The Research On Mechanism Of Ultra-High Speed Grinding

Ultra-high speed grinding (UHSG) breaks through the concept of conventional grinding. Combined with raw and finish working, it can attain the highest removal rate up to cutting, milling and planing. The difficult-to-grind material can also be ground with high performance. UHSG has been thought to be the peak of modern grinding. Focusing on the UHSG in China, the basic theory and experimental research are insufficient, which to some extent hold back its development and application. Certain questions on mechanism of the ultra-high speed grinding are researched deeply in this paper, all that can lay a theory foundation for the development of UHSG in China.Firstly, based on referring to a lot of relevant literature, this paper gives an overview of the development and current situation of UHSG at home and abroad, summarizes the characteristic and superiority of UHSG, expounds the application of UHSG on HEDG (High Efficiency Deep Grinding) Cylindrical Grinding Quick point Grinding etc, and lists the significance. Secondly, according to the mechanism of ultra-high speed impact and results of UHSG experiments, the model of chip-formation due to shock in quasi-flow phase under UHSG is established, a new mechanism of chip-formation under UHSG is advanced. Materials are removed by the shear action of grinding grain's cutting edge under general grinding, but this is done by the high speed impact of grinding grain and work piece under UHSG, a elliptic flow phase of high temperature and high pressure is shaped in front of and below grinding grain, it overflows from the front of the grinding grain at the grain's extruding and is brought out from the grinding area and chips are come into being. Therefore, under UHSG, maximum undeformed chip thickness and grinding force are small, grinding wheel is more durable, temperature of grinding area is high but burn layer is light and material removal rate is high.Then, based on the characteristic of HEDG, thermal models of HEDG are studied, temperature of grinding area and temperature of grinding grain are analyzed by experiment and theory calculation, the results indicate that temperature of grinding area is high enough to soften the ground material in front of the grain in a moment and quasi-flow phase even flow phase emerges, all that can prove it correct that establishing model of chip-formation due to shock in quasi-flow phase under UHSG in this paper. In addition, based on the theory of specific energy composition, energy consuming of UHSG and affect factors of specific energy under UHSG are analyzed.Finally, generation and influence of grinding heat under UHSG are studied, commonly used methods of supplying coolants into grinding area are briefly introduced. Enhancing heat transfer of grinding contact zone by radial jet impinging is emphasizely introduced by revealing the heat transferring mechanism of grinding contact zone under UHSG, then the heat transfer effect between it and normal supplying coolant is compared comprehensively.