Segmented Cutting Insert Geometry for Chip Flow and Clamping
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Solution Overview
Problem
Conventional cutting inserts with breaker grooves suffer from inadequate chip treatability due to the negative side rake angle on the rake face, which hinders chip flow and leads to contact with the machined surface, and altering the rake angle to improve chip treatability compromises clamping force during high-load machining.
Innovation Solution
A cutting insert design featuring a side cutting edge with a negative side rake angle and a breaker groove that cuts into the flank of an adjacent cutting edge, forming an invasive cut portion to facilitate chip discharge without compromising clamping force, with the breaker groove's shape and structure allowing smooth chip flow and enhanced treatability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a negative side rake angle is provided on the rake face to ensure stable clamping during high-load machining, then clamping force is improved, but chip treatability deteriorates and chips contact the machined surface
Solution Approach 1:
The rake face is segmented into multiple regions: a first region with a negative side rake angle for stable clamping, a second region with a positive side rake angle for improved chip flow, and a third region with an intermediate angle. This segmentation allows each region to perform its specific function independently, resolving the contradiction between clamping force and chip treatability.
Solution Approach 2:
Different portions of the rake face are given different local properties (different rake angles) according to their specific functional requirements. The first region has negative angles for clamping stability, while the second region has positive angles for chip discharge, creating local quality variations that solve the overall contradiction.
2Object-generated harmful factors
If the rake face is modified to improve chip discharge, then chip treatability is improved, but clamping force during high-load machining is compromised
Solution Approach 1:
The rake face is divided into functional segments where the second region with positive side rake angle specifically addresses chip discharge, while the first region with negative angles maintains clamping force. This segmentation enables simultaneous achievement of both chip treatability and clamping strength.
Solution Approach 2:
The solution moves from a single rake angle design to a multi-dimensional rake angle distribution across the rake face surface. By varying the rake angle in different spatial regions (first, second, and third regions), the invention achieves multiple functions that cannot be obtained with a uniform rake angle.
3Object-generated harmful factors
If a breaker groove is added to enhance chip treatability, then chip discharge is improved, but the complexity of the cutting insert structure increases
Solution Approach 1:
The breaker groove functionality is merged with the rake face geometry itself. The groove is formed as an integral part of the rake face structure, combining chip breaking and chip guiding functions into a single geometric feature rather than adding separate components.
Data Source
AI summary
A cutting insert has cutting edges having the same shape and provided at respective corners of a polygon in rotational symmetry about the center axis of the polygon, is clamped in an upright position to a holder, and has a negative side rake angle on a rake face of a side cutting edge. A side cutting edge is present at an intersection ridge between a polygonal face and an outer peripheral face. The outer peripheral face includes a rake face of the cutting edge and a flank of an end cutting edge of another cutting edge different from the side cutting edge. The flank has a positive slope angle in opposition to a negative side rake angle of the side cutting edge. A breaker groove extending in a front-rear direction is formed in the rake face and cuts into the flank, in such a manner as to divide the rake face.