Segmented Cutting Insert Geometry for Short Chip Division
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Solution Overview
Problem
Existing cutting tools 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 with a rake face featuring 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 breaker projection is divided into multiple segments: a first breaker projection and a second breaker projection positioned at different heights and locations. This segmentation allows the chip to be broken at multiple points simultaneously, effectively dividing it into short pieces rather than just curling it, thereby resolving the inability to achieve short chip lengths with conventional single-breaker designs
Solution Approach 2:
The invention introduces a vertical dimension to chip breaking by positioning the second breaker projection at a different height (in the direction perpendicular to the seating surface) than the first breaker projection. This multi-level arrangement in three-dimensional space enables effective chip division into short pieces, transforming the conventional two-dimensional breaker design into a three-dimensional chip control system
2Ease of manufacture
If the rake face geometry is simplified, then manufacturing is easier, but chip control and breaking effectiveness deteriorate
Solution Approach 1:
The rake face is designed with locally differentiated features: inclined portions positioned between the breaker projections and the cutting edge, and step surfaces connecting the breaker projections at different heights. This local quality variation optimizes chip control at specific locations while maintaining overall manufacturability, ensuring reliable chip breaking without requiring complete redesign of the entire rake face geometry
Data Source
AI summary
A cutting edge includes a nose portion, a first cutting edge portion, and a second cutting edge portion. 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.