Internal turning of sintered carbide parts: tool wear and surface roughness evaluation

Abstract

Turning of sintered carbide parts has not been a common theme in the literature such as the case of other hardened materials. This is a statement made on the basis of recent research on this subject in which journals and conference proceedings were consulted. However, cutting of sintered cemented carbide parts, especially the turning operation, is an important task for a large number of applications where the typical properties of these materials are required. Therefore, the aim of this research was to carry out internal turning experiments in the manufacture of sintered cemented carbide dies used to forge beer cans. The focus of the experiments was to measure and analyze the workpiece surface roughness and wear of cutting edges used in internal turning process. Therefore, samples of sintered cemented carbide WC-Co (12% Co) were submitted to internal turning process with PCD insert tool. Cutting speed and feed rate were used as input variables in the experiments. It was found that, neither very low cutting speeds, nor high feeds can be used to avoid early breakage of the tool. Moreover, for the experiments where no early tool breakage occurred, the increase of feed caused the number of cutting passes prior to the cutting edge breakage to decrease and the workpiece surface roughness to increase. The experiments performed in this work confirm that sintered cemented carbide internal turning, besides being viable, is also feasible to be used to replace grinding operations, at least in terms of surface quality obtained.