Chemical mechanical polishing method and device for nanocrystalline diamond arc blade turning tool

Abstract

The application provides a chemical mechanical polishing method of a nanometer polycrystal diamond arc blade lathe tool, which comprises the following steps: preparing type A and type B polishing liquids; using a glass disc in a water immersion state as a rough polishing disc, placing the nanometer polycrystal diamond arc blade lathe tool on the glass disc through a clamp, setting rough polishing process parameters, and using the type A polishing liquid to perform rough polishing on the nanometer polycrystal diamond arc blade lathe tool, so as to obtain a nanometer polycrystal diamond arc blade lathe tool with a cutting edge roundness radius of 100-200 nm; selecting alumina with inertia and moderate hardness as abrasive grains, placing the nanometer polycrystal diamond arc blade lathe tool on the glass disc through the clamp, setting fine polishing process parameters, and using the type B polishing liquid to polish the nanometer polycrystal diamond arc blade lathe tool, so as to obtain a nanometer polycrystal diamond arc blade lathe tool with a roundness radius of less than 50 nm. The nanometer polycrystal diamond arc blade lathe tool with a sharp blade edge can be obtained by using the application, and the material removal rate is higher.

Description

Technical Field

[0001] This invention relates to the field of chemical mechanical polishing technology, and in particular to a chemical mechanical polishing method and apparatus for a nano-polycrystalline diamond circular arc-shaped cutting tool. Background Technology

[0002] Nanocrystalline diamond (NPD) has a hardness exceeding that of single-crystal diamond and polycrystalline diamond, and its wear resistance is comparable to that of high-wear-resistance directions in single-crystal diamond. Therefore, nanocrystalline diamond circular arc-cut turning tools have broad application prospects. Traditional processing methods for removing nanocrystalline diamond materials mainly include abrasive mechanical grinding, thermochemical grinding, and breccia grinding. Abrasive mechanical grinding creates a relatively sharp grinding edge on the grinding wheel, causing softer diamond particles to be ground off. However, abrasive mechanical grinding has low grinding efficiency. Thermochemical grinding raises the temperature in the grinding zone, causing some diamond grains to graphitize and oxidize. After the reaction, the material's hardness and wear resistance decrease, making it easier to remove. Brokenness grinding creates cracks on the surface of the grinding wheel with inherent defects, causing grains to detach along grain boundaries, undergo localized fracture, or break apart.

[0003] Traditional machining methods require significant grinding forces to achieve effective material removal. However, excessive grinding forces can damage the cutting edge of the tool, making it difficult to reduce the tool's blunt radius to below 100 nm. Furthermore, the mechanical grinding of nanocrystalline diamond tools requires substantial mechanical loads to achieve effective material removal, which leads to the continuous generation of new chips during the grinding process.

[0004] Therefore, to obtain a good cutting edge for nanocrystalline diamond tools, this invention proposes chemical mechanical polishing (CMP), which utilizes the synergistic effect of chemicals and machinery. After chemically oxidizing the material to generate a relatively soft altered layer, effective material removal is achieved using relatively small mechanical abrasion, thus resolving the contradiction between material removal and cutting edge quality in mechanical grinding. By using a glass disc for CMP while continuously adding polishing fluid, the abrasive grains are kept in a free state. The use of abrasive grains that are softer than diamond further reduces the grinding force of the abrasive grains, thereby ensuring effective material removal without causing new cutting edge damage. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a chemical mechanical polishing method for nanocrystalline diamond circular arc-shaped cutting tools. By combining alumina abrasive grains with a wetted glass disc, the grinding force is reduced, preventing the shedding of cutting edge grains from the nanocrystalline diamond circular arc-shaped cutting tool. Based on this, a suitable polishing slurry is prepared, and the chemical mechanical polishing method achieves stable material removal under relatively low grinding force, resulting in an ultra-sharp cutting edge with a blunt radius of less than 50 nm. This resolves the contradiction between material removal and the required grinding force for intergranular bonding strength, as well as the form of the abrasive grains.

[0006] This invention provides a chemical mechanical polishing method for a nano-polycrystalline diamond circular arc-shaped cutting tool, the specific implementation steps of which are as follows:

[0007] S1. Preparation of Type A polishing slurry:

[0008] S11. Place deionized water, phosphoric acid, diamond abrasive and spherical silica into a beaker in sequence. Then use an ultrasonic disperser and a vortex mixer to shake and disperse the reagents in the beaker for 10-20 minutes. Let it stand for 5 minutes and judge whether the solution has separated into layers. If it has separated into layers, continue to shake repeatedly. If there is no separation, a mixed solution is obtained and step S12 is performed.

[0009] S12. Add potassium permanganate to the mixed solution obtained in S11 and stir with a glass rod. Disperse the well-stirred mixed solution by ultrasonication for 5 minutes to obtain type A polishing solution.

[0010] S2. Preparation of Type B polishing slurry:

[0011] S21. Place deionized water, alumina abrasive particles, and spherical silica into a beaker in sequence. Add a certain amount of phosphoric acid using a dropper, followed by a certain amount of ferrous sulfate powder. Use an ultrasonic disperser and a vortex mixer to ultrasonically disperse the reagents in the beaker for 10-20 minutes. Let it stand for 5 minutes and check if the solution has separated into layers. If it has separated into layers, continue to shake repeatedly. If there is no separation, a mixed solution is obtained and proceed to step S22.

[0012] S22. Add a certain amount of NaOH to deionized water, stir and let stand for later use;

[0013] S23. Take a certain amount of 30% hydrogen peroxide solution with a dropper and add it dropwise to the mixed solution obtained in S21. Stir the mixture and then sonicate it for 5 minutes. Next, slowly add the NaOH solution prepared in S22 to the ultrasonically dispersed mixed solution with a dropper until the pH drops to 3 to obtain type B1 polishing solution.

[0014] S24. Deionized water, phosphoric acid, alumina abrasive particles and spherical silica are placed into a beaker in sequence. Then, the reagents in the beaker are dispersed by ultrasonic dispersion and vortex mixer for 10-20 minutes. Let it stand for 5 minutes and judge whether the solution has separated into layers. If it has separated into layers, continue to shake repeatedly. If there is no separation, a mixed solution is obtained and step S25 is performed.

[0015] S25. Add potassium permanganate to the mixed solution obtained in S24 and stir. Then, ultrasonically disperse the well-stirred mixed solution for 5 minutes to obtain type B2 polishing liquid.

[0016] S3. Rough polishing of nano-polycrystalline diamond circular arc-shaped cutting tool using Type A polishing fluid:

[0017] S31. Using a glass disk immersed in water to provide a free environment for abrasive particles, perform chemical mechanical polishing on a nano-polycrystalline diamond circular arc cutting tool.

[0018] S32. Flatten the glass disk and attach it to the grinding machine. Use a fixture to place the nano-polycrystalline diamond circular arc cutting tool on the glass disk.

[0019] S33. Set the rotation speed of the glass disk and apply a certain polishing pressure to the fixture. At the same time, use a peristaltic pump to drop polishing liquid onto the glass disk at a flow rate of 3 ml / min to polish the nano-polycrystalline diamond circular arc cutting tool, and obtain a nano-polycrystalline diamond circular arc cutting tool with a cutting edge blunt radius of 100 mm-200 nm.

[0020] S34. The nano-polycrystalline diamond circular arc cutting tool obtained in step S33 is inspected using a 100x optical microscope to obtain a rough-polished nano-polycrystalline diamond circular arc cutting tool.

[0021] S4. Fine polishing of nano-polycrystalline diamond circular arc-shaped cutting tools using Type B polishing fluid:

[0022] S41. In order to reduce grain shedding from the cutting edge of the nano-polycrystalline diamond circular arc cutting tool during the fine polishing process, alumina with inertness and moderate hardness is selected as the abrasive.

[0023] S42. Flatten the glass disk and attach it to the grinding machine. Use a fixture to place the nano-polycrystalline diamond circular arc cutting tool on the glass disk.

[0024] S43. Set the rotation speed of the glass disk and apply a certain polishing pressure to the fixture. At the same time, use a peristaltic pump to drop polishing liquid onto the glass disk at a flow rate of 3 ml / min to polish the nano-polycrystalline diamond circular arc cutting tool.

[0025] S44. The nano-polycrystalline diamond circular arc-shaped cutting tool obtained in step S33 is inspected using a 500x optical microscope to obtain a finely polished nano-polycrystalline diamond circular arc-shaped cutting tool.

[0026] Preferably, in S1 and S2, the amount of ferrous sulfate added is 1-5 g / 100 ml, the diameter of the diamond abrasive grains is 1-5 μm, and the diameter of the spherical silica is 20 nm.

[0027] Preferably, in the B1 type polishing slurry, the oxidant is hydrogen peroxide with a concentration of 30%, the abrasive particles are aluminum oxide with a diameter of 1-5 micrometers, and the additive is silicon dioxide with a diameter of 20 nm.

[0028] Preferably, in the B2 type polishing slurry, the oxidant is an acidic potassium permanganate solution, the abrasive particles are 1-5 micrometers of alumina, and the additive is silicon dioxide with a diameter of 20 nm.

[0029] Preferably, the acid buffer used in solutions A, B1, and B2 is phosphoric acid, and the alkaline regulator used is sodium hydroxide.

[0030] In another aspect, the present invention provides a chemical mechanical polishing apparatus for a nano-polycrystalline diamond circular arc-edged turning tool, comprising a glass disk, a cast iron disk, a spindle, a weight block, a fixture, a nano-polycrystalline diamond circular arc-edged turning tool, an anti-corrosion fixture, a waste liquid discharge channel, and a waste liquid collector. The lower end of the cast iron disk is fixedly connected to the output end of the spindle, the upper end of the cast iron disk is connected to the first mounting end of the anti-corrosion fixture, the second mounting end of the anti-corrosion fixture is connected to the glass disk, the anti-corrosion fixture is provided with a waste liquid discharge channel, the waste liquid discharge channel is connected to the waste liquid collector, the fixture is located at the upper end of the glass disk, the mounting end of the fixture is provided with a weight block, the fixed end of the fixture is fixedly connected to a base, and the working end of the fixture is fixedly connected to the mounting end of the nano-polycrystalline diamond circular arc-edged turning tool.

[0031] Preferably, the waste liquid collector is symmetrically arranged on both sides of the main shaft, and the rotation centers of the glass disk, the cast iron disk, and the main shaft are on the same straight line.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. This invention uses a method combining diamond and hard glass disk in the rough polishing stage, plus the effect of a strong oxidant, to achieve a material removal rate of 600-800 nm / h, which is a higher material removal rate.

[0034] 2. In the fine polishing stage, this invention uses a glass disc as the polishing disc, changing the abrasive state from the solidified / semi-solidified abrasive grinding of traditional mechanical grinding to free abrasive grinding. At the same time, it uses alumina abrasive with moderate hardness, which fundamentally avoids the grain shedding at the cutting edge of the lathe tool caused by mechanical scratching, reduces the damage to the cutting edge of the nano-polycrystalline diamond arc-shaped lathe tool, and obtains a sharp cutting edge. Attached Figure Description

[0035] Figure 1 This is a flowchart of the chemical mechanical polishing method for a nano-polycrystalline diamond circular arc-shaped cutting tool according to the present invention;

[0036] Figure 2 This is a structural diagram of the chemical mechanical polishing device for the nano-polycrystalline diamond circular arc-shaped cutting tool of the present invention;

[0037] Figures 3a-3d This is a metallographic microscope comparison of the nano-polycrystalline diamond circular arc-edge turning tool after traditional mechanical grinding, chemical mechanical polishing (CMP) rough polishing, and chemical mechanical polishing (CMP) fine polishing in the chemical mechanical polishing method of the present invention.

[0038] Figures 4a-4c This is a comparison of SEM images of the cutting edge of the nano-polycrystalline diamond circular arc-edged lathe tool after traditional mechanical grinding, fine polishing with B1 type polishing liquid, and B2 polishing liquid in the chemical mechanical polishing method of the present invention.

[0039] Figures 5a-5b The images show AFM images of the cutting edge of the nano-polycrystalline diamond circular arc-shaped turning tool after fine polishing with type A polishing solution and type B1 polishing solution in the chemical mechanical polishing method of the present invention.

[0040] Key reference numerals:

[0041] Polishing fluid 1, glass disc 2, cast iron disc 3, spindle 4, load block 5, fixture 6, nano-polycrystalline diamond circular arc cutting tool 7, corrosion-resistant fixture 8, waste liquid discharge channel 9, waste liquid collector 10. Detailed Implementation

[0042] To provide a detailed description of the technical content, objectives, and effects of this invention, the following description will be provided in conjunction with the accompanying drawings.

[0043] The chemical mechanical polishing method for nanocrystalline diamond circular arc-shaped cutting tools is achieved as follows: Figure 1 As shown.

[0044] S1. Prepare type A polishing slurry.

[0045] S2. Prepare type B polishing slurry.

[0046] S3. Use type A polishing fluid to rough polish the nano-polycrystalline diamond circular arc cutting tool 7.

[0047] S4. Use type B polishing fluid to perform fine polishing on the nano-polycrystalline diamond circular arc cutting tool 7.

[0048] Specifically, this invention uses a combination of Type A and Type B polishing slurries to polish a nano-polycrystalline diamond circular arc-edged turning tool 7. During polishing, Type A ensures polishing efficiency, while Type B uses alumina as the abrasive. Alumina ensures the cutting edge radius of the nano-polycrystalline diamond circular arc-edged turning tool 7 reaches 40 nm, and the rake face of the tool is free of scratches and pits. Type A is used for rough polishing, aiming for better cutting edge quality and a high material removal rate; Type B is used for fine polishing, aiming for better rake face surface quality and a small cutting edge blunt radius. Using this combined polishing slurry for two-step chemical-mechanical polishing of the nano-polycrystalline diamond circular arc-edged turning tool 7 ensures both polishing efficiency and excellent cutting edge sharpness.

[0049] Furthermore, the process for preparing type A polishing slurry in step S1 is as follows:

[0050] S11. Place deionized water, phosphoric acid, diamond abrasive grains and spherical silica into a beaker in sequence. Then, use an ultrasonic disperser and a vortex mixer to disperse the reagents in the beaker for 10-20 minutes. Let it stand for 5 minutes and check whether the solution has separated into layers. If it has separated into layers, continue to shake it repeatedly. If there is no separation, a mixed solution is obtained and proceed to step S12.

[0051] S12. Add potassium permanganate to the mixed solution obtained in S11 and stir with a glass rod. Then, ultrasonically disperse the well-stirred mixed solution for 5 minutes to obtain type A polishing solution.

[0052] Furthermore, the process for preparing type B polishing slurry in step S2 is as follows:

[0053] S21. Place deionized water, alumina abrasive particles, and spherical silica into a beaker in sequence. Add a certain amount of phosphoric acid using a dropper, followed by a certain amount of ferrous sulfate powder. Use an ultrasonic disperser and a vortex mixer to ultrasonically disperse the reagents in the beaker for 10-20 minutes. Let it stand for 5 minutes and check if the solution has separated into layers. If it has separated into layers, continue to shake repeatedly. If there is no separation, a mixed solution is obtained and proceed to step S22.

[0054] S22. Add 2g of NaOH to 50ml of deionized water, stir and let stand for later use.

[0055] S23. Take a certain amount of 30% hydrogen peroxide solution using a dropper and add it dropwise to the mixed solution obtained in S21. Stir with a glass rod and ultrasonically disperse the stirred mixed solution for 5 minutes. Then, slowly add the NaOH solution prepared in S22 dropwise to the ultrasonically dispersed mixed solution using a dropper until the pH drops to 3, obtaining type B1 polishing solution.

[0056] S24. Place deionized water, phosphoric acid, alumina abrasive particles, and spherical silica into a beaker in sequence. Then, use an ultrasonic disperser and a vortex mixer to ultrasonically disperse the reagents in the beaker for 10-20 minutes. Let it stand for 5 minutes and check whether the solution has separated into layers. If it has separated into layers, continue to shake it repeatedly. If there is no separation, a mixed solution is obtained and proceed to step S25.

[0057] S25. Add potassium permanganate to the mixed solution obtained in S24 and stir evenly with a glass rod. Perform ultrasonic dispersion on the evenly stirred mixed solution for 5 minutes to obtain type B2 polishing solution.

[0058] Specifically, in S1 and S2, the amount of ferrous sulfate added is 1-5 g / 100 ml, the diameter of the diamond abrasive grains is 1-5 μm, and the diameter of the spherical silica is 20 nm. In the B1 type polishing slurry, the oxidant is 3%-10% hydrogen peroxide, the abrasive grains are 1-5 μm alumina, and the additive is 20 nm diameter silica. In the B2 type polishing slurry, the oxidant is an acidic potassium permanganate solution, the abrasive grains are 1-5 μm alumina, and the additive is 20 nm diameter silica. The acidic buffer used in solutions A, B1, and B2 is phosphoric acid, and the alkaline adjuster used is sodium hydroxide.

[0059] Furthermore, the specific steps for rough polishing the nano-polycrystalline diamond circular arc-shaped cutting tool 7 using type A polishing fluid in S3 include:

[0060] S31. Using the glass disk 2 in a water-immersed state to provide a free environment for the abrasive particles, chemical mechanical polishing is performed on the nano-polycrystalline diamond circular arc cutting tool 7.

[0061] S32. Flatly bond the glass disk 2 onto the grinding machine, and place the nano-polycrystalline diamond circular arc cutting tool 7 on the glass disk 2 using the fixture 6.

[0062] S33. Set the rotation speed of the glass disk 2 to 110 rpm, apply a certain polishing pressure to the fixture 6, and at the same time, use a peristaltic pump to drop polishing liquid 1 onto the glass disk 2 at a flow rate of 3 ml / min to polish the nano-polycrystalline diamond circular arc cutting tool 7, thereby obtaining a nano-polycrystalline diamond circular arc cutting tool 7 with a cutting edge blunt radius of 100 mm-200 nm.

[0063] S34. The nano-polycrystalline diamond circular arc-shaped cutting tool 7 obtained in step S33 is inspected using a 100x optical microscope to obtain a rough-polished nano-polycrystalline diamond circular arc-shaped cutting tool 7.

[0064] Specifically, due to its excessive hardness, diamond, while achieving a high removal rate when polishing a nano-polycrystalline diamond arc-shaped cutting tool 7 using diamond abrasive grains, is prone to large grain detachment, often resulting in more harm than good. This invention utilizes a glass disk 2 and moisture to provide a free state for the diamond abrasive grains, significantly reducing their destructive impact on the cutting edge. Compared to traditional mechanical grinding, chemical mechanical polishing using diamond abrasive grains, a glass disk 2, and a suitable oxidant produces smaller grain detachment, while achieving comparable material removal rates despite significant differences in rotational speed. Therefore, diamond abrasive grains, a glass disk 2, and a suitable oxidant are used for the rough polishing of the nano-polycrystalline diamond arc-shaped cutting tool 7.

[0065] Furthermore, the specific steps for fine polishing the nano-polycrystalline diamond circular arc-shaped cutting tool 7 using type B polishing fluid in S4 include:

[0066] S41. In order to reduce grain shedding from the cutting edge of the nano-polycrystalline diamond circular arc cutting tool 7 during the fine polishing process, alumina with inertness and moderate hardness is selected as the abrasive.

[0067] S42. Flatly bond the glass disk 2 onto the grinding machine, and place the nano-polycrystalline diamond circular arc cutting tool 7 onto the glass disk 2 using the fixture 6.

[0068] S43. Set the rotation speed of the glass disk 2 to 110 rpm, apply a certain polishing pressure to the fixture, and at the same time, use a peristaltic pump to drop polishing liquid 1 onto the glass disk 2 at a flow rate of 3 ml / min to polish the nano-polycrystalline diamond circular arc cutting tool 7.

[0069] S44. The nano-polycrystalline diamond circular arc cutting tool 7 obtained in step S33 is inspected using a 500x optical microscope to obtain a nano-polycrystalline diamond circular arc cutting tool 7 with a blunt radius of less than 50nm.

[0070] Specifically, when polishing the nano-polycrystalline diamond circular arc cutting tool 7 using alumina abrasive grains and glass disk 2 in S4, the alumina abrasive grains have moderate hardness and are in a free state. Even under conditions without oxidants, prolonged abrasive flow polishing will not cause the cutting edge grains in the nano-polycrystalline diamond circular arc cutting tool 7 to fall off. However, when using alumina abrasive grains, glass disk 2, and a suitable oxidant as a combination for chemical mechanical polishing of the nano-polycrystalline diamond circular arc cutting tool 7, an extremely sharp cutting edge can be obtained.

[0071] In a preferred embodiment of the present invention, a chemical mechanical polishing apparatus for a nanocrystalline diamond circular arc-shaped cutting tool 7, such as... Figure 2 As shown, the assembly includes a glass disc 2, a cast iron disc 3, a spindle 4, a weight block 5, a fixture 6, a nano-polycrystalline diamond circular arc cutting tool 7, an anti-corrosion fixture 8, a waste liquid discharge channel 9, and a waste liquid collector 10. The anti-corrosion fixture 8 is customized for different polishing processes. The lower end of the cast iron disc 3 is fixedly connected to the output end of the spindle 4, the upper end of the cast iron disc 3 is connected to the first mounting end of the anti-corrosion fixture 8, and the second mounting end of the anti-corrosion fixture 8 is connected to the glass disc 2. The anti-corrosion fixture 8 has a baffle plate to prevent polishing liquid from splashing. The anti-corrosion fixture 8 is equipped with... Waste liquid discharge channel 9 is connected to waste liquid collector 10, which is fixed on the base and used to collect waste liquid dripping from waste liquid discharge channel 9. Clamp 6 is located at the upper end of glass disk 2. The outlet of polishing liquid 1 and clamp 6 are located on the same side. During the polishing process, polishing liquid 1 is continuously dripped onto glass disk 2. The mounting end of clamp 6 is equipped with a load block 5. The fixed end of clamp 6 is fixedly connected to the base. The working end of clamp 6 is fixedly connected to the mounting end of nano-polycrystalline diamond arc-shaped cutting tool 7. Corrosion-resistant clamp 8 rotates together with spindle 4.

[0072] Furthermore, the waste liquid collector 10 is symmetrically arranged on both sides of the main shaft 4, and the rotation centers of the glass disk 2, the cast iron disk 3 and the main shaft 4 are on the same straight line.

[0073] The following describes in further detail the chemical mechanical polishing method and apparatus for a nano-polycrystalline diamond circular arc-shaped cutting tool of the present invention, with reference to specific embodiments:

[0074] In this embodiment, nanocrystalline diamond blocks are first processed into blanks for nano-polycrystalline diamond circular arc-cutting turning tools through welding, laser cutting, and mechanical grinding. The rake face of the blanks is then ground and polished using the chemical mechanical polishing method of this invention. The specific implementation steps are as follows:

[0075] S1. Prepare type A polishing slurry.

[0076] S11. Place a beaker on a corrosion-resistant horizontal table. Add 70ml of deionized water, 2ml of phosphoric acid, 2g of diamond abrasive, and 2g of spherical silica with a particle size of about 20nm into the beaker in sequence. Then, use an ultrasonic disperser and a vortex mixer to disperse the reagents in the beaker for 10-20 minutes. Let it stand for 5 minutes and check whether the solution has separated into layers. If it has separated into layers, continue to shake it repeatedly. If there is no separation, a mixed solution is obtained and proceed to step S12.

[0077] S12. Using a spatula, add 1-6.4g of potassium permanganate to the mixed solution obtained in S11 and stir with a glass rod. Then, add deionized water to the 100ml mark in the beaker, place the beaker in an ultrasonic disperser and shake for 5 minutes. Remove the beaker and seal the mouth of the beaker with plastic wrap. Place it on a vortex mixer and shake for 5 minutes to obtain type A polishing solution.

[0078] S2. Prepare type B polishing slurry.

[0079] S21. Place a beaker on a corrosion-resistant horizontal table. Add 70ml of deionized water, 2g of alumina abrasive particles, and 2g of spherical silica with a particle size of about 20nm into the beaker. Add 2ml of phosphoric acid using a dropper, followed by 0.5-2g of ferrous sulfate powder. Stir with a glass rod for several tens of seconds, then place the beaker in an ultrasonic disperser and vibrate for 5 minutes. Remove the beaker and seal the mouth with plastic wrap. Place it on a vortex mixer and vibrate for 5 minutes. Let it stand for 5 minutes and check if the solution separates into layers. If it separates into layers, continue to vibrate repeatedly. If there is no separation, a mixed solution is obtained and proceed to step S22.

[0080] S22. Add 2g of NaOH to 50ml of deionized water, stir and let stand for later use.

[0081] S23. Take 5-20 ml of 30% hydrogen peroxide solution using a dropper and slowly add it to the mixed solution obtained in S21. Stir with a glass rod and sonicate the stirred mixed solution for 5 minutes. Then, slowly add the NaOH solution prepared in S22 to the ultrasonically dispersed mixed solution using a dropper until the pH drops to 3. Add deionized water to the 100 ml mark in the beaker to obtain the B1 type polishing solution.

[0082] S24. Place a beaker on a corrosion-resistant horizontal table. Add 70ml of deionized water, phosphoric acid, 2g of alumina abrasive particles, and 2g of spherical silica particles with a diameter of about 20nm into the beaker in sequence. Then, stir with a glass rod and place the beaker in an ultrasonic disperser to vibrate for 5 minutes. Remove the beaker and seal the mouth of the beaker with plastic wrap. Place it on a vortex mixer and vibrate for 5 minutes. Let it stand for 5 minutes and check whether the solution has separated into layers. If it has separated into layers, continue to vibrate repeatedly. If there is no separation, a mixed solution is obtained and proceed to step S25.

[0083] S25. Using a spatula, take 1-6.4g of potassium permanganate powder and add it to the mixed solution obtained in S24. Add deionized water to the beaker to the 100ml mark, stir evenly with a glass rod, and then sonicate the evenly stirred mixed solution for 5 minutes to obtain type B2 polishing solution.

[0084] S3. Use type A polishing fluid to rough polish the nano-polycrystalline diamond circular arc cutting tool 7.

[0085] S31. Using the glass disk 2 in a water-immersed state to provide a free environment for the abrasive particles, chemical mechanical polishing is performed on the nano-polycrystalline diamond circular arc cutting tool 7.

[0086] S32. Flatly adhere the glass disk 2 to the grinding machine, and pour the A-type polishing liquid obtained in S1 into the peristaltic pump container that drips the polishing liquid onto the glass disk 2.

[0087] S33. Turn on the surface polisher, set the rotation speed (90-140 rpm) and planetary amplitude of the glass disk 2, and simultaneously add polishing liquid 1 to the glass disk 2 at a flow rate of 3 ml / min using a peristaltic pump. Finally, place the nano-polycrystalline diamond circular arc cutting tool 7 on the glass disk 2 using the fixture 6, and apply a certain polishing pressure to the fixture 6 to continuously polish the nano-polycrystalline diamond circular arc cutting tool 7.

[0088] S34. During the polishing process in S33, observe the nano-polycrystalline diamond circular arc cutting tool 7 obtained in step S33 every 2 hours using a metallographic microscope until no obvious defects are observed using a 100x optical microscope. Then, first remove the fixture 6, and then turn off the peristaltic pump and the surface polisher in sequence to obtain the rough polished nano-polycrystalline diamond circular arc cutting tool 7. At this time, the cutting edge blunt radius of the nano-polycrystalline diamond circular arc cutting tool 7 is 100mm-200nm.

[0089] S4. Use type B polishing fluid to perform fine polishing on the nano-polycrystalline diamond circular arc cutting tool 7.

[0090] S41. In order to completely avoid grain shedding from the cutting edge of the nano-polycrystalline diamond circular arc cutting tool 7 during the fine polishing process, alumina with inertness and moderate hardness is selected as the abrasive.

[0091] S42. Flatly adhere the glass disk 2 to the grinding machine, and pour the B1 type polishing liquid obtained in S23 or the B2 type polishing liquid obtained in S25 into the peristaltic pump that drips polishing liquid onto the glass disk 2.

[0092] S43. Turn on the surface polisher, set the rotation speed (90-140 rpm) and planetary amplitude of the glass disk 2, and simultaneously add polishing liquid 1 to the glass disk 2 at a flow rate of 3 ml / min using a peristaltic pump. After the polishing disk is wetted, carefully place the fixture 6 on the polishing disk 2 and apply a certain polishing pressure to the fixture 6 to polish the nano-polycrystalline diamond circular arc cutting tool 7.

[0093] S44. During the polishing process in S43, observe the material every 2 hours using a metallographic microscope until no obvious defects are observed in the nanocrystalline diamond circular arc-shaped cutting tool 7 obtained in step S43 using a 500x optical microscope. Then, first remove the fixture 6, then stop the rotation of the spindle 4 in the surface polishing machine, and then turn off the peristaltic pump and the surface polishing machine in sequence. At this point, the blunt radius of the nanocrystalline diamond circular arc-shaped cutting tool 7 is approximately 50 nm.

[0094] Metallurgical microscope comparison images of the nano-polycrystalline diamond circular arc-edged lathe tool obtained using this invention and the nano-polycrystalline diamond circular arc-edged lathe tool 7 obtained by conventional mechanical grinding, as shown below. Figures 3a-3d As shown, Figure 3a The images are metallographic microscope images of a nano-polycrystalline diamond circular arc-edged lathe tool 7 obtained by conventional mechanical grinding. The left image is an optical image of the rake face of the nano-polycrystalline diamond circular arc-edged lathe tool 7 under a 200x microscope, and the right image is an optical image of the flank face of the nano-polycrystalline diamond circular arc-edged lathe tool 7 under a 500x microscope. Figure 3b The images are metallographic microscope images of the nano-polycrystalline diamond circular arc-edged turning tool 7 obtained after the rough polishing process using liquid A in this invention. The left image is an optical image of the front face of the nano-polycrystalline diamond circular arc-edged turning tool 7 under a 200x microscope, and the right image is an optical image of the back face of the nano-polycrystalline diamond circular arc-edged turning tool 7 under a 500x microscope. Figure 3c The images are metallographic microscope images of the nano-polycrystalline diamond circular arc-edge turning tool 7 obtained after the fine polishing process using B1 liquid (special Fenton polishing liquid) in this invention. The left image is an optical image of the front cutting face of the nano-polycrystalline diamond circular arc-edge turning tool 7 under a 200x lens, and the right image is an optical image of the back cutting face of the nano-polycrystalline diamond circular arc-edge turning tool 7 under a 500x lens. Figure 3d The images shown are metallographic microscope images of the nano-polycrystalline diamond circular arc-edge turning tool 7 obtained after the fine polishing process using B2 liquid (a specially formulated potassium permanganate polishing liquid) according to the present invention. The left image is an optical image of the front face of the nano-polycrystalline diamond circular arc-edge turning tool 7 under a 200x microscope, and the right image is an optical image of the back face of the nano-polycrystalline diamond circular arc-edge turning tool 7 under a 500x microscope.

[0095] from Figure 3a It can be seen that the nano-polycrystalline diamond circular arc-shaped cutting tool 7 obtained by traditional mechanical grinding exhibits obvious chipping under a metallographic microscope; from Figure 3b It can be seen that after the rough polishing process of this invention, the cutting edge quality of the nano-polycrystalline diamond arc-shaped turning tool 7 has been significantly improved. Figure 3b The image on the right shows that the chipping of the nano-polycrystalline diamond circular arc-shaped cutting tool 7 is extremely minor. Figure 3bAs can be seen from the left image, the rough polishing process caused deep scratches on the rake face of the nano-polycrystalline diamond circular arc-edged turning tool 7, therefore, further fine polishing of the nano-polycrystalline diamond circular arc-edged turning tool 7 is required; from Figure 3c As can be seen from the 3D images, regardless of whether the B1 or B2 polishing slurry of this invention is used for fine polishing, no defects are observed on either the rake face or the flank face of the finished nanocrystalline diamond circular arc-cutting turning tool 7 under a metallographic microscope. The above data demonstrates that this invention effectively improves the quality of the nanocrystalline diamond circular arc-cutting turning tool 7.

[0096] Figure 4 shows a comparison of SEM (scanning electron microscope) images of the nano-polycrystalline diamond circular arc-edge turning tool obtained using the present invention and the nano-polycrystalline diamond circular arc-edge turning tool 7 obtained by conventional mechanical grinding. Figure 4a SEM image of the nano-polycrystalline diamond circular arc-cut turning tool 7 prepared by mechanical grinding; Figure 4b SEM image of nano-polycrystalline diamond circular arc-shaped turning tool 7, which was finely polished using B1 liquid (special Fenton polishing liquid); Figure 4c SEM image of a nano-polycrystalline diamond circular arc-shaped turning tool 7, prepared by fine polishing with B2 solution (a specially formulated potassium permanganate polishing solution). From Figure 4a It can be seen that the cutting edge of tools obtained by traditional mechanical grinding has dense grain shedding, and the microscopic cutting edge is not sharp; from Figure 4b as well as Figure 4c It can be seen that, regardless of whether B1 or B2 polishing slurry is used, the cutting edge of the finished nano-polycrystalline diamond circular arc-edged turning tool 7 remains very sharp even under a scanning electron microscope, with no obvious chipping observed. The above data demonstrates that this invention effectively improves the cutting edge sharpness of the nano-polycrystalline diamond circular arc-edged turning tool 7.

[0097] The AFM (Atomic Force Microscopy) images and blunt radius data of the nano-polycrystalline diamond circular arc-edge turning tool obtained using this invention and the nano-polycrystalline diamond circular arc-edge turning tool 7 obtained by conventional mechanical grinding are shown below. Figures 5a-5b As shown, Figure 5a AFM image and blunt radius data of the nano-polycrystalline diamond circular arc cutting tool 7 prepared by conventional mechanical grinding show that the blunt radius of the nano-polycrystalline diamond circular arc cutting tool 7 is 116nm. Figure 5b The AFM image and blunt radius data of the nano-polycrystalline diamond circular arc cutting tool 7, which was finely polished using type B1 polishing fluid, show that the blunt radius of the nano-polycrystalline diamond circular arc cutting tool 7 is 48 nm. Figure 5 shows that the present invention can effectively reduce the blunt radius of the cutting edge of the nano-polycrystalline diamond circular arc cutting tool 7.

[0098] The above comparisons demonstrate the superiority and practicality of this invention.

[0099] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A chemical mechanical polishing method for a nano-polycrystalline diamond circular arc-shaped cutting tool, characterized in that, The specific implementation steps are as follows: S1. Preparation of Type A polishing slurry: S11. Place deionized water, phosphoric acid, diamond abrasive and spherical silica into a beaker in sequence. Then use an ultrasonic disperser and a vortex mixer to shake and disperse the reagents in the beaker for 10-20 minutes. Let it stand for 5 minutes and judge whether the solution has separated into layers. If it has separated into layers, continue to shake repeatedly. If there is no separation, a mixed solution is obtained and step S12 is performed. S12. Add potassium permanganate to the mixed solution obtained in S11 and stir with a glass rod. Disperse the well-stirred mixed solution by ultrasonication for 5 minutes to obtain type A polishing solution. S2. Preparation of Type B polishing slurry: S21. Place deionized water, alumina abrasive particles, and spherical silica into a beaker in sequence. Add a certain amount of phosphoric acid using a dropper, followed by a certain amount of ferrous sulfate powder. Use an ultrasonic disperser and a vortex mixer to ultrasonically disperse the reagents in the beaker for 10-20 minutes. Let it stand for 5 minutes and check if the solution has separated into layers. If it has separated into layers, continue to shake repeatedly. If there is no separation, a mixed solution is obtained and proceed to step S22. S22. Add a certain amount of NaOH to deionized water, stir and let stand for later use; S23. Take a certain amount of 30% hydrogen peroxide solution with a dropper and add it dropwise to the mixed solution obtained in S21. Stir the mixture and then sonicate it for 5 minutes. Next, slowly add the NaOH solution prepared in S22 to the ultrasonically dispersed mixed solution with a dropper until the pH drops to 3 to obtain type B1 polishing solution. S24. Deionized water, phosphoric acid, alumina abrasive particles and spherical silica are placed into a beaker in sequence. Then, the reagents in the beaker are dispersed by ultrasonic dispersion and vortex mixer for 10-20 minutes. Let it stand for 5 minutes and judge whether the solution has separated into layers. If it has separated into layers, continue to shake repeatedly. If there is no separation, a mixed solution is obtained and step S25 is performed. S25. Add potassium permanganate to the mixed solution obtained in S24 and stir. Then, ultrasonically disperse the well-stirred mixed solution for 5 minutes to obtain type B2 polishing liquid. S3. Rough polishing of nano-polycrystalline diamond circular arc-shaped cutting tool using Type A polishing fluid: S31. Using a glass disk immersed in water to provide a free environment for abrasive particles, perform chemical mechanical polishing on a nano-polycrystalline diamond circular arc cutting tool. S32. Flatten the glass disk and attach it to the grinding machine. Use a fixture to place the nano-polycrystalline diamond circular arc cutting tool on the glass disk. S33. Set the rotation speed of the glass disk and apply a certain polishing pressure to the fixture. At the same time, use a peristaltic pump to drop polishing liquid onto the glass disk at a flow rate of 3 ml / min to polish the nano-polycrystalline diamond circular arc cutting tool, and obtain a nano-polycrystalline diamond circular arc cutting tool with a cutting edge blunt radius of 100 mm-200 nm. S34. The nano-polycrystalline diamond circular arc cutting tool obtained in step S33 is inspected using a 100x optical microscope to obtain a rough-polished nano-polycrystalline diamond circular arc cutting tool. S4. Fine polishing of nano-polycrystalline diamond circular arc-shaped cutting tools using Type B polishing fluid: S41. In order to reduce grain shedding from the cutting edge of the nano-polycrystalline diamond circular arc cutting tool during the fine polishing process, alumina with inertness and moderate hardness is selected as the abrasive. S42. Flatten the glass disk and attach it to the grinding machine. Use a fixture to place the nano-polycrystalline diamond circular arc cutting tool on the glass disk. S43. Set the rotation speed of the glass disk and apply a certain polishing pressure to the fixture. At the same time, use a peristaltic pump to drop polishing liquid onto the glass disk at a flow rate of 3 ml / min to polish the nano-polycrystalline diamond circular arc cutting tool. S44. The nano-polycrystalline diamond circular arc-shaped cutting tool obtained in step S33 is inspected using a 500x optical microscope to obtain a finely polished nano-polycrystalline diamond circular arc-shaped cutting tool.

2. The chemical mechanical polishing method for a nano-polycrystalline diamond circular arc-shaped cutting tool according to claim 1, characterized in that, In S1 and S2, the amount of ferrous sulfate added is 1-5 g / 100 ml, the diameter of the diamond abrasive grains is 1-5 μm, and the diameter of the spherical silica is 20 nm.

3. The chemical mechanical polishing method for a nano-polycrystalline diamond circular arc-shaped cutting tool according to claim 1, characterized in that, In the B1 type polishing slurry, the oxidant is hydrogen peroxide with a concentration of 3%-10%, the abrasive is aluminum oxide with a diameter of 1-5 micrometers, and the additive is silicon dioxide with a diameter of 20nm.

4. The chemical mechanical polishing method for a nano-polycrystalline diamond circular arc-shaped cutting tool according to claim 1, characterized in that, In the B2 type polishing slurry, the oxidant is an acidic potassium permanganate solution, the abrasive particles are 1-5 micrometer alumina, and the additive is silicon dioxide with a diameter of 20 nm.

5. The chemical mechanical polishing method for a nano-polycrystalline diamond circular arc-shaped cutting tool according to claim 1, characterized in that, The acidic buffer used in solutions A, B1, and B2 is phosphoric acid, and the alkaline regulator used is sodium hydroxide.

6. A chemical mechanical polishing method for a nano-polycrystalline diamond circular arc-shaped cutting tool according to any one of claims 1-5, characterized in that, Chemical mechanical polishing (CMP) is performed using a CMP apparatus. The apparatus includes a glass disc, a cast iron disc, a spindle, a weight, a fixture, a nanocrystalline diamond circular arc-cutting turning tool, an anti-corrosion fixture, a waste liquid discharge channel, and a waste liquid collector. The lower end of the cast iron disc is fixedly connected to the output end of the spindle. The upper end of the cast iron disc is connected to the first mounting end of the anti-corrosion fixture, and the second mounting end of the anti-corrosion fixture is connected to the glass disc. The anti-corrosion fixture has a waste liquid discharge channel connected to the waste liquid collector. The fixture is located at the upper end of the glass disc, and the mounting end of the fixture has a weight. The fixed end of the fixture is fixedly connected to a base, and the working end of the fixture is fixedly connected to the mounting end of the nanocrystalline diamond circular arc-cutting turning tool.

7. The chemical mechanical polishing method for a nano-polycrystalline diamond circular arc-shaped cutting tool according to claim 6, characterized in that, The waste liquid collectors are symmetrically arranged on both sides of the main shaft, and the rotation centers of the glass disk, the cast iron disk, and the main shaft are on the same straight line.

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