切削抵抗と切りくず生成状態に及ぼすチップブレーカの影響

Abstract

In order to measure independently forces acting on rake face and on chip breaker, a tool dynamometer has been designed and constructed. Using step-type and groove-type chip breakers, orthogonal cutting and oblique cutting experiments have been performed. For a step-type chip breaker, decreasing the distance between cutting edge and a chip breaker (chip breaker distance) gives the chip formation for tools with smaller tool-chip contact length than that of a conventional tool. The thrust force acting on the rake face decreases about 75% of that of the conventional tool. For groove-type chip breakers using tools with shortly restricted tool-chip contact lengths, it is found that the magnitudes of forces acting on the rake face are constant in spite of the chip breaker distance. This shows that the forces acting on the cutting point are scarcely influenced by external forces acting near the chip breaker. Even in the case of small broken chip produced at small chip breaker distance in oblique cutting, chip flow direction calculated from forces on the rake face approximately supports Stabler's chip flow rule.