| Summary: | 碩士 === 國立成功大學 === 機械工程學系專班 === 94 === This thesis will discuss the influences of scribing force, specific energy, and surface geometry on the tool geometry, rake angle, material, and cutting velocity of scribing process.
The influences of cutting geometry on the rake angle are analyzed to observe the variation of the area contacted between tool flank and machined surface for different rake angles in the same cutting depth, and radial cutting coefficient changed with the rake angle. The results of experiments show that scribing leading by edge, the smaller the rake angle is, the greater the specific energy is. While scribing leading by face, the smaller the rake angle is, the smaller the specific energy is.
After separating friction from cutting force, the variation trend of the rake angle and the specific energy which does not consider friction is the same with the case that friction is considered. By observing the specific energy which does not consider friction, size effect makes higher specific energy in lower cutting depth in scribing ductile material. While scribing brittle material, the transformation of cutting mechanism makes the specific energy become lower. From relationship between friction coefficient and the material area contacted with tool, the smaller the area is, the lower the friction coefficient is. This phenomenon can be used to decide the optimal rake angle of cut. It also can be observed that the promotion of the cutting velocity makes specific energy is reduced and groove geometry is more complete.
|
|---|
