Electrochemical discharge auxiliary grinding equipment

Abstract

The invention discloses electrochemical discharge auxiliary grinding equipment which is characterized in that the electrochemical discharge auxiliary grinding equipment comprises a frequency converter, a power source, a main shaft, an electricity leading device, a tool electrode chuck, a tool electrode, a nozzle, a workpiece, a workpiece clamp, electrolyte, a water pump, a filter, cooling water and a liquid collecting tank; the tool electrode consists of the following components in parts by weight: 30-100 parts of novel alloy powder, 5-70 parts of copper powder and 5-20 parts of diamond abrasive, the tool electrode adopted by the electrochemical discharge auxiliary grinding machining equipment has high melting point, electric corrosion resistance, strength and hardness, high-temperature mechanical property, wear resistance and corrosion resistance; the electric corrosion loss and abrasive particle abrasion of the diamond tool electrode in the discharge auxiliary grinding machining process can be effectively reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of electrical machining, and in particular relates to an electrochemical discharge assisted grinding processing device and a tool electrode. Background Art

[0002] Metal matrix composites (MMCs) refer to a multiphase material system composed of a metal matrix and other metal, ceramic and other reinforcing phases. Common metal matrix composites include aluminum-based silicon carbide composites (SiCp / Al) and magnesium-based silicon carbide composites (SiCp / Mg). Among them, aluminum-based silicon carbide composites are widely used in aerospace, aviation, automobiles, optical precision devices, and electronics industries due to their high strength, high modulus, high toughness and low density.

[0003] In order to meet the use requirements, metal matrix composites usually need to be processed secondary. However, the huge difference in mechanical properties between the metal matrix and the reinforcement phase makes it a composite material that is extremely difficult to process. At present, the processing methods of metal matrix composites are mainly divided into traditional processing, special processing and composite processing. Traditional processing mainly includes turning, milling, drilling and grinding. Special processing mainly includes electrospark processing, laser processing, abrasive water jet processing, etc. Taking aluminum-based silicon carbide as an example, the traditional processing method has the advantages of simple operation and mature technology, but it is difficult to process high-hardness silicon carbide particles, resulting in severe tool wear and affecting processing efficiency and surface quality. When using special processing methods, although laser processing and abrasive water jet processing can remove efficiently and without tool loss, the processed surface is usually accompanied by serious processing defects and is difficult to use to process parts with complex three-dimensional shapes; although electrospark processing can process parts with complex three-dimensional shapes, it is difficult for electric sparks to vaporize or melt and remove high-melting-point and non-conductive silicon carbide particles, and as the processing proceeds, the debris is difficult to be discharged in time in the narrow discharge gap, resulting in poor processing stability, and both processing efficiency and surface quality are affected; electrochemical discharge machining is a processing method that combines the electrolytic effect and the electric spark discharge effect. Its discharge gap can be 5-10 times larger than that of electric spark machining, which is more conducive to the discharge of debris, so it can obtain a material removal efficiency far higher than that of electric spark and electrolytic machining. However, due to the existence of the electric spark discharge effect, defects such as the recast layer and electrolytic pits on the processed surface still exist.

[0004] In order to improve the processing efficiency and surface quality of metal-based composite materials, researchers in the industry have proposed the introduction of grinding in electrical discharge machining. For example, patent CN202010112088.1 proposes a new type of electrode - bronze-bonded diamond tool electrode, which is used for discharge-assisted grinding of metal-based composite materials. The tool electrode is sintered by diamond abrasive and bronze binder. During the machining process, grinding, electrolytic machining, and electrospark machining are carried out simultaneously. Electrospark machining can remove the matrix material and the reinforcement phase at high temperature to produce pits and heat-affected zones; at the same time, high temperature will soften the material, greatly improving the grinding efficiency. In addition, grinding can remove the pits and heat-affected zones produced by electric sparks, as well as the surface passivation layer produced by electrolytic machining, etc., improving the surface quality while ensuring the continuous progress of electrolytic machining. Electrolytic machining can electrolytically remove electrolytic pits and recast layers, thereby improving the surface quality. However, this method still has a serious problem of electrode loss: on the one hand, due to the existence of electric spark discharge, the tool electrode will inevitably suffer from electro-erosion, especially when high current is used for higher processing efficiency, the electro-erosion problem is more prominent and the electrode life is greatly shortened; on the other hand, the reinforcing phase with high melting point and high hardness will wear the tool electrode. The above two loss modes make the tool electrode prone to deformation or even breakage during the processing, which seriously affects the processing efficiency, surface quality and processing accuracy, and increases the processing cost. Summary of the invention

[0005] In order to solve the problem of electrode loss in discharge-assisted grinding, the present invention proposes an electrochemical discharge-assisted grinding equipment. The tool electrode used is designed into a new alloy with high melting point, corrosion resistance, high strength, hardness, wear resistance, high temperature stability and high temperature creep resistance through special material design and preparation method. The diamond tool electrode prepared by using the new alloy or its copper-based composite material can reduce the problems of corrosion loss and wear, thereby ensuring the processing efficiency, surface quality and processing accuracy.

[0006] The object of the present invention is to provide an electrochemical discharge assisted grinding processing device, the electrochemical discharge assisted grinding processing device comprising a frequency converter (1), a power supply (2), a spindle (3), a power supply device (4), a tool electrode chuck (5), a tool electrode (6), a nozzle (7), a workpiece (8), a workpiece fixture (9), an electrolyte (10), a water pump (11), a filter (12), cooling water (13), and a liquid collecting tank (14); the frequency converter (1) is used to control the rotation speed of the spindle (3); the cooling water (13) is used to cool the spindle (3) in a working state. Cooling down; the tool electrode (6) is clamped on the tool electrode chuck (5); the positive pole of the power supply (2) is connected to the workpiece (8), and the workpiece (8) is fixed by the workpiece clamp (9); the negative pole of the power supply (2) is connected to the tool electrode (6) through the power supply device (4), and as the spindle (3) feeds downward, the tool electrode (6) is immersed in the electrolyte (10); the water pump (11) sucks the used electrolyte (10) and filters it through the filter (12) and stores it in the liquid collection tank (14), and the water pump (11) and the nozzle (7) are used to perform lateral flushing on the processing surface of the workpiece (8);

[0007] Furthermore, the tool electrode (6) is a hollow or solid electrode, and its structure is cylindrical or milling cutter-shaped, etc.;

[0008] Furthermore, the tool electrode (6) is composed of the following components in parts by weight: 30-100 parts of new alloy powder, 5-70 parts of copper powder, and 5-20 parts of diamond abrasive;

[0009] The novel alloy powder is prepared by mixing more than four elements of Cu, Cr, Fe, Mn, Ni, Al, Co, Zn, Mg, Mo and W in a molar ratio of (0.05-1.5):(0.05-1.5), and has a particle size of 5-100 μm.

[0010] The diamond abrasive is one of uncoated diamond, W-coated diamond and Ti-coated diamond, and its particle size is 10-400 μm. The particle size of the diamond abrasive of the present invention helps to improve the processing accuracy and surface quality because they can more easily enter the microstructure of the workpiece for cutting. Too small abrasive particles may increase the conductivity of the electrolyte and cause heat accumulation during the processing, thereby affecting the processing efficiency and the surface quality of the workpiece.

[0011] Furthermore, the method for preparing the tool electrode comprises the following steps:

[0012] (1) Weighing the new alloy powder according to the required weight, and ball milling the new alloy powder in an argon / nitrogen atmosphere for 5-50 hours, with a ball-to-powder ratio of (10-30):1 and a rotation speed of 200-500 rpm;

[0013] (2) Weighing copper powder and diamond abrasive according to the required weight proportions, mixing with the novel alloy powder obtained in step (1) and ball milling, wherein the ball mill speed is 200-450 r / min, the ball milling time is 1-5 h, the protective atmosphere is argon or nitrogen, and the total volume of the raw materials does not exceed 2 / 3 of the volume of the ball mill;

[0014] (3) placing the mixed material obtained in step (2) into a hard alloy cold pressing mold with a size of Φ30 mm for cold pressing to obtain a green body, wherein the green body has a green body density of 40 to 60%, a cold pressing pressure of 100 to 250 MPa, and a cold pressing time of 5 min;

[0015] (4) hot pressing and sintering the green body obtained above, heating to 750-1450°C at a heating rate of 20-100°C / min, keeping the temperature for 5-40min, the sintering pressure in the heating stage is 20-100MPa, the protective atmosphere is argon or nitrogen, and cooling to room temperature with the furnace to obtain the EDM tool electrode.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The tool electrode used in the electrochemical discharge-assisted grinding equipment of the present invention is a high-entropy alloy abrasive electrode, which has a high melting point, electro-corrosion resistance, strength and hardness, high-temperature mechanical properties, wear resistance and corrosion resistance; it can effectively reduce the electro-corrosion loss and abrasive wear of the diamond tool electrode during the discharge-assisted grinding process, thereby ensuring efficient, high-quality and high-precision processing of materials; compared with the diamond tool electrodes currently used for discharge-assisted grinding, the designed diamond tool electrode based on the new alloy has a higher melting point and better electro-corrosion resistance, can better cope with the environment and conditions in discharge-assisted grinding, and reduce the electro-corrosion loss of the diamond tool electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the electrochemical discharge assisted grinding processing equipment of the present invention.

[0019] Figure 2 It is a schematic diagram of the principle of electrochemical discharge assisted grinding processing of the present invention.

[0020] Figure 3 The present invention shows (a) a novel alloy-W-plated diamond abrasive blank sample; (b) a novel alloy-W-plated diamond abrasive electrode sample.

[0021] Figure 4 This is the SEM image of the surface of the new alloy-W-plated diamond abrasive electrode of the present invention.

[0022] Figure 5 The loss and average material removal rate of two tool electrodes in Example 2 of the present invention.

[0023] Figure 6 The wear and average material removal rate of the two tool electrodes in Example 3 of the present invention.

[0024] Figure 7 These are the processing results of high entropy alloy abrasive electrodes with different compositions according to the present invention.

[0025] Figure 8 This is the XRD spectrum of the high entropy alloy FeCrCoNiMo mixed metal powder (before ball milling) and the molded sample of Example 4 of the present invention.

[0026] Fig. 9 This is the macroscopic morphology of the tool electrode end of the high entropy alloy abrasive electrode and the copper-based abrasive electrode after multiple processing in Example 4 of the present invention.

[0027] Fig.10 The present invention is constructed as a cylindrical or milling cutter-shaped hollow tool electrode.

[0028] Description of reference numerals:

[0029] In the figure: 1. frequency converter; 2. power supply; 3. spindle; 4. power supply device; 5. tool electrode chuck; 6. tool electrode; 7. nozzle; 8. workpiece; 9. workpiece fixture; 10. electrolyte; 11. water pump; 12. filter; 13. cooling water; 14. collecting tank; 15. new alloy matrix; 16. diamond abrasive grains; 17. hydrogen bubbles; 18. electric spark discharge; 19. diamond particles; 20. recast layer; 21. metal matrix; 22. reinforcement particles; 23. flushing hole; 24. processing gap. DETAILED DESCRIPTION

[0030] Below is a combination of the embodiments and the attached Figure 1-10 The present invention is described in further detail.

[0031] Example 1

[0032] An electrochemical discharge assisted grinding processing device, comprising a frequency converter (1), a power supply (2), a spindle (3), a power supply device (4), a tool electrode chuck (5), a tool electrode (6), a nozzle (7), a workpiece (8), a workpiece fixture (9), an electrolyte (10), a water pump (11), a filter (12), cooling water (13), and a liquid collecting tank (14); the frequency converter (1) is used to control the rotation speed of the spindle (3); the cooling water (13) is used to cool the spindle (3) in a working state; The tool electrode (6) is clamped on the tool electrode chuck (5); the positive electrode of the power supply (2) is connected to the workpiece (8), and the workpiece (8) is fixed by the workpiece clamp (9); the negative electrode of the power supply (2) is connected to the tool electrode (6) through the power supply device (4), and as the spindle (3) feeds downward, the tool electrode (6) is immersed in the electrolyte (10); the water pump (11) sucks the used electrolyte (10) and filters it through the filter (12) and stores it in the liquid collection tank (14), and the water pump (11) and the nozzle (7) are used to perform lateral flushing on the processing surface of the workpiece (8);

[0033] Through Figure 1 The discharge-assisted grinding processing equipment shown in the figure realizes the processing of metal-based composite materials. The new alloy-bonded diamond tool electrode (6) proposed by the present invention is clamped on the tool electrode chuck (5), the positive electrode of the power supply (2) is connected to the workpiece (8) to be processed, and the negative electrode of the power supply (2) is connected to the new alloy-bonded diamond tool electrode (6) through the power supply device (4). As the spindle (3) is fed downward, the tool electrode (6) is immersed in the electrolyte.

[0034] Figure 2The present invention is a schematic diagram of the principle of discharge-assisted grinding of metal-based composite materials using a new alloy binder diamond tool electrode (6). After the power supply (2) is turned on, the workpiece (8) and the tool electrode (6) begin to undergo an electrochemical reaction in the electrolyte (10). According to Faraday's law of electrolysis, the workpiece (8) as the anode begins to gradually dissolve, and the tool electrode (6) as the cathode begins to produce hydrogen bubbles (17) on the surface. As the reaction proceeds, the resistance between the tool electrode (6) and the surface of the workpiece (8) in the machining gap continues to increase due to the hydrogen bubbles (17) produced by the electrochemical reaction, and the voltage between the two electrodes also increases as the resistance increases. When the inter-electrode voltage reaches the voltage that breaks through the bubbles (17) to produce discharge, an electric spark discharge (18) in the form of an arc is generated. The local instantaneous high temperature formed by the discharge melts and vaporizes the metal material, and finally the discharge removal of the workpiece material is completed. Among the EDM debris formed in this process, there are a large number of melted debris that will be reshaped around the discharge erosion pits, and finally form a recast layer (20) on the machined surface, which seriously affects the machining quality. The new tool electrode proposed by the present invention is a tool electrode with a new alloy matrix (15) composited with diamond abrasive grains (16). A large number of diamond abrasive grains (16) are randomly exposed on the surface of the tool electrode (6) obtained after powder metallurgy and wire cutting. Under the rotation of the spindle (3), the diamond abrasive grains (16) exposed on the surface of the tool electrode will mechanically grind the workpiece during machining. The metal matrix (21) in the metal matrix composite material workpiece is directly removed by the grinding action of the diamond abrasive grains (16), while the removal of the reinforcement particles (22) is carried out in the form of crushing or overall pulling out. Since the high-temperature workpiece matrix material (21) generated by the EDM effect is softened, the grinding effect of the diamond abrasive grains (16) is further improved. At the same time, the non-conductive property of the diamond abrasive grains (16) eliminates the risk of short circuit due to micro-grinding contact during machining, ensuring uninterrupted and stable machining operations. As machining continues, new diamond grains (19) can continue to be exposed from the inside of the tool electrode (6) under the electric spark effect and electrochemical effect to form new cutting edges, thereby maintaining the grinding effect of machining.

[0035] Increasing the rotation speed of the tool electrode (6) helps to enhance the grinding action and improve the chip removal effect. The preferred maximum rotation speed of the spindle (3) can reach 24,000 rpm. The frequency converter (1) is used to control the rotation speed of the spindle (3). At the same time, in order to achieve that the spindle (3) still maintains a high precision under high-speed operation, the preferred spindle precision is 0.003 mm. Cooling water (13) is used to cool the spindle (3) in the working state by water cooling.

[0036] For the electrolyte (10) used in processing, the electrolyte circulation system can suck the used electrolyte through the water pump (11) and filter it through the filter (12) and store it in the liquid collection tank (14), and perform lateral flushing on the processing surface of the workpiece (8) through the water pump (11) and the nozzle (7), thereby completing the recycling of the electrolyte.

[0037] Fig.10 The present invention is a hollow tool electrode in the shape of a cylinder or a milling cutter. Fig.10 (a) is a three-dimensional diagram of the working of the tool electrode 6, Fig.10 (b) is a top view of the tool electrode 6 in operation. The hollow tool electrode (6) is provided with a flushing hole (23). When performing electromachining, the electrolyte (10) can enter from the top of the tool electrode through the flushing hole (23) and then flow into the machining gap (24) at the bottom of the tool electrode, thereby achieving the effect of electrolysis while machining. In addition, the tool electrode is configured to be in the shape of a milling cutter, which can form a comprehensive milling and grinding effect on the workpiece during the electromachining process, and the machining effect will be better.

[0038] Example 2

[0039] The method for preparing the tool electrode (6) comprises the following steps:

[0040] (1) Cr, Fe, Ni, Al, and Co powders (particle size 10 μm) were weighed in a molar ratio of 1:1:1:1:1 and ball-milled for 50 h under argon atmosphere with a ball-to-material ratio of 20:1;

[0041] (2) 90 parts of the new alloy powder, 20 parts of copper powder, and 10 parts of diamond abrasive (particle size 40 μm) were placed in a ball mill and mixed. The ball mill speed was 300 rpm and the ball milling time was 5 h.

[0042] (3) placing the mixed powder obtained above into a cemented carbide cold pressing die for cold pressing at a pressure of 220 MPa for 5 min to obtain a green body with a green body density of 55%;

[0043] (4) The green body obtained above was subjected to hot pressing sintering in a protective atmosphere, and the green body was heated to 1200°C at a heating rate of 80°C / min, and kept at this temperature for 20 minutes, while applying a pressure of 60 MPa. After cooling in the furnace, a new alloy-diamond bulk material was obtained.

[0044] Through testing, the hardness of the alloy material is greater than 800Hv, the compressive strength is greater than 1400MPa, the wear resistance is good, and the electro-corrosion resistance is improved by 94.4% compared with pure Cu. Diamond tool electrodes are processed from the block material prepared above by the electric spark wire cutting method, clamped to the processing equipment, and used in the electrochemical discharge assisted grinding and drilling of high volume fraction aluminum-based silicon carbide composite materials (50vol.%SiCp). The results show that the loss of the new alloy diamond tool electrode is much lower than that of the pure Cu binder diamond tool, and the average material removal rate of the new alloy diamond tool electrode is greatly improved compared with the pure Cu binder diamond tool electrode (see Figure 5 As shown). In summary, the obtained new alloy diamond tool electrode has high wear resistance, electrical corrosion resistance and processing efficiency.

[0045] Figure 3 The novel alloy-W-plated diamond sintered block sample and the novel alloy-W-plated diamond tool electrode sample prepared by the inventor are cylinders with a diameter of 3 mm and a height of 10 mm.

[0046] Figure 4 Surface SEM image and EDS surface scanning image of the new alloy-W-coated diamond tool electrode sample.

[0047] Example 3

[0048] The method for preparing the tool electrode (6) comprises the following steps:

[0049] (1) Cr, Fe, Ni, Al, and Co powders (particle size 10 μm) were weighed in a molar ratio of 1:1:1:1:1 and ball-milled for 50 h under argon atmosphere with a ball-to-material ratio of 20:1;

[0050] (2) 70 parts of the new alloy powder, 40 parts of Cu powder and 10 parts of diamond abrasive (particle size 40 μm) were mixed in a ball mill at a speed of 300 rpm for 5 h;

[0051] (3) placing the mixed powder obtained above into a cemented carbide cold pressing die for cold pressing at a pressure of 220 MPa for 5 min to obtain a green body with a green body density of 60%;

[0052] (4) The green body obtained above was subjected to hot pressing sintering in a protective atmosphere, and the green body was heated to 1100°C at a heating rate of 80°C / min, and kept at this temperature for 20 minutes, while applying a pressure of 60 MPa. After cooling in the furnace, a new alloy-diamond bulk material was obtained.

[0053] Through testing, the hardness of the alloy material is greater than 645Hv, the compressive strength is greater than 1200MPa, the wear resistance is good, and the electro-corrosion resistance is improved by 68.4% compared with pure Cu. Diamond tool electrodes are processed from the block material prepared above by the electric spark wire cutting method, clamped to the processing equipment, and used in the electrochemical discharge assisted grinding and drilling of low volume fraction aluminum-based silicon carbide composite materials (20vol.%SiCp). The results show that the loss of the new alloy / copper bond diamond tool electrode is much lower than that of the pure Cu bond diamond tool, and the average material removal rate of the new alloy / copper bond diamond tool electrode is greatly improved compared with the pure Cu bond diamond tool electrode (see Figure 6 As shown). In summary, the obtained new alloy / copper bond diamond tool electrode has high wear resistance, electrical corrosion resistance and processing efficiency.

[0054] Example 4

[0055] The method for preparing the tool electrode (6) comprises the following steps:

[0056] (1) Cr, Fe, Ni, Co, and Mo powders (particle size 10 μm) were weighed in a molar ratio of 1:1:1:1:1 and ball-milled for 50 h under argon atmosphere with a ball-to-material ratio of 20:1;

[0057] (2) 70 parts of the new alloy powder, 40 parts of Cu powder and 10 parts of diamond abrasive (particle size 40 μm) were mixed in a ball mill at a speed of 300 rpm for 5 h;

[0058] (3) placing the mixed powder obtained above into a cemented carbide cold pressing die for cold pressing at a pressure of 220 MPa for 5 min to obtain a green body with a green body density of 60%;

[0059] (4) The green body obtained above was subjected to hot pressing sintering in a protective atmosphere, and the green body was heated to 1100°C at a heating rate of 80°C / min, and kept at this temperature for 20 minutes, while applying a pressure of 60 MPa. After cooling in the furnace, a new alloy-diamond bulk material was obtained.

[0060] In the preparation process of the high-entropy alloy FeCrCoNiMo sample, the mixed metal powder is ball-milled in a planetary ball mill. Since hard balls of different sizes and masses continuously collide at high speed and generate heat in the ball mill, the alloy powder undergoes plastic deformation after continuous collision and cold welding, resulting in large distortion of the powder lattice and promoting solid solution between atoms of each element. Therefore, the mixed powder after ball milling is verified to have been high-entropy, and is finally sintered through a powder metallurgy process to become a high-entropy alloy sample used in the present invention. Figure 8The XRD patterns of the high entropy alloy FeCrCoNiMo samples prepared in this chapter and the XRD patterns of the mixed metal powders before ball milling. Figure 8 It can be seen that it is difficult to detect the diffraction peaks of each element in the XRD of the formed high entropy alloy FeCrCoNiMo sample. This indicates that the high entropy alloy sample has undergone a high entropy process to form a FeCrCoNiMo high entropy alloy with an FCC structure. At the same time, there are three diffraction peaks in the XRD pattern, corresponding to the three crystal planes (111), (200) and (220) of the face-centered cubic solid solution (FCC).

[0061] Fig. 9 The images shown are the macroscopic morphologies of the tool electrode ends of high entropy alloy abrasive electrodes (Hea / C electrodes) and copper-based abrasive electrodes after multiple machining. Fig. 9 It can be observed in (a) that the center of the end of the high entropy alloy abrasive electrode after processing is convex. This is because the loss of the area near the side wall of the end is greater than that of the center area of ​​the end. It is worth noting that Fig. 9 In (b), the diameter of the end of the copper-based abrasive electrode after processing is larger than the diameter of the rest of the electrode, and it is in a flattened shape extending in all directions. It can be observed from the figure that the color of the outer edge of the end is bright red, and the number of diamond abrasive grains on the end face and the outer edge is less than that on the rest of the electrode side wall; the reason for this electrode morphology is believed to be that a large amount of molten copper during the processing process is quickly re-condensed and formed on the end face of the tool electrode and the surface of the workpiece due to the cooling effect of the working fluid, forming a Fig. 9 (b) shows the abnormal electrode morphology. At the same time, it was found during the experiment that this abnormal electrode morphology continued to intensify as the processing continued, and a layer of carbon in the form of a solid solution would quickly form on the electrode surface during the electric spark discharge, which would reduce the number of diamond particles involved in auxiliary grinding, and ultimately lead to a decrease in material removal efficiency. More importantly, the abnormal morphology of the electrode end would cause the aperture of the small holes prepared in the experiment to become larger, seriously affecting the processing accuracy and threatening the stability of the processing. Therefore, compared with copper-based abrasive electrodes, high-entropy alloy-based abrasive electrodes are more suitable for G-ECDM processing of aluminum-based silicon carbide composites.

[0062] Example 5

[0063] The method for preparing the tool electrode (6) comprises the following steps:

[0064] (1) Cr, Fe, Ni, Al, Co, MO, and W powders (particle size 10 μm) were weighed in a molar ratio of 1:1:1:1:1 and ball-milled for 50 h under argon atmosphere with a ball-to-material ratio of 20:1;

[0065] (2) 90 parts of the new alloy powder, 20 parts of copper powder, and 10 parts of diamond abrasive (particle size 40 μm) were placed in a ball mill and mixed. The ball mill speed was 300 rpm and the ball milling time was 5 h.

[0066] (3) placing the mixed powder obtained above into a cemented carbide cold pressing die for cold pressing at a pressure of 220 MPa for 5 min to obtain a green body with a green body density of 55%;

[0067] (4) The green body obtained above was subjected to hot pressing sintering in a protective atmosphere, and the green body was heated to 1200°C at a heating rate of 80°C / min, and kept at this temperature for 20 minutes, while applying a pressure of 60 MPa. After cooling in the furnace, a new alloy-diamond bulk material was obtained.

[0068] Example 6

[0069] The method for preparing the tool electrode (6) comprises the following steps:

[0070] (1) Cr, Fe, Ni, Al, Co, and Mn powders (particle size 10 μm) were weighed in a molar ratio of 1:1:1:1:1 and ball-milled for 50 h under argon atmosphere with a ball-to-material ratio of 20:1;

[0071] (2) 90 parts of the new alloy powder, 20 parts of copper powder, and 10 parts of diamond abrasive (particle size 40 μm) were placed in a ball mill and mixed. The ball mill speed was 300 rpm and the ball milling time was 5 h.

[0072] (3) placing the mixed powder obtained above into a cemented carbide cold pressing die for cold pressing at a pressure of 220 MPa for 5 min to obtain a green body with a green body density of 55%;

[0073] (4) The green body obtained above was subjected to hot pressing sintering in a protective atmosphere, and the green body was heated to 1200°C at a heating rate of 80°C / min, and kept at this temperature for 20 minutes, while applying a pressure of 60 MPa. After cooling in the furnace, a new alloy-diamond bulk material was obtained.

[0074] like Figure 7In the present invention, the workpiece to be processed is an aluminum-based silicon carbide composite material with a volume fraction of 60% of the particle reinforcement phase, and the electrochemical discharge machining, FeCoNiCrAl as a typical high entropy alloy prepared into an electrode is not effective in G-ECDM processing. Among the selected high entropy alloy electrodes, its MRR is the lowest and TWR is the largest. Through comparative experiments, it was found that the high entropy alloy FeCoNiCrMo abrasive electrode and the high entropy alloy FeCoNiCrMoW abrasive electrode showed a higher material removal rate in G-ECDM, and had a lower loss rate than the other abrasive electrodes in the experiment. However, the FeCoNiCrMoW abrasive electrode experienced electrode breakage, and the tool loss caused by it was much greater than the TWR exhibited during normal processing.

[0075] Comparative Example 1

[0076] The difference between Comparative Example 1 and Example 2 is that the same weight fraction of Cu powder is used to replace the new alloy powder;

[0077] Comparative Example 2

[0078] The difference between Comparative Example 2 and Example 3 is that the same weight fraction of Cu powder is used to replace the abrasive;

[0079] Comparative Example 3

[0080] The only difference between Comparative Example 3 and Example 2 is that the particle size of the new alloy powder is 120 μm;

[0081] Comparative Example 4

[0082] The only difference between Comparative Example 4 and Example 3 is that the particle size of the diamond abrasive is 450 μm;

[0083] Comparative Example 5

[0084] The only difference between Comparative Example 5 and Example 2 is that the particle size of the new alloy powder is 120 μm;

[0085] Comparative Example 6

[0086] The only difference between Comparative Example 6 and Example 3 is that the particle size of the diamond abrasive is 450 μm;

[0087] Comparative Example 7

[0088] The difference between Comparative Example 7 and Example 2 is that the same weight proportions of Cr, Fe, Ni powders are used instead of Cr, Fe, Ni, Al, and Co powders;

[0089] Comparative Example 8

[0090] The difference between Comparative Example 8 and Example 3 is that the same weight proportions of Cr, Fe, Ni powders are used instead of Cr, Fe, Ni, Al, and Co powders;

[0091] The above test data are recorded in Table 1.

[0092] Table 1

[0093]

[0094]

[0095] It can be seen from Table 1 that the particle size and composition of the new alloy powder and the particle size of the diamond abrasive also have a certain influence on the electrode loss and material removal rate. Among them, the change of the composition of the new alloy powder has a relatively large influence on these effects. Compared with the electrodes in Comparative Examples 1-2, the tool electrode of the present invention has very good performance.

[0096] The above content is the best specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An electrochemical discharge assisted grinding device, characterized in that: The electrochemical discharge assisted grinding equipment comprises a frequency converter (1), a power supply (2), a spindle (3), a power supply device (4), a tool electrode chuck (5), a tool electrode (6), a nozzle (7), a workpiece (8), a workpiece fixture (9), an electrolyte (10), a water pump (11), a filter (12), cooling water (13), and a liquid collecting tank (14); the frequency converter (1) is used to control the rotation speed of the spindle (3); the cooling water (13) is used to cool the spindle (3) in a working state; the tool electrode (6 ) is clamped on a tool electrode chuck (5); the positive electrode of the power supply (2) is connected to a workpiece (8), and the workpiece (8) is fixed by a workpiece clamp (9); the negative electrode of the power supply (2) is connected to a tool electrode (6) via a power supply device (4), and as the spindle (3) feeds downward, the tool electrode (6) is immersed in an electrolyte (10); a water pump (11) sucks the used electrolyte (10) and filters it through a filter (12) and stores it in a liquid collection tank (14), and the water pump (11) and the nozzle (7) are used to perform lateral flushing on the machining surface of the workpiece (8).

2. The electrochemical discharge assisted grinding equipment according to claim 1, characterized in that: The tool electrode (6) is a hollow or solid electrode and is constructed in a cylindrical or milling cutter shape.

3. The electrochemical discharge assisted grinding equipment according to claim 2, characterized in that: The tool electrode (6) is composed of the following components in parts by weight: 30-100 parts of new alloy powder, 5-70 parts of copper powder, and 5-20 parts of diamond abrasive; The novel alloy powder is prepared by mixing more than four elements of Cu, Cr, Fe, Mn, Ni, Al, Co, Zn, Mg, Mo and W in a molar ratio of (0.05-1.5):(0.05-1.5), and has a particle size of 5-100 μm. The diamond abrasive is one of uncoated diamond, W-coated diamond and Ti-coated diamond, and its particle size is 10-400 μm.

4. The electrochemical discharge assisted grinding equipment according to claim 3, characterized in that: The method for preparing the tool electrode (6) comprises the following steps: (1) Weigh the new alloy powder according to the required weight, place the new alloy powder in an argon / nitrogen atmosphere and ball mill for 5-50 hours, with a ball-to-powder ratio of (10-30):1 and a rotation speed of 200-500 rpm; (2) Weighing copper powder and diamond abrasive according to the required weight proportions, mixing with the novel alloy powder obtained in step (1) and ball milling, wherein the ball mill speed is 200-450 r / min, the ball milling time is 1-5 h, the protective atmosphere is argon or nitrogen, and the total volume of the raw materials does not exceed 2 / 3 of the volume of the ball mill; (3) placing the mixed material obtained in step (2) into a hard alloy cold pressing mold with a size of Φ30 mm for cold pressing to obtain a green body, wherein the green body has a green body density of 40 to 60%, a cold pressing pressure of 100 to 250 MPa, and a cold pressing time of 5 min; (4) hot pressing and sintering the green body obtained above, heating to 750-1450°C at a heating rate of 20-100°C / min, keeping the temperature for 5-40min, the sintering pressure in the heating stage is 20-100MPa, the protective atmosphere is argon or nitrogen, and cooling to room temperature with the furnace to obtain the EDM tool electrode.

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