Laser-electrolytic combined milling machining tool head

Abstract

The application patent belongs to the field of laser-electrolytic composite machining, and particularly relates to a laser-electrolytic composite milling tool bit. The milling tool bit mainly comprises a tool bit main body, an external power supply, a linear strip-shaped laser beam, a light transmission glass and a grid; the tool bit main body comprises a liquid return channel, a light transmission channel, a liquid inlet channel, a liquid suction port, an array current equalization hole and a light transmission window, the outer side of the outer side wall of the liquid inlet channel is provided with a current stabilizing cavity, the top surface of the light transmission channel is provided with two light transmission slits with the same shape and size, the bottom end of each light transmission channel is respectively provided with a light transmission window, and the middle part of the liquid return channel is provided with a pressure equalizing grid. In the milling process, the linear strip-shaped laser beam passes through the light transmission glass and enters the light transmission channel through the light transmission slit, and is emitted from the bottom light transmission window of the tool bit to perform laser-electrolytic composite machining on the workpiece anode. The tool bit has a simple structure and can realize efficient, high-precision and high-quality milling of large-format metal workpieces.

Description

Technical Field

[0001] This invention patent belongs to the field of laser-electrolysis composite machining, specifically a laser-electrolysis composite milling head. Background Technology

[0002] Difficult-to-machine metal alloys such as stainless steel, titanium alloys, and nickel-based alloys are widely used in the manufacture of structural components in the aerospace field. With technological advancements, the design and manufacturing requirements for large-sized, thin-walled, weakly rigid components are becoming increasingly stringent. High precision, high efficiency, high surface quality, and low-cost machining are current research goals, but also significant challenges. Mechanical milling is the most widely used machining technology, but it is limited by workpiece hardness and stiffness, suffers from tool wear, and has relatively low machining accuracy. Laser processing technology is versatile and flexible, offering advantages such as high processing efficiency and no material limitations. However, the processed surfaces often exhibit defects such as heat-affected zones, recast layers, and surface microcracks, and existing millimeter-level laser spots have low material removal efficiency per unit time. Electrochemical machining technology offers advantages such as high surface precision, no tool wear, and no recast layers or microcracks, but there is still considerable room for improvement in the accuracy of dimensional and shape processing and processing efficiency. Therefore, the aforementioned single-energy-field-based machining technologies all have certain limitations and are not ideal for the high-quality and high-efficiency machining of large, thin-walled, weakly rigid components. Given that electrochemical processing and laser processing each have their own unique processing principles and technological advantages, in recent years, academia and industry have integrated these two processing methods, leveraging their strengths and avoiding their weaknesses, to develop a variety of laser-electrolysis composite processing methods.

[0003] Chinese patent CN114850596A discloses a laser-jet electrolysis composite machining dual-tube tool electrode and milling method. This patent utilizes a dual-tube tool electrode and a ring-shaped laser beam, significantly increasing the machining area per pass and greatly improving machining efficiency. However, due to the high difficulty and cost of implementing this ring-shaped laser technology, it is not suitable for engineering applications.

[0004] Chinese patent CN115007958A discloses a liquid-guided laser-electrolysis composite machining tool electrode system and milling method. This patent utilizes a dual-channel system (external spray and internal suction) to transport the electrolyte, removing accumulated slag and debris during the laser-electrolysis composite machining process to improve surface finish. It also innovatively proposes water-guided laser technology to enhance material removal efficiency. However, because the laser is transmitted through the electrolyte, its transmission is severely interfered with, resulting in significant energy attenuation and difficulty in beam focusing, leading to less than ideal process results. Furthermore, the temperature rise caused by laser transmission in the electrolyte increases costs and causes process instability. Moreover, the electrode's structural design can lead to uneven flow field distribution, further reducing machining accuracy. Minimizing the negative impact of the electrolyte on the laser transmission process remains a key technical challenge in laser-electrolysis composite machining.

[0005] Chinese patent CN116140725A discloses a laser-electrolysis composite milling tool cathode. Although the laser in this tool cathode does not directly interact with the electrolyte during transmission, the laser's role in the cathode is relatively limited, only used for side milling, and does not maximize the combined effect of laser and electrolysis.

[0006] To overcome the shortcomings of the existing technology, this patent proposes a new laser-electrolytic composite milling head that can process metal materials at a lower cost, higher precision, and higher efficiency. Summary of the Invention

[0007] To address the shortcomings of existing laser-electrolysis composite machining heads, this invention provides a laser-electrolysis composite milling head to achieve efficient, high-precision, and high-quality milling of large-format metal workpieces.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows.

[0009] A laser-electrolytic composite milling head includes a head body, a linear laser beam, a transparent glass, and a grid. The head body comprises a return channel, two light-passing channels, a liquid inlet channel, a liquid extraction port, an array of flow equalization holes, and a transparent window. The two light-passing channels are symmetrically arranged on the left and right sides of the return channel. The two liquid inlet channels are symmetrically arranged on both sides of the return channel, each located outside the light-passing channels. A flow stabilizing cavity is provided on the outer side of the outer wall of each liquid inlet channel. Each flow stabilizing cavity has a... It has a liquid inlet; a pressure equalization grid is installed in the middle of the return channel; the two liquid extraction ports are symmetrically installed on the upper part of the two narrow side walls of the cutter head body; the array of flow equalization holes are symmetrically arranged on the outer side wall of the liquid inlet channel; the light-transmitting glass is tightly pressed against the top of the cutter head body; the top surface of the light passage has two light-transmitting slits of the same shape and size; the bottom end of each of the two light passages is provided with a light-transmitting window; the linear laser beam passes through the light-transmitting glass, enters the light passage through the light-transmitting slits, and then exits from the light-transmitting window.

[0010] The width of the light-transmitting slit is 100–300 μm.

[0011] The width of the linear laser beam is 30–200 μm, and its length is equal to the length of the light-transmitting slit.

[0012] The array of flow equalization holes is arranged in a straight line with equal spacing and a diameter of 100-500 μm. The size of the holes decreases uniformly from the center to both sides by a difference of 20 μm.

[0013] The through-hole size of the equalizing grid is 100-300μm, and the value decreases uniformly from the center outwards in increments of 10μm.

[0014] The width of the liquid inlet channel is 100–500 μm, and the width of the liquid return channel is 500–1000 μm.

[0015] The grid is made of acid and alkali resistant metal material and is fixed at the inlet end of the return liquid channel. The grid has uniformly distributed and equal-sized through holes, ranging from 100 to 300 μm.

[0016] The described linear laser beam is green light with a wavelength of 532±0.5nm.

[0017] The outer wall thickness of the liquid inlet channel is 800-1200 μm, the inner wall thickness of the liquid inlet channel is 200-400 μm, and the outer wall thickness of the liquid return channel is 400-600 μm. All of them are made of acid and alkali resistant metal materials.

[0018] The working principle of the laser-electrolytic composite milling head of the present invention is briefly described below.

[0019] S1: After the machining head body is installed and fixed, place it vertically directly above the starting position of the machining area of ​​the workpiece, and make the distance between the lower end of the machining head body and the starting position of the machining area 0.2~0.5mm; connect the workpiece to the positive terminal of the external power supply and connect the machining head to the negative terminal of the external power supply.

[0020] S2: Start the electrolyte circulation and electrolyte suction equipment to drive the electrolyte into the flow stabilizing chamber through the inlet, and then into the inlet channel through the array of flow equalization holes. After passing through the gap between the machining head body and the workpiece, it is finally discharged from the suction port through the return channel and the pressure equalization grid in the middle.

[0021] S3: Start the laser equipment according to the set power, output a linear laser beam, the linear laser beam passes through the light-transmitting glass, enters the light-transmitting channel through the light-transmitting slit, and finally irradiates the surface of the workpiece vertically through the light-transmitting window;

[0022] S4: The external power supply is activated according to the set voltage value to supply power to the machining head body and the workpiece. At the same time, the machining head body is driven to move along the given path. At this time, the workpiece material directly opposite the lower end of the machining head body is uniformly dissolved and removed under the combined action of the laser irradiation thermal field, electric field, electrochemical field, flow field, etc.

[0023] S5: After the machining head body completes all movements according to the given milling path and reaches the end position of the machining area, the external power supply, electrolyte circulation and electrolyte suction equipment, laser equipment and machining head drive equipment are turned off to complete the milling process.

[0024] The main advantages of this invention compared to the prior art are as follows.

[0025] 1. This invention essentially eliminates the influence of the electrolyte on the transmission process of the linear laser, resulting in higher laser energy utilization, better beam quality, and more controllable application to the processing area. In this invention, the coupling transmission between the laser and the electrolyte exists only within the processing gap. Therefore, the interaction length between the laser and the electrolyte is significantly reduced, making the laser virtually unaffected by the electrolyte. This enhances the controllability of the linear laser beam and reduces energy attenuation and divergence in the electrolyte. It also significantly reduces the heating effect of the laser on the electrolyte, avoiding cost losses caused by electrolyte evaporation. Furthermore, the short contact distance between the laser and the electrolyte makes the laser easier to focus and improves its quality, resulting in better laser-electrolysis composite processing and improved surface precision and quality.

[0026] 2. Higher processing efficiency can be achieved. The laser-electrolytic hybrid milling head proposed in this invention has a larger external dimension and a wider coverage area of ​​the green ribbon laser beam, resulting in a larger milling area per scan. Furthermore, a grid is installed at the inlet of the return channel, significantly increasing the cathode surface area at the bottom of the head, thus subjecting the processing area to a larger electric field. The staggered distribution of the light-passing channels ensures that the attenuation loss of the ribbon laser beam in the electrolyte is almost zero, thereby maximizing the thermal field effect of laser irradiation. In addition, the external spray and internal suction liquid supply method enables rapid removal of processing products and air bubbles, thereby increasing the electric field amplitude in the processing area. In summary, compared with existing laser-electrolytic hybrid milling technologies, the processing head of this invention can achieve higher processing efficiency.

[0027] 3. The electrolyte flow field distribution is more uniform, and the electric field distribution in the machining gap is more uniform. This results in higher machining accuracy and efficiency. The laser-electrolysis composite milling head proposed in this invention is equipped with buffer and flow equalization devices such as a flow stabilizing cavity, an array of flow equalization holes, and a pressure equalization grid at the electrolyte inlet and outlet. This makes the electrolyte flow field distribution more uniform in both the inlet and outlet scenarios, thereby making the electric field distribution in the machining gap more uniform, the current density higher, improving the surface quality and accuracy of the machined surface, increasing the material removal rate, and reducing the surface roughness. Attached Figure Description

[0028] Figure 1 A schematic diagram of narrow-side machining for a laser-electrolytic composite milling head;

[0029] Figure 2 A schematic diagram of wide-side machining for a laser-electrolytic composite milling head;

[0030] Figure 3 Axonometric schematic diagram of a laser-electrolytic composite milling head;

[0031] The labels in the diagram are as follows: 1. Cutting head body; 2-1, 2-2. Liquid inlet; 3-1, 3-2. Flow stabilizing cavity; 4-1, 4-2. Array of flow equalization holes; 5-1, 5-2. Liquid inlet channel; 6. Liquid return channel; 7-1, 7-2. Light passage channel; 8. Grid; 9. Pressure equalization grid; 10-1, 10-2. Light transmission slit; 11-1, 11-2. Light transmission window; 12-1, 12-2. Linear laser beam; 13. Light transmission glass; 14. Electrolyte; 15. External power supply; 16, 17. Liquid extraction port; 18-1, 18-2. Narrow side wall; 19. Workpiece being processed; 20-1, 20-2. Outer wall of the liquid inlet channel; 21-1, 21-2. Inner wall of the liquid inlet channel; 22-1, 22-2. Outer wall of the liquid return channel. Detailed Implementation

[0032] The implementation of the present invention will be further described below with reference to the accompanying drawings.

[0033] A laser-electrolytic composite milling head includes a head body 1, linear laser beams 12-1 and 12-2, a transparent glass 13, and a grid 8. The head body 1 includes a return channel 6, two light-passing channels 7-1 and 7-2, a liquid inlet channel 5-1 and 5-2, a liquid extraction port 16 and 17, an array of flow equalization holes 4-1 and 4-2, and transparent windows 11-1 and 11-2. The two light-passing channels 7-1 and 7-2 are symmetrically arranged on the left and right sides of the return channel 6, staggered from the return channel 6, and not connected to each other, with a width of 300 μm. The top surfaces of the light-passing channels 7-1 and 7-2 have two transparent slits 10-1 and 10-2 of the same shape and size. The slit width is 200μm, and the length is the same as that of the light-transmitting channels 7-1 and 7-2. The light-transmitting glass 13 is tightly pressed against the top of the cutter head body 1, and the length, width, and height of the light-transmitting glass 13 are 55×10×5mm. Light-transmitting windows 11-1 and 11-2 are installed at the bottom of the light-transmitting channels 7-1 and 7-2, and the length and width of the light-transmitting windows 11-1 and 11-2 are the same as those of the light-transmitting channels 7-1 and 7-2. The linear laser beams 12-1 and 12-2 pass through the light-transmitting glass 13, enter the light-transmitting channels 7-1 and 7-2 through the light-transmitting slits 10-1 and 10-2 respectively, and then exit from the light-transmitting windows 11-1 and 11-2. The linear laser beams 12-1 and 12-2 have a wavelength of 532±0.The light emitted is 5nm green light. The two inlet channels 5-1 and 5-2 are symmetrically arranged on both sides of the return channel 6, each located outside the light transmission channels 7-1 and 7-2 respectively. The widths of inlet channels 5-1 and 5-2 are 300μm, and the width of the return channel 6 is 600μm. The sum of the cross-sectional areas of inlet channels 5-1 and 5-2 is less than the cross-sectional area of ​​the return channel 6. This design ensures that the electrolyte 14 has a high pressure and flow rate when flowing through the processing area, and is confined within the processing area. The electrolyte 14 is a 15wt% NaNO3 solution at a temperature of 25±2℃. Flow stabilizing cavities 3-1 and 3-2 are provided on the outer walls 20-1 and 20-2 of the inlet channels 5-1 and 5-2. Each of the flow stabilizing cavities 3-1 and 3-2 has an inlet 2-1 and 2-2 on its outer side. The electrolyte 14 is... The electrolyte 14 enters the flow stabilization chambers 3-1 and 3-2 through inlets 2-1 and 2-2, where it undergoes its first flow stabilization. The array of flow equalization holes 4-1 and 4-2 are symmetrically arranged on the outer walls 20-1 and 20-2 of the inlet channels 5-1 and 5-2 in a straight line with equal spacing. The hole diameter decreases uniformly from 500 μm at the center to 100 μm at both sides. The electrolyte 14 flows through the array of flow equalization holes 4-1 and 4-2 into the inlet channels 5-1 and 5-2. This design ensures that the electrolyte 14 undergoes a second flow stabilization without affecting the high flushing speed over a large area, resulting in a more uniform flow field distribution in the processing area. The return channel 6 is equipped with a pressure equalization grid 9 with 200 μm through holes, the size of which decreases uniformly from the center to the periphery. This design significantly reduces electrolyte flow rate fluctuations in the processing area caused by uneven suction pressure distribution. The two suction ports 16 and 17 are symmetrically installed on the upper parts of the two narrow sidewalls 18-1 and 18-2 of the cutter head body 1; the grid 8 is fixed to the inlet end of the return channel 6, and the grid 8 has dimensions of 50×2×1mm, with uniformly distributed, equal-sized through holes of 250μm.

[0034] The working principle of the laser-electrolytic composite milling head of the present invention is briefly described below.

[0035] S1. After the machining head body 1 is installed and fixed, it is placed vertically directly above the starting position of the machining area of ​​the workpiece 19, and the distance between the lower end of the machining head body 1 and the starting position of the machining area is 0.3mm; the workpiece 19 is electrically connected to the positive terminal of the external power supply 15, and the machining head body 1 is electrically connected to the negative terminal of the external power supply 15.

[0036] S2. Start the electrolyte circulation and electrolyte suction equipment, drive the electrolyte 14 into the flow stabilizing chambers 3-1 and 3-2 through the inlet ports 2-1 and 2-2 at a speed of 30m / s, and then enter the inlet channels 5-1 and 5-2 through the array flow equalization holes 4-1 and 4-2. After passing through the gap between the machining head body 1 and the workpiece 19, it is finally discharged from the suction ports 16 and 17 through the return channel 6 and the pressure equalization grid 9 in the middle.

[0037] S3. Start the laser equipment according to the set power and output linear laser beams 12-1 and 12-2. The linear laser beams 12-1 and 12-2 pass through the light-transmitting glass 13, enter the light-transmitting channels 7-1 and 7-2 through the light-transmitting slits 10-1 and 10-2, and finally irradiate the surface of the workpiece 19 vertically through the light-transmitting windows 11-1 and 11-2.

[0038] S4. Power supply 15 is started with a voltage of 40V to supply power to the machining head body 1 and the workpiece 19. At the same time, the machining head body 1 is driven to move along the given path at a feed speed of 10mm / min-1. At this time, the workpiece material directly opposite the lower end of the machining head body 1 is uniformly dissolved and removed under the combined action of the laser irradiation thermal field, electric field, electrochemical field, flow field, etc.

[0039] S5. After the machining head body 1 completes all movements according to the given milling path and reaches the end position of the machining area, the external power supply 15, electrolyte circulation and electrolyte suction equipment, laser equipment and machining head drive equipment are turned off at the same time to complete the milling process.

Claims

1. A laser-electrolytic composite milling head, comprising a head body (1), an external power supply (15), a strip laser beam (12-1, 12-2), a transparent glass (13), and a grid (8), characterized in that: The cutter head body (1) includes a return channel (6), two light-passing channels (7-1, 7-2), two liquid inlet channels (5-1, 5-2), two suction ports (16, 17), two arrayed flow equalization holes (4-1, 4-2), and two light-transmitting windows (11-1, 11-2). The two light-passing channels (7-1, 7-2) are symmetrically arranged on the left and right sides of the return channel (6). The two liquid inlet channels (5-1, 7-2) are arranged on the left and right sides of the return channel (6). 5-2) Symmetrically arranged on both sides of the return channel (6) and each located outside the light passage (7-1, 7-2); the outer walls (20-1, 20-2) of the inlet channels (5-1, 5-2) are each provided with a flow stabilizing cavity (3-1, 3-2); each of the flow stabilizing cavities (3-1, 3-2) is provided with an inlet (2-1, 2-2) on the outer side; a pressure equalization grid (9) is installed inside the return channel (6). The two suction ports (16, 17) are symmetrically installed on the upper part of the two narrow side walls (18-1, 18-2) of the cutter head body (1); the array of flow equalization holes (4-1, 4-2) are symmetrically arranged on the outer side walls (20-1, 20-2) of the liquid inlet channel (5-1, 5-2); the light-transmitting glass (13) is tightly pressed against the top of the cutter head body (1); the top surface of the light-passing channel (7-1, 7-2) Two light-transmitting slits (10-1, 10-2) of the same shape and size are provided; light-transmitting windows (11-1, 11-2) are respectively installed at the bottom of the two light-transmitting channels (7-1, 7-2); the linear laser beams (12-1, 12-2) pass through the light-transmitting glass (13), enter the light-transmitting channels (7-1, 7-2) through the light-transmitting slits (10-1, 10-2) respectively, and then exit from the light-transmitting windows (11-1, 11-2).

2. The laser-electrolytic composite milling head according to claim 1, characterized in that: The width of the light-transmitting slits (10-1, 10-2) is 100~300μm.

3. The laser-electrolytic composite milling head according to claim 1, characterized in that: The width of the linear laser beam (12-1, 12-2) is 30~200μm, and the length is equal to the length of the light-transmitting slit (10-1, 10-2).

4. The laser-electrolytic composite milling head according to claim 1, characterized in that: The array of flow equalization holes (4-1, 4-2) are arranged in a straight line with equal spacing and a diameter of 100~500μm. Their size decreases uniformly from the center to both sides by a difference of 20μm.

5. The laser-electrolytic composite milling head according to claim 1, characterized in that: The through-hole size of the equalizing grid (9) is 100~300μm, and the value decreases uniformly from the center outwards in increments of 10μm.

6. The laser-electrolytic composite milling head according to claim 1, characterized in that: The width of the liquid inlet channel (5-1, 5-2) is 100~500μm, and the width of the liquid return channel (6) is 500~1000μm.

7. The laser-electrolytic composite milling head according to claim 1, characterized in that: The grid (8) is made of a metal material that is resistant to acid and alkali corrosion and is fixed at the inlet end of the return channel (6). The through holes of the grid (8) are evenly distributed and of equal size, ranging from 100 to 300 μm.

8. The laser-electrolytic composite milling head according to claim 1, characterized in that: The aforementioned linear laser beams (12-1, 12-2) are green light with a wavelength of 532±0.5nm.

9. A laser-electrolytic composite milling head according to claim 1, characterized in that: The outer wall (20-1, 20-2) of the liquid inlet channel (5-1, 5-2) has a wall thickness of 800~1200μm, the inner wall (21-1, 21-2) of the liquid inlet channel (5-1, 5-2) has a wall thickness of 200~400μm, and the outer wall (22-1, 22-2) of the liquid return channel (6) has a wall thickness of 400~600μm. They are all made of acid and alkali resistant metal materials.

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