An Investigation of the Mechanics in the Machining of Ceramic Material

Abstract

This study is an investigation into the mechanics in machining ceramic materials. Extensive experimentation is done in an effort to understand the process of material removal. The theory of fracture mechanics is used to explain experimental findings. A five stage model of the machining of ceramics is proposed, and based on this understanding, guidelines are provided to adapt the traditional methods to machine ceramics. The possibility of developing a new submerged machining process is studied. The significant new findings in this research are: Cutting force has little change with increase in the cutting speed as a result of the combined effects of increase in loading rate and increase in temperature on the fracture toughness.<P>The quality of the surface formed is better controlled by the variation in the chip size than by the mean of the chip size. Submerged machining create a unique environment which keeps the chip size variation under control.<P>Variation of the chip size increases with increase in the depth of cut, consequently degrading the finish quality. Similar effect of feed has also been observed, however, feed is not as significant as depth of cut.<P>The apparent coefficient of friction controls the tensile stress distribution in the vicinity of the cutting zone. A large friction force induces a tensile stress field confined to a narrow region, parallel to the machined surface, promoting chip formation.