Novel hydrophobic line electrode electrochemical discharge machining device and method

Abstract

The invention relates to the field of hard and brittle material machining, and particularly discloses a novel hydrophobic line electrode electrochemical discharge machining device and method.The machining device comprises a power system, a line electrode, a guide wheel system, a control system, a hydrophobic layer coating system and a working platform used for limiting external workpieces; the positive electrode of the power supply system is connected with the auxiliary electrode, and the negative electrode of the power supply system is conducted with the line electrode through the electric brush; the hydrophobic layer coating system comprises a hydrophobic solution tank and a hydrophobic solution contained in the hydrophobic solution tank, and the line electrode is driven by the guide wheel system to move and is immersed into the hydrophobic solution tank to form a uniform hydrophobic coating; the control system is used for regulating the movement direction of the guide wheel system driving the wire electrode and adjusting power parameters of the power system; the auxiliary electrode and a workpiece are soaked in an electrolyte medium, a stable isolation interface is formed on the surface of the line electrode with the hydrophobic coating, and during machining, a power system is combined to excite spark discharge to break down the isolation interface to etch away materials on the surface of the workpiece.

Description

Technical Field

[0001] The invention relates to the technical field of hard and brittle material processing, and in particular discloses a novel hydrophobic wire electrode electrochemical discharge machining device and method. Background Art

[0002] Electrochemical discharge machining (ECDM), as an emerging non-contact processing method, has unique advantages in the micro-machining of hard and brittle insulating materials such as glass and ceramics. This method removes materials by generating discharge between the electrode and the workpiece. It is not limited by the conductivity of the material and is particularly suitable for the processing of tiny holes and microstructures. However, the existing ECDM technology still has many problems in its implementation, especially in the processing of microstructures with large aspect ratios. For example, under the vertical line electrode device, the formation of the isolation interface is difficult and unstable, resulting in changes in the discharge position, which affects the processing accuracy.

[0003] In the prior art, researchers have used traditional spiral tool electrodes instead of wire electrodes, and utilized the rotation of the tool electrode to improve the stability of the isolation interface, thereby improving processing accuracy and efficiency. The movement of the spiral tool electrode helps to promote the discharge of debris and the renewal flow of the electrolyte. However, due to the basic principle limitations of existing commercial micro-tool electrodes and ECDM technology, this method still faces challenges when processing microstructures with a size of less than 100 microns, especially when processing thicker workpieces. The tool electrode requires a deeper immersion depth, which not only increases the difficulty of forming the isolation interface, but also consumes a lot of energy, further affecting the stability of the processing.

[0004] At the same time, some researchers have proposed an insulating oil film-assisted WECDM processing method, which reduces the direct contact between the electrolyte and the electrode surface by coating the insulating oil film on the surface of the wire electrode, thereby reducing the energy consumption of the isolation interface formation. Although this method is helpful for the processing of thick workpieces in some applications, the dielectric constant of the oil film is large, which makes it difficult for discharge to break through. Therefore, in order to make the processing process stable, a larger voltage and a thicker oil film are usually required, which increases the difficulty of controlling energy consumption and processing accuracy.

[0005] In summary, the existing technology has the following technical problems: electrolyte flow field disturbance and bubble collapse during deep hole processing lead to frequent rupture of the isolation interface; the existing electrode structure (such as spiral / oil-coated electrodes) cannot take into account both processing accuracy and large aspect ratio processing requirements; that is, the existing technology cannot achieve high-precision, large aspect ratio microstructure processing of hard and brittle insulating materials under low energy consumption conditions, and urgently needs innovative electrode design, isolation interface regulation and energy transfer mechanism. Summary of the invention

[0006] In order to overcome the shortcomings and deficiencies in the prior art, the object of the present invention is to provide a novel hydrophobic wire electrode electrochemical discharge machining device and method to solve the above technical problems.

[0007] To achieve the above-mentioned purpose, a novel hydrophobic wire electrode electrochemical discharge machining device of the present invention comprises a power supply system, a wire electrode, a guide wheel system, a control system, a hydrophobic layer coating system and a working platform for limiting an external workpiece; and further comprises an auxiliary electrode, a brush and an electrolyte medium, wherein the positive electrode of the power supply system is electrically connected to the auxiliary electrode, and the negative electrode thereof is electrically connected to the wire electrode via the brush, and the wire electrode is driven to reciprocate in both directions or to move in one direction via the guide wheel system;

[0008] The hydrophobic layer coating system includes a hydrophobic solution tank and a hydrophobic solution contained in the hydrophobic solution tank, and a wire electrode driven by a guide wheel system is placed in the hydrophobic solution in the hydrophobic solution tank; the control system is electrically coordinated with the guide wheel system and the power supply system to control the movement direction of the wire electrode driven by the guide wheel system and to adjust the voltage and current parameters of the power supply system; the auxiliary electrode and the workpiece are immersed in an electrolyte medium, and the wire electrode is immersed in an electrolyte medium, so that the hydrophobic coating on the surface of the wire electrode forms an isolation interface on the surface of the wire electrode, and the working platform is located on one side of the wire electrode. Under the action of the power supply system, the wire electrode releases electric sparks to break through the isolation interface, so as to discharge the workpiece on the working platform and remove the surface material of the workpiece.

[0009] Furthermore, the hydrophobic solution includes one or more combinations of silica particles, methanol solvent, ethanol solvent and ammonia catalyst, wherein the mass proportion of silica particles is at least 5%-20%.

[0010] Furthermore, the particle size of the silicon dioxide particles is 20-50 μm, and the sphericity thereof needs to be >95%.

[0011] Furthermore, the formula ratio of the hydrophobic solution is: 15wt% silicon dioxide+0.8wt% polyethylene glycol 600+3:7 methanol / ethanol.

[0012] Furthermore, the electrolyte medium is an alkaline solution, and its chemical formula is: 10wt% NaOH+0.1wt% Triton X-100+5wt% NaNO 3 , the temperature is controlled at 25-40°.

[0013] Furthermore, the electrical discharge machining device also includes an oscilloscope, which is connected to the positive electrode and the auxiliary electrode of the power supply system and is used for real-time monitoring of the current and voltage during the micro-electrochemical electrical discharge machining process.

[0014] Furthermore, in order to replenish the electrolyte medium more quickly, an electrolyte medium supply system is set up, and electrolyte medium solution tanks are set on the wire electrodes on both sides of the workpiece, and a replenishing pump is provided outside the electrolyte medium solution tank, the liquid inlet end of the replenishing pump is connected to the electrolyte medium solution storage tank, and the liquid inlet end of the replenishing pump is placed in the electrolyte medium solution tank, and a liquid level sensor is provided in the electrolyte medium solution tank, and the liquid level sensor is electrically connected to the replenishing pump and the control system; when the liquid level sensor detects that the liquid level in the tank is lower than the minimum liquid level, it sends a liquid shortage signal to the control system, and the control system generates a control logic signal based on the signal and then controls the replenishing pump to perform the replenishing operation.

[0015] Furthermore, the electrical discharge machining device also includes a curing system, which includes an ultraviolet curing lamp arranged on one side of the wire electrode, an ultraviolet light protection cover arranged above the ultraviolet curing lamp, and an optical mirror arranged on the other side of the wire electrode.

[0016] Furthermore, the curing system can be a low-temperature oven. By introducing the wire electrode into the low-temperature oven, setting the baking temperature to 60° to 120°, and the baking time to 200 seconds, the hydrophobic solution on the surface of the wire electrode can be cured to its surface. It should be noted that if a low-temperature oven is used, the wire electrode needs to be immersed in the hydrophobic solution in advance and baked and cured in advance. After the curing is completed, the wire electrode is introduced into the guide wheel system and released to one side of the working platform by unidirectional movement.

[0017] Furthermore, the electrical discharge machining device also includes an auxiliary coating system, which includes an ultrasonic amplitude transformer arranged in the hydrophobic solution tank and a scraper arranged in the hydrophobic solution tank near the lead-out end of the wire electrode, and the scraper is a circular ring knot or a strip-like structure symmetrically distributed along the central axis of the wire electrode.

[0018] Furthermore, the electrolyte medium supply system includes a high-pressure nozzle arranged on one side of the working platform and a jet pump connected to the high-pressure nozzle. The liquid inlet end of the jet pump is placed in the electrolyte medium solution. The jet pump is used to atomize the electrolyte medium solution through the high-pressure nozzle and evenly spray it onto the workpiece and wire electrode surface on the working platform to quickly replenish the electrolyte medium required for electrochemical discharge machining.

[0019] Furthermore, the guide wheel system includes a fixed member, a rotating guide wheel rotatably arranged on the fixed member, a first driving member connected to the rotating guide wheel, and at least two guide wheels rotatably arranged on the fixed member; the guide wheels are sequentially distributed along the movement direction of the wire electrode, and the starting end of the wire electrode is unwound through the rotating guide wheel and sequentially passes through the guide wheels to form a movement path.

[0020] Furthermore, the guide wheel system also includes a winding wheel arranged in cooperation with the rotating guide wheel and a second driving member connected to the winding wheel. After the starting end of the wire electrode is unwound by the rotating guide wheel, it is sequentially wound around the guide wheel and finally recovered by the winding wheel to form a unidirectional motion path.

[0021] Furthermore, the tail end of the wire electrode passes through the rotating guide wheel in the opposite direction via the guide wheel to form a closed loop path, so that the wire electrode reciprocates between the rotating guide wheel and the guide wheel.

[0022] Furthermore, a FBG sensor is embedded in the stress concentration area of ​​the fixing part of the guide wheel system (at the bearing seat of the guide wheel) to monitor the tension at the contact point between the guide wheel and the wire electrode; the FBG sensor is connected to the spectrum demodulation system (such as Micron Optics SM125 demodulator) through armored optical fiber, and the demodulated tension data is transmitted to the control system through the RS485 interface. When the FBG detects abnormal tension (such as a sudden increase of >5N), the control system immediately triggers the emergency braking of the guide wheel (braking time <10ms), and reversely rewinds the wire electrode through the reel (speed 0.5m / s) to prevent wire breakage.

[0023] A novel hydrophobic wire electrode electrochemical discharge machining method of the present invention comprises the following steps:

[0024] S1, providing a power supply system, a wire electrode, a guide wheel system, a control system, a hydrophobic layer coating system, a curing system, a working platform, an auxiliary electrode, a brush and an electrolyte medium, wherein the wire electrode adopts a microcrystalline tungsten wire with a surface treated with plasma microstructure;

[0025] S2, using the first driving member of the guide wheel system, the rotating guide wheel, the guide wheel, the second driving member and the winding wheel to drive the wire electrode to move unidirectionally through the processing area, or only using the first driving member of the guide wheel system, the rotating guide wheel and the guide wheel to drive the wire electrode to move bidirectionally through the processing area;

[0026] S3, allowing the wire electrode driven by the guide wheel system to pass through a hydrophobic solution tank filled with a hydrophobic solution, so that the surface of the wire electrode is coated with the hydrophobic solution, so as to form a hydrophobic coating with self-repairing properties on the surface of the wire electrode;

[0027] S4, immersing the auxiliary electrode and the workpiece in an electrolyte medium, connecting the negative electrode of the power system to the wire electrode via a brush, and connecting the positive electrode to the auxiliary electrode to form a path; applying a pulse voltage by the power system to generate spark discharge between the isolation interface on the surface of the wire electrode and the workpiece to perform electrical discharge machining on the surface of the workpiece, and coating and replenishing the hydrophobic solution by the hydrophobic layer coating system, and constructing the hydrophobic solution on the surface of the wire electrode to form a hydrophobic coating on its surface by the curing system;

[0028] S5, using the self-repairing properties of the hydrophobic coating and the bubbles generated during the electrolysis process to repair the isolation interface, so that the thickness of the isolation interface remains stable to maintain the discharge stability of the wire electrode;

[0029] S6, using the control system to control the guide wheel system to adjust the wire electrode movement speed, and adjust the voltage parameters of the power supply system and the electrolyte medium replenishment frequency to complete the large depth-to-width ratio microstructure processing of the workpiece.

[0030] Furthermore, the curing system in step S4 cures the hydrophobic solution on the surface of the wire electrode by ultraviolet irradiation or 60-120° thermal curing, and the ultraviolet curing time is 0.1-0.2s.

[0031] The principle of the technical solution of the present invention is as follows: the surface of the wire electrode is treated with plasma microstructure to form a nano-scale rough surface (such as honeycomb micropores), and the guide wheel system is used to drive the wire electrode to immerse in a hydrophobic solution tank so that the solution evenly coats the electrode surface. In the alkaline electrolyte medium, the low surface energy characteristics of the hydrophobic coating and the hydrogen / oxygen bubbles generated by the electrolysis reaction synergize to form a stable isolation interface with controllable thickness (5-15μm). The existence of the isolation interface effectively isolates the wire electrode from direct contact with the electrolyte medium, reduces the background noise of the electrolysis current, and at the same time, through the high-pressure nozzle and ultraviolet curing system and the self-healing performance of the hydrophobic solution under the discharge effect, the problem of rupture or excessive thickness of the isolation interface during processing is avoided.

[0032] When a pulse voltage is applied, a high-intensity electric field (>10 6 V / m), the isolation interface is partially broken down to produce a micro plasma discharge channel, and the instantaneous high temperature (>10,000℃) causes the surface material of the workpiece to vaporize or melt and peel off. The device accurately controls the movement trajectory of the wire electrode through the guide wheel system (one-way or two-way circulation), and combines the liquid level sensor and the replenishing pump to replenish the electrolyte medium solution in real time to ensure the stability of electrochemical discharge machining. The curing system (ultraviolet or low-temperature baking) quickly cures the hydrophobic solution to ensure that the hydrophobic coating on the surface of the wire electrode can quickly form an isolation interface in the electrolyte medium to ensure the continuity and stability of the processing. At the same time, the control system adjusts the voltage, current and electrode movement speed, uses optical fiber sensors to monitor the wire electrode tension, suppresses processing vibration, and realizes microstructure processing with a large aspect ratio.

[0033] Beneficial effects of the present invention:

[0034] (1) Improved stability of isolation interface: The self-healing properties of the hydrophobic coating combined with bubble compensation ensure that the thickness fluctuation of the isolation interface is ≤±5μm, and the discharge position deviation is reduced to ±2μm, solving the problem of easy rupture of the isolation interface of traditional ECDM;

[0035] (2) Optimization of processing accuracy and efficiency: Silica nanoparticles (particle size 20-50nm, sphericity >95%) enhance the wear resistance of the coating. Combined with a bidirectional reciprocating guide wheel system, the microstructure aspect ratio is >50:1 and the surface roughness Ra <0.1μm, which improves the processing efficiency by 40%;

[0036] (3) Improvement of energy consumption and adaptability: Alkaline medium formula (containing NaNO 3 Anti-polarizer) reduces the breakdown voltage to 20-50V, reduces the energy consumption per unit material removal by 60%, and is compatible with the processing of insulating / conductive materials (such as silicon carbide and titanium alloy). BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic structural diagram of the electrochemical discharge machining device of the present invention when the wire electrode moves in both directions;

[0038] Figure 2 It is a schematic diagram of the hydrophobic coating of the present invention spontaneously forming an isolation interface and wire electrode discharge machining;

[0039] Figure 3 (a) Schematic diagram of the hydrophobic coating spontaneously forming a uniform isolation interface on the wire electrode;

[0040] Figure 3 (b) Schematic diagram of hydrophobic coating wear and isolation interface damage;

[0041] Figure 3 (c) Schematic diagram of the hydrophobic coating spontaneously repairing the isolation interface and repairing the isolation interface by electrolysis and bubbling;

[0042] Figure 3 (d) is a schematic diagram of the worn hydrophobic coating being repaired by immersing it in a hydrophobic solution;

[0043] Figure 4 This is a schematic diagram of curing the hydrophobic coating on the online electrode of the present invention;

[0044] Figure 5 It is a schematic structural diagram of the electrochemical discharge machining device of the present invention when the wire electrode moves in one direction;

[0045] Figure 6 It is a schematic flow chart of the novel hydrophobic wire electrode electrochemical discharge machining method of the present invention.

[0046] Reference numerals include:

[0047] 1. Power supply system; 2. Wire electrode; 21. Hydrophobic coating; 22. Isolation interface; 23. Bubbles; 3. Guide wheel system; 4. Control system; 41. Oscilloscope; 5. Hydrophobic layer coating system; 6. Working platform; 61. Workpiece; 7. Auxiliary electrode; 8. Brush; 9. Electrolyte medium; 31. Fixing part; 32. Rotating guide wheel; 33. Guide wheel; 34. Winding wheel; 51. Hydrophobic solution tank; 52. Hydrophobic solution; 53. Curing system; 531. UV curing lamp; 532. UV protection cover; 533. Optical mirror; 54. Auxiliary coating system; 541. Servo motor; 542. Ultrasonic amplitude transformer; 543. Wiping part; 55. Jet pump; 56. High-pressure nozzle. DETAILED DESCRIPTION

[0048] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments and drawings. The contents mentioned in the implementation modes are not intended to limit the present invention.

[0049] See also Figures 1 to 6 As shown, a novel hydrophobic wire electrode electrochemical discharge machining device of the present invention comprises a power supply system 1, a wire electrode 2, a guide wheel system 3, a control system 4, a hydrophobic layer coating system 5, and a working platform 6 for limiting an external workpiece 61; it also comprises an auxiliary electrode 7, a brush 8, and an electrolyte medium 9, wherein the positive electrode of the power supply system 1 is electrically connected to the auxiliary electrode 7, and the negative electrode thereof is electrically connected to the wire electrode 2 via the brush 8, and the wire electrode 2 is driven to reciprocate in both directions or to move in one direction via the guide wheel system 3;

[0050] The hydrophobic layer coating system 5 includes a hydrophobic solution tank 51 and a hydrophobic solution 52 contained in the hydrophobic solution tank 51. The wire electrode 2 driven by the guide wheel system 3 is placed in the hydrophobic solution 52 of the hydrophobic solution tank 51; the control system 4 is electrically coordinated with the guide wheel system 3 and the power supply system 1 to control the movement direction of the wire electrode 2 driven by the guide wheel system 3 and to adjust the voltage and current parameters of the power supply system 1; the auxiliary electrode 7 and the workpiece 61 are immersed in the electrolyte medium 9 so that the hydrophobic solution 52 forms an isolation interface 22 on the surface of the wire electrode 2, and the working platform 6 is located on one side of the wire electrode 2. Under the action of the power supply system 1, the wire electrode 2 releases electric sparks to break through the isolation interface 22 to discharge the workpiece 61 on the working platform 6 to remove the surface material of the workpiece 61.

[0051] Specifically, this embodiment uses a microcrystalline tungsten wire with a diameter of 0.1 mm, and the surface is electrolytically polished to enhance the adhesion of the hydrophobic coating 21. The negative electrode of the power system 1 is connected to the brush 8, the positive electrode is connected to the auxiliary electrode 7, and the brush 8 is connected to the wire electrode 2, ensuring that the circuit of the electrochemical discharge machining is in a pass state. The brush 8 is connected to the rotating guide wheel 32 (the brush 8 has a soft characteristic to prevent the brush 8 from damaging the hydrophobic solution 52), and the wire electrode 2 is guided by the guide wheel 33. After passing through three guide wheels 33, it is wound back to the rotating guide wheel 32 to make the wire electrode 2 reciprocate.

[0052] Specifically, the rotating guide wheel 32 is driven by a gear-connecting rod combination to achieve bidirectional rotation. The driving gear of the gear-connecting rod combination is driven by a stepping electrode as a power source. The symmetrical driven gears of the gear-connecting rod combination are meshed with the driving gears and are respectively installed on both sides of the rotating guide wheel 32 to achieve reverse rotation. The connecting rod mechanism of the gear-connecting rod combination connects the driven gear and the sliding rod of the rotating guide wheel 32 to convert the rotational motion of the gear into the rotational motion of the rotating guide wheel 32. The servo motor 541 drives the driving gear to rotate forward and reverse at a preset frequency (such as 0.5Hz alternating). When the driving gear rotates forward, the driven gear on the left drives the connecting rod counterclockwise; when reversed, the driven gear on the right drives the connecting rod clockwise. The connecting rod drives the guide wheel shaft to swing in the slideway to achieve alternating clockwise / counterclockwise rotation.

[0053] Specifically, see Figure 1 As shown, the wire electrode 2 is immersed in the hydrophobic solution 52 of the hydrophobic solution tank 51 under the guidance of the guide wheel system 3, and the wire electrode 2 performs micro-electrochemical discharge machining under the control of the control system 4. In order to replenish the electrolyte medium 9 more quickly, electrolyte medium solution tanks are set on both sides of the workpiece 61, and a refilling pump is provided outside the electrolyte medium solution tank. The liquid inlet end of the refilling pump is connected to the electrolyte medium solution storage tank, and the liquid inlet end of the refilling pump is placed in the electrolyte medium solution tank. A liquid level sensor is provided in the electrolyte medium solution tank, and the liquid level sensor is electrically connected to the refilling pump and the control system 4; when the liquid level sensor detects that the liquid level in the tank is lower than the minimum liquid level, it sends a liquid shortage signal to the control system 4, and the control system 4 generates a control logic signal according to the signal and then controls the refilling pump to perform the refilling operation.

[0054] Since the hydrophobic solution 52 is coated on the surface of the wire electrode 2 by immersion, and since the wire electrode 2 is in a cylindrical shape, the solution can be more evenly coated on the surface of the wire electrode 2 by immersion.

[0055] Specifically, the oscilloscope 41 is connected to the positive electrode of the power supply system 1 and the auxiliary electrode 7, and is used to monitor the current and voltage in real time during the micro-electrochemical discharge machining process. The external workpiece 61 is fixed on the working platform 6, and the machining process is precisely controlled by the control system 4, that is, the guide wheel system 3 is coordinated to drive the circular motion of the wire electrode 2, the power supply system 1 is controlled to supply power to the wire electrode 2, and the hydrophobic layer coating system 5 is controlled to dynamically establish a hydrophobic coating 21 on the surface of the wire electrode 2 to provide a prerequisite for the subsequent formation of an isolation interface 22.

[0056] Specifically, see Figure 1 As shown, the high-pressure nozzle 56 is arranged on one side of the workpiece 61. During the machining process, the electrolyte medium 9 is sprayed on the surface of the wire electrode 2 and the surface of the workpiece 61 through the cooperation of the high-pressure nozzle 56 and the jet pump 55 to further supplement the electrolyte medium 9 required for electrochemical discharge machining.

[0057] Specifically, the hydrophobic solution 52 includes one or more combinations of silica particles, methanol solvent, ethanol solvent, and ammonia catalyst, wherein the mass proportion of silica particles is at least 5%-20%. The particle size of the silica particles is 20-50 μm, and the sphericity rate must be >95%.

[0058] Silica is the core component of the hydrophobic solution 52, providing a rough surface structure to achieve hydrophobic properties. Methanol and ethanol are used as solvents and dispersants to help evenly disperse the silica nanoparticles while reducing the surface tension of the solution to promote uniform coating. Ammonia is used as an alkaline catalyst to adjust the pH of the solution, control the generation and stability of silica particles, and ensure that the size and distribution of the nanoparticles meet the requirements of the hydrophobic coating 21

[0059] Specifically, the formula ratio of the hydrophobic solution 52 is: 15wt% silicon dioxide+0.8wt% polyethylene glycol 600+3:7 methanol / ethanol.

[0060] Specifically, the electrolyte medium 9 is an alkaline solution, and its chemical formula is: 10wt% NaOH+0.1wt% Triton X-100+5wt% NaNO 3 , the temperature is controlled at 25-40°.

[0061] Specifically, the auxiliary electrode 7 and the workpiece 61 are immersed in the electrolyte medium 9, and the wire electrode 2 is connected to the negative pole of the power supply, and a closed loop is formed between them. The hydrophobic solution 52 coated on the surface of the wire electrode 2 forms a hydrophobic coating 21, and the hydrophobic coating 21 spontaneously forms a uniform isolation interface 22 in the electrolyte medium 9. The uniform and thin isolation interface 22 is conducive to the electrochemical discharge machining, thereby improving the machining accuracy. When the working voltage is further increased, a spark discharge phenomenon will be formed on the surface of the wire electrode 2, and the material on the surface of the workpiece 61 will be removed by high-temperature spark discharge, thereby achieving the purpose of machining insulating materials. It is further explained that the materials to be processed are not limited to insulating materials, and difficult-to-process conductive materials can also be processed without being limited by the guiding properties of the materials.

[0062] Specifically, see Figure 3 As shown, since the surface of the wire electrode 2 is coated with a hydrophobic coating 21, a uniform isolation interface 22 can be spontaneously formed on the surface of the wire electrode 2 without the action of electrolysis; by increasing the voltage of the pulse power supply, spark discharge is generated on the surface of the wire electrode 2, and normal electrochemical discharge machining begins. Figure (a) is a schematic diagram of the hydrophobic coating 21 spontaneously forming a uniform isolation interface 22 on the wire electrode 2.

[0063] After a period of processing, the isolation interface 22 formed on the surface of the wire electrode 2 will be damaged, and the hydrophobic coating 21 will also be worn. Figure 3 (b) is a schematic diagram of the wear of the hydrophobic coating 21 and the damage of the isolation interface 22. The damage of the isolation interface 22 can be spontaneously repaired by the hydrophobic coating 21. At the same time, the bubbles 23 generated by electrolysis can repair the damaged isolation interface 22, which is conducive to further maintaining the stability of the isolation interface 22 during the processing and ensuring good processing accuracy and processing quality. Figure 3 (c) is a schematic diagram of the hydrophobic coating 21 spontaneously repairing the isolation interface 22 and repairing the isolation interface 22 by electrolyzing bubbles 23. After the hydrophobic coating 21 on the surface of the wire electrode 2 is worn, it continues to be immersed in the hydrophobic solution tank 51. The wire electrode 2 is driven by the guide wheel system 3 to reciprocate in both directions, thereby dynamically repairing the hydrophobic coating 21. Figure 3 (d) is a schematic diagram of repairing the worn hydrophobic coating 21 by soaking in a hydrophobic solution.

[0064] like Figure 3As shown, (a) is a schematic diagram of the hydrophobic coating 21 spontaneously forming an isolation interface 22 and discharge machining, (b) is a schematic diagram of the isolation interface 22 being damaged and the hydrophobic coating 21 being worn, (c) is a schematic diagram of the isolation interface 22 being spontaneously repaired by the hydrophobic coating 21 and repaired by electrolysis, and (d) is a schematic diagram of the hydrophobic coating 21 being repaired by immersion. Through the reciprocating working process of (a)-(d), the effect of online high-precision machining of insulating materials with a large aspect ratio and online repair of the wire electrode 2 coated with the hydrophobic coating 21 can be achieved.

[0065] For details, please refer to Figure 1 and Figure 4 As shown, the EDM device further includes an auxiliary coating system 54, which includes an ultrasonic horn 542 disposed in the hydrophobic solution tank 51 and a scraper 543 disposed at the lead-out end of the hydrophobic solution tank 51 near the wire electrode 2, and the scraper 543 is two trapezoidal strips symmetrically distributed along the central axis of the wire electrode 2. The power input end of the ultrasonic horn 542 is connected to a servo electrode, and the ultrasonic horn 542 has an ultrasonic generator built in it. The hydrophobic solution 52 is ultrasonically stirred by using the ultrasonic wave generated by the ultrasonic generator and the rotational force driven by the servo electrode, so that the solution is more uniform and the solidification quality of the solution is improved. The scraper 543 is two trapezoidal strips symmetrically disposed on both sides of the wire electrode 2. With the help of the movement of the wire electrode 2, the hydrophobic solution 52 that may be suspended on the surface of the wire electrode 2 can be scraped off to prevent the solution from being solidified unevenly on the surface of the wire electrode 2.

[0066] Specifically, see Figure 4 As shown, the electrical discharge machining device further includes a curing system 53, which includes an ultraviolet curing lamp 531 disposed on one side of the wire electrode 2, an ultraviolet light protection cover 532 disposed above the ultraviolet curing lamp 531, and an optical mirror 533 disposed on the other side of the wire electrode 2. The wire electrode 2 soaked from the hydrophobic solution tank 51 is rapidly cured by the irradiation of the ultraviolet light. At the same time, an optical mirror 533 installed below the ultraviolet lamp allows the ultraviolet rays irradiated on the optical mirror 533 to be reflected and irradiated on the wire electrode 2 for a second time, which can improve the light utilization rate of the ultraviolet lamp, so that the solution is uniformly and rapidly cured on the surface of the wire electrode 2.

[0067] In another embodiment, the hydrophobic solution 52 can be cured using a low-temperature oven. The wire electrode 2 is introduced into the low-temperature oven, and the baking temperature is set to 60° to 120° and the baking time is 200 seconds. The hydrophobic solution 52 on the surface of the wire electrode 2 can be cured to its surface. It should be noted that if a low-temperature oven is used, the wire electrode 2 needs to be immersed in the hydrophobic solution 52 in advance and baked and cured in advance. After the curing is completed, the wire electrode 2 is introduced into the guide wheel system 3 and released to the side of the working platform 6 by unidirectional movement.

[0068] Specifically, see Figure 5 As shown, in another embodiment of the present invention, the moving direction of the wire electrode 2 is unidirectional. Except that the guide wheel system 3 is different from the previous embodiment, the other system configurations are basically the same as the previous embodiment. Figure 5 The wire electrochemical discharge machining is performed in a unidirectional wire-feeding manner, and the used wire electrode 2 is continuously recovered by the wire electrode 2 winding wheel 34; for the wire electrode 2 in the unidirectional system, after the forward-moving wire electrode 2 is used along the length direction, the control system 4 is used to control the first driving member to drive the rotating guide wheel 32 to reversely drive the wire electrode 2, so that the wire electrode 2 moves in the reverse direction for use, and is used repeatedly in the forward and reverse cycles. The wire electrode 2 in the bidirectional system is set in an annular structure, and the wire electrode 2 can be used in a continuous forward rotation or in a continuous reverse rotation. It is further explained that the hydrophobic coating 21 on the surface of the wire electrode 2 of the unidirectional wire electrode 2 system is cured in advance and can be used directly, which further improves the processing efficiency and ensures the processing quality.

[0069] Specifically, the wire electrode 2 hydrophobic solution 52 in this solution can be cured online using an ultraviolet lamp, or the pre-cured wire electrode 2 hydrophobic solution 52 can be electrochemically discharged. The wire electrode 2 in the bidirectional system can be used for reciprocating motion, while the wire electrode 2 in the unidirectional system can only be used once in one direction.

[0070] Specifically, the stress concentration area (the bearing seat of the guide wheel 33) of the fixing part 31 of the guide wheel system 3 is embedded with a FBG sensor to monitor the dynamic tension of the contact point between the guide wheel 33 and the wire electrode 2; the FBG sensor is connected to the spectrum demodulation system (such as Micron Optics SM125 demodulator) through the armored optical fiber, and the demodulated tension data is transmitted to the control system 4 through the RS485 interface. When the FBG detects abnormal tension (such as a sudden increase of >5N), the control system 4 immediately triggers the emergency braking of the guide wheel (braking time <10ms), and reversely rewinds the wire electrode 2 through the reel 34 (speed 0.5m / s) to prevent wire breakage.

[0071] A novel hydrophobic wire electrode electrochemical discharge machining method comprises the following steps:

[0072] S1, providing a power supply system 1, a wire electrode 2, a guide wheel system 3, a control system 4, a hydrophobic layer coating system 5, a curing system 53, a working platform 6, an auxiliary electrode 7, a brush 8 and an electrolyte medium 9, wherein the wire electrode 2 is a microcrystalline tungsten wire with a surface treated with plasma microstructure and a wire diameter of 0.1 mm;

[0073] S2, using the first driving member of the guide wheel system 3, the rotating guide wheel 32, the guide wheel 33, the second driving member and the winding wheel 34 to drive the wire electrode 2 to move unidirectionally through the processing area; in another embodiment, only the first driving member of the guide wheel system 3, the rotating guide wheel 32 and the guide wheel 33 are used to drive the wire electrode 2 to move bidirectionally through the processing area;

[0074] S3, the wire electrode 2 driven by the guide wheel system 3 passes through a hydrophobic solution tank 51 filled with a hydrophobic solution 52, so that the surface of the wire electrode 2 is coated with the hydrophobic solution 52, so as to form a hydrophobic coating 21 with self-repairing performance on the surface of the wire electrode 2;

[0075] S4, immersing the auxiliary electrode 7 and the workpiece 61 in the electrolyte medium 9, connecting the negative electrode of the power supply system 1 to the wire electrode 2 via the brush 8, and connecting the positive electrode to the auxiliary electrode 7 to form a path; applying a pulse voltage by the power supply system 1 to generate spark discharge between the isolation interface 22 on the surface of the wire electrode 2 and the workpiece 61 to perform electrical discharge machining on the surface of the workpiece 61, and coating the hydrophobic solution 52 by the hydrophobic layer coating system 5, and constructing the hydrophobic solution 52 on the surface of the wire electrode 2 to its surface by the curing system 53;

[0076] S5, using the self-repairing property of the hydrophobic coating 21 and the bubbles 23 generated during the electrolysis process to repair the isolation interface 22, so that the thickness of the isolation interface 22 remains stable to maintain the discharge stability of the wire electrode 2;

[0077] S6, using the control system 4 to control the guide wheel system 3 to adjust the movement speed of the wire electrode 2, and adjust the voltage parameters of the power supply system 1 and the electrolyte medium solution replenishment frequency to complete the high aspect ratio microstructure processing of the workpiece 61.

[0078] Specifically, during the bidirectional reciprocating wire feeding process of the wire electrode 2, the hydrophobic coating 21 device repeatedly constructs the hydrophobic coating 21 on the surface of the wire electrode 2, wherein the curing of the hydrophobic coating 21 is irradiated by ultraviolet light, so as to realize the dynamic construction of the hydrophobic surface of the wire electrode 2 during the WECDM process, and realize the continuous and stable discharge process through the dynamically constructed hydrophobic coating 21 wire electrode 2, thereby improving the processing accuracy of the WECDM. Through the above steps, the surface of the wire electrode 2 is subjected to dynamic hydrophobic treatment to achieve stable discharge, which can improve the processing performance of the WECDM and solve the problem of processing narrow grooves with large aspect ratios of difficult-to-conduct materials.

[0079] The present invention discloses an electrochemical discharge machining device and method for a wire electrode 2 based on a hydrophobic coating 21. By coating a hydrophobic coating (with silica composite nanoparticles as functional components) on the surface of the wire electrode 2, a stable isolation interface 22 is induced to form in the machining medium, and a pulsed electric spark discharge mechanism (voltage 50-300V, frequency 10kHz-1MHz) is coupled to achieve micro-nanoscale machining of insulating / difficult-to-machine materials. The system integrates a pulse power supply, a dynamic tension guide wheel system 3 (including FBG sensor real-time monitoring), a self-healing hydrophobic coating system (including ultrasonic stirring and UV curing) and a closed-loop control system 4. The parasitic reaction caused by the electrolyte is suppressed through the dynamic balance mechanism of the isolation interface 22 (electrolytic bubbles 23 cooperate with the self-healing of the hydrophobic coating 21), so that the material removal rate is increased to 0.5-5mm 3 / min, surface roughness Ra≤0.2μm. The innovative introduction of online coating repair strategy (solution tank recoating) and guide wheel emergency braking algorithm (tension mutation threshold 5N, response time <10ms) ensures the continuity and consistency of large aspect ratio microstructure processing, which is not only suitable for glass, ceramics and other processing fields, but also can be extended to the precision processing of silicon nitride, sapphire, etc.

[0080] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, according to the concept of the present invention, there will be changes in the specific implementation methods and application scopes. The content of this specification should not be understood as limiting the present invention.

Claims

1. A novel hydrophobic wire electrode electrochemical discharge machining device, characterized in that: The invention comprises a power supply system (1), a wire electrode (2), a guide wheel system (3), a control system (4), a hydrophobic layer coating system (5) and a working platform (6) for limiting an external workpiece (61); and further comprises an auxiliary electrode (7), a brush (8) and an electrolyte medium (9); the positive electrode of the power supply system (1) is electrically connected to the auxiliary electrode (7), and the negative electrode thereof is electrically connected to the wire electrode (2) via the brush (8); the wire electrode (2) is driven to move in a bidirectional reciprocating motion or in a unidirectional motion via the guide wheel system (3); The hydrophobic coating system (5) comprises a hydrophobic solution tank (51) and a hydrophobic solution (52) contained in the hydrophobic solution tank (51); the wire electrode (2) is placed in the hydrophobic solution (52) in the hydrophobic solution tank (51) so that the hydrophobic solution (52) is disposed on the surface of the wire electrode (2) to form a hydrophobic coating (21); the control system (4) is electrically coordinated with the guide wheel system (3) and the power supply system (1) to control the movement direction of the wire electrode (2) driven by the guide wheel system (3) and to adjust the power supply system (1). The auxiliary electrode (7) and the workpiece (61) are immersed in an electrolyte medium (9); the working platform (6) is located on one side of the wire electrode (2); the hydrophobic coating (21) on the surface of the wire electrode (2) forms an isolation interface (22) between the surface of the wire electrode (2) and the electrolyte medium (9); the wire electrode (2) releases electric sparks under the action of the power supply system (1) to break through the isolation interface (22) to discharge the workpiece (61) on the working platform (6) and remove the surface material of the workpiece (61).

2. The novel hydrophobic wire electrode electrochemical discharge machining device according to claim 1 is characterized in that: The hydrophobic solution (52) comprises silicon dioxide particles, methanol solvent, ethanol solvent and ammonia catalyst, wherein the mass proportion of silicon dioxide particles is at least 5%-20%.

3. The novel hydrophobic wire electrode electrochemical discharge machining device according to claim 1 is characterized in that: The electrical discharge machining device further comprises a curing system (53) arranged in cooperation with the hydrophobic layer coating system (5), wherein the curing system (53) is used to generate ultraviolet light or high-temperature gas to cure the hydrophobic solution (52) coated on the surface of the wire electrode (2) by the hydrophobic layer coating system (5) to form a hydrophobic coating (21).

4. The novel hydrophobic wire electrode electrochemical discharge machining device according to claim 1 is characterized in that: The electrical discharge machining device further comprises an auxiliary coating system (54), wherein the auxiliary coating system (54) comprises an ultrasonic horn (542) arranged in a hydrophobic solution tank (51) and a scraper (543) arranged in the hydrophobic solution tank (51) near the lead-out end of the wire electrode (2), wherein the scraper (543) is a circular ring structure or a strip-shaped structure symmetrically distributed along the central axis of the wire electrode (2).

5. The novel hydrophobic wire electrode electrochemical discharge machining device according to claim 1 is characterized in that: The hydrophobic layer coating system (5) further comprises a high-pressure nozzle (56) arranged on one side of the working platform (6) and a jet pump (55) connected to the high-pressure nozzle (56), wherein the liquid inlet end of the jet pump (55) is placed in the hydrophobic solution (52), and the jet pump (55) is used to atomize the electrolyte medium (9) through the high-pressure nozzle (56) and then evenly spray it onto the surface of the wire electrode (2), so as to quickly provide the electrolyte medium (9) required for the electrochemical reaction.

6. The novel hydrophobic wire electrode electrochemical discharge machining device according to claim 1 is characterized in that: The guide wheel system (3) comprises a fixed part (31), a rotating guide wheel (32) rotatably arranged on the fixed part (31), a first driving part connected to the rotating guide wheel (32), and at least two guide wheels (33) rotatably arranged on the fixed part (31); the guide wheels (33) are sequentially distributed along the moving direction of the wire electrode (2), and the starting end of the wire electrode (2) is unwound via the rotating guide wheel (32) and sequentially passes through the guide wheels (33) to form a moving path.

7. The novel hydrophobic wire electrode electrochemical discharge machining device according to claim 6 is characterized in that: The guide wheel system (3) also includes a winding wheel (34) arranged in cooperation with the rotating guide wheel (32) and a second driving member connected to the winding wheel (34). After the starting end of the wire electrode (2) is unwound by the rotating guide wheel (32), it is wound around the guide wheel (33) in sequence and finally recovered by the winding wheel (34), forming a unidirectional movement path.

8. The novel hydrophobic wire electrode electrochemical discharge machining device according to claim 6 is characterized in that: The tail end of the wire electrode (2) passes through the rotating guide wheel (32) in the reverse direction via the guide wheel (33) to form a closed loop path, so that the wire electrode (2) reciprocates between the rotating guide wheel (32) and the guide wheel (33).

9. A novel hydrophobic wire electrode electrochemical discharge machining method, characterized in that: The following steps are involved: S1, providing a power supply system (1), a wire electrode (2), a guide wheel system (3), a control system (4), a hydrophobic layer coating system (5), a curing system (53), a working platform (6), an auxiliary electrode (7), a brush (8) and an electrolyte medium (9); the wire electrode (2) is made of at least one of tungsten wire, molybdenum wire, copper wire and refractory high entropy alloy, the surface of which is microstructured by plasma, laser, sandblasting or the like; S2, using the first driving member of the guide wheel system (3), the rotating guide wheel (32), the guide wheel (33), the second driving member and the winding wheel (34) to drive the wire electrode (2) to move unidirectionally through the processing area, or only using the first driving member of the guide wheel system (3), the rotating guide wheel (32) and the guide wheel (33) to drive the wire electrode (2) to move bidirectionally through the processing area; S3, allowing the wire electrode (2) driven by the guide wheel system (3) to pass through a hydrophobic solution tank (51) containing a hydrophobic solution (52), so that the surface of the wire electrode (2) is coated with the hydrophobic solution (52), thereby forming a hydrophobic coating (21) on the surface of the wire electrode (2); S4, immersing the auxiliary electrode (7) and the workpiece (61) in an electrolyte medium (9), connecting the negative electrode of the power supply system (1) to the wire electrode (2) via a brush (8), and connecting the positive electrode to the auxiliary electrode (7) to form a passage; dynamically coating the wire electrode (2) with a hydrophobic coating system (5), and constructing a hydrophobic solution (52) on the surface of the wire electrode (2) to form a hydrophobic coating (21) on the surface of the wire electrode (2) using a curing system (53), so that the hydrophobic coating (21) on the surface of the wire electrode (2) spontaneously forms an isolation interface (22) in the electrolyte, and applying a pulse voltage using the power supply system (1) to generate spark discharge between the isolation interface (22) on the surface of the wire electrode (2) having the hydrophobic coating (21) and the workpiece (61), thereby performing electrical discharge machining on the surface of the workpiece (61); S5, utilizing the self-repairing property of the hydrophobic coating (21) and the bubbles (23) generated during the electrolysis process to repair the isolation interface (22), so that the state and thickness of the isolation interface (22) remain stable to maintain the discharge stability of the wire electrode (2).

10. The novel hydrophobic wire electrode electrochemical discharge machining method according to claim 9, characterized in that: The curing system (53) in step S4 cures the hydrophobic solution (52) on the surface of the wire electrode (2) by ultraviolet irradiation or baking at 60-120°, and the ultraviolet curing time is 0.1-0.2s.

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