Water-guided laser large-depth-diameter-ratio round hole machining device and machining method

Abstract

The invention discloses a water guide laser large depth-diameter ratio round hole machining device and method. The machining device comprises a machining head, a to-be-machined material, a clamp and a water guide laser head. Wherein the clamp is used for fixing a material to be processed, and the end part of the processing head is a water guide laser head; a water jet is arranged at the water guide laser head, and the water jet is jetted towards a material to be processed; the periphery of the water jet jetted by the machining head is coated with coaxial surrounding protective gas; and a set angle is arranged on the clamp in an inclined and inverted manner. Based on the scheme provided by the invention, drainage and deslagging are promoted by adding the drainage groove and adopting the inclined upside-down process method, so that the machining efficiency of the large depth-diameter ratio is improved.

Description

Technical Field

[0001] This invention belongs to the field of water-guided laser processing technology, specifically relating to a water-guided laser large aspect ratio circular hole processing device and processing method. Background Technology

[0002] Materials with a high aspect ratio (depth to diameter ratio exceeding 20) are widely used in aerospace, energy, automotive, and electronics industries, playing a crucial role, particularly in cooling holes for turbine blades, micro-pore design for gas turbine engines, and cooling channels for nuclear reactors. These designs effectively improve thermal management efficiency, enhance structural strength, and optimize space utilization. Especially in high-temperature environments, deep-hole structures effectively disperse heat, preventing overheating while reducing material usage. Due to the high precision machining requirements of these applications, methods such as electrical discharge machining (EDM), laser drilling, mechanical drilling, and ultrasonic-assisted machining are commonly employed.

[0003] However, traditional machining methods each have their drawbacks in deep hole machining. Electrical discharge drilling offers high precision but is slow and has a large heat-affected zone; laser drilling, while suitable for hard and brittle materials, is prone to thermal damage; mechanical drilling is prone to misalignment in deep hole machining, leading to reduced precision; and ultrasonic-assisted machining requires a robust cooling system to handle debris. Compared to these traditional methods, water-guided laser machining offers significant advantages. By cooling the laser's active area with water flow, water-guided lasers not only reduce the heat-affected zone but also improve machining accuracy and efficiency. It is particularly suitable for machining hard and brittle materials and complex holes, enabling high-precision, non-contact deep hole machining and avoiding the thermal damage problems of traditional methods.

[0004] However, when water-guided lasers process holes with large diameters, the hole walls block the outward-exploding water jet due to the excessive depth and small diameter. This causes water and slag to accumulate inside the hole and cannot be discharged smoothly, affecting the laminar flow state of the water jet in the water-guided laser. Consequently, the total internal reflection state of the laser inside the "water fiber" is broken, and the laser energy dissipates, thus reducing processing efficiency. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a water-guided laser large aspect ratio circular hole processing device and processing method. By adding a drainage groove and a tilting and inverting process, drainage and slag removal are promoted, thereby improving the processing efficiency of large aspect ratio.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: One aspect of the present invention provides a water-guided laser-guided circular hole machining apparatus, the apparatus comprising: a machining head, a material to be machined, a fixture, and a water-guided laser head; wherein, the fixture is used to fix the material to be machined, and the end of the machining head is a water-guided laser head; a water jet is provided at the water-guided laser head, and the direction of the water jet is directed toward the material to be machined; The water jet ejected from the processing head is surrounded by a protective gas arranged coaxially.

[0007] Furthermore, the water jet is sprayed vertically downwards towards the material to be processed.

[0008] Furthermore, the processing head is fixed on a rotating shaft, and the processing head can rotate along the axis of the rotating shaft and swing in space, so that the water jet is sprayed vertically in an inverted manner onto the material to be processed.

[0009] On the other hand, based on the above-mentioned device, this application also provides a method for processing a water-guided laser-guided circular hole with a large aspect ratio, the processing method comprising the following steps: Clean the surface of the material to be processed and dry it. The material to be processed is fixed on the fixture, with the surface to be processed facing the processing direction of the water-guided laser head; The coupling between the laser and the water jet is detected by the camera software to ensure that the laser can undergo total internal reflection in the water jet; Adjust the protective gas flow rate to ensure that the coupled water jet reaches the maximum processing length; Design processing trajectories and methods; Determine the laser power, laser frequency, and scanning speed parameters in the water jet, and perform processing according to the designed processing trajectory and method.

[0010] Furthermore, when the three-axis water-guided laser processing equipment performs processing, the designed processing trajectory and method are specifically as follows: When performing core taking: set appropriate drainage channels according to the core taking position of the material to be processed, and add drainage channels around the processing trajectory; After completing each circular trajectory, a straight line trajectory is then processed along the tangent. When making holes: pre-fabricate drainage through holes at the hole-making location using conventional machining methods. After each circular trajectory is completed, machine a spiral line along the tangent to the pre-drilled through hole inside to ensure that the water flow and waste material from each cut can be discharged from the through hole in a timely manner.

[0011] Furthermore, when the five-axis water-guided laser processing equipment performs processing, the designed processing trajectory and method are specifically as follows: The material to be processed is tilted and inverted on the fixture at a set angle, maintaining a stable and effective jet above a set distance. The water and slag in the deep hole, with the help of gravity and the explosive force of the plasma in the molten pool, form a downward stable flow field, reducing the accumulation of liquid and waste in the hole, and enabling the depth-to-diameter ratio of the water-guided laser-processed hole to exceed 20:1.

[0012] In a preferred embodiment of this application, the laser power in the water jet is 23W, the laser frequency is 8KHz, and the scanning speed is 5mm / s.

[0013] The beneficial effects of this invention are: 1. Simple and convenient to operate.

[0014] 2. Adding drainage channels and using an inclined inverted design can effectively remove wastewater generated during processing, preventing waste liquid from stagnating or unevenly distributing in deep holes, thus ensuring the stability of the water jet transmission to the bottom of the hole. Stable water flow helps maintain uniform laser energy transmission, ensuring the processing accuracy and consistency of holes with large depth-to-diameter ratios, and avoiding processing errors caused by water flow fluctuations.

[0015] 3. The drainage channel and tilted inverted design help to quickly remove wastewater and heat, reduce heat accumulation, and optimize the cooling effect of the water-guided laser processing area. This avoids localized overheating, ensures uniform temperature distribution on the workpiece surface during processing, effectively controls the heat-affected zone, reduces material deformation and surface damage, and improves processing quality.

[0016] 4. The drainage channel and tilted inverted design help remove debris, air bubbles, and steam generated during processing, preventing them from accumulating inside the hole and affecting laser transmission and processing results. Good chip removal ensures the stability of the laser beam and efficient cutting, preventing debris from reflecting the laser or interfering with the processing, thereby improving the surface quality.

[0017] 5. The design of the drainage channel and the tilted inverted structure effectively discharges wastewater and heat, avoiding water stagnation or heat accumulation during processing. This not only optimizes cooling and chip removal but also reduces equipment load and processing time, thereby improving the overall efficiency of water-guided laser high aspect ratio processing and shortening the production cycle. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the triaxial water-guided laser processing structure in an embodiment of this application; Figure 2 This is a schematic diagram of the five-axis water-guided laser processing structure in an embodiment of this application; Figure 3 A schematic diagram of the machining trajectory for center core extraction with a large depth-to-diameter ratio; Figure 4 This is a schematic diagram of the machining trajectory for edge coring with a large aspect ratio. Figure 5 A schematic diagram of the machining trajectory for drilling holes with a large depth-to-diameter ratio; Figure 6 A schematic diagram of a structure for "inverted" machining with a large aspect ratio; In the diagram, 1. machining head, 2. water jet, 3. machining material, and 4. fixture. Detailed Implementation

[0019] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0020] Example 1:

[0021] Reference Figure 1 As shown, this invention provides a water-guided laser machining device for large aspect ratio circular holes. In this embodiment, the machining device is a three-axis water-guided laser machining device. The machining head 1 is vertically fixed, and the water jet 2 can only be sprayed downwards in a vertical direction. The material to be processed 3 is fixed on the worktable by a clamp 4, and the material to be processed 3 is located directly below the water jet 2. The water jet sprayed by the machining head 1 is surrounded by a coaxial protective gas, characterized by its low density and low viscosity.

[0022] Example 2:

[0023] This embodiment, based on the overall concept of Embodiment 1, provides a five-axis water-guided laser processing device, referring to... Figure 2 As shown, in this embodiment, the processing head 1 can swing arbitrarily in space, and in particular, the water jet 2 can be sprayed in an inverted position. Simultaneously, the material to be processed 3 is fixed by a clamp 4. The key feature is that the hole feature of the material to be processed 3 can be tilted into an "inverted" position. This five-axis water-guided laser processing device can achieve a spatial motion trajectory and posture of the processing head 1 that is lower than the characteristic posture of the material to be processed 3.

[0024] Example 3:

[0025] Based on the water-guided laser processing apparatus provided in the above embodiments, this application also provides a method for processing large aspect ratio circular holes using water-guided lasers. This method utilizes a water-guided laser to process silicon carbide micro-holes with a large aspect ratio, and includes the following steps: 1. Place the parts in distilled water and ultrasonically clean them for 5 minutes at a frequency of 50kHz to clean the surface. Then place the parts in a drying oven to dry them.

[0026] 2. Place the cleaned and dried parts on the fixture to effectively prevent damage caused by stress during processing.

[0027] 3. Before processing, set the pressure of the water jet to 300 bar, and check the coupling between the laser and the water jet using camera software to ensure that the laser can undergo total internal reflection in the water jet; then adjust the helium flow rate to 1 L / min to ensure that the coupled water jet reaches the maximum processing length, thus guaranteeing the processing of deep holes in the workpiece.

[0028] 4. Design the processing trajectory and method.

[0029] For triaxial water-guided laser processing equipment: When performing core extraction: Appropriate drainage channels should be set according to the core extraction location of the silicon carbide material to improve processing efficiency. Taking core extraction from the center of the material as an example, drainage channels can be added around the processing trajectory, such as... Figure 3 After each circular trajectory is completed, a straight trajectory is then followed along the tangent to ensure that the water flow and waste material from each cut can be discharged from the external drainage channel in a timely manner; if there are no requirements for the core sampling position, the processing starting point can be directly set at the edge of the silicon carbide material, such as... Figure 4 .

[0030] When performing hole-making: A drainage through-hole needs to be pre-drilled at the hole location using conventional machining methods such as long-pulse laser (where precision and thermal damage requirements are not high). After each circular trajectory is completed, a spiral line is machined along the tangent to the pre-drilled through-hole (the middle through-hole can be used). This ensures that water and waste material from each cut can be discharged promptly through the drainage through-hole. Figure 5 .

[0031] For five-axis water-guided laser processing equipment: The material to be processed can be mounted on the fixture at a 20°~30° angle, such as... Figure 6 Due to its high kinetic energy jet and the protection of the surrounding low-density gas, the optical-water coupled energy beam can maintain a stable and effective jet of over 80mm, overcoming the influence of gravity on the jet shape and position. In the "inverted" tilting machining process, the water and slag accumulated in the deep hole can form a stable downward flow field with the help of gravity and the detonation force of the plasma in the molten pool, reducing the accumulation of liquid and waste in the hole and enabling the depth-to-diameter ratio of water-guided laser-machined holes to exceed 20:1.

[0032] 5. Determine the laser power in the water jet to be 23W, the laser frequency to be 8KHz, and the scanning speed to be 5mm / s.

[0033] 6. Processing begins.

[0034] 7. Processing ends when the cut is complete.

[0035] 8. Inspect the machining accuracy of the workpiece and write a report.

[0036] In water-guided laser processing, molten material (such as metals and ceramics) and cutting waste need to be removed promptly to prevent them from re-solidifying or accumulating in the processing area. Based on the flow channel in this application, water can be guided to quickly discharge molten material and debris, accelerating material removal while preventing slag from forming a solidified layer on the hole wall or bottom. The water flow not only aids in slag removal but also provides cooling.

[0037] During laser processing, intense heat accumulates in the processing area, leading to excessively high temperatures. The drainage channel allows the laminar "water fiber" to guide the laser more smoothly to the processing area and quickly drains it after the laser's thermal effect, preventing water flow turbulence and slag accumulation. The water flow also helps remove air bubbles from deep holes, as the presence of bubbles can affect laser transmission efficiency and cause the beam to deviate from the intended focus.

[0038] In conventional laser cutting, it's impossible to remove deposited debris simply by adding drainage channels or holes. There are three main reasons for this. First, conventional laser cutting melts the material into a molten pool, which is then purged with inert gas to create a kerf. However, the inert gas purging pressure is typically 0.2-0.5 MPa, resulting in very weak purging force, making it difficult to remove slag. Even adding chip removal channels doesn't significantly improve the process. Water-guided laser cutting, on the other hand, melts the material with laser, and high-pressure water washes away the slag. The high-pressure water pressure is 30-50 MPa, providing a strong and sustained purging force. With water channels, a continuous drainage flow field is created, transporting the slag. Second, conventional lasers cannot process holes with a depth-to-diameter ratio greater than 10. This is because conventional lasers have a divergence angle, resulting in a taper in the drilled hole. Furthermore, with excessively large depth-to-diameter ratios, the purging gas in conventional lasers cannot penetrate deep holes. The bottom of the hole remains a blind hole until it is fully penetrated, making it difficult for purging gas to enter. Therefore, conventional lasers are not suitable for processing holes with large depth-to-diameter ratios. Third, water-guided lasers effectively utilize the fluidity and transport properties of water, allowing them to carry molten slag from metals or ceramics in a flowing manner. In contrast, the purging gas used in conventional lasers lacks continuous transport capabilities, causing slag to adhere to the walls or solidify at the orifice opening or bottom, resulting in slag buildup.

[0039] The solution provided in this application, which incorporates a drainage channel and an inverted tilting mechanism, effectively removes wastewater generated during processing, preventing the retention or uneven distribution of waste liquid in deep holes and ensuring the stability of the water jet delivery to the bottom of the hole. Stable water flow helps maintain uniform laser energy transfer, ensuring the processing accuracy and consistency of holes with large depth-to-diameter ratios and avoiding processing errors caused by water flow fluctuations.

[0040] The drainage channels and tilted inverted design facilitate rapid removal of wastewater and heat, reducing heat accumulation and optimizing cooling in the water-guided laser processing area. This prevents localized overheating, ensures uniform temperature distribution on the workpiece surface during processing, effectively controls the heat-affected zone, reduces material deformation and surface damage, and improves processing quality.

[0041] The drainage channels and tilted inverted design help remove debris, air bubbles, and steam generated during processing, preventing them from accumulating inside the hole and affecting laser transmission and processing results. Excellent chip removal ensures laser beam stability and efficient cutting, preventing debris from reflecting the laser or interfering with the processing, thereby improving the surface quality.

[0042] The design, featuring drainage channels and an inverted tilt, effectively discharges wastewater and heat, preventing water stagnation or heat accumulation during processing. This not only optimizes cooling and chip removal but also reduces equipment load and processing time, thereby improving the overall efficiency of water-guided laser high aspect ratio machining and shortening the production cycle.

[0043] This invention has many specific applications. The above description is only a preferred embodiment of this invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. A water-guided laser-guided circular hole machining device with a large aspect ratio, characterized in that, The processing device includes: a processing head, a material to be processed, a fixture, and a water-guided laser head; wherein, the fixture is used to fix the material to be processed, and the end of the processing head is a water-guided laser head; a water jet is provided at the water-guided laser head, and the direction of the water jet is towards the material to be processed; The water jet ejected from the processing head is surrounded by a protective gas arranged coaxially.

2. The water-guided laser large aspect ratio circular hole processing device according to claim 1, characterized in that, The water jet is sprayed vertically downwards toward the material to be processed.

3. The water-guided laser large aspect ratio circular hole processing device according to claim 1, characterized in that, The processing head is fixed on a rotating shaft, and the processing head can rotate along the axis of the rotating shaft and swing in space, so that the water jet is sprayed vertically in an inverted manner onto the material to be processed.

4. A method for machining water-guided laser-guided circular holes with a large aspect ratio, characterized in that, The processing method includes the following steps: Clean the surface of the material to be processed and dry it. The material to be processed is fixed on the fixture, with the surface to be processed facing the processing direction of the water-guided laser head; The coupling between the laser and the water jet is detected by the camera software to ensure that the laser can undergo total internal reflection in the water jet; Adjust the protective gas flow rate to ensure that the coupled water jet reaches the maximum processing length; Design processing trajectories and methods; Determine the laser power, laser frequency, and scanning speed parameters in the water jet, and perform processing according to the designed processing trajectory and method.

5. The method for processing a water-guided laser-guided circular hole with a large aspect ratio according to claim 4, characterized in that, When the three-axis water-guided laser processing equipment is used for processing, the specific design of the processing trajectory and method is as follows: When performing core taking: set appropriate drainage channels according to the core taking position of the material to be processed, and add drainage channels around the processing trajectory; After completing each circular trajectory, a straight line trajectory is then processed along the tangent. When making holes: pre-fabricate drainage through holes at the hole-making location using conventional machining methods. After each circular trajectory is completed, machine a spiral line along the tangent to the pre-drilled through hole inside to ensure that the water flow and waste material from each cut can be discharged from the through hole in a timely manner.

6. The method for processing water-guided laser-guided circular holes with a large aspect ratio according to claim 4, characterized in that, When the five-axis water-guided laser processing equipment performs processing, the designed processing trajectory and method are as follows: The material to be processed is tilted and inverted on the fixture at a set angle, maintaining a stable and effective jet above a set distance. The water and slag in the deep hole, with the help of gravity and the explosive force of the plasma in the molten pool, form a downward stable flow field, reducing the accumulation of liquid and waste in the hole, and enabling the depth-to-diameter ratio of the water-guided laser-processed hole to exceed 20:

1.

7. The method for processing water-guided laser-guided circular holes with a large aspect ratio according to claim 4, characterized in that, The laser power in the water jet is 23W, the laser frequency is 8KHz, and the scanning speed is 5mm / s.

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