Precision Diamond Grinding Products Developed

Ultra-precision machining is an important process technology today, which requires not only high-precision and high quality, but also low-cost and high reproducibility. Because of its features of unique principles and less prerequirments in processing equipment and environmental factors, ultra-precision grinding and polishing process, which can achieve nanometer or even atomic-scale processing, has become an important part of ultra-precision machining technology, while the precision grinding products are the keypoint of ultra-precision grinding polishing technique. Diamond powder with high hardness and corrosion resistance properties become the first choice of raw materials of precision grinding products.In this paper, a lower HLB value of nonionic surfactant is used as a modifier to disperse and modify the surface of nano-diamond in alkane solvent by high-energy ultrasound irritation. The capillary and viscosity methods are used to estimate the hydrophobic of nano-diamond powder before and after modification, and FTIR as well as thermal analysis to study the adsorption of modifier on the surface. Span-60 can be used to modified the surface of nano-diamond, and the surface of nano-diamond modified becomes lipophilic. The chemical adsorption of Span-60 has taken place on the surface of nano-diamond, resulting in a better dispersion in the organic solvents.The oil-based diamond slurry was prepared in the following procedure: modified nano-diamond powders, chosen as an abrasive, was first dispersed in an appropriate light oil with suitable surfactants under ultrasonic irratation, and then gathered by centrifugation. The influence of the type and amount of dispersant on the properties of slurry were studied, as well as ultrasonic time, centrifugation speed and time. Dispersion, anti-oxidation and polishing properties of slurry are characterized. The results showed that: white oil is a suitable dispersion medium while the DBS and PEG composition surfactant is the best dispersant. The optimized ultrasonic irratation parameters for minimum settlement of suspension is the power of 150W and the time of 20 minutes. The rotate speed of centrifuge is 2500r/min, and centrifugal process 30min, the secondary particle of slurry tend to the smallest. The surface roughness of silicon wafer after polishing with the resultant abrasive slurry is 0.306 nm.The modified single-crystal diamond powder is mixed with plastic resin to produce slurry, and tape-casted onto the polyester substrates. The precision diamond abrasive film was obtained after dry-curing. The effects of performance factors of the slurry on the abrasive film quality were studied, including the casting machine blade height, the height of fluid level, cast speed, drying temperature, the viscosity of slurry, and abrasive solid content. When fumed silica of 1.8 wt% was added as rheological agent, the viscosity of slurry raises from 190mPa.s to 260mPa.s at 10s^-1 shear rate. The settlement of slurry decreased to the minimum value after ball milling 30 minutes at 600 r/min with planetary mill. With the dry surface to reduce the size of The Benard vortex of dry film will increases evidently with the particle size reduces. The rill marks of dry film disappeared with the viscosity of slurry reduces from 25s to 15s; With the propotion of abrasive increased, the grinding ratio increases while the tensile strength reduced.