Abstract
This paper describes the micro cutting of wear and impact resistant cemented carbides using PCD (Poly-crystalline Diamond) cutting tools in performance with SEM (Scanning Electron Microscope) direct observation method. The purpose of this study is to make clear the cutting mechanism of cemented carbides and the behavior of WC particles in the deformation zone in orthogonal micro cutting in order to build up the proper cutting condition. Summary of the results are as follows. (1) It has been found that there are two chip formation types. One is a type where the shear angle is comparatively small and the crack of the shear plane becomes wide. The other is a type where the shear angle is above 45 degrees and the crack of the shear plane does not widen. These differences are caused by the stress condition which gives rise to the friction at the shear plane which is caused by the interaction of carbide grain. (2) From the SEM in-situ observation in cutting the cemented carbide, WC particles are broken and come into contact with the tool edge directly. This causes tool wear in which the portions scrape the tool. (3) Different behavior of the crack has been observed for the three rake angles on the shear plane.
