Machining with chamfered tools

Abstract

The application of chamfered tools in metal cutting is yet very much limited. Despite their better edge strength, relatively little research have been done so far to understand the effect of tool geometry on cutting variables and the mechanics of chip formation. The present study focuses on the performance of chamfered tools during continuous and interrupted turning of medium carbon low alloy steel. Several cutting tests were conducted in turning on a conventional lathe machine with cemented carbide chamfered solid tools and its performance with respect to cutting force, tool life and chip formation have been investigated. The tools were ground to different chamfer widths varying from 0.10 to 0.40 mm at a constant chamfer angle of 45° and to a varying main cutting edge chamfer angles ranging from 15° to 35° at a constant chamfer width of 0.20 mm. For the purpose of interrupted turning, four axial slots were milled on the cylindrical work material. It has been observed that both in continuous and interrupted turning, with the increase chamfer width, both the main cutting force and feed forces increases and the effect on the feed force is more significant. With the increase of chamfer angle, cutting forces increased but at the maximum chamfer angle, both main cutting force and feed force were low. The chip thickness was observed to decrease with increasing chamfer width. However the effect of chamfer angle on the chip thickness was insignificant. Shear angle increased with the increase of both width and angle of the chamfer.