Chipping and Breakage of Carbide Tools

The paper deals with chipping and breakage of carbide tools and it is based on a combination of turning tests, examination of fracture surfaces, and analysis of stresses in the tool as produced by the cutting force. Thermal stresses are so far not considered. It is concluded that chipping is a ductile failure due to high shear stresses at the cutting edge and breakage is brittle fracture originating at the rake face at a local maximum of tensile stress. For the finite element stress analysis, a new method of successively refining mesh while diminishing the analyzed area is introduced which is rather effective and economical in that all computation except for the final field is done once only for various loading cases.