Cutting Insert Breaker Geometry for Chip Discharge and Edge Strength
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Solution Overview
Problem
Existing cutting inserts face challenges in efficiently discharging chips during high-feed machining, leading to potential damage to the machined wall surface and reduced insert strength due to the formation of breakers along the main cutting edge.
Innovation Solution
A cutting insert with a polygonal plate shape, featuring a rake surface with a first plane and a breaker that includes first and second inclined surfaces, is designed to ensure effective chip discharge and enhance cutting edge strength. The breaker is formed on the entire circumference of the cutting insert, with specific distance relationships between the cutting edge, the first plane, and the breaker's deepest portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a breaker is formed deeply on the rake surface to improve chip discharge performance, then chip discharge performance is improved, but the thickness of the insert is reduced and the strength of the insert is reduced
Solution Approach 1:
The patent applies local quality by forming the breaker only in specific regions of the rake surface rather than uniformly across the entire surface. The breaker is formed with varying depth and inclination angles in different zones: a first breaker region with a first inclination angle and a second breaker region with a second inclination angle. This localized variation allows optimal chip discharge in critical areas while preserving insert thickness and strength in other regions.
Solution Approach 2:
The patent employs parameter changes by varying the inclination angles and depths of the breaker surfaces. The first inclined surface has a first inclination angle and the second inclined surface has a second inclination angle, with the breaker depth controlled to satisfy specific distance relationships (L11>L12>L13). These parameter variations enable effective chip discharge while maintaining sufficient insert strength.
2Force
If a continuous integral breaker surface is formed to reduce cutting resistance, then cutting resistance is reduced, but chip discharge direction becomes unstable and may damage the machined wall surface
Solution Approach 1:
The patent applies segmentation by dividing the continuous breaker surface into distinct zones: a first breaker region with a first inclined surface and a second breaker region with a second inclined surface. This segmentation allows different regions to perform different functions - one region controls chip flow direction while the other reduces cutting resistance, preventing chips from damaging the machined wall surface.
Solution Approach 2:
Different regions of the breaker are given different local properties through varying inclination angles. The first inclined surface has a first inclination angle optimized for chip discharge control, while the second inclined surface has a second inclination angle optimized for reducing cutting resistance. This local differentiation resolves the contradiction between stable chip discharge and low cutting resistance.
3Stability of the object's composition
If the breaker is formed deeply to suppress chip elongation, then chip deformation is suppressed, but the insert thickness is reduced and the insert may be damaged at an early stage
Solution Approach 1:
The patent uses parameter changes to control breaker depth and inclination angles, satisfying the relationship L11>L12>L13 where L11 is the distance from the seating surface to the cutting edge tip, L12 is the distance from the seating surface to the first plane, and L13 is the distance from the seating surface to the deepest portion of the breaker. This controlled parameter variation suppresses chip elongation while preserving sufficient insert thickness and strength.
Data Source
AI summary
A rake surface of a cutting insert according to the present disclosure is formed with a first plane parallel to a seating surface. An outer periphery of the first plane includes a plurality of curved portions having different radii of curvature. On the rake surface, a breaker is provided between a cutting edge portion and the first plane around an entire circumference of the cutting insert. When a distance from the seating surface to a tip of the cutting edge portion in a thickness direction is denoted by L11, a distance from the seating surface to the first plane in the thickness direction is denoted by L12, and a distance from the seating surface to a deepest portion of the breaker in the thickness direction is denoted by L13, a relationship of L11>L12>L13 is satisfied over an entire circumference of the cutting edge portion.