Rake-Face Cutting Insert Structure for Short Chip Division
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Solution Overview
Problem
Existing cutting inserts struggle to divide chips into short pieces during the pulling process, as described in Japanese Patent Laying-Open No. 2005-1024, Japanese Patent Laying-Open No. 06-55312, and Japanese Patent Laying-Open No. 2007-301669.
Innovation Solution
A cutting insert design featuring a rake face with specific projections and breaker portions, including a bisector and inclined surfaces, allows for the division of chips into short pieces by applying stress to the chip ends, enabling effective curling and fragmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional breaker projections are used on the rake face, then chip breaking is attempted, but the chips cannot be divided into short pieces effectively
Solution Approach 1:
The single breaker projection is segmented into multiple breaker projections (first breaker projection and second breaker projection) arranged at different positions and angles on the rake face. This segmentation allows the chip to be broken at multiple points simultaneously, effectively dividing it into short pieces rather than attempting to break the entire chip length at once.
Solution Approach 2:
Each breaker projection is given different local characteristics - different positions, different inclination angles, and different distances from the cutting edge. The first breaker projection has a first inclination angle while the second breaker projection has a second inclination angle different from the first. This local quality variation enables effective chip breaking at different locations along the chip path.
2Ease of operation
If multiple breaker projections are added to improve chip division, then chip management improves, but the rake face structure becomes more complex
Solution Approach 1:
The multiple breaker projections serve multiple functions simultaneously - they act as chip breakers, define chip flow paths, and control chip curling. By integrating these functions into a single rake face structure with strategically positioned projections, the design achieves effective chip management without adding separate complex mechanisms.
Data Source
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AI summary
A cutting insert has a rake face, a flank face, and a seating surface. A cutting edge includes a nose portion, a first cutting edge portion, and a second cutting edge portion. The rake face is provided with a first projection, a second projection, a third projection, and a fourth projection. When a boundary between a first inclined portion and a first breaker portion, a boundary between a first step surface and a second breaker portion, a boundary between a second inclined portion and a third breaker portion, and a boundary between a second step surface and a fourth breaker portion are a first position, a second position, a third position, and a fourth position, respectively, the second position is higher than the first position and the fourth position is higher than the third position in a direction perpendicular to the seating surface, and a distance between the first position and the third position is greater than a distance between the second position and the fourth position in a direction parallel to the seating surface.