Strength Model Of Pre-sintered Alumina And Its Micro Machining Characteristics

Ceramics is widely used in micro components and micro features because of its excellent properties such as resistance to erosion and high temperature. Ceramic micro structure can be easily processed by machining pre-sintered compact. In the machining process, the strength of pre-sintered compact has a significant impact on edge quality and tool wear. However, the relationship between compact strength and pre-sintering condition is not clear. It is also necessary to select the optimal strength of pre-sintered alumina for micro machining.Pre-sintering temperature and time are key factors that affect the strength of ceramic compact by controlling the growth of sintering neck between particles. In this paper, alumina green compacts were pre-sintered, and then three-point flexure strength tests were carried out. Meanwhile, the theoretical strength of pre-sintered compact was obtained by calculating the size of sintering neck. From experimental results, it can be seen that strength is an exponential function of pre-sintering temperature and is also a logarithmic function of pre-sintering time approximately. And theoretical strengths match well with the experimental values. Therefore the model and be used to select the proper strength and its pre-sintering condition.In micro-machining, the edge quality of machined micro features and tool wear are directly influenced by the strength of alumina. In this paper, experiments of under different machining parameters and strength were carried out. The evaluation parameters such as damage extent of edge length, width of edge damage, length of tool wear and shape change of tool end was also been established. And the relationship between evaluation parameters and strength provides a basis for optimal selection of strength. The experimental results show that7.302-9.404MPa is the proper choice when both edge quality and tool wear are taken as the evaluation parameters. The higher strength will improve edge quality. And the lower strength will improve the efficiency of preparing pre-sintered alumina and reduce the tool wear.In summary, it is an effective way to improve the machining equality and efficiency that optimizing pre-sintering conditions and strength selection, which are respectively based on the theoretical prediction model and the relationship between strength and evaluation parameters.