Cutting Insert Edge Geometry for Fracture Resistance and Chip Flow
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Solution Overview
Problem
Conventional cutting inserts with circular-arc-shaped cutting edges having small curvature radias are prone to fracture and suffer from inefficient chip discharge, leading to reduced tool life and chip trapping issues during machining.
Innovation Solution
A cutting insert design featuring a cutting edge with a convex circular-arc shape and a concave circular-arc shape, both with specific curvature radii and orientations, along with a bottom edge, to enhance resistance to fracturing and improve chip discharge efficiency, where the cutting edge is rotated relative to the workpiece and mounted on a tool body to facilitate effective cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a circular-arc-shaped cutting edge with a small curvature radius is formed at the apex of the bell-shaped major cutting edge, then the cutting edge can achieve a sharp apex for effective cutting, but the cutting edge becomes prone to fracture when contacting the workpiece material
Solution Approach 1:
The cutting edge is designed with a convex circular-arc shape having a first curvature radius, replacing the conventional small curvature radius apex. This larger curvature radius at the cutting edge provides better strength and fracture resistance while maintaining effective cutting capability, directly resolving the contradiction between sharpness and strength.
2Ease of operation
If the major cutting edge is inclined such that height decreases from the central axis toward the outer periphery, then the cutting edge can effectively engage the workpiece, but chips are prone to move toward the outer periphery and become trapped between the cutting insert and the wall surface
Solution Approach 1:
The invention introduces a new dimensional feature by forming a second connecting part with a concave circular-arc shape that extends further in the third direction (radial direction) than the first connecting part. This creates a chip discharge path in the radial dimension, allowing chips to escape laterally rather than being forced toward the outer periphery, thus preventing chip trapping while maintaining effective cutting engagement.
3Volume of moving object
If the cutting edge is positioned closer to the central axis, then the cutting insert can maintain a compact structure, but chip discharge efficiency deteriorates due to restricted chip movement space
Solution Approach 1:
The cutting edge is segmented into multiple functional parts: a first connecting part with convex circular-arc shape for cutting engagement, and a second connecting part with concave circular-arc shape extending further radially for chip discharge. This segmentation allows the cutting insert to maintain a compact overall structure while providing dedicated space for efficient chip evacuation, resolving the contradiction between compactness and chip discharge efficiency.
Data Source
AI summary
In an end view, a cutting insert 10 comprises a first connecting part 30A which is inclined such that the first connecting part 30A travels in a first direction as it heads away from a second peripheral side surface part 18 and approaches a fourth peripheral side surface part 22, and also comprises a second connecting part 30B which is connected to a center point serving as an end of the first connecting part 30A and which is inclined such that the second connecting part 30B travels in a third direction as it heads away from the second peripheral side surface part 18 and approaches the fourth peripheral side surface part 22. A cutting edge 24 comprises: a first cutting edge part 24A which is formed on the first connecting part 30A so as to be distant, by a first distance L1, from a virtual plane PR1 including a center point C1; a second cutting edge part 24B which has, in a side view, a concave circular-arc shape having a second curvature radius smaller than a first curvature radius and which is formed on the second connecting part 30B so as to be distant, by a second distance L2 greater than the first distance L1, from the virtual plane PR1; and a third cutting edge part 24C connecting the first cutting edge part 24A and the second cutting edge part 24B.