Cutting Insert Flank Geometry for Corner Edge Damage Reduction
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Solution Overview
Problem
Conventional cutting inserts face challenges in suppressing damage to the corner cutting edge during machining, particularly when the clearance angle of the corner cutting edge is large and the wedge angle is small, leading to reduced tool life.
Innovation Solution
A cutting insert with a curved third side surface part and negative clearance angle, where the length in the width direction of the third side surface part is largest at one boundary and gradually decreases towards another, and the clearance angle varies to minimize damage, combined with a through hole for indexable use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the clearance angle of the corner cutting edge is increased to improve chip discharge, then the wedge angle becomes smaller, but this leads to increased damage to the corner cutting edge and reduced tool life
Solution Approach 1:
The patent applies different clearance angle values to different regions of the flank surface. The third side surface part (corresponding to the corner cutting edge) has a first clearance angle, while the first and second side surface parts (corresponding to major cutting edges) have a second clearance angle that is larger than the first. This local differentiation allows the corner cutting edge to maintain sufficient wedge angle for strength while other regions have larger clearance angles for chip discharge.
Solution Approach 2:
The flank surface is segmented into three distinct side surface parts (first, second, and third) with different clearance angle characteristics. The third side surface part connecting to the corner cutting edge has a smaller clearance angle, while the first and second side surface parts connecting to major cutting edges have larger clearance angles. This segmentation resolves the contradiction by allowing optimized parameters for each specific cutting edge function.
2Ease of manufacture
If the flank is designed with a uniform negative clearance angle to simplify manufacturing, then the corner cutting edge clearance angle becomes large, but this makes it difficult to suppress damage in the corner cutting edge
Solution Approach 1:
The patent implements a non-uniform negative clearance angle design where the third side surface part has a different clearance angle than the first and second side surface parts. This local quality differentiation maintains the overall negative clearance angle concept for manufacturability while specifically protecting the corner cutting edge region from excessive damage.
3Productivity
If the third side surface part has a large clearance angle to improve chip discharge, then chip flow is enhanced, but the wedge angle becomes small leading to corner cutting edge damage
Solution Approach 1:
The patent assigns a smaller clearance angle to the third side surface part compared to the first and second side surface parts. This creates a local quality difference where the corner cutting edge region maintains higher strength through larger wedge angle, while other regions optimize for chip discharge with larger clearance angles.
Data Source
AI summary
A cutting insert has two end surfaces and a side surface joined to the two end surfaces, and the cutting insert is formed in a substantially polygonal shape. The cutting insert comprises a cutting edge and a flank connected to the cutting edge on the side surface and having a negative clearance angle. The cutting edge has a major cutting edge, an inner cutting edge, and a corner cutting edge that is formed in a curved shape between the major cutting edge and the inner cutting edge. The flank has a first to third side surface parts that are connected to the major cutting edge, the inner cutting edge and the corner cutting edge, respectively. The length in the width direction of the third side surface part is largest at a first boundary between the third side surface part and the first side surface part and gradually decreases from the first boundary to at least an intermediate position toward a second boundary between the third side surface part and the second side surface part.