Papers by Keyword: Grinding Tool

Abstract: In order to improve the surface quality of sapphire substrates ground by diamond wheel, the chemo-mechanical grinding (CMG) tools for sapphire grinding was investigated in this paper. According to the processing principle of CMG, three CMG tools with different abrasives of SiO2, Fe2O3 and MgO were developed respectively. The compositions of the CMG tools were designed and optimized based on the physicochemical characteristics of sapphire. The grinding experiments were performed with the developed CMG tools and the grinding performance of three kind of tools were evaluated by comparing the surface roughness and the MRR of sapphire. The experiment results show that the grinding performance of SiO2 CMG tool was worst. The surface roughness and MRR corresponding to SiO2 CMG tool were all significantly poorer than Fe2O3 and MgO CMG tools. The highest MRR could be obtained by Fe2O3 CMG tool, but the best surface quality was obtained by MgO CMG tool.

Abstract: Nano-Cr2O3 was added to vitrified bond CBN grinding tools to improve their properties. Effects of nano-Cr2O3 on properties and microstructures of vitrified bond CBN grinding tools were investigated. The samples were characterized by differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and related detecting techniques. Results show that the refractoriness of vitrified bond firstly decreases and then increases with the addition of nano-Cr2O3, but the fluidity has the opposite change. Compared with basic vitrified bond, the refractoriness and fluidity of vitrified bond (4 wt.% nano-Cr2O3) are reduced by 25°C and increased by 5.4%, respectively. The bending strength of CBN grinding tools can be enhanced obviously with the addition of nano-Cr2O3, and it has the maximum bending strength (59.27MPa) when adding 4 wt.% nano-Cr2O3. SEM result shows that CBN grinding tool has the most dense structure and the least pore when adding 4 wt.% nano-Cr2O3.

Abstract: Aiming at the severe surface/subsurface damage of Al₂O₃ceramic ground by diamond grinding wheel, the chemical-mechanical grinding (CMG) tools were studied in this paper. According to the principle of CMG, three types of CMG tools with different abrasives were developed. The chemical compositions of the grinding tools were selected and optimized considering the physicochemical characteristics of Al₂O₃ceramic. By comparing the surface roughness and material removal rate (MRR) of Al₂O₃ceramic respectively ground with SiO₂ , Fe₂O₃ and MgO grinding tools, the grinding performance of those grinding tools were evaluated. The experiment results showed that the grinding performance of SiO₂ grinding tool was the best. The surface roughness and MRR versus SiO₂ grinding tool were all better than other grinding tools, and can reach 28 nm and 15 μm/h respectively. The grinding performance of Fe₂O₃ grinding tool was the worst.

Abstract: In order to improve the grinding performance and service life of electroplating composite coatings with high percent of hard abrasives, the composite coatings of Ni-Co/SiC were prepared by occlusion electroplating technology and their microstructure and tribological properties were studied. The research results show that the cathodal electric-current density in occlusion electroplating process and the SiC abrasive size have great influence on microstructure and tribological properties of Ni-Co/SiC coatings. The optimum value of cathodal electric-current density is 1 A/dm2 and the proper SiC abrasive size is about 20 μm, in which the Ni-Co/SiC coatings have excellent wear resistance and high grinding ability. The main wear mechanisms of Ni-Co/SiC coatings are micro-cutting and adhesive wear of matrix alloy, and micro-cracking wear and spalling of SiC abrasives.

Abstract: Cubic boron nitride(CBN) is a superhard materials with many advantages and many uses. Vitrified bond CBN grinding tool is a promising abrasive tool of high performance used for high speed, high efficiency, high precision grinding with lower grinding cost and less environment pollution. Sintering of vitrified bond CBN grinding tool was investigated in this paper. The results showed that practical sintering temperature of this tool was much lower than the initial oxidation temperature of CBN particle measured by comprehensive thermal analysis. The upper limit of sintering temperature should be determined by taking account of the thermal analyzing results, heating process of CBN and its change in strength and structure. Within the sintering temperature range of the vitrified bond, relatively higher sintering temperature was beneficial to the strength of bond bridge and the holding strength between bond and CBN abrasive particles. CBN tool sintered at relatively lower temperature tended to fracture through the bond bridge, while the one sintered at higher temperature tended to fracture along the boundary between CBN abrasive grain and vitrified bond.

Abstract: In recent work, a creative idea has been proposed by applying the rapid prototyping technology to develop a new diamond-coated blade based on ultraviolet-cured resin bond. The new technology features many advantages such as fast processing speed, low environmental pollution, and low energy consuming. This paper makes an investigation on the adherence and abrasion mechanisms of such diamond blades. The experimental plan is well designed for selection of an optimal prescription of the mixture to achieve good mechanical performance and a manufacturing process is proposed to produce ultraviolet-cured resin bonded diamond coated blades. Practical experiments are carried to test the blade performance and to compare with different tools in incising artificial crystal. Furthermore, this paper also observes how the tensile strength and elastic modulus of ultraviolet-cured resin affect the crevasse and quality of machined edge surfaces.