Cutting insert for low ranges of feed and depth of cut

Abstract

An indexable cutting insert of the type having a corner radius and a corner angle adapted for finishing operations comprises a pair of substantially parallel spaced apart faces and at least one peripheral side surface being substantially normal to said faces. A pair of straight cutting edge extend away from the corner at the juncture of the peripheral side surface and a plane positioned closely adjacent and below the juncture of a respective face. To break the chips formed during cutting, a chip breaker recess extents rearwardly and along the cutting edges. The chip breaker recess includes a descending control surface leading to the bottom of the recess followed by an ascending control surface. The descending control surface comprises a first and second planar descending control surface with the first surface being at a shallow angle and the second surface being at a steep angle. The ascending surface directs the chip upwardly toward a central island formed within the plane of a respective face and away from the insert and the cutting edge. The chip breaker recess incorporates an additional shallow chip control recess formed by a raised land extending outwardly toward a corner from the central island along a bisector of a respective corner and a raised bottom surface extending above the bottom of the main chip breaker recess and around the corner. The additional chip control surfaces forming the shallow recess include an ascending corner chip control surface extending upwardly from the raised corner bottom control surface at a relatively steep angle. The recess is configured to change the curling motion of the chip at various depths of cut to enhance the chip breaking forces.