Cutting Insert Clearance Geometry for Edge Bite Resistance

The patent applies local quality by providing different clearance angle characteristics at different locations of the major cutting edge. Specifically, a first clearance angle changing portion is provided near the corner edge where the cutting edge first bites into the workpiece, with a smaller clearance angle to reduce initial load and prevent damage. A second clearance angle changing portion is provided farther from the corner edge with a larger clearance angle to ensure smooth engagement and chip flow. This localized differentiation resolves the contradiction between smooth engagement and damage resistance.

The patent modifies the conventional rectangular cutting insert by adding a protruding portion at the corner region where the major cutting edge connects to the corner edge. This protruding portion creates a localized reinforcement structure that increases edge strength precisely where the cutting edge is most vulnerable during biting. The rest of the insert maintains its simple rectangular shape, preserving ease of manufacture while locally enhancing strength where needed.

The patent applies parameter changes by varying the clearance angle parameter along the length of the protruding portion. The first clearance angle changing portion has a smaller clearance angle near the corner edge to strengthen the edge and prevent damage during initial biting. The second clearance angle changing portion has a larger clearance angle farther from the corner edge to facilitate chip flow and prevent entrapment. This gradual parameter change optimizes both edge strength and chip evacuation.