Method for efficiently processing small hole with large depth-diameter ratio by water guide laser

Abstract

The application relates to the technical field of water guide laser micro-hole machining, and provides a method for efficiently machining a small hole with a large depth-diameter ratio by using a water guide laser, which comprises the following steps: S1, cleaning and fixing a workpiece to be machined on a clamp; S2, setting process parameters according to machining requirements and material characteristics, and calculating the optimal scanning circle number required for machining a through hole by using a formula; S3, moving a water guide laser machining head to a machining origin, adopting a concentric circle track or a spiral line track, and scanning and machining the workpiece at the optimal scanning circle number until a through hole is formed; S4, after detecting that the workpiece is penetrated to form a through hole, reducing the scanning circle number to 25% of the optimal scanning circle number, and calling a machining subprogram to perform trimming machining on the small hole; and S5, after completing the machining of the current small hole, moving the workpiece or the machining head to a next machining position, resetting the scanning circle number to the optimal scanning circle number, and repeating steps S3 to S4 to realize periodical machining. The method realizes high-quality, efficient and stable machining of a small hole with a large depth-diameter ratio.

Description

A method for efficient machining of small holes with large aspect ratio using water-guided lasers Technical Field

[0001] This application relates to the field of water-guided laser micro-hole processing technology, and more specifically, to a method for efficiently processing small holes with a large aspect ratio using water-guided laser. Background Technology

[0002] Currently, while existing water-guided laser technology demonstrates advantages such as no thermal damage and high hole wall quality in the machining of small holes with large aspect ratios, significant technical bottlenecks still exist in actual processing. As the machining depth increases, water accumulation due to poor drainage within the hole severely interferes with the stability of the water jet, disrupting the total internal reflection condition essential for laser transmission. This leads to laser energy dissipation, a sharp decline in material removal efficiency, and even processing interruption. Furthermore, debris generated during processing is difficult to effectively remove within the narrow kerf, further hindering the continuous action of the water jet on the workpiece, resulting in efficiency lock-in. To address this problem, existing technologies either employ hybrid processes for pre-drilling holes, increasing equipment complexity and the risk of positioning errors; or rely on operator experience for trial-and-error process parameter adjustments, lacking precise theoretical model guidance, resulting in poor process controllability, limited efficiency improvements, and weak process portability. Therefore, there is an urgent need for a water-guided laser processing method that can fundamentally improve the water jet state in deep holes, enhance chip removal and drainage capabilities, and enable precise and efficient decision-making of process parameters, so as to break through the efficiency bottleneck of machining small holes with large aspect ratios and meet the needs of aerospace and other fields for high-quality multi-hole manufacturing. Summary of the Invention

[0003] This application aims to at least address the technical problems in the related technologies, such as the use of hybrid processes for pre-drilling holes, reliance on operator experience for trial and error of process parameters, lack of precise theoretical model guidance, resulting in poor controllability of the processing and limited efficiency improvement.

[0004] To solve the above-mentioned technical problems, this application is implemented as follows:

[0005] This application provides a method for efficient water-guided laser processing of small holes with a large aspect ratio, comprising: S1, workpiece clamping: cleaning and fixing the workpiece to be processed onto a fixture; S2, parameter setting and calculation: setting the process parameters for water-guided laser processing according to processing requirements and material properties, including laser power, water pressure, repetition frequency, scanning speed, and nozzle diameter; calculating the optimal number of scanning circles required for processing the through hole using the formula d[n-(n-1)α]=2Htanθ; where d is the water jet diameter, θ is the water jet reflection angle, H is the hole depth, and α is the coupling energy beam overlap of adjacent circles in the scanning trajectory. S3, Through-hole machining: Move the water-guided laser machining head to the machining origin, use a concentric circle trajectory or a spiral trajectory, and scan the workpiece with the optimal number of scans until a through hole is formed; S4, Trimming machining: After detecting that the workpiece has been penetrated to form a through hole, reduce the number of scans to 25% of the optimal number of scans, and call the machining subroutine to trim the small hole; S5, Cyclic machining: After completing the machining of the current small hole, move the workpiece or machining head to the next machining position, reset the number of scans to the optimal number of scans, and repeat steps S3 to S4 to achieve cyclic machining.

[0006] This application provides a method for efficient machining of small holes with large aspect ratios using water-guided lasers. By establishing a precise machining model and implementing a staged machining approach, it achieves a synergistic improvement in machining efficiency and quality. In scenarios requiring precise decision-making of process parameters, this method directly calculates the optimal number of scans n based on key physical quantities such as the water jet diameter d, the hole depth H, the water jet reflection angle θ, and the overlap ratio α. This eliminates the need for traditional time-consuming trial-and-error experiments, enabling scientific, rapid, and portable determination of machining parameters, thus laying a theoretical foundation for efficient machining. In scenarios requiring efficient drilling and drainage / chip removal, the machining head first performs concentric circle or spiral trajectory scanning with the calculated optimal number of scans n. This number of scans effectively suppresses the interference of splashed water inside the hole on the water jet, enhances the stability of the water jet, and improves its ability to flush away accumulated water and debris, thereby quickly penetrating the workpiece to form a through hole, solving a core obstacle in deep hole machining. In scenarios requiring high-quality trimming and maximum efficiency, once a through-hole is detected, the system immediately invokes the processing subroutine, reducing the number of scans to 25% of the optimal number for trimming. This method, while ensuring the surface quality and shape accuracy of the hole wall, completely eliminates the "empty scan" time, utilizing laser energy entirely for the effective processing area. This minimizes the total processing time for a single hole, achieving an order-of-magnitude improvement in efficiency, and ultimately enabling high-quality, high-efficiency, and stable processing of small holes with large aspect ratios.

[0007] Additional aspects and advantages of this application will become apparent in the following description or may be learned by practice of this application. Attached Figure Description

[0008] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0009] Figure 1 is a flowchart of a method for efficient processing of small holes with large aspect ratio using water-guided laser according to an embodiment of this application;

[0010] Figure 2 is a flowchart illustrating a method for efficient processing of small holes with large aspect ratio using water-guided lasers according to an embodiment of this application;

[0011] Figure 3 is a cross-sectional schematic diagram of the small hole structure during processing in a water-guided laser high-efficiency processing method for small holes with a large aspect ratio according to an embodiment of this application.

[0012] Figure 4 is a schematic diagram of concentric circle trajectory coupling energy beam overlap in a method for efficient processing of small holes with large aspect ratio using water-guided laser according to an embodiment of this application.

[0013] The correspondence between the reference numerals and component names in Figure 3 is as follows:

[0014] 100 for machining workpieces, 110 for coupling energy beams, and 120 for water jets. Detailed Implementation

[0015] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0016] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0017] The following describes, with reference to Figures 1 to 4, a method for efficient water-guided laser processing of small holes with large aspect ratios according to some embodiments of this application, which improves the flow state of water jets in deep hole environments and the ability to transport etching products, thereby increasing the processing efficiency of small hole structures with large aspect ratios.

[0018] As shown in Figure 1, an embodiment of this application provides a method for efficient water-guided laser processing of small holes with a large aspect ratio, comprising: S1, workpiece clamping: cleaning and fixing the workpiece to be processed onto a fixture; S2, parameter setting and calculation: setting the process parameters for water-guided laser processing according to processing requirements and material properties, including laser power, water pressure, repetition frequency, scanning speed, and nozzle diameter; calculating the optimal number of scanning circles required for processing the through hole using the formula d[n-(n-1)α]=2Htanθ; where d is the water jet diameter, θ is the water jet reflection angle, H is the hole depth, and α is the radius of curvature of adjacent circles in the scanning trajectory. Coupled energy beam overlap rate, n is the optimal number of scan circles; S3, Through hole processing: Move the water-guided laser processing head to the processing origin, use a concentric circle trajectory or a spiral trajectory, and scan the workpiece with the optimal number of scan circles until a through hole is formed; S4, Trimming processing: After detecting that the workpiece has been penetrated to form a through hole, reduce the number of scan circles to 25% of the optimal number of scan circles, and call the processing subroutine to trim the small hole; S5, Cyclic processing: After completing the current small hole processing, move the workpiece or processing head to the next processing position, and reset the number of scan circles to the optimal number of scan circles, repeat steps S3 to S4 to achieve cyclic processing.

[0019] Specifically, as shown in Figure 1, the method for efficient water-guided laser processing of small holes with a large aspect ratio provided in this application includes: S1, cleaning and fixing the workpiece to be processed on a fixture; S2, setting the process parameters for water-guided laser processing according to processing requirements and material properties, including laser power, water pressure, repetition frequency, scanning speed, and nozzle diameter; calculating the optimal number of scanning circles required for processing the through hole using the formula d[n-(n-1)α]=2Htanθ; where d is the water jet diameter, θ is the water jet reflection angle, H is the hole depth, and α is the radius of curvature of adjacent circles in the scanning trajectory. Coupled energy beam overlap rate, n is the optimal number of scan circles; S3, move the water-guided laser processing head to the processing origin, use a concentric circle trajectory or a spiral trajectory, and scan the workpiece with the optimal number of scan circles until a through hole is formed; S4, after detecting that the workpiece has been penetrated to form a through hole, reduce the number of scan circles to 25% of the optimal number of scan circles, and call the processing subroutine to perform edge trimming processing on the small hole; S5, after completing the current small hole processing, move the workpiece or processing head to the next processing position, and reset the number of scan circles to the optimal number of scan circles, repeat steps S3 to S4 to achieve cycle processing.

[0020] In this way, the optimal number of scanning revolutions n is precisely calculated using the mathematical formula d[n-(n-1)α]=2Htanθ, which includes the water jet diameter d, the orifice depth H, the reflection angle θ, and the overlap ratio α. Based on this, two stages are performed: full-revolution through-hole machining and 25%-revolution trimming. This ensures that during the through-hole machining stage, the water jet maintains stability and sufficient coverage of the machining area with the most suitable number of scanning revolutions, thereby effectively suppressing the backsplash interference of water accumulation in the hole and enhancing the water jet's ability to flush and remove etching products. Subsequently, the number of scanning revolutions is significantly reduced during the trimming stage, which can accurately eliminate burrs and uneven areas generated after the through-hole is opened, while avoiding ineffective empty sweeping of the laser in the already penetrated area. This significantly improves the water jet flow state and chip removal efficiency in the deep hole machining environment, breaking through the efficiency bottleneck caused by poor drainage and chip removal in traditional water-guided laser machining of small holes with large aspect ratios. Thus, while ensuring the hole wall quality, a magnitude increase in processing efficiency is achieved.

[0021] Compared with existing technologies, the method for efficient processing of small holes with large aspect ratios using water-guided lasers provided in this application has the following advantages: First, the optimal number of scanning revolutions is directly calculated using mathematical formulas, avoiding extensive trial-and-error experiments, reducing waste of time, materials, energy, and manpower. Furthermore, the parameters have a wide range of applicability and strong portability. Processing small holes using the optimal number of scanning revolutions suppresses the interference of splashing on the stability of the water jet, enhances the ability to remove accumulated water and debris, and avoids efficiency degradation caused by too many or too few scanning revolutions, thus improving processing quality and efficiency. Second, the processing method combining the optimal number of scanning revolutions for perforation with fewer scanning revolutions for trimming eliminates ineffective laser transmission time and idle scanning time while ensuring surface integrity, improving processing efficiency by at least 30 times. Third, the entire processing flow is simple and continuous, achieving a dual improvement in quality and efficiency when facing the demand for processing large numbers of large aspect ratio holes.

[0022] Specifically, currently, large aspect ratio small holes require extremely high machining accuracy and surface quality, especially in high-end fields such as aerospace and medical devices, but traditional technologies have significant drawbacks. For example, during mechanical drilling, the tool is not only prone to wear but also generates significant stress; electrical discharge machining (EDM) can create thermal defects and microcracks, reducing fatigue life, and is only suitable for conductive materials; conventional laser machining suffers from prominent heat-affected zones, recast layers, and taper issues; while femtosecond lasers can reduce thermal damage, they still present ridge structure and efficiency bottlenecks in deep hole machining. These defects directly affect component lifespan and system safety. Water-guided lasers transmit laser light through total internal reflection using a high-pressure water jet, achieving a "cold machining" effect, breaking through the limitations of traditional technologies and offering advantages such as no thermal damage, high surface quality, high hole wall perpendicularity, and wide material adaptability. Nevertheless, efficiency challenges remain in deep hole machining. As hole depth increases, water accumulation and splashing disrupt the total internal reflection at the water-air interface, causing laser energy dissipation and a sharp drop in machining efficiency. In addition, the narrow cutting kerf restricts the debris discharge channel, leading to residue accumulation during processing and frequent interruptions to the processing flow, which further reduces the etching efficiency.

[0023] A study in the Journal of Materials Processing Tech. 335(2025)118671 indicates that during drilling, the water jet is easily interfered with by splashback, resulting in 54.6% of the laser's ineffective transmission time and reducing the material removal efficiency. The proposed method of suppressing splashback using porous water-absorbing materials can only absorb splashback above the micropores, offering limited improvement to the material removal efficiency.

[0024] Patent CN118527858A discloses a method for processing silicon carbide micro-holes with large aspect ratios using a water-guided laser. This method improves the movement state of the water jet by using a needle-like object to break off the cylinder formed inside the unformed micro-hole during processing, thereby increasing the processing efficiency of the water-guided laser. However, removing the cylinder from difficult-to-machine materials is challenging and introduces stress damage and additional processes, failing to effectively improve processing efficiency and quality.

[0025] To address the shortcomings of existing technologies, this application aims to provide a method for efficient water-guided laser processing of small holes with large aspect ratios, which addresses the problem of rapidly decreasing material removal efficiency in water-guided laser processing of small holes with large aspect ratios. This method improves the flow state of the water jet in the deep hole environment and the ability to transport etched products, thereby increasing the processing efficiency of small hole structures with large aspect ratios.

[0026] Specifically, as shown in Figure 1, the method for efficient processing of small holes with large aspect ratio using water-guided lasers provided in this application includes the following steps:

[0027] S1. Workpiece clamping: Clean the workpiece to be processed and fix it on the fixture;

[0028] S2. Parameter setting and calculation: Set the process parameters for water-guided laser processing according to the processing requirements and material properties. The process parameters include laser power, water pressure, repetition frequency, scanning speed and nozzle diameter.

[0029] The optimal number of scanning revolutions required to process the through hole is calculated using the formula d[n-(n-1)α]=2Htanθ, where d is the water jet diameter, θ is the water jet reflection angle, H is the hole depth, α is the coupling energy beam overlap rate of adjacent circles in the scanning trajectory, and n is the optimal number of scanning revolutions.

[0030] S3. Through-hole machining: Move the water-guided laser machining head to the machining origin, use a concentric circle trajectory or a spiral trajectory, and scan the workpiece with the optimal number of scans until a through hole is formed;

[0031] S4. Trimming: After detecting that the workpiece has been penetrated to form a through hole, the number of scans is reduced to 25% of the optimal number of scans, and the machining subroutine is called to trim the small hole.

[0032] S5. Cyclic processing: After completing the current small hole processing, move the workpiece or processing head to the next processing position, and reset the number of scan circles to the optimal number of scan circles. Repeat steps S3 to S4 to achieve cyclic processing.

[0033] The method for high-efficiency machining of small holes with large aspect ratios using water-guided lasers provided in this application achieves a synergistic improvement in machining efficiency and quality by establishing a precise machining model and implementing a staged machining approach. In scenarios requiring precise decision-making of process parameters, this method directly calculates the optimal number of scans n based on key physical quantities such as the water jet diameter d, the hole depth H, the water jet reflection angle θ, and the overlap rate α, using the constructed mathematical model d[n-(n-1)α]=2Htanθ. This eliminates the need for traditional time-consuming trial-and-error experiments, achieving scientific, rapid, and portable determination of machining parameters, thus laying a theoretical foundation for high-efficiency machining. In scenarios requiring high-efficiency drilling and drainage / chip removal, the machining head first performs concentric circle or spiral trajectory scanning with the calculated optimal number of scans n. This number of scans effectively suppresses the interference of splashed water inside the hole on the water jet, enhances the stability of the water jet and its ability to flush away accumulated water and debris, thereby quickly penetrating the workpiece to form a through hole, solving a core obstacle in deep hole machining. In scenarios requiring high-quality trimming and maximum efficiency, once a through-hole is detected, the system immediately invokes the processing subroutine, reducing the number of scans to 25% of the optimal number for trimming. This method, while ensuring the surface quality and shape accuracy of the hole wall, completely eliminates the "empty scan" time, utilizing laser energy entirely for the effective processing area. This minimizes the total processing time for a single hole, achieving an order-of-magnitude improvement in efficiency, and ultimately enabling high-quality, high-efficiency, and stable processing of small holes with large aspect ratios.

[0034] In some embodiments, optionally, the relationship between the water jet diameter and the nozzle diameter satisfies: d = D × C, where d is the water jet diameter, D is the nozzle diameter, and C is the shrinkage coefficient, with the shrinkage coefficient C ranging from 0.82 to 0.85.

[0035] Specifically, by introducing a clear mathematical relationship d=D×C between the water jet diameter d and the nozzle diameter D, and limiting the range of the contraction coefficient C to 0.82~0.85, a precise conversion bridge is constructed from equipment parameters to key input parameters of the processing model. This relationship reflects the physical law of diameter change caused by the flow field contraction effect when high-pressure water is ejected from the nozzle, and the limited range of the contraction coefficient can accurately describe the empirical value of the actual shape of the water jet under common process conditions. This provides an accurate and reliable input value of the water jet diameter d for the aforementioned mathematical model for calculating the optimal number of scanning revolutions, thereby ensuring the scientific nature of the entire process parameter optimization process and the reliable reproducibility of the final processing results, and avoiding processing failures or efficiency losses caused by inaccurate parameter estimation.

[0036] In some embodiments, the process parameters for water-guided laser processing can be set according to processing requirements and material properties. Specifically, the set water-guided laser processing process parameters range as follows: laser power 20W~400W, water pressure 5MPa~50MPa, repetition frequency 5kHz~30kHz, scanning speed 1mm / s~15mm / s, and pulse width 10ns~200ns.

[0037] Specifically, by limiting the laser power to 20W~400W, water pressure to 5MPa~50MPa, repetition frequency to 5kHz~30kHz, scanning speed to 1mm / s~15mm / s, and pulse width to 10ns~200ns, this combination of process parameters works together to create stable and efficient material removal conditions on the workpiece surface. Suitable laser power and pulse width ensure that the single-pulse energy is sufficient to vaporize the material while controlling the heat-affected zone. Reasonable water pressure is crucial for maintaining a stable laminar flow state and sufficient momentum in the water jet, directly affecting laser transmission efficiency and debris removal capability. The matching of repetition frequency and scanning speed determines the spot overlap rate and the spatiotemporal distribution of energy injection, jointly ensuring the continuity and uniformity of the processing trajectory. Within this optimized parameter range, the water-guided laser processing can simultaneously achieve high removal efficiency and excellent processing quality, such as low taper and a small heat-affected zone, thus ensuring that this method can achieve efficient and high-quality processing results under different material and aperture requirements.

[0038] In some embodiments, an auxiliary gas, argon, may be introduced during the processing, with a flow rate ranging from 1 L / min to 10 L / min.

[0039] Specifically, by introducing argon gas at a flow rate of 1 L / min to 10 L / min as an auxiliary gas during the processing, a controllable local atmosphere is provided for the water-guided laser processing zone. Since the inert argon gas effectively drives away and isolates air within the processing area, it fundamentally inhibits the oxidation reaction of the workpiece material under the high temperature of the laser. Simultaneously, this stable airflow helps to disperse any steam and plasma that may be trapped in the waterjet head or processing area, reducing their shielding effect on the incident laser and ensuring more efficient transmission of laser energy to the workpiece surface. This reduces oxide inclusions and recast layers inside the processed holes, improves the surface quality of the hole walls, and indirectly assists in the stability of the waterjet and the efficiency of removing etched products by maintaining a cleaner processing gap, thereby improving the final processing quality and process reliability of small holes with large aspect ratios.

[0040] In some embodiments, optionally, before moving the water-guided laser processing head to the processing origin, using a concentric circle trajectory or a spiral trajectory, and scanning the workpiece with the optimal number of scans, it further includes: adjusting the Z-axis height of the water-guided laser processing head so that the distance between it and the workpiece surface is 10mm~20mm.

[0041] Specifically, by precisely controlling the distance between the water-guided laser processing head and the workpiece surface within the range of 10mm to 20mm, an ideal working distance is provided for the coupled energy beam. Firstly, this ensures that the high-pressure water jet ejected from the nozzle has sufficient distance to complete the hydrodynamic stabilization process before reaching the workpiece surface, forming a stable jet section with good laminar flow characteristics. This is a prerequisite for the stable transmission of laser energy through total internal reflection. Secondly, this distance avoids the risks of water splashing and contamination / damage to the nozzle and optical window caused by excessively close distances, while also preventing water jet jitter, divergence, or even breakage that may occur due to excessively large distances. This ensures that laser energy is delivered accurately and efficiently to the processing area. Optimizing the working distance provides a fundamental guarantee for the effective execution of the optimal number of scans calculated based on mathematical models, ultimately improving the stability, repeatability, and processing quality of the processing.

[0042] In some embodiments, optionally, when a workpiece is detected to have been penetrated to form a through hole, the method specifically includes: determining whether the workpiece has been penetrated by monitoring acoustic emission signals, visual images, or backlight detection methods during the processing.

[0043] Specifically, by employing acoustic emission signals, visual images, or backlight detection as the criteria for determining through-hole formation, these three methods capture characteristic abrupt changes in the processing state from different physical dimensions. Specifically, the acoustic emission sensor identifies penetration events by monitoring changes in the stress wave signal characteristics released by the material during laser ablation and penetration; the vision system makes judgments by analyzing changes in the hole morphology or light transmission characteristics in the image of the processing area; and backlight detection detects the intensity of the light signal transmitted through the micro-hole from the back of the workpiece. These three methods achieve rapid, accurate, and automated identification of through-hole events, ensuring that the processing system can seamlessly switch from the high-efficiency piercing stage to the fine trimming stage in a timely manner. This avoids problems such as wasted laser energy, overburning of the hole opening, or insufficient trimming caused by human error or response delay. Thus, while ensuring the final hole morphology quality, it further improves the automation level and time utilization efficiency of the entire processing flow.

[0044] In some embodiments, optionally, the coupling energy beam overlap rate α of adjacent circles in the scanning trajectory is 20%.

[0045] Specifically, by limiting the overlap rate α of the coupled energy beams between adjacent circles in the scanning trajectory to 20%, this overlap rate is an optimized value determined based on the balance between material removal characteristics and processing efficiency. A 20% overlap ensures sufficient overlap between adjacent scanning trajectories to completely cover and eliminate any untreated material or protrusions left from the previous cycle, avoiding spiral processing marks. Simultaneously, it minimizes the energy overlap between adjacent spots, preventing the expansion of the heat-affected zone or excessive material ablation due to excessive local energy accumulation. Thus, in the through-hole machining stage, this specific overlap rate, combined with the calculated optimal number of scanning cycles, enables uniform and continuous material removal throughout the entire machining area, effectively improving the perpendicularity and surface smoothness of the hole wall, and ensuring the final quality and precision of the small hole machining.

[0046] In some embodiments, the depth-to-diameter ratio of the aperture may be greater than 10:1.

[0047] Specifically, by explicitly limiting the depth-to-diameter ratio of the small hole to greater than 10:1, when the depth-to-diameter ratio exceeds this threshold, the drainage and chip removal channels within the hole become extremely narrow. This drastically worsens water accumulation and splashing during processing, severely compromising the stability of the water jet and the energy transmission of the laser. The method provided in this application, which determines the optimal number of scanning revolutions based on a mathematical model and performs staged processing, is precisely effective in addressing this extreme condition. Compared to conventional techniques, this method possesses unique advantages and applicable boundaries in solving the problem of machining small holes with large depth-to-diameter ratios. It ensures that the optimal number of scanning revolutions calculation model and the two-stage processing strategy can be activated and maximize their effectiveness under the most challenging machining conditions, thereby improving both processing efficiency and quality in this specific high-difficulty machining field.

[0048] In some embodiments, optionally, a processing subroutine is invoked to perform edge trimming on the small hole, specifically including: the outer diameter of the scanning trajectory of the edge trimming is the same as the outer diameter of the through hole processing.

[0049] Specifically, by ensuring that the outer diameter of the scanning trajectory for trimming is consistent with that of the through-hole machining stage, microscopic unevenness or burrs often remain on the edge of the hole wall after machining, caused by heat, slag adhesion, or incomplete material removal. Strictly limiting the trimming area to the already formed hole diameter boundary ensures that laser energy is concentrated and precisely applied to the hole wall area requiring trimming, especially the exit edge. This avoids wasting laser energy in the center area where material has been completely removed or unnecessarily enlarging the hole diameter, improving laser energy utilization efficiency and the targeted nature of the trimming process. Furthermore, it ensures that the final formed hole has a consistent and precise diameter throughout its entire depth, effectively improving the roundness of the hole opening and the overall hole shape quality. This allows the hole size and shape obtained in the through-hole machining stage to be maintained and optimized after high-quality trimming.

[0050] In some embodiments, the workpiece material to be processed may be a high-temperature alloy, titanium alloy, ceramic matrix composite material, carbon fiber reinforced matrix composite material, or silicon carbide.

[0051] Specifically, by clearly defining the materials to be processed as high-temperature alloys, titanium alloys, ceramic matrix composites, carbon fiber reinforced matrix composites, and silicon carbide, these materials generally possess characteristics such as high hardness, high melting point, high wear resistance, or anisotropy, making them typical difficult-to-machine materials. Traditional mechanical or conventional laser processing methods are prone to problems such as tool wear, thermal cracking, delamination, or large heat-affected zones. The water-guided laser processing method provided in this application, combined with its physical model-based parameter optimization and staged control strategy, effectively processes the workpieces due to its "cold processing" characteristics and precise energy control. In core applications of high-end manufacturing, this method fully leverages the unique advantages of water-guided laser technology in fabricating high-quality, high-aspect-ratio micro-holes in materials sensitive to thermal damage and difficult to process, providing an efficient and reliable process solution for solving the micro-hole processing challenges of key components in aerospace, semiconductor, and other fields.

[0052] In a specific application, as shown in Figure 2, this application provides a method for efficient processing of small holes with large aspect ratio using water-guided lasers, which specifically includes the following steps:

[0053] Step 1: After cleaning and drying, the workpiece to be processed is precisely positioned on the reference surface of the fixture and fixed with uniform clamping force to ensure no displacement or vibration during processing;

[0054] Step 2: After confirming that the equipment is operating normally, set the optimal water-guided laser processing parameters according to the processing requirements and material characteristics;

[0055] Step 3: Move the machining head to the machining origin and adjust the Z-axis height so that the distance between it and the workpiece surface is 15mm. Use a concentric circle trajectory to machine the through hole in the workpiece.

[0056] Step 4: After detecting that the workpiece has been penetrated to form a through hole, reduce the number of scan cycles to perform edge trimming on the machined small hole;

[0057] Step 5: After observing and judging the surface quality and taper of the small hole to meet the expectations, proceed to the next processing step;

[0058] Step 6: Move the workpiece relative to the machining head to the next machining position, and adjust the number of scan circles to the initial machining settings to achieve cycle machining.

[0059] When setting the optimal water-guided laser processing parameters based on processing requirements and material properties, the following principles are followed when selecting the process parameters: ensuring that the coupled energy beam can penetrate the workpiece to obtain the fastest processing efficiency while meeting the processing quality requirements; ensuring that there is no empty scanning state during trimming to obtain the fastest processing efficiency, and ensuring good small hole morphology quality and low taper.

[0060] Specifically, the processing parameters of the water-guided laser include: laser power 80W, water pressure 30MPa, repetition frequency 10kHz, scanning speed 10mm / s, argon flow rate 5 / min, nozzle orifice diameter 100μm, and pulse width 50ns.

[0061] Specifically, the water jet diameter d and the nozzle orifice diameter D satisfy the following relationship: d = D × C, where the contraction coefficient C is 0.85. The calculated water jet diameter d is 85 μm.

[0062] Specifically, as shown in Figures 3 and 4, the method of efficiently processing small holes with large aspect ratios using water-guided lasers employs a concentric circular trajectory to process through holes in the workpiece 100. In the scanning trajectory, the overlap width between the coupled energy beams 110 of adjacent circles is W, and the water jet reflection angle θ is determined based on the reflection state of the water jet 120 under experimental conditions. The water jet reflection angle θ is 2° to ensure that total reflection conditions can be maintained during the processing.

[0063] Specifically, the optimal number of scanning revolutions in the processing parameters is determined according to the following formula: d[n-(n-1)α]=2Htanθ, where the overlap rate of the coupling energy beam between adjacent circles in the scanning trajectory is 20%, the orifice depth H is 12mm, the water jet reflection angle θ is 2°, and the micro-orifice diameter is 0.8mm. The calculated optimal number of scanning revolutions n is 12.

[0064] Specifically, after detecting that the workpiece has been penetrated to form a through hole, the number of scans is reduced to perform trimming processing on the processed small hole. The process includes: when the workpiece is detected to have been penetrated to form a through hole, a processing subroutine is called to reduce the number of scans to 25% of the original number of scans for trimming processing, that is, the number of scans in the trimming processing is 3.

[0065] Specifically, adjusting the number of scan circles to the initial processing settings includes adjusting the number of scan circles from the fewer scan circles used during trimming to the calculated optimal number of scan circles, that is, restoring the number of scan circles from 3 to 12.

[0066] Specifically, the material of the workpiece to be processed is a ceramic matrix composite material.

[0067] In the description of this application, the term "multiple" refers to two or more. Unless otherwise expressly defined, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0068] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0069] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for efficient processing of small holes with large aspect ratio using water-guided lasers, characterized in that, include: S1. Workpiece clamping: Clean and fix the workpiece to be processed onto the fixture; S2. Parameter setting and calculation: Set the process parameters for water-guided laser processing according to the processing requirements and material properties. The process parameters include laser power, water pressure, repetition frequency, scanning speed, and nozzle diameter; calculate the optimal number of scanning revolutions required for processing the through hole using the formula d[n-(n-1)α]=2Htanθ; where d is the water jet diameter, θ is the water jet reflection angle, H is the hole depth, α is the coupling energy beam overlap rate of adjacent circles in the scanning trajectory, and n is the optimal number of scanning revolutions; S3. Through hole processing Step 1: Move the water-guided laser processing head to the processing origin, use a concentric circle trajectory or a spiral trajectory, and scan the workpiece with the optimal number of scans until a through hole is formed; Step 2: Trimming: After detecting that the workpiece has been penetrated to form a through hole, reduce the number of scans to 25% of the optimal number of scans, and call the processing subroutine to trim the small hole; Step 3: Cyclic processing: After completing the current small hole processing, move the workpiece or processing head to the next processing position, reset the number of scans to the optimal number of scans, and repeat steps S3 to S4 to achieve cyclic processing.

2. The method for efficient processing of small holes with large aspect ratio using water-guided lasers according to claim 1, characterized in that, The relationship between the water jet diameter and the nozzle diameter satisfies: d = D × C, where d is the water jet diameter, D is the nozzle diameter, and C is the shrinkage coefficient, which ranges from 0.82 to 0.

85.

3. The method for efficient processing of small holes with large aspect ratio using water-guided lasers according to claim 1, characterized in that, The process parameters for water-guided laser processing are set according to processing requirements and material properties. Specifically, the range of water-guided laser processing parameters is as follows: laser power 20W~400W, water pressure 5MPa~50MPa, repetition frequency 5kHz~30kHz, scanning speed 1mm / s~15mm / s, and pulse width 10ns~200ns.

4. The method for efficient processing of small holes with large aspect ratio using water-guided lasers according to claim 3, characterized in that, An auxiliary gas, argon, is introduced during the processing, with a flow rate ranging from 1 L / min to 10 L / min.

5. The method for efficient machining of small holes with large aspect ratio using water-guided lasers according to claim 1, characterized in that, Before moving the water-guided laser processing head to the processing origin using a concentric circle trajectory or a spiral trajectory and scanning the workpiece with the optimal number of scans, the process specifically includes: adjusting the Z-axis height of the water-guided laser processing head so that the distance between it and the workpiece surface is 10mm~20mm.

6. The method for efficient machining of small holes with large aspect ratio using water-guided lasers according to claim 1, characterized in that, The method of detecting that a workpiece has been penetrated to form a through hole specifically includes: determining whether the workpiece has been penetrated by monitoring acoustic emission signals, visual images, or backlight detection methods during the processing.

7. The method for efficient machining of small holes with large aspect ratio using water-guided lasers according to claim 1, characterized in that, The overlap rate α of the coupling energy beams of adjacent circles in the scanning trajectory is 20%.

8. The method for efficient machining of small holes with large aspect ratio using water-guided lasers according to claim 1, characterized in that, The depth-to-diameter ratio of the small hole is greater than 10:

1.

9. The method for efficient machining of small holes with large aspect ratio using water-guided lasers according to claim 1, characterized in that, The step of calling the processing subroutine to perform edge trimming on the small hole specifically includes: the outer diameter of the scanning trajectory of the edge trimming process is the same as the outer diameter of the through hole process.

10. The method for efficient processing of small holes with large aspect ratio using water-guided lasers according to claim 1, characterized in that, The material of the workpiece to be processed is a high-temperature alloy, titanium alloy, ceramic matrix composite material, carbon fiber reinforced matrix composite material, or silicon carbide.

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