Design of tool grinding processes for indexable inserts made of rocks

Using natural rocks as alternative cutting tool material poses a possibility to meet actual environmental, economic and geopolitical challenges. The present state of knowledge, however, is not sufficient to allow a knowledge-based design of the tool grinding process of cutting tools made of rock. For this reason, this study presents an investigation of the significance of the grinding process parameters and grinding tool specifications for the flank face and cutting edge roughness as well as for the cutting edge microgeometry besides an analysis of the scatter of the grinding results in tool grinding of rock inserts. Thus, the study contributes to a knowledge-based design of tool grinding processes of rock tools. In this context, confocal and focus variation microscopes are used besides SEM images to investigate the above mentioned factors in the plunge face grinding of rock inserts from five different rocks. The results identify the axial feed velocity of the plunge face grinding process as a highly significant influence factor for cutting edge roughness and microgeometry, while cutting speed only shows a significant influence on cutting edge microgeometry. Besides that, highly significant influences of the used rock type and the abrasive grain size are identified for all three mentioned factors. Grinding result analyses show a scatter between 0.04 and 25.00 µm depending on the parameter and rock investigated. Additionally, recommendations for the design of the tool grinding process of rock tools are presented deduced from the obtained results.