AN ANALYTICAL EVALUATION OF THE CUTTING FORCES IN SELF-PILOTING DRILLING USING THE MODEL OF SHEAR ZONE WITH PARALLEL BOUNDARIES .1. THEORY

The performance of a self-piloting tool is affected by its design and geometry parameters. These parameters constitute the tool-force system which directly defines quality of the machined holes, tool life and r equired power. This paper presents an analytical approach to describe the cutting forces in self-piloting drilling. The approach is useful a t the level of tool and process design. The subject has been covered i n two parts. Part one deals with the analysis of the cutting mechanics employing the shear-zone model with parallel boundaries. The analysis of the continuity condition results in better understanding of the tr aditional cutting model's characteristics, such as the chip compressio n ratio and velocity diagram. Based on this analysis and using the the rmomechanical model of the work-material resistance to cutting, a cutt ing-force model is proposed and has been verified experimentally. Copy right (C) 1996 Elsevier Science Ltd