A Common Denominator for Optimal Cutting Tool Geometry

Abstract

Summary Previous investigations of cutting tool geometries have shown that for maximum tool life there is an optimal clearance angle which varies significantly for different types of cutting tools. The increase in tool life up to the optimum clearance angle is related to less flank wear by sliding. Above the optimal clearance angle increased flank wear and shorter tool life is often associated with a greater tendency for microchipping. Therefore, stresses located in the vicinity of the cutting edge might be responsible for the decrease in tool life at larger clearance angles and for the existence of an optimal clearance angle. The present investigation was undertaken to examine whether the optimize clearance angle found for different types of high speed steel cutting tools have a stress related common denominator. A simplified loaded cutting tool model was used to describe the stresses in the tool wedge. Optimal geometries for substantially different types of cutting tools including end mills, fly cutters and drills were found to have almost the identical stress values on the tool rake faces. This result would seem to be particularly useful for optimal design and selection of tool geometries.