Abstract
In the 1st part of this investigation a cutting model and energy method considering the condition of side-curl of the chip was extended to the drilling with curved cutting edge drills. In this paper the torque and thrust force and the chip formation such as shear angle chip flow angle are measured and compared with those through theoretical prediction. In the case of the drills having concave or convex main cutting edges the predicted results are in good agreement with the experimental results. By using the measured values relating to the radius of side-curl of the chip and the chip flow angle at the midpoint of the cutting edge the cutting model including the cutting edge at the drill center enables to explain the variation of the torque chip flow angle and chip thickness along the cutting edge when the chip form changes from conical-helical chip into long-pitch helical one. As a result, it becomes clear that the whole chip formation along the cutting edge of the drill having curved cutting edges can be treated by using the values based on the chip form expanded to a plane.
