Method for preparing diamond grinding disc through sand net

Abstract

The invention belongs to the technical field of precise grinding tool manufacturing, and discloses a sand net preparation process of a high-precision corrosion-resistant diamond grinding disc. Through sand net mechanical fixing and plastic formwork cooperative positioning, single-hole single-sand accurate filling of carborundum is achieved; a staged gradient electroplating technology is adopted, electroplating is performed in two stages of strengthening and thickening under the current density of 1-30 A / dm, the height deviation of nickel layer coated sand grains is smaller than or equal to + / -3 microns, and the size precision of grooves reaches + / -8 microns. The innovative composite anti-corrosion system is combined with the palladium-nickel / rhodium alloy and the trivalent chromium plating layer, and the salt mist anti-corrosion time is prolonged to 300-500 hours (compared with traditional 120 hours, the salt mist anti-corrosion time is remarkably prolonged). And through flame ablation of the sand net and precise polishing treatment, the roughness Ra of the tank wall is reduced to be smaller than or equal to 0.5 mu m, and the binding force of the plating layer is larger than or equal to 55 MPa. According to the process, the service life of a product reaches 800-1200 hours, the wafer removal non-uniformity is smaller than 2%, the process is suitable for the high-precision polishing field of semiconductor wafers and the like, and the technical bottlenecks that a traditional process is low in precision and poor in corrosion resistance are solved.

Description

Technical Field

[0001] The invention relates to the technical field of precision grinding tool manufacturing, and in particular to a method for preparing a diamond grinding disc using a sand net. Background Art

[0002] In the field of precision machining and tool manufacturing, the technology of setting diamond abrasive grains on the surface of the substrate to improve the friction performance of the tool surface has been widely used. The traditional method usually uses photolithography technology to etch a groove structure of a predetermined size, then fixes the diamond abrasive grains in the groove through an adhesive material, and finally achieves surface encapsulation through nickel plating.

[0003] However, the existing technology has two significant defects: first, in the process of groove preparation, due to the inherent characteristics of the dry film lithography method (such as the developer diffusion effect and exposure accuracy limitations), key dimensional parameters such as the depth and width of the groove are difficult to accurately control, which directly affects the positioning accuracy of the corundum particles and the subsequent processing quality; second, when a nickel-plated layer is used as a surface protective layer, the nickel layer is prone to oxidation corrosion and grain boundary erosion in acid and alkali corrosion or high temperature and high humidity environments, resulting in a decrease in the bonding strength of the corundum particles, seriously affecting the product life.

[0004] The above technical bottlenecks are mainly caused by two factors: in terms of materials, the traditional dry film resist method has a low tolerance, which is prone to defects such as sidewall tilt or bottom overetching in micron-level groove processing; in terms of structural protection, the inherent porosity defects and electrochemical activity of the nickel plating layer make it difficult to form an effective protective barrier in corrosive media. Therefore, how to achieve precise control of the groove structure and improve the corrosion resistance of the product has become a technical problem that needs to be overcome in this field. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method for preparing a diamond grinding disc with a sand net, which solves the problem that the groove size is difficult to control and increases the anti-corrosion performance of the product. The method of the present invention comprises the following steps: (1) Sand screen fixing and pattern preparation: The sand screen with designed mesh size is mechanically fixed on the surface of SUS304 stainless steel diamond grinding substrate, the diameter of the diamond grinding substrate is 108±0.5mm and the thickness is 6.2±0.02mm. When fixing, a plastic pattern template is set under the sand screen; (2) Diamond positioning: Fill diamond into the sand mesh, and the radius of the sand particles should satisfy 1 / 2R sand mesh < R sand < R sand mesh, ensuring that each hole has one sand and the entire hole is covered; (3) Electroplating reinforcement: Place the substrate carrying the sand screen in a carrier. The carrier is immersed in a nickel-containing electroplating solution at an inclination angle of 15 - 20° and connected to the negative pole of the power supply for electroplating. The current density of the electroplating is 1 - 10 A / dm², the pH of the nickel-containing electroplating solution is 3 - 5, the electroplating temperature is 40 - 70°C. After electroplating for 2 hours, remove the sand screen; (4) Electroplating thickening: Use a thickening electroplating solution for secondary electroplating until the nickel layer covers 1 / 5 - 1 / 3 of the height of the sand grains, and then perform post-treatment to remove burrs. The electroplating conditions are a current density of 1 - 30 A / dm², pH 3 - 5, temperature 40 - 85°C, and electroplating time of 2 hours; (5) Anticorrosion coating: After performing palladium-nickel alloy or rhodium alloy electroplating, perform trivalent chromium electroplating; (6) Cleaning and packaging: Perform ultrasonic cleaning, organic solvent treatment, and vacuum packaging.

[0006] Further, the nickel-containing electroplating solution in step (3) of the present invention contains: nickel sulfate 100 - 600 g / L, nickel chloride 40 - 150 g / L, boric acid 20 - 100 g / L, and additive 40 - 205 g / L.

[0007] Further, the additives of the present invention include saccharin 5 - 30 g / L, sodium dihexyl sulfosuccinate 5 - 30 g / L, chloral hydrate 5 - 20 g / L, alkynol ether 5 - 30 g / L, sodium propynylsulfonate 5 - 30 g / L, sodium hydroxymethylsulfonate 5 - 30 g / L, propynol glycerol ether 5 - 25 g / L, and coumarin 5 - 20 g / L.

[0008] Further, the thickening electroplating solution in step (4) of the present invention contains: nickel sulfate 200 - 800 g / L, nickel chloride 80 - 300 g / L, boric acid 50 - 200 g / L, and additive 106 - 126 g / L.

[0009] Further, the additives of the present invention include saccharin 10 g / L, sodium allylsulfonate 60 - 80 g / L, propargyl alcohol 1 g / L, propynol ethoxylate 2 g / L, hydroxypropyl propargyl ether 5 g / L, 2-methyl-3-butyn-2-amine acid 6 g / L, sodium vinylsulfonate 3 g / L, polyphenylene sulfide 2 g / L, N,N-diethylpropargylamine 5 g / L, polyethyleneimine alkyl salt 6 g / L, and sodium zirconate lead 6 g / L.

[0010] Further, the anti-corrosion coating in step (5) of the present invention comprises: Palladium-nickel alloy coating implementation conditions: palladium content 35 - 80 g / L, nickel content 8 - 15 g / L, current density 1 - 5 A / dm², pH 6.5 - 8, temperature 22 - 40 °C, electroplating time 5 minutes; Trivalent chromium chrome plating layer implementation conditions: conductive salt 400 g / L, chromium additive 200 ml / L, current density 8 A / dm², temperature 55 °C, pH 4.5, electroplating time 1 - 3 minutes.

[0011] Further, the sand mesh of the present invention is removed by flame ablation method, and the ablation temperature is controlled at 300 - 500 °C, and the duration is 30 - 120 seconds.

[0012] Further, the burr treatment in step (4) of the present invention adopts precision mechanical polishing, and the polishing particle size is controlled at 800 - 5000 mesh, and the polishing pressure is 0.1 - 0.5 MPa.

[0013] Further, the cleaning step of the present invention comprises: ultrasonic cleaning frequency 28 - 120 kHz, resistivity of deionized water ≥ 18 MΩ·cm, organic solvent selected from isopropyl alcohol or acetone, and vacuum packaging pressure ≤ 10 Pa.

[0014] Compared with the prior art, a method for preparing a diamond grinding disc with a sand mesh of the present invention has the following technical effects: ‌1. Precise control of groove dimensions‌ (1) Adopting the ‌sand mesh template collaborative positioning technology‌: By mechanically fixing the sand mesh and the plastic pattern template (error ≤ ±5 μm), the patterned arrangement of emery on the substrate surface is realized, ensuring that the dimensional deviation of the groove width and spacing is controlled within ±8 μm (the traditional process is ±30 μm); (2) ‌Optimization of the staged electroplating process‌: Through the gradient current control of the electroplating reinforcement stage (current density 1 - 10 A / dm²) and the thickening stage (current density 1 - 30 A / dm²), the coating height accuracy of the nickel layer on the sand grains reaches ±3 μm, and the groove depth volatility ≤ 5% (the traditional process ≥ 15%); (3) ‌Suppression of sand mesh ablation residue‌: The flame ablation parameters (300 - 500 °C / 30 - 120 s) and the polishing process (800 - 5000 mesh) act synergistically to eliminate the burrs on the groove edge caused by the sand mesh residue, and the surface roughness Ra of the groove wall ≤ 0.5 μm (the traditional process Ra ≥ 2.0 μm).

[0015] ‌2. Significantly improved corrosion resistance‌ (1)Composite coating synergistic protection: The palladium-nickel / rhodium alloy coating (porosity ≤ 0.8 pores / cm²) and trivalent chromium coating (thickness 0.5 - 1.2 μm) form a double barrier. The corrosion resistance time in the neutral salt spray test (ASTM B117) reaches 300 - 500 hours, which is 150% - 316% higher than that of the single-layer nickel coating (120 hours); (2)Coating adhesion strengthening: By optimizing the electroplating solution additives (such as sodium propynylsulfonate, sodium hydroxymethylsulfonate), the adhesion between the anti-corrosion coating and the nickel substrate is ≥ 55 MPa (traditional process ≤ 35 MPa), avoiding the coating peeling caused by the penetration of corrosive media; (3)Microstructure densification: The trivalent chromium electroplating process (pH 4.5 / 55 °C) forms an amorphous coating with a microhardness of 800 - 1000 HV and a porosity < 0.1%, significantly delaying the occurrence of pitting corrosion. Description of the Drawings

[0016] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 It is a schematic flow chart of a method for preparing a diamond grinding disc with a sand mesh according to the present invention Drawings

[0017] 1 - Sand mesh, 2 - Plastic pattern, 3 - Substrate, 4 - Emery, 5 - Nickel layer, 6 - Anti-corrosion coating, 7 - Chromium layer. Detailed Embodiments

[0018] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] As Figure 1 shown, a method for preparing a diamond grinding disc with a sand mesh includes the following steps: (1)Fixing the sand mesh 1 and pattern preparation: Mechanically fix the sand mesh 1 with the designed mesh number on the surface of the SUS304 stainless steel diamond grinding substrate 3. The diameter of the diamond grinding substrate 3 is 108 ± 0.5 mm and the thickness is 6.2 ± 0.02 mm. When fixing, set a plastic pattern 2 template under the sand mesh 1; (2)Emery 4 positioning: Fill the emery 4 into the holes of the sand mesh 1, and ensure that the radius of the sand grains satisfies 1 / 2R < R sand < R hole of the sand mesh 1 hole, ensuring single sand in a single hole and full hole coverage; (3) Electroplating reinforcement: Place the substrate 3 carrying the sand screen 1 in a carrier. The carrier is immersed in a nickel-containing electroplating solution at an inclination angle of 15 - 20° and connected to the negative electrode of the power supply for electroplating. The current density of the electroplating is 1 - 10 A / dm², the pH of the nickel-containing electroplating solution is 3 - 5, the electroplating temperature is 40 - 70°C. After electroplating for 2 hours, remove the sand screen 1. The sand screen 1 of the present invention is removed by flame ablation method, and the ablation temperature is controlled at 300 - 500°C, and the duration is 30 - 120 seconds.

[0020] The nickel-containing electroplating solution contains: nickel sulfate 100 - 600 g / L, nickel chloride 40 - 150 g / L, boric acid 20 - 100 g / L, and additive 40 - 205 g / L.

[0021] The additive of the present invention includes saccharin 5 - 30 g / L, sodium dihexyl sulfosuccinate 5 - 30 g / L, chloral hydrate 5 - 20 g / L, alkynol ether 5 - 30 g / L, sodium propynylsulfonate 5 - 30 g / L, sodium hydroxymethylsulfonate 5 - 30 g / L, propynol glycerol ether 5 - 25 g / L, and coumarin 5 - 20 g / L.

[0022] (4) Electroplating thickening: Use the thickening electroplating solution for secondary electroplating until the nickel layer 5 covers 1 / 5 - 1 / 3 of the height of the abrasive grains 1, and then remove the burrs by post-treatment. The electroplating conditions are current density 1 - 30 A / dm², pH 3 - 5, temperature 40 - 85°C, and electroplating time 2 hours; the burr treatment is carried out by precision mechanical polishing, and the polishing particle size is controlled at 800 - 5000 mesh, and the polishing pressure is 0.1 - 0.5 MPa.

[0023] The thickening electroplating solution contains: nickel sulfate 200 - 800 g / L, nickel chloride 80 - 300 g / L, boric acid 50 - 200 g / L, and additive 106 - 126 g / L.

[0024] The additive of the present invention includes saccharin 10 g / L, sodium allylsulfonate 60 - 80 g / L, propargyl alcohol 1 g / L, propynol ethoxylate 2 g / L, hydroxypropyl propargyl ether 5 g / L, 2-methyl-3-butyn-2-amine acid salt 6 g / L, sodium vinylsulfonate 3 g / L, polyphenylene sulfide 2 g / L, N,N-diethylpropargylamine 5 g / L, polyethyleneimine alkyl salt 6 g / L, and sodium zirconate lead 6 g / L.

[0025] (5) Anticorrosive coating 6: After palladium-nickel alloy or rhodium alloy electroplating, trivalent chromium electroplating is carried out; the anticorrosive coating 6 includes: Conditions for palladium-nickel alloy coating: palladium content 35 - 80 g / L, nickel content 8 - 15 g / L, current density 1 - 5 A / dm², pH 6.5 - 8, temperature 22 - 40 °C, electroplating time 5 minutes; Conditions for trivalent chromium electroplated layer 7: conductive salt 400 g / L, chromium additive 200 ml / L, current density 8 A / dm², temperature 55 °C, pH 4.5, electroplating time 1 - 3 minutes.

[0026] (6) Cleaning and packaging: After ultrasonic cleaning, organic solvent treatment and vacuum packaging, the cleaning steps include: ultrasonic cleaning frequency 28 - 120 kHz, resistivity of deionized water ≥ 18 MΩ·cm, organic solvents selected from isopropanol or acetone, and vacuum packaging pressure ≤ 10 Pa.

[0027] The following combines the accompanying drawings to detail the technical solutions provided by each embodiment of the present invention. Example 1

[0028] A method for preparing a diamond grinding disc from a sand screen is as follows: ‌Step 1: Fixing the sand screen and pattern preparation‌ Select a SUS304 stainless steel substrate with a diameter of 108 mm and a thickness of 6.2 mm, and the surface is treated by electrolytic polishing (Ra ≤ 0.1 μm).

[0029] Lay a 500-mesh nylon sand screen on the surface of the substrate, and place a radial stripe pattern template (line width 0.5 mm) made of polycarbonate below.

[0030] Use a vacuum adsorption device (vacuum degree -90 kPa) to fix the sand screen, and after ensuring no wrinkles, bond the edge of the sand screen with epoxy resin glue in dots.

[0031] ‌Step 2: Diamond abrasive positioning‌ Select diamond abrasives with a particle size of 30 - 40 μm (corresponding to the sand screen hole radius R_sand screen hole = 25 μm), satisfying the condition of 1 / 2R_sand screen hole (12.5 μm) < R_sand (15 - 20 μm) < R_sand screen hole.

[0032] Fill the diamond abrasives evenly into the mesh holes through a vibrating sieve (amplitude 2 mm, frequency 50 Hz), and the single-hole filling rate is detected by a microscope to be ≥ 98%.

[0033] ‌Step 3: Electroplating reinforcement‌ Prepare electroplating solution: nickel sulfate 400 g / L, nickel chloride 80 g / L, boric acid 50 g / L. The additives include saccharin 15 g / L, sodium dihexyl sulfosuccinate 10 g / L, and chloral hydrate 8 g / L.

[0034] Tilt the carrier by 18° and immerse it in the plating bath. The cathode current density is 5 A / dm², pH is 4.0, temperature is 55 °C. After electroplating for 2 hours, ablate the sand screen with a propane flame (400 °C) for 60 seconds.

[0035] ‌Step 4: Electroplating for thickening‌ Prepare thickening electroplating solution: nickel sulfate 500 g / L, nickel chloride 150 g / L, boric acid 100 g / L. The additives include sodium allylsulfonate 70 g / L and hydroxypropyl propargyl ether 5 g / L.

[0036] Adopt pulse electroplating (duty cycle 30%, frequency 100 Hz), current density 15 A / dm², pH 4.2, temperature 60 °C. After electroplating for 2 hours, the height of the nickel layer coating the sand grains reaches 1 / 4.

[0037] Use a 5000-mesh diamond polishing wheel (pressure 0.3 MPa) to remove burrs.

[0038] ‌Step 5: Anticorrosion coating‌ Palladium-nickel alloy coating: palladium content 50 g / L, nickel content 10 g / L, current density 3 A / dm², pH 7.0, temperature 30 °C, electroplate for 5 minutes.

[0039] Trivalent chromium electroplating: conductive salt 400 g / L, current density 8 A / dm², pH 4.5, temperature 55 °C, electroplate for 2 minutes, coating thickness 0.8 μm.

[0040] ‌Step 6: Cleaning and packaging‌ Ultrasonic cleaning at 40 kHz (deionized water resistivity 18.2 MΩ·cm) for 10 minutes, soak in acetone for dehydration, and vacuum package (pressure 5 Pa). Example 2

[0041] The difference from Example 1 is: In Step 5, rhodium alloy electroplating is used instead of palladium-nickel alloy. The plating solution contains rhodium 35 g / L and cobalt 5 g / L, and the current density is 2 A / dm²; The trivalent chromium electroplating time is extended to 3 minutes, and the coating thickness is 1.2 μm.

[0042] Perform sand grain shedding rate, coating adhesion, and anticorrosion life tests on the diamond grinding discs prepared in Examples 1 and 2. The test results are shown in the following table:

[0043] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A method for preparing a diamond grinding disc with a sand mesh, characterized in that, It includes the following steps: (1) Sand mesh fixation and pattern preparation: Mechanically fix a sand mesh with a designed mesh count on the surface of a SUS304 stainless steel diamond grinding substrate. The diameter of the diamond grinding substrate is 108 ± 0.5 mm and the thickness is 6.2 ± 0.02 mm. When fixing, set a plastic pattern template under the sand mesh; (2) Emery positioning: Fill the sand mesh holes with emery. The radius of the sand grains satisfies 1 / 2R sand mesh hole < R sand < R sand mesh hole to ensure single sand in a single hole and full-hole coverage; (3) Electroplating reinforcement: Place the substrate with the sand mesh in a carrier. The carrier is immersed in a nickel-containing electroplating solution at an inclined angle of 15 - 20° and connected to the negative electrode of the power supply for electroplating. The current density of the electroplating is 1 - 10 A / dm², the pH of the nickel-containing electroplating solution is 3 - 5, the electroplating temperature is 40 - 70 °C. After electroplating for 2 hours, remove the sand mesh; (4) Electroplating thickening: Use a thickening electroplating solution for secondary electroplating until the nickel layer covers 1 / 5 - 1 / 3 of the height of the sand grains. After post-treatment to remove burrs, the electroplating conditions are a current density of 1 - 30 A / dm², pH 3 - 5, temperature 40 - 85 °C, and electroplating time of 2 hours; (5) Anticorrosion coating: After implementing palladium-nickel alloy or rhodium alloy electroplating, perform trivalent chromium electroplating; (6) Cleaning and packaging: Carry out ultrasonic cleaning, organic solvent treatment, and vacuum packaging.

2. The method according to claim 1, wherein The nickel-containing electroplating solution in step (3) contains: nickel sulfate 100 - 600 g / L, nickel chloride 40 - 150 g / L, boric acid 20 - 100 g / L, and additive 40 - 205 g / L.

3. The method according to claim 2, wherein The additive includes saccharin 5 - 30 g / L, sodium dihexyl sulfosuccinate 5 - 30 g / L, chloral hydrate 5 - 20 g / L, alkynol ether 5 - 30 g / L, sodium propynylsulfonate 5 - 30 g / L, sodium hydroxymethylsulfonate 5 - 30 g / L, propynol glycerol ether 5 - 25 g / L, and coumarin 5 - 20 g / L.

4. The method according to claim 1, wherein The thickening electroplating solution in step (4) contains: nickel sulfate 200 - 800 g / L, nickel chloride 80 - 300 g / L, boric acid 50 - 200 g / L, and additive 106 - 126 g / L.

5. The method according to claim 4, characterized in that, The additive includes saccharin 10 g / L, sodium allylsulfonate 60 - 80 g / L, propargyl alcohol 1 g / L, propynol ethoxylate 2 g / L, hydroxypropyl propargyl ether 5 g / L, 2-methyl-3-butyn-2-amine acid 6 g / L, sodium vinylsulfonate 3 g / L, polyphenylene sulfide 2 g / L, N,N-diethylpropargylamine 5 g / L, polyethyleneimine alkyl salt 6 g / L, and sodium zirconate lead 6 g / L.

6. The method according to claim 1, wherein The anticorrosion coating in step (5) contains: Conditions for implementing the palladium-nickel alloy coating: palladium content 35 - 80 g / L, nickel content 8 - 15 g / L, current density 1 - 5 A / dm², pH 6.5 - 8, temperature 22 - 40 °C, electroplating time 5 minutes; Conditions for implementing the trivalent chromium electroplating layer: conductive salt 400 g / L, chromium additive 200 ml / L, current density 8 A / dm², temperature 55 °C, pH 4.5, electroplating time 1 - 3 minutes.

7. The method according to claim 1, wherein The sand mesh is removed by the flame ablation method. The ablation temperature is controlled at 300 - 500 °C, and the duration is 30 - 120 seconds.

8. The method according to claim 1, wherein The burr treatment in step (4) uses precision mechanical polishing, with the polishing grit size controlled between 800 and 5000 mesh and the polishing pressure between 0.1 and 0.5 MPa.

9. The method according to claim 1, wherein The cleaning steps include: ultrasonic cleaning frequency of 28 - 120 kHz, resistivity of deionized water ≥ 18 MΩ·cm, organic solvents selected as isopropanol or acetone, and vacuum packaging pressure ≤ 10 Pa.

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