Investigação dos mecanismos de remoção de material de insertos de metal duro de diferentes classes durante a retificação

Abstract

After pressing and sintering processes, cutting inserts must be ground in order to obtain the necessary surface finish and tolerances for their application in machining operations. An appropriate process design requires a detailed investigation of the material removal mechanisms, in order not only to obtain a good surface finish, but also an efficient process. Within this context, an investigation of the material removal mechanisms associated with the analysis of process forces and specific energy during plunge-face grinding of cemented tungsten carbide cutting inserts of different grades (K10, P10, M10, and NbC-Ni) was carried out. All the studied materials showed, in general and with similar trends, increased values of the grinding force components and a reduction of specific energy with higher values of average single grain chip thickness. In addition, a very similar critical single grain chip thickness of 0.25 μm was obtained and changes in the material removal mechanism from ductile to brittle mode could be observed close to this value. The cemented carbide ISO grade K10 presented better results than those obtained for the other materials with regard to specific energy, surface and edge quality. No relationships were found between the results obtained in the performed scratching tests and those generated through grinding.