快削性セラミックスの切削性能に関する研究 Ｉ 刃先形状と仕上面粗さ

Abstract

In recent years, many ceramics with various kinds of properties have appeared on the market. These ceramics are employed for a few mechanical and electronic parts. The purpose of this paper is to clarify the machining performance of machinable ceramics which have been newly developed. The machining performance of machinable ceramics is investigated and is discussed from view point of the relation between the flank wear of tool edge and the roughness of machined surface on the workpiece. The tools were K10 sintered carbide and CBN. In cutting tests by turning, the cutting speed was varied from 50 m/min to 200 m/min. The flank wear was measured by a tool makers microscope, and worn parts of the tools were observed with the SEM.The results obtained are as follows:(1) In the finish cutting for machinable ceramics, the best cutting condition was obtained as cutting speed of 50 m/min, feed 0.025 mm/rev, depth of cut 0.2 mm by tool of WC sintered carbide, and these condition for CBN tool was cutting speed of 100 m/min, feed 0.025 mm/rev, depth of cut 0.1 mm.(2) Tool life of CBN tool was larger than WC sintered carbide.(3) The cutting force increased at high speed cutting.(4) The chamfer angle of -15 on the tool edge gives the best surface-finish and the long tool life.