Cutting Insert Breaker Projection Curvature for Chip Control
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Solution Overview
Problem
Conventional cutting inserts face issues with chip crush and adhesion during high-feed machining or deep cutting, leading to unstable chip disposal, damage to the edge portion, and reduced tool lifetime, as well as inadequate chip control during shallow cutting.
Innovation Solution
A cutting insert with a breaker projection on the rake face that bulges gradually along the bisector, featuring a convex circular arc front apex portion and a concave circular arc side portion, designed to curl and fragment chips effectively, reducing contact area and preventing adhesion, while the inclined cutting edge and recess guide chips away from the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inclination of the breaker projection is reduced or if the breaker projection is separated farther from the nose, then chip adhesion and crush are avoided, but the chip controlling force during shallow cutting becomes weak
Solution Approach 1:
The breaker projection is designed with a convex circular arc in section along the bisector and a concave circular arc in section perpendicular to the bisector, creating a three-dimensional curved surface that optimizes chip flow control while preventing adhesion and crush
Solution Approach 2:
Different portions of the breaker projection have different curvatures tailored to specific functions: the convex circular arc provides chip controlling force during shallow cutting, while the concave circular arc prevents chip adhesion and crush during deep cutting or high-feed machining
2Ease of operation
If the breaker projection has high inclination or is close to the nose, then chip controlling force is strong, but chips are compressed, crushed, or adhere to the breaker projection
Solution Approach 1:
The convex circular arc provides the necessary inclination for strong chip controlling force, while the concave circular arc creates a surface geometry that prevents chip compression and adhesion by reducing contact area
Solution Approach 2:
The breaker projection extends in three dimensions with different curvatures in different sections: the convex circular arc in section along the bisector provides chip control, while the concave circular arc in section perpendicular to the bisector prevents adhesion, creating a multi-dimensional solution
3Device complexity
If conventional breaker projection design is used, then simple structure is maintained, but chip disposal becomes unstable during high-feed machining or deep cutting
Solution Approach 1:
The breaker projection features a convex circular arc in section along the bisector and a concave circular arc in section perpendicular to the bisector, creating an optimized three-dimensional curved surface that ensures stable chip disposal across varying machining conditions while maintaining structural simplicity
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
Provided is a cutting insert including an insert body (1) in the form of a substantially rhombic flat plate, a rake face (2) on at least one rhombic surface of the insert body (1), a corner portion provided at a corner of the rake face (2), and at least one pair of cutting edges (4) provided at a side ridge portion of the rake face (2) and crossing the corner portion (3). A breaker projection (10) is provided on the rake face (2) near the corner portion (3) so as to bulge gradually along a bisector (L) of the corner portion (3) with distance from the corner portion (3). The breaker projection (10) includes a front apex portion (11) substantially in the shape of a convex circular arc in a section along the bisector (L) and a side portion (12) which includes a recess (12a) substantially in the shape of a concave circular arc in a section perpendicular to the bisector (L). Thus, if the feed rate or depth of cut is changed, the chip disposability can be improved to obtain a highly precise finished surface quality and a long tool lifetime.