A kind of bubble chamber mediated jet plasma processing device and method

Abstract

The application discloses a kind of bubble cavity mediated jet plasma processing device and method, belong to special processing technical field, in view of the poor stability and controllability of jet discharge behavior in prior art, a kind of bubble cavity mediated jet plasma processing device and method of the application, by hollow tube electrode to workpiece spray containing micro-bubble alkaline electrolyte, micro-bubble forms bubble cavity in thin liquid film and preferentially breaks down, induces plasma enhanced base activation depolymerization reaction, realizes low damage processing.The device includes rack, workbench, conducting clamp, liquid and gas supply system, micro-bubble generator and hollow tube electrode, independent supply electrolyte and micro-bubble.When processing, it can be connected to power and medium is input.The application changes passive gas evolution into active bubble control, and the discharge is stable, the damage is low, and the structure is simple.

Description

Technical Field

[0001] This invention relates to the field of special processing technology, and in particular to a cavity-mediated jet plasma processing apparatus and method for insulating hard and brittle materials. Background Technology

[0002] Fused silica (FMS) possesses high transmittance, a low coefficient of thermal expansion, and excellent chemical stability, making it a key material in aerospace optics, microfluidic chips, and glass-based packaging. With the miniaturization of devices, the demand for low-damage fabrication of structures such as micropores and microgrooves on FMS is increasing. However, FMS is also characterized by its hardness, brittleness, insulation, transparency, and chemical inertness, making it extremely difficult to process. Machining easily leads to edge chipping and cracking; laser processing easily creates heat-affected zones; wet etching relies on masks, has poor three-dimensional controllability, and often uses hazardous reagents such as hydrofluoric acid.

[0003] Electrolyte jet machining offers advantages such as non-contact operation and no tool wear, but its traditional mechanism relies on workpiece conductivity and anodic dissolution, making it difficult to directly apply to insulating glass. To address this, jet electrochemical discharge machining (Jet-ECDM) technology emerged. It utilizes a metal nozzle, an electrolyte jet, and a conductive fixture to form a circuit, allowing bubbles electrolytically ejected from the nozzle to be transported by the jet to the glass surface and form a gas-containing thin liquid film. Under the influence of an electric field, dielectric breakdown discharge occurs, thus achieving non-contact machining of insulating materials. However, the bubbles in Jet-ECDM primarily originate from the electrolytically ejected gas from the electrodes. Their quantity, size, and distribution are strongly coupled with process parameters such as voltage and flow rate, making independent control impossible and limiting the stability and controllability of the discharge behavior. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a cavity-mediated jet plasma processing method, which can actively control the plasma formation process to achieve localized low-damage processing of insulating, hard, and brittle materials, and provides an apparatus for this method.

[0005] This invention provides a cavity-mediated jet plasma processing method, comprising: S1. Clean the workpiece to be processed, whose main component is SiO2, dry it, clamp it with a conductive clamp, and connect the hollow tube electrode to an external alkaline electrolyte and gas source through a microbubble generator. S2. Using a hollow tube electrode, an alkaline electrolyte containing exogenous microbubbles is sprayed onto the surface of the workpiece, forming a jet impact thin liquid film on the surface of the workpiece, so that the microbubbles form local bubble cavities in the thin liquid film. S3. Connect the conductive clamp to one pole of the power supply and the hollow tube electrode to the other pole of the power supply, so that an electric field is generated between the hollow tube electrode and the workpiece, and the voltage is increased to produce a local alkali-activated depolymerization reaction. S4. The hollow tube electrode is controlled to move relative to the surface of the workpiece with a certain motion trajectory to perform fixed-point dwelling processing of micro-pits or scanning processing of micro-grooves, thereby achieving localized material removal.

[0006] As an improvement of the present invention, the alkaline electrolyte is an aqueous solution of NaOH with a concentration ranging from 0.5 mol / L to 2 mol / L.

[0007] As an improvement of the present invention, the gas in the exogenous microbubbles is one of air, nitrogen or oxygen, and the gas injection flow rate increases from 0-10 sccm.

[0008] An apparatus for implementing the above-described cavity-mediated jet plasma processing method includes: A workbench is provided with a frame and a conductive clamp for holding the workpiece. A liquid supply and gas supply system, mounted on a frame, includes a liquid supply system for supplying alkaline electrolyte and a gas supply system for supplying exogenous microbubbles, as well as microbubble generators located at the ends of both the liquid supply system and the gas supply system. A processing execution device, mounted on a frame, includes a hollow tube electrode. The inner hole of the hollow tube electrode is connected to the output end of the microbubble generator. The hollow tube electrode is capable of spraying a gas-liquid two-phase mixed medium onto the workpiece. A power supply is provided on the frame, with one pole connected to the conductive clamp and the other pole connected to the hollow tube electrode.

[0009] As an improvement of the present invention, a driving device is also included, which is disposed on the frame and is capable of driving the microbubble generator to move.

[0010] As an improvement of the present invention, the workbench is further provided with a first electrolyte tank, and the conductive clamp is disposed in the first electrolyte tank.

[0011] As an improvement of the present invention, the microbubble generator includes a liquid inlet and an air inlet at the tail end, and a liquid cavity and a venturi tube constriction section disposed inside the liquid cavity; the liquid inlet is connected to the liquid cavity, the air inlet has a micro-through hole inside, and the air inlet is connected to the liquid cavity through the micro-through hole; the venturi tube constriction section is disposed at the front end of the liquid cavity, and the front end of the venturi tube constriction section is the output end.

[0012] As an improvement of the present invention, the liquid supply system includes a second electrolyte tank, and an alkali-resistant micro-liquid pump and a liquid flow meter connected in sequence to the pipeline of the second electrolyte tank, wherein the liquid flow meter pipeline is connected to the liquid inlet.

[0013] As an improvement of the present invention, the gas supply system includes a micro gas flow meter, one end of which is connected to an external gas source, and the other end of which is connected to the gas inlet. Additional aspects and advantages of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention: 1. The bubble cavity-mediated jet plasma processing method provided by this invention does not rely on the electrolytic gas separation of electrodes. Instead, it actively introduces exogenous microbubbles into a hollow tube electrode, making them independent and tunable mediating units for plasma formation. The microbubbles form "bubble cavities" within the thin liquid film of the jet impact zone. Because the dielectric breakdown threshold of gas is lower than that of liquid, the bubble cavities preferentially undergo local breakdown, inducing jet plasma formation. The local micro-heating, transient electric field, and active species effect of the plasma can significantly enhance the alkaline activation and depolymerization reaction of the Si-O-Si network in materials such as fused silica glass by the alkaline electrolyte. This process achieves coupled control of "bubble cavity formation - plasma induction - enhanced chemical reaction," solving the problem of uncontrollable gas phase media in traditional Jet-ECDM, and obtaining more stable discharge behavior and higher quality, low-damage processed surfaces.

[0014] 2. The bubble cavity-mediated jet plasma processing device provided by this invention has a simple structure and is easy to assemble. Through an alkali-resistant micro-liquid pump and a micro-gas flow meter, the electrolyte flow rate and microbubble content can be independently and precisely adjusted, decoupling the key process variable of the bubble cavity from the strong coupling of voltage and flow rate. The hollow tube electrode integrates gas-liquid delivery and electrode functions, naturally matching the spindle rotation and feed functions of existing machine tools such as EDM small hole machines. Its mechanical platform, clamping, and motion mechanism can be directly utilized. Only an independent alkali-resistant liquid and gas supply system and an external pulse power supply are needed to upgrade existing equipment, significantly reducing implementation costs. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the process of a cavity-mediated jet plasma processing method according to the present invention; Figure 2 This is a schematic diagram illustrating the dielectric breakdown principle of the bubble cavity in this invention. Figure 3This is a partial structural diagram of the bubble cavity-mediated jet plasma processing device of the present invention; Figure 4 For the present invention Figure 3 Enlarged view of point A in the middle; Figure 5 This is a schematic diagram of the microbubble generator structure of the present invention; Figure 6 This is a schematic cross-sectional view of the microbubble generator of the present invention; Figure 7 For the present invention Figure 6 Enlarged view of section B in the middle.

[0017] Figure label: Frame 1; Workbench 2; Microbubble generator 3; Liquid inlet 31; Liquid chamber 311; Air inlet 32; Micro-through hole 33; Venturi tube contraction section 34; Hollow tube electrode 4; First electrolyte tank 5; Drive device 6; Conductive clamp 7; Micro gas flow meter 8; Second electrolyte tank 9; Alkali-resistant micro-liquid pump 91; Liquid flow meter 92; Power supply 10. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 Depend on Figure 1-2 A cavity-mediated jet plasma processing method is provided, comprising: S1. Degrease the workpiece to be processed and wash it with deionized water. After drying, clamp it with conductive clamp 7 and position it accurately. Adjust the position of the hollow tube electrode 6 of the machine tool and the initial gap between it and the workpiece. Connect the hollow tube electrode 4 to the alkaline electrolyte and gas source through the microbubble generator 3. S2. Using the hollow tube electrode 4, an alkaline electrolyte containing exogenous microbubbles is sprayed onto the surface of a workpiece whose main component is SiO2, forming a jet impact thin liquid film on the workpiece surface, so that the microbubbles form local bubble cavities in the thin liquid film. S3. Connect the workpiece to one pole of the power supply 10 through the conductive clamp 7, and connect the hollow tube electrode 4 to the other pole of the power supply 10, so that an electric field is generated between the hollow tube electrode 4 and the workpiece, and the voltage is increased to produce a local alkali-activated depolymerization reaction. S4. Control the hollow tube electrode 4 to move relative to the surface of the workpiece with a certain motion trajectory, perform fixed-point dwelling processing of micro pits or scanning processing of micro grooves, realize localized material removal, after processing is completed, turn off the power supply 10, turn off the alkali-resistant micro liquid pump 91 and the air source, and take out the workpiece.

[0020] An electric field is applied between the conductive clamp 7 at the anode and the hollow tube electrode 4 at the cathode, causing ionization and breakdown of the gas within the bubble cavity. Because the plasma is generated and quenched within the extremely small bubble cavity, its energy is highly localized. The resulting transient high temperature and strong electric field effectively reduce the surrounding OH... - The activation energy of the ions greatly accelerates the reaction rate with the SiO2 network, while the scouring effect of the jet can quickly remove the reaction products and expose fresh surfaces.

[0021] In a preferred embodiment, the alkaline electrolyte is an aqueous solution of NaOH with a concentration ranging from 0.5 mol / L to 2 mol / L. NaOH is the key chemical substance driving material removal in this method, and its concentration directly affects the rate of the alkaline-activated depolymerization reaction. During processing, the electrolyte flow rate is controlled at 3-15 ml / min.

[0022] In a preferred embodiment, the gas used for the exogenous microbubbles is one of air, nitrogen, or oxygen, and the gas injection flow rate increases from 0-10 sccm to form a discrete microbubble flow.

[0023] Example 2 Depend on Figure 3-7 Provided is an apparatus for implementing the above-described cavity-mediated jet plasma processing method, comprising: Workbench 2, on which a frame 1 is provided, and a conductive clamp 7 for holding the workpiece is also provided on the workbench 2; The liquid supply and gas supply system is mounted on the frame 1 and includes a liquid supply system for supplying alkaline electrolyte and a gas supply system for supplying external microbubbles, as well as a microbubble generator 3 located at the ends of both the liquid supply system and the gas supply system. The processing execution device is mounted on the frame 1 and includes a hollow tube electrode 4. The inner hole of the hollow tube electrode 4 is connected to the output end of the microbubble generator 3. The hollow tube electrode 4 can spray a gas-liquid two-phase mixed medium onto the workpiece. Before processing, the position of the hollow tube electrode 4 needs to be adjusted to maintain a working gap between its outlet and the workpiece surface. This working gap can be selected between 0.5 mm and 2.0 mm, and optimized according to the voltage and electrolyte concentration. The inner diameter of the hollow tube electrode 4 can be selected from 0.3 mm to 1.0 mm.

[0024] Stainless steel, platinum, or platinum-plated metal capillary tubes can be selected as the hollow tube electrode 4. To prevent premature discharge caused by the electric field concentrating at the sharp electrode outlet edge, the outer wall of the hollow tube electrode 4 can be insulated, for example, by coating it with a layer of polyimide or polytetrafluoroethylene heat shrink tubing, exposing only the inner hole of the end face. By controlling the relative movement between the hollow tube electrode 4 and the workpiece to be processed, the processing of fixed-point micro-pits and scanning micro-grooves can be achieved. By programming and controlling the motion trajectory, the processing of complex micro-patterns can be realized.

[0025] A power supply 10 is mounted on the frame 1. One terminal of the power supply 10 is connected to the conductive clamp 7, and the other terminal is connected to the hollow tube electrode 4. The power supply 10 adopts a pulsed high-voltage output mode, with an output voltage range preferably from 100V to 300V, and is connected in series with a 10-100kΩ current-limiting resistor. Using the pulse mode can effectively control the energy injection of a single pulse, avoiding arc discharge and thermal damage. At the same time, an oscilloscope is used to monitor the electrical signals during processing in real time through voltage and current probes to determine the state of the bubble cavity discharge.

[0026] As a preferred embodiment, the device further includes a driving device 6, which is disposed on the frame 1 and is capable of driving the microbubble generator 3 to move.

[0027] In a preferred embodiment, the workbench 2 is further provided with a first electrolyte tank 5, and the conductive clamp 7 is disposed in the first electrolyte tank 5.

[0028] In a preferred embodiment, the microbubble generator 3 includes a liquid inlet 31 and an air inlet 32 ​​at the tail end, as well as a liquid cavity 311 and a venturi tube constriction section 34 disposed inside the liquid cavity 311. The liquid inlet 31 is connected to the liquid cavity 311, and the air inlet 32 ​​has a micro-through hole 33 inside, through which the air inlet 32 ​​is connected to the liquid cavity 311. The venturi tube constriction section 34 is located at the front end of the liquid cavity 311, and the front end of the venturi tube constriction section 34 is the output end.

[0029] Sodium hydroxide electrolyte is introduced through inlet 31, and micro-holes 33 are integrated inside inlet 32. These micro-holes 33 form a micropore array structure, through which gas is dispersed to form initial microbubbles that come into preliminary contact with the electrolyte. The gas-liquid mixture then enters the venturi tube contraction section 34, where the high-speed shear force generated by the Venturi effect further refines the bubble size and enhances the gas-liquid mixing effect. This device can stably generate electrolytes containing microbubbles with uniform size and controllable gas content, providing a stable gas-liquid two-phase medium for bubble-cavity mediated jet plasma processing.

[0030] The main body of the microbubble generator 3 is made of polyphenylene sulfone (PPSU), which has excellent resistance to corrosion from sodium hydroxide alkaline electrolyte. The entire device is formed using a three-dimensional additive manufacturing process. After the additive manufacturing is completed, the micropore array at the internal gas inlet end is processed with a femtosecond laser to create micropores with a single pore diameter of 30μm, which can achieve uniform gas dispersion and stable initial microbubble generation.

[0031] In a preferred embodiment, the liquid supply system includes a second electrolyte tank 9, and an alkali-resistant micro-liquid pump 91 and a liquid flow meter 92 connected in sequence to the second electrolyte tank 9 via pipelines. The liquid flow meter 92 is connected to the liquid inlet 31 via pipelines. The second electrolyte tank 9 contains sodium hydroxide electrolyte.

[0032] In a preferred embodiment, the gas supply system includes a micro gas flow meter 8, one end of which is connected to an external gas source, and the other end is connected to the air inlet 31. By using the micro gas flow meter 8, the gas flow rate is adjusted from an extremely low flow rate (e.g., 0.1 sccm) to ensure the formation of discrete microbubble flows rather than a continuous gas column.

[0033] The microstructure fabrication of hard and brittle insulating materials such as fused silica glass is a bottleneck restricting the development of fields such as aerospace optics and microfluidics. Although existing jet electrochemical discharge machining (Jet-ECDM) has solved the problem of inducing discharge on the insulating surface, its gaseous medium comes from the electrolytic gas of the nozzle. The generation of bubbles is strongly coupled with voltage and flow rate and cannot be independently controlled, resulting in poor discharge stability and easy thermal damage.

[0034] Compared to Jet-ECDM, this invention provides a cavity-mediated jet plasma processing method that transforms the gas phase medium from "passive electrolytic gas removal" to "active cavity control." By independently and precisely supplying exogenous microbubbles, controllable "cavities" are formed within the thin liquid film of the jet impact zone, serving as discharge-mediating units. When an external electric field is applied, the field preferentially concentrates within the gas phase cavities with low dielectric constants and low breakdown thresholds, inducing breakdown and the formation of jet plasma. The micro-heat, electric field, and active species generated by this plasma locally enhance the alkaline activation and depolymerization reaction of the fused silica glass Si-O-Si network by the alkaline electrolyte, thereby achieving stable, localized, and low-damage material removal. This method establishes a direct control chain of "cavity parameters - breakdown behavior - plasma stability - processing results," fundamentally improving processing quality and controllability.

[0035] This invention discloses a cavity-mediated jet plasma processing method. Using a hollow tube electrode 4, an alkaline electrolyte containing exogenous microbubbles is sprayed through the inner hole of the hollow tube electrode 4 into the surface of a workpiece, such as fused silica glass, whose main component is SiO2. The workpiece is clamped on a conductive fixture 7, and the hollow tube electrode 4 and the conductive fixture 7 are respectively connected to the two poles of a power supply 10. After the gas-liquid mixture reaches the workpiece surface, it forms a jet impacting a thin liquid film. The morphology of the exogenous microbubbles within this film is restricted, transforming into localized gas-phase dielectric cavities, i.e., bubble cavities. These bubble cavities are not simple free bubbles, but rather resident gas cavities formed by the coalescing of discrete microbubbles supplied externally and transported to the workpiece surface by the electrolyte jet within the thin liquid film of the jet impact zone. These bubble cavities, as localized weak dielectric regions, preferentially undergo dielectric breakdown under an applied electric field, forming plasma discharge channels. When the voltage applied by power supply 10 reaches the breakdown threshold, dielectric breakdown preferentially occurs inside the bubble cavity, generating local plasma, thereby enhancing the local alkaline activation depolymerization reaction of the glass by the alkaline electrolyte, achieving efficient and low-damage removal of the material.

[0036] Compared to laser processing, the method proposed in this invention is a non-thermal melting "cold" chemical enhancement processing method that does not generate heat-affected zones or microcracks. Compared to hydrofluoric acid wet etching, this invention uses diluted NaOH solution, which is environmentally friendly, highly safe, and can achieve localized three-dimensional structure processing without a mask. Compared to the traditional Jet-ECDM method, this invention significantly improves discharge stability and processing repeatability through "cavity-mediated" active control, avoiding random discharge and surface damage caused by the instability of electrolytic gas.

[0037] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

Claims

1. A bubble cell mediated jet plasma processing apparatus, characterized by, include: Workbench (2), on which a frame (1) is provided, and on which a conductive clamp (7) for holding the workpiece is also provided; The liquid supply and gas supply system is mounted on the frame and includes a liquid supply system for supplying alkaline electrolyte and a gas supply system for supplying external microbubbles, as well as microbubble generators (3) located at the ends of the liquid supply system and the gas supply system. The processing execution device is mounted on the frame and includes a hollow tube electrode (4). The inner hole of the hollow tube electrode (4) is connected to the output end of the microbubble generator (3). The hollow tube electrode (4) can spray a gas-liquid two-phase mixed medium onto the workpiece. A power supply (10) is provided on the frame, one pole of the power supply (10) is connected to the conductive clamp (7), and the other pole is connected to the hollow tube electrode (4).

2. The processing apparatus of claim 1, wherein It also includes a drive device (6), which is disposed on the frame (1) and is capable of driving the microbubble generator (3) to move.

3. The apparatus of claim 1 wherein, The workbench (2) is also provided with a first electrolyte tank (5), and the conductive clamp (7) is located in the first electrolyte tank (5).

4. The apparatus of claim 1 wherein, The microbubble generator (3) includes a liquid inlet (31) and an air inlet (32) at the tail end, as well as a liquid cavity (311) and a venturi tube constriction section (34) located inside the liquid cavity (311). The liquid inlet (31) is connected to the liquid cavity (311), and the air inlet (32) has a micro-through hole (33) inside. The air inlet (32) is connected to the liquid cavity (311) through the micro-through hole (33). The venturi tube constriction section (34) is located at the front end of the liquid cavity (311), and the front end of the venturi tube constriction section (34) is the output end.

5. The processing apparatus of claim 4, wherein The liquid supply system includes a second electrolyte tank (9), and an alkali-resistant micro-liquid pump (91) and a liquid flow meter (92) connected in sequence to the second electrolyte tank (9). The liquid flow meter (92) is connected to the liquid inlet (31).

6. The apparatus of claim 4 wherein, The gas supply system includes a micro gas flow meter (8), one end of which is connected to an external gas source and the other end is connected to the air inlet (32).

7. A method for implementing the cavity-mediated jet plasma processing apparatus as described in any one of claims 1 to 6, characterized in that, include: S1. Clean the workpiece whose main component is SiO2, dry it and clamp it with a conductive clamp (7). Connect the hollow tube electrode (4) to an alkaline electrolyte and a gas source through a microbubble generator (3). S2. Using the hollow tube electrode (4), an alkaline electrolyte containing external microbubbles is sprayed onto the surface of the workpiece to form a jet impact thin liquid film on the surface of the workpiece, so that the microbubbles form local bubble cavities in the thin liquid film. S3. Connect the conductive clamp (7) to one pole of the power supply (10) and the hollow tube electrode (4) to the other pole of the power supply (10), so that an electric field is generated between the hollow tube electrode (4) and the workpiece, and the voltage is increased to produce a local alkali-activated depolymerization reaction. S4. Control the hollow tube electrode (4) to move relative to the surface of the workpiece with a certain motion trajectory, perform fixed-point dwelling processing of micro pits or scanning processing of micro grooves, and realize localized material removal.

8. The processing method according to claim 7, characterized in that, The alkaline electrolyte is an aqueous solution of NaOH with a concentration ranging from 0.5 mol / L to 2 mol / L.

9. The processing method according to claim 7, characterized in that, The gas in the exogenous microbubbles is one of air, nitrogen, or oxygen, and the gas injection flow rate increases from 0-10 sccm.

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