Reversible Cutting Insert Flank Geometry for Chip Abrasion Control
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Solution Overview
Problem
Conventional cutting inserts with negative-type configurations face issues where chip abrasion damages the rake face, leading to changes in cutting performance and machining surface quality due to the narrowing of the space above the rake face and potential deviations in the insert's posture during use.
Innovation Solution
A cutting insert design featuring a major cutting edge, minor cutting edges, and connecting cutting edges with specific clearance angles, allowing for a larger gap between the flank and rotational trajectory without a negative radial rake angle, and enabling the insert to be reversed for continued use without damaging the rake face.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the radial rake angle is set to a negative value to prevent edge portion overlap, then the gap between flank and rotational trajectory increases, but the space above the rake face narrows causing poor chip discharge
Solution Approach 1:
The flank is divided into multiple segments with different clearance angles: the first flank portion has a first clearance angle, while the second flank portion has a second clearance angle that is larger than the first. This segmentation allows different regions of the flank to serve different functions - the first portion maintains strength and prevents overlap, while the second portion creates space for chip discharge.
Solution Approach 2:
Different portions of the flank are given different geometric properties (clearance angles). The first flank portion has a smaller clearance angle optimized for preventing overlap and maintaining strength, while the second flank portion has a larger clearance angle optimized for chip discharge space. This local differentiation resolves the contradiction between strength and chip discharge.
2Duration of action of stationary object
If the cutting insert is reversed for continued use, then the service life extends, but the rake face may be damaged by chip abrasion
Solution Approach 1:
The patent designs the flank geometry in advance to prevent chip abrasion of the rake face before it occurs. By creating sufficient space between the flank and rotational trajectory through the dual-clearance-angle design, chips are directed away from the rake face, preventing abrasion damage and enabling safe reversal for extended service life.
3Strength
If the first minor cutting edge flank is recessed toward the center side, then the gap between flank and rotational trajectory increases, but the structural strength may be reduced
Solution Approach 1:
The flank is designed with non-uniform clearance angles where the first portion has a smaller angle and the second portion has a larger angle. This local differentiation allows the first portion to maintain structural integrity while the second portion provides the necessary gap for chip discharge, resolving the contradiction between gap size and structural strength.
Data Source
AI summary
A cutting insert has a cutting edge formed on part of an intersecting ridge line portion of an upper face or a lower face and a side face. The cutting edge includes a major cutting edge, a minor cutting edge, and a connecting cutting edge that connects the major cutting edge and the minor cutting edge. A minor cutting edge flank that is part of the side face and that corresponds to the minor cutting edge includes a first minor cutting edge flank that connects to the minor cutting edge and that has a clearance angle of 0°, and a second minor cutting edge flank that connects to the first minor cutting edge flank and that has a clearance angle of a negative value. A connecting cutting edge flank that is part of the side face and that corresponds to the connecting cutting edge includes a first connecting cutting edge flank that connects to the connecting cutting edge and that has a clearance angle of 0° or greater, and a second connecting cutting edge flank that connects to the first connecting cutting edge flank and has a clearance angle that is greater than the clearance angle of the first connecting cutting edge flank.