A single point solid electrolyte electrochemical machining method

Abstract

The application discloses a single-point solid electrolyte electrochemical machining method, which comprises the following steps: preparing a gel solid for single-point solid electrolyte electrochemical machining; manufacturing a single-point solid electrolyte electrochemical machining tool; and machining by using the single-point solid electrolyte electrochemical machining tool. In the machining process, the application uses a solid electrolyte, and a series of problems caused by liquid electrolyte flow and sputtering in traditional electrochemical machining are avoided in the machining environment. The application adopts the solid electrolyte to perform electrochemical machining, so that the electrolyte can be constrained, and local and selective material removal can be realized. The machining tool manufactured by using the gel solid with low roughness is used to perform electrochemical machining, so that good surface quality can be obtained. The single-point solid electrolyte electrochemical machining tool in the application can be conveniently installed on various motion platforms and machine tools, and through trajectory programming, machining of complex shapes can be realized, so that the application range is wide, and the machining efficiency is high.

Description

Technical Field

[0001] This invention belongs to the field of precision and special processing technology, and specifically relates to a single-point solid electrolyte electrochemical processing method. Background Technology

[0002] Electrochemical machining (ECM) is a non-traditional machining technique based on the anodic dissolution of metallic materials. This unique material removal mechanism offers several advantages for ECM, including a material removal rate independent of the material's hardness, relatively high machining efficiency, excellent surface finish, and the absence of machining stress and tool wear. Due to these characteristics, ECM has wide applications in scenarios where conventional machining methods are difficult to perform, particularly in aerospace, medical device, and other fields with extremely high precision and quality requirements.

[0003] Traditional electrochemical machining (ECM) typically employs two methods to achieve specific shapes: one-time forming using a template replication method or machining along a path using small tools. RR in the UK has successfully machined engine fan blades in a single pass using a 360° ECM machine, and other domestic and international companies also utilize ECM for one-time forming as a crucial manufacturing method. However, the template replication method has limitations in terms of part shape complexity, and the templates require cost and time investment, hindering production efficiency. With increasing part shape complexity and the demand for high-efficiency manufacturing, electrochemical milling, which uses small tools to achieve specific shapes along a path, has gained traction. This method combines the advantages of computer numerical control (CNC) and electrochemical machining: zero cathode wear, no macroscopic cutting forces, suitability for machining various difficult-to-machine materials, and high production efficiency due to CNC-controlled surface creation motion. GE in the US has adopted electrochemical milling technology using small tools to form integral bladed disks for aero-engines.

[0004] In electrochemical milling, which uses small tools to shape materials via trajectory motion, the workpiece needs to be immersed in an electrolyte or a nozzle needs to be used to deliver liquid electrolyte to the gap between the electrode and the workpiece. However, the full contact between the liquid electrolyte and the workpiece can cause corrosion of the workpiece material outside the machining area, reducing the localization of material removal. Researchers have proposed electrochemical jet machining (EJCM), which uses a high-pressure electrolyte jet to impact the workpiece. The current is concentrated at the center of the electrolyte jet, resulting in selective machining of the jet area. However, electrolyte splashing requires the machining equipment to have higher corrosion resistance and also causes environmental pollution. Furthermore, hybrid corrosion in the surrounding area is difficult to completely eliminate. Natsu et al. used an electrolyte suction tool to restrict the flow of electrolyte and achieved localized selective electrochemical machining. However, this method is affected by many factors, including liquid flow direction, gas generation, and air intake, making the machining process difficult to control.

[0005] Compared to liquid electrolytes, solid electrolytes can better define the processing area of ​​the workpiece. In 2005, Grzybowski et al. proposed a chemical wet stamping technique, using pre-patterned agarose with high gel strength immersed in the desired etching solution as a stamp, which can create microstructures on metal that are roughly the same as the master stamp. Sun Wen et al. from Xiamen University improved this chemical wet stamping technique, using polyacrylamide gel as a stamp, achieving good results in the etching of glass microfluidic chips. Murata et al. used a solid polymer electrolyte to locally oxidize the surface of GaN, and then removed the material by chemically dissolving the oxide. All of these researchers used solid electrolytes to limit the electrolyte, avoiding the equipment corrosion and environmental pollution problems caused by the flow and sputtering of liquid electrolytes. However, these are all solid electrolyte electrochemical machining within the scope of template replication, requiring the fabrication of solid electrolyte template tools with complex shapes, and only capable of processing quasi-3D structures. The template fabrication process is complex, has a long production cycle, low processing efficiency, and lacks the flexibility of electrochemical milling technology.

[0006] In summary, to date, there is no electrochemical machining technology that can avoid the problems of low machining accuracy, equipment corrosion, and environmental pollution caused by liquid electrolyte flow and sputtering, while also taking into account the advantages of high efficiency, flexibility, high degree of automation, and wide application range of electrochemical milling. Summary of the Invention

[0007] To address the aforementioned problems in existing technologies, this invention provides a single-point solid electrolyte electrochemical processing method that avoids a series of processing accuracy and environmental pollution problems caused by liquid electrolyte sputtering and flow, and achieves localized quantitative material removal with high processing efficiency and wide application range.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: a single-point solid electrolyte electrochemical processing method, comprising the following steps:

[0009] A. Preparation of gel solids for single-point solid electrolyte electrochemical processing

[0010] A1. Prepare a pre-solution of gel solid in a beaker;

[0011] A2. Insert the glass tube into the gel solid pre-formed solution so that the gel solid pre-formed solution fills the specified length of the glass tube;

[0012] A3. Insert a rubber plug into the upper end of the glass tube to form a sealed air pressure column, and then slowly lift out the glass tube filled with the pre-prepared gel solid solution; or put a mold on the lower end of the glass tube and then slowly lift out the glass tube filled with the pre-prepared gel solid solution.

[0013] A4. At room temperature, let the glass tube filled with the pre-prepared gel solid solution stand and wait for the pre-prepared solution to solidify and form a gel solid.

[0014] B. Fabrication of single-point solid electrolyte electrochemical machining tools

[0015] B1. Prepare electrolytes for use in conventional electrochemical machining;

[0016] B2. Immerse the gel solid formed in step A in an electrolyte used for conventional electrochemical processing for a period of time before removing it.

[0017] B3. Fill the glass tube containing the gel solid with electrolyte and insert the cathode to assemble a single-point solid electrolyte electrochemical processing tool.

[0018] C. Processing using a single-point solid electrolyte electrochemical machining tool

[0019] C1. Fix the single-point solid electrolyte electrochemical machining tool on a high-precision motion platform and connect the cathode of the power supply to the platinum wire;

[0020] C2. Fix the workpiece on the force sensor and connect it to the anode of the power supply;

[0021] C3. Adjust the high-precision motion platform to make the single-point solid electrolyte electrochemical machining tool contact the workpiece with a specified pressure;

[0022] C4. Turn on the power switch, adjust the power parameters, and control the high-precision motion platform to move along the specified trajectory to begin processing.

[0023] Furthermore, the gel solid described in step A comprises polyethylene oxide, polyacrylamide, polyvinyl alcohol, or polyacrylonitrile polymer gel solid.

[0024] Furthermore, the specified length mentioned in step A1 is 10-15 mm.

[0025] Furthermore, the surface roughness of the mold described in step A3 is less than Ra 50 nm.

[0026] Furthermore, the mold shape described in step A3 is user-defined, including hemispherical, cylindrical, or conical molds.

[0027] Furthermore, the electrolyte in step B1 includes an acidic electrolyte, an alkaline electrolyte, a neutral electrolyte, or an organic electrolyte.

[0028] Furthermore, the time period described in step B2 is 15-20 minutes.

[0029] Furthermore, the platinum wire described in step B3 needs to be fixed after being inserted into the electrolyte in the glass tube to prevent displacement.

[0030] Furthermore, the specified pressure mentioned in step C3 is an average contact pressure of 5 × 10⁻⁶. 4 -10×10 4 Pa.

[0031] Furthermore, the power supply parameters mentioned in step C4 include waveform, voltage, frequency, and duty cycle.

[0032] Compared with existing processing methods, the outstanding advantages of this invention are:

[0033] 1. Green and environmentally friendly, low cost

[0034] This invention uses a solid electrolyte in the processing, avoiding a series of problems caused by the flow and splashing of liquid electrolytes in traditional electrochemical processing. Traditional electrochemical processing using liquid electrolytes not only incurs the cost of large-scale liquid electrolyte demand but also faces the problem of corrosion of equipment components caused by liquid electrolyte splashing. Furthermore, the management of liquid electrolytes and the treatment of waste liquid are extremely difficult and can easily cause environmental pollution.

[0035] 2. It can achieve localized and selective material removal.

[0036] This invention employs a solid electrolyte for electrochemical machining, wherein the solid electrolyte consists of a polymer matrix and an electrolyte. The polymer matrix is ​​formed by the polymerization and cross-linking of monomeric compounds, and is rich in a three-dimensional network structure formed by chemical bond cross-linking, which can store the electrolyte. The electrolyte can reside within the micro-nano three-dimensional network structure of the polymer matrix without overflowing, thus achieving electrolyte confinement. When the workpiece surface comes into contact with a single-point solid electrolyte electrochemical machining tool, the workpiece also comes into contact with the electrolyte in the tool. Under the action of an electric field, an electrochemical reaction occurs in the area of ​​the workpiece surface in contact with the solid electrolyte, resulting in material removal, while other areas do not experience material removal. Therefore, localized and selective material removal can be achieved.

[0037] 3. Good surface finish

[0038] The single-point solid electrolyte electrochemical machining tool used in this invention forms a hemispherical droplet from a gel solid through the combined forces of gravity, atmospheric pressure, and liquid surface tension of a pre-prepared solution, followed by static solidification. Because the droplet before solidification is sufficiently smooth, the solidified gel exhibits very low surface roughness. When using a mold to assist in gel solidification, the mold surface roughness is less than 50 nm, thus also resulting in a gel with low roughness. Electrochemical machining using a tool made from this low-roughness gel solid yields excellent surface quality.

[0039] 4. The processing method is flexible, convenient, and easy to implement.

[0040] This invention allows for the creation of solid electrolyte electrochemical machining tools of various shapes using molds of different shapes. By adjusting the polymerization and cross-linking reactions, gel solids with varying porosities and hardness can be formed. Furthermore, the reaction rate of the electrochemical machining process can be controlled by adjusting the electrolyte formulation, adapting to different applications and materials. The single-point solid electrolyte electrochemical machining tool of this invention can be easily installed on various motion platforms and machine tools. Through trajectory programming, it can achieve the machining of complex shapes, offering wide applicability and high processing efficiency. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the preparation process of gel solids in a single-point solid electrolyte electrochemical processing tool.

[0042] Figure 2 A schematic diagram of the fabrication process for a single-point solid electrolyte electrochemical machining tool;

[0043] Figure 3 This is a schematic diagram of a single-point solid electrolyte electrochemical processing device.

[0044] Figure 4 Photograph of the single-point solid electrolyte electrochemical processing tool prepared for this invention.

[0045] Figure 5 This is a photograph of the trench obtained by the present invention using a single-point solid electrolyte electrochemical machining tool.

[0046] In the diagram: 1-Beaker, 2-Glass tube, 3-Gel solid pre-prepared solution, 4-Rubber plug, 5-Mold, 6-Gel solid, 7-Electrolyte, 8-Platinum wire, 9-High-precision three-axis motion platform, 10-Clamping fixture, 11-Workpiece, 12-Pressure sensor, 13-Leveling assembly, 14-Power supply, 15-Computer. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to the accompanying drawings.

[0048] Figure 1 This is a schematic diagram illustrating the preparation process of the gel solid in the single-point solid electrolyte electrochemical processing tool according to an embodiment of the present invention. In this embodiment, the gel solid is prepared using polyacrylamide (PAM). Figure 1 In the process, steps a1-a4 involve the natural formation of hemispherical droplets using the gravity, atmospheric pressure, and surface tension of the droplets, followed by solidification to form a gel solid; steps b1-b4 involve the formation of hemispherical droplets using a mold, followed by solidification to form a gel solid. First, a gel solid pre-preparation solution 3 is prepared in beaker 1. The PAM pre-preparation solution is prepared as follows: 100 ml of solution is prepared with 260 mg / ml acrylamide (AM), 6 mg / ml methylenebisacrylamide (BIS), and 5 mg / ml ammonium persulfate (APS). After thorough stirring until completely dissolved, 0.5 μl / ml tetramethylethylenediamine (TEMED) is added as a catalyst and stirred until homogeneous. Insert glass tube 2 into gel solid pre-prepared solution 3 by 10 mm; as shown in step a2, insert rubber plug 4 into the upper end of glass tube 2; as shown in step a3, slowly pull glass tube 2 upwards. At this time, due to the combined effect of droplet gravity, atmospheric pressure and liquid surface tension, there will be a column of gel solid pre-prepared solution 3 inside glass tube 2, and the column of gel solid pre-prepared solution 3 forms a hemispherical droplet downwards; as shown in step a3, wait for gel solid pre-prepared solution 3 to solidify, and solidify to form a gel solid 6 in a single-point solid electrolyte electrochemical processing tool, with the lower end of gel solid 6 being hemispherical; as shown in step a4, remove rubber plug 4.

[0049] Figure 2The flowchart illustrates the process of fabricating a single-point solid electrolyte electrochemical machining tool after the preparation of gel solid 6. In this embodiment, the electrolyte 7 is a phosphoric acid-based electrolyte (85% phosphoric acid + 9% anhydrous ethanol + 6% lactic acid + 0.03–0.4 mol / L ammonium salt solid + 0.04–0.05 mol / L corrosion inhibitor). The lower end of gel solid 6 is immersed in electrolyte 7 for 20 minutes; as shown in step c1, gel solid 6 is removed from electrolyte 7, and electrolyte 7 is filled into glass tube 2 containing gel solid 6; as shown in step c2, platinum wire 8 is inserted as a cathode, and the single-point solid electrolyte electrochemical machining tool is assembled.

[0050] Figure 3 This is a schematic diagram of a single-point solid electrolyte electrochemical machining device according to an embodiment of the present invention. In this embodiment, the workpiece 11 is a copper workpiece. The workpiece 11 is fixed on the pressure sensor 12, and the upper surface of the workpiece 11 is made horizontal by the leveling component 13. The workpiece 11 is then connected to the anode of the power supply 14. The glass tube 2 of the single-point solid electrolyte electrochemical machining tool is clamped using the clamp 10, and the single-point solid electrolyte electrochemical machining tool is fixed on the high-precision three-axis motion platform 9. The platinum wire 8 is connected to the cathode of the power supply 14. The high-precision three-axis motion platform 9 is controlled by the computer 15 to move, so that the gel solid 6 at the lower end of the single-point solid electrolyte electrochemical machining tool contacts the workpiece 11, and the pressure sensor 12 reads 10g. The power parameters of the power supply 14 are set to DC and the voltage is 5V. The high-precision three-axis motion platform 9 is controlled to move according to the set trajectory.

[0051] Figure 4 The single-point solid electrolyte electrochemical processing tool prepared by different formulations in the embodiments of the present invention has a hemispherical gel solid at the lower end. Figure 5 In this embodiment of the invention, the groove is obtained by controlling the machining tool to perform a linear reciprocating motion trajectory for 10 minutes. The groove depth is 12μm and the bottom of the groove is smooth with a roughness of Sa70nm.

[0052] This invention is not limited to this embodiment. Any equivalent concept or modification within the technical scope disclosed in this invention shall be included within the protection scope of this invention.

Claims

1. A single-point solid electrolyte electrochemical processing method, characterized in that: Includes the following steps: A. Preparation of gel solids for single-point solid electrolyte electrochemical processing (6) A1. Prepare a pre-solution (3) of gel solid in beaker (1); A2. Insert the glass tube (2) into the gel solid pre-prepared solution (3) so that the gel solid pre-prepared solution (3) fills the specified length of the glass tube (2); A3. Insert a rubber plug (4) into the upper end of the glass tube (2) to form a sealed air pressure column, and then slowly lift out the glass tube (2) filled with the gel solid pre-prepared solution (3); or put a mold (5) on the lower end of the glass tube (2) and then slowly lift out the glass tube (2) filled with the gel solid pre-prepared solution (3). A4. At room temperature, let the glass tube (2) filled with the gel solid pre-solution (3) stand still and wait for the gel solid pre-solution (3) to solidify and form a gel solid (6). B. Fabrication of single-point solid electrolyte electrochemical machining tools B1. Prepare an electrolyte for conventional electrochemical machining (7); B2. Immerse the gel solid (6) formed in step A in the electrolyte (7) used for conventional electrochemical processing for a period of time and then take it out. B3. Fill the glass tube (2) containing gel solid (6) with electrolyte (7) and insert the cathode to assemble a single-point solid electrolyte electrochemical processing tool. C. Processing using a single-point solid electrolyte electrochemical machining tool C1. Fix the single-point solid electrolyte electrochemical machining tool on the high-precision three-axis motion platform (9) and connect the platinum wire (8) to the cathode of the power supply (14); C2. Fix the workpiece (11) on the force sensor and connect it to the anode of the power supply (14); C3. Adjust the high-precision three-axis motion platform (9) so that the single-point solid electrolyte electrochemical machining tool and the workpiece (11) are in contact with the specified pressure; C4. Turn on the power switch (14), adjust the power parameters, and control the high-precision three-axis motion platform (9) to move along the specified trajectory to start processing.

2. The single-point solid electrolyte electrochemical processing method according to claim 1, characterized in that: The gel solid (6) mentioned in step A includes polyethylene oxide gel solid, polyacrylamide gel solid, polyvinyl alcohol gel solid or polyacrylonitrile polymer gel solid.

3. The single-point solid electrolyte electrochemical processing method according to claim 1, characterized in that: The specified length mentioned in step A1 is 10-15mm.

4. The single-point solid electrolyte electrochemical processing method according to claim 1, characterized in that: The surface roughness of the mold (5) described in step A3 is less than Ra 50nm.

5. The single-point solid electrolyte electrochemical processing method according to claim 1, characterized in that: The shape of the mold (5) mentioned in step A3 is user-defined, including hemispherical mold, cylindrical mold or conical mold.

6. The single-point solid electrolyte electrochemical processing method according to claim 1, characterized in that: The electrolyte (7) mentioned in step B1 includes an acidic electrolyte (7), an alkaline electrolyte (7), a neutral electrolyte (7), or an organic electrolyte (7).

7. The single-point solid electrolyte electrochemical processing method according to claim 1, characterized in that: The time period mentioned in step B2 is 15-20 minutes.

8. The single-point solid electrolyte electrochemical processing method according to claim 1, characterized in that: The platinum wire (8) described in step B3 needs to be fixed after being inserted into the electrolyte (7) in the glass tube (2) to prevent displacement.

9. The single-point solid electrolyte electrochemical processing method according to claim 1, characterized in that: The specified pressure mentioned in step C3 is an average contact pressure of 5 × 10⁻⁶. 4 -10×10 4 Pa.

10. The single-point solid electrolyte electrochemical processing method according to claim 1, characterized in that: The power supply parameters mentioned in step C4 include waveform, voltage, frequency, and duty cycle.

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