Cutting Insert Rake Geometry for Strength and Chip Evacuation
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Solution Overview
Problem
Cutting inserts face challenges in balancing cutting edge strength and chip evacuation, with negative axial rake angles enhancing strength but leading to chip clogging, and positive angles improving evacuation but reducing strength.
Innovation Solution
A cutting insert design with a negative land that gradually changes to a positive angle, combined with a wiper edge and a predominantly flat upper surface, enhances cutting edge strength while improving chip evacuation and surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a negative axial rake angle is used, then cutting edge strength increases, but chip evacuation deteriorates causing clogging and rubbing
Solution Approach 1:
The invention applies different rake angle characteristics to different regions of the cutting insert. The corner region (adjacent to the corner edge) has a negative rake angle to enhance cutting edge strength, while the central region has a positive rake angle to improve chip evacuation. This spatial differentiation of geometric properties resolves the contradiction between strength and chip flow.
Solution Approach 2:
The rake surface is divided into distinct zones: a corner region with negative rake angle and a central region with positive rake angle. This segmentation allows each zone to fulfill its specific function - the corner zone provides strength while the central zone facilitates chip evacuation, eliminating the need to choose between conflicting requirements.
2Object-generated harmful factors
If a positive axial rake angle is used, then chip evacuation improves, but cutting edge strength decreases
Solution Approach 1:
The invention applies different rake angle characteristics to different regions of the cutting insert. The corner region (adjacent to the corner edge) has a negative rake angle to enhance cutting edge strength, while the central region has a positive rake angle to improve chip evacuation. This spatial differentiation of geometric properties resolves the contradiction between strength and chip flow.
Solution Approach 2:
The rake surface is divided into distinct zones: a corner region with negative rake angle and a central region with positive rake angle. This segmentation allows each zone to fulfill its specific function - the corner zone provides strength while the central zone facilitates chip evacuation, eliminating the need to choose between conflicting requirements.
3Manufacturing precision
If the upper surface is made flat for precise grinding, then manufacturing precision improves, but chip evacuation may be affected
Solution Approach 1:
The invention applies different surface characteristics to different regions. The central upper surface is made flat to enable precise grinding and manufacturing, while the corner region incorporates a negative rake angle that provides both manufacturing precision and improved chip evacuation. This localized differentiation resolves the contradiction between manufacturability and chip flow.
Data Source
AI summary
A cutting insert which is excellent in both cutting edge strength and chip evacuation is provided. A corner edge of the cutting insert is formed in an arc shape. In a direction perpendicular to a rotation axis of a body, a width of the corner edge is 40% or more and 50% or less of a width of the cutting insert. An upper surface has a negative land which is formed along a cutting edge and has a negative angle. The angle of the negative land increases from one end, which is connected to an inner cutting edge, of both ends of the corner edge toward the other end.