at 1-3 mm / s, the jet height is 5-10 mm, and a spiral feed method is used to process layer by layer from the outside to the inside to ensure that the inner wall of the hole is uniform and smooth, and to improve the hole roundness and overall processing quality. During the processing, the processing status is continuously monitored, and parameters are adjusted when necessary to cope with changes in material properties or processing abnormalities.

[0076] In step S4, a combination of natural cooling and forced cooling is adopted. The material is naturally cooled on the femtosecond laser processing platform for 10-15 minutes, and then forced cooling is performed until it cools to room temperature, so as to further reduce thermal stress and improve processing quality.

[0077] The roundness, surface quality and accuracy of the drilled holes are checked by measuring tools to determine whether they meet the processing requirements.

[0078] Embodiment 1

[0079] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, characterized by comprising the following steps;

[0080] S1. Pretreating the iron-based high-temperature alloy material;

[0081] The material size is 150mm*150mm*4mm; use acetone as an organic solvent to clean the material surface to remove grease, dust and other pollutants. After cleaning, use compressed air to blow dry to ensure that the material surface is completely dry;

[0082] S2, preliminary processing of the iron-based high-temperature alloy material by water jet-assisted millisecond laser to perform the first drilling;

[0083] S21. Use a fixture to firmly fix the iron-based high-temperature alloy material on the millisecond laser processing platform, accurately determine the punching position through the laser positioning system, and mark the surface of the material to record the coordinates;

[0084] S22, calibrating parameters of the water jet assisted laser;

[0085] Water jet parameters: a sapphire nozzle with a diameter of 30 μm, a water jet pressure of 250 bar, and an auxiliary gas flow rate of 1.5 Nl / min; millisecond laser parameters: laser power of 16 W, pulse width of 200 μs, repetition frequency of 0.8 kHz, and focused spot diameter of 45 μm; the vertical spacing between the convex lens inside the laser and the coupling nozzle is 3 mm;

[0086] S23, using spiral feeding method, processing layer by layer from outside to inside, the scanning speed is 10mm / s, the jet height is 7mm, the processing times are 2 iterative scans, and after the processing is completed, the processing area is cooled and cleaned with a water jet;

[0087] S3, transferring the iron-based high-temperature alloy material to be finely processed under femtosecond laser, and performing a second drilling in combination with ultrasonic vibration;

[0088] S31, repositioning and fixing the iron-based high-temperature alloy material that has been preliminarily processed by the millisecond laser on the femtosecond laser processing platform using the previously recorded coordinates to ensure precise alignment;

[0089] S32, calibrating the processing parameters of ultrasonic vibration-assisted femtosecond laser;

[0090] Ultrasonic vibration parameters: vibration frequency is 20kHz, amplitude is 5μm; femtosecond laser parameters: laser power is 1W, pulse width is 100fs, repetition frequency is 1MHz, and focus spot diameter is 20μm;

[0091] S33, turning on the ultrasonic vibration device, and simultaneously starting the femtosecond laser, using a spiral feeding method, scanning from the inside to the outside, with the scanning speed controlled at 1 mm / s and the jet height at 5 mm, performing fine processing, and continuously monitoring the processing status;

[0092] S4. After the drilling is completed, the iron-based high-temperature alloy material is cooled and the quality and accuracy of the processed holes are checked; a combination of natural cooling and forced cooling is used, and the material is naturally cooled on the femtosecond laser processing platform for 10 minutes, and then forced cooling is performed until it cools to room temperature.

[0093] Embodiment 2

[0094] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the first embodiment will not be repeated, the difference between this embodiment and the first embodiment is;

[0095] The vertical distance between the laser internal convex lens and the coupling nozzle is 5 mm;

[0096] Embodiment 3

[0097] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the first embodiment will not be repeated, the difference between this embodiment and the first embodiment is;

[0098] The vertical distance between the convex lens inside the laser and the coupling nozzle is 7 mm;

[0099] Embodiment 4

[0100] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the first embodiment will not be repeated, the difference between this embodiment and the first embodiment is;

[0101] The vertical distance between the laser internal convex lens and the coupling nozzle is 9 mm;

[0102] Embodiment 5

[0103] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the first embodiment will not be repeated, the difference between this embodiment and the first embodiment is;

[0104] The water jet pressure is 275 bar;

[0105] Embodiment 6

[0106] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the second embodiment will not be repeated, the difference between this embodiment and the second embodiment is;

[0107] The water jet pressure is 275 bar;

[0108] Embodiment 7

[0109] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the third embodiment will not be repeated, the difference between this embodiment and the third embodiment is;

[0110] The water jet pressure is 275 bar;

[0111] Embodiment 8

[0112] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the fourth embodiment will not be repeated, the difference between this embodiment and the fourth embodiment is;

[0113] The water jet pressure is 275 bar;

[0114] Embodiment 9

[0115] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the first embodiment will not be repeated, the difference between this embodiment and the first embodiment is;

[0116] The water jet pressure is 300 bar;

[0117] Embodiment 10

[0118] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the second embodiment will not be repeated, the difference between this embodiment and the second embodiment is;

[0119] The water jet pressure is 300 bar;

[0120] Embodiment 11

[0121] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the third embodiment will not be repeated, the difference between this embodiment and the third embodiment is;

[0122] The water jet pressure is 300 bar;

[0123] Embodiment 12

[0124] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the fourth embodiment will not be repeated, the difference between this embodiment and the fourth embodiment is;

[0125] The water jet pressure is 300 bar;

[0126] Embodiment 13

[0127] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the fourth embodiment will not be repeated, the difference between this embodiment and the fourth embodiment is;

[0128] The water jet pressure is 300 bar;

[0129] Embodiment 14

[0130] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the seventh embodiment will not be repeated, the difference between this embodiment and the seventh embodiment is;

[0131] The vibration frequency of ultrasonic vibration is 30kHz;

[0132] Embodiment 15

[0133] A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, the same as the seventh embodiment will not be repeated, the difference between this embodiment and the seventh embodiment is;

[0134] The vibration frequency of ultrasonic vibration is 40kHz;

[0135] Comparative Example 1

[0136] A millisecond laser-femtosecond secondary composite hole making method, the same as the first embodiment will not be repeated, the difference between this embodiment and the first embodiment is;

[0137] This experiment does not perform water jet-assisted millisecond laser operation, but directly performs millisecond laser operation;

[0138] Comparative Example 2

[0139] A femtosecond laser composite hole making method, the same points as those of the seventh embodiment are not repeated here, and the difference between this embodiment and the first embodiment is that;

[0140] In this experiment, only femtosecond laser assisted by ultrasonic vibration was performed;

[0141] Comparative Example 3

[0142] A femtosecond laser hole making method, the same points as those of the seventh embodiment are not repeated here, and the difference between this embodiment and the first embodiment is that;

[0143] In this experiment, only femtosecond laser was performed;

[0144] Test Example 1

[0145] This test example selects the iron-based high-temperature alloy materials prepared in Examples 1 to 13 and Comparative Example 1, and performs hole roundness, surface quality and precision inspection on the punched holes;

[0146] Use a roundness meter to measure the roundness of the hole; use a surface roughness measuring instrument to measure the surface roughness of the hole. By scanning the surface of the hole, the average roughness value of the surface can be calculated; use a laser rangefinder to measure the diameter and position accuracy of the hole; as shown in Table 1:

[0147] Table 1 Experimental data on the effect of water jet assisted millisecond laser

[0148]

[0149]

[0150] In summary, in Example 7, the vertical spacing between the convex lens inside the laser and the coupling nozzle is 7mm, and the drilling effect is best when the water jet pressure is 275bar. From Example 1 to Example 13, it can be seen that after the preliminary processing using the water jet to assist the millisecond laser, and then the femtosecond laser finishing, the roundness, average roughness and accuracy of the hole are significantly improved. This verifies the effectiveness of the water jet-assisted millisecond laser in reducing the heat-affected zone, reducing thermal deformation and thermal damage, thereby providing a better foundation for subsequent femtosecond laser finishing; in particular, when the vertical spacing between the convex lens inside the laser and the coupling nozzle is adjusted within the range of 3-10mm, the hole roundness and accuracy show good results, indicating that the appropriate vertical spacing helps to accurately locate the laser focus, avoid focus drift, and improve the processing quality; the change of water jet pressure also has a certain impact on the processing results. Increasing the water jet pressure within a certain range helps to further improve the processing quality, but excessive pressure may cause the water jet to interfere with the laser beam, which in turn affects the processing effect. Therefore, the water jet pressure and the appropriate vertical distance between the convex lens inside the laser and the coupling nozzle can make the coupling between the laser and the water jet more adaptable, thereby achieving a better drilling effect.

[0151] Test Example 2

[0152] This test example selects the iron-based high-temperature alloy materials prepared in Example 7, Example 14 and Example 15, and Comparative Examples 2 and 3, and performs hole roundness, surface quality and precision inspection on the punched holes;

[0153] A roundness meter is used to measure the roundness of the hole; a surface roughness measuring instrument is used to measure the surface roughness of the hole. By scanning the surface of the hole, the average roughness value of the surface can be calculated; a laser rangefinder is used to measure the diameter and position accuracy of the hole; as shown in Table 2:

[0154] Table 2 Effect of ultrasonic vibration-assisted femtosecond laser

[0155]

[0156] By comparing Example 7 with Comparative Examples 2 and 3, it can be clearly seen that the introduction of ultrasonic vibration assistance significantly improves the roundness, average roughness and precision of the holes, verifying the effectiveness of ultrasonic vibration in reducing heat accumulation during laser processing, reducing the size of the heat-affected zone and improving material removal efficiency; from the data of Example 7 to Example 15, it can be seen that with the increase of the ultrasonic vibration frequency, the hole roundness increases slightly, from 7μm to 8μm, because the higher vibration frequency increases the material removal efficiency, but may also lead to an increase in the slight irregularities of the hole wall; at an ultrasonic vibration frequency of 30kHz, the best surface quality is achieved, because the vibration helps to distribute the laser energy more evenly, thereby reducing the surface roughness.

[0157] The water jet-assisted millisecond laser-femtosecond secondary composite hole-making method of the present invention effectively solves the technical difficulties of iron-based high-temperature alloy materials in the process of femtosecond laser drilling by optimizing laser parameters and processing strategies. This method not only improves the roundness and surface quality of the hole, but also significantly improves the processing accuracy, providing a new solution for the high-precision processing of iron-based high-temperature alloy materials.

[0158] The above is based on the ideal embodiment of the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method, characterized in that: Includes steps: S1. Pretreating the iron-based high-temperature alloy material; S2, preliminary processing of the iron-based high-temperature alloy material by water jet-assisted millisecond laser to perform the first drilling; S3, transferring the iron-based high-temperature alloy material to be finely processed under femtosecond laser, and performing a second drilling in combination with ultrasonic vibration; S4. After the drilling is completed, the iron-based high-temperature alloy material is cooled and the quality and accuracy of the processed holes are checked.

2. The water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method according to claim 1, characterized in that: In step S2, the steps of water jet assisted millisecond laser processing include: S21, fixing the iron-based high-temperature alloy material on the millisecond laser processing platform and determining the punching position; S22, calibrating laser parameters of the water jet assisted laser; S23, water jet assisted millisecond laser processing, the punching position is processed layer by layer from the outside to the inside.

3. The water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method according to claim 1, characterized in that: In step S22, the water jet assisted laser uses a sapphire nozzle with a diameter of 30-50 μm; Water jet parameters: water jet pressure is 250-300bar, auxiliary gas flow rate is 1.5-3Nl / min; Millisecond laser parameters: laser power is 16-20W, pulse width is 200-250μs, repetition frequency is 0.8-1kHz, and focused spot diameter is 45-55μm.

4. The water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method according to claim 3, characterized in that: In step S23, a spiral feeding method is used to process layer by layer from the outside to the inside to perform the first punching operation. The scanning speed is 10-15 mm / s, and the jet height is 7-13 mm. The number of processing times is 2-3 iterative scannings.

5. The water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method according to claim 1, characterized in that: In step S3, the steps of combining ultrasonic vibration with femtosecond laser processing include: S31, repositioning and fixing the iron-based high-temperature alloy material that has been preliminarily processed by the millisecond laser on the femtosecond laser processing platform to ensure accurate alignment with the initial drilling position; S32, calibrating the processing parameters of ultrasonic vibration-assisted femtosecond laser; S33, turning on the ultrasonic vibration device and simultaneously starting the femtosecond laser to perform fine processing on the position of the initial punching, scanning processing from the inside to the outside, and performing a second punching.

6. The water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method according to claim 5, characterized in that: In step S32, the ultrasonic vibration parameters are set to: vibration frequency of 20-40kHz, amplitude of 5-15μm; the femtosecond laser parameters are set to: laser power of 1-3W, pulse width of 100-200fs, repetition frequency of 1-5MHz, and the focus spot diameter is adjusted to 20-30μm.

7. The water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method according to claim 5, characterized in that: In step S33, ultrasonic vibration-assisted femtosecond laser is used for processing in a low-speed, high-precision mode, the scanning speed is controlled at 1-3 mm / s, the jet height is 5-10 mm, and a spiral feeding method is used to process layer by layer from the outside to the inside.

8. The water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method according to claim 1, characterized in that: A combination of natural cooling and forced cooling was used. The material was naturally cooled on the femtosecond laser processing platform for 10 minutes and then forced cooled until it cooled to room temperature.

9. The water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method according to claim 1, characterized in that: In step S1, the iron-based high-temperature alloy material is cut and polished to a size of 150 mm*150 mm*4 mm.

10. The water jet-assisted millisecond laser-femtosecond laser secondary composite hole making method according to claim 1, characterized in that: In step S1, the surface of the iron-based high-temperature alloy material is cleaned by an organic solvent to remove grease, dust and other pollutants on the surface; the organic solvent is one of acetone and alcohol; after cleaning, it is blown dry with compressed air or dried naturally.

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