Variable-Rake Cutting Insert for Durable Acute-Angle Machining
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Solution Overview
Problem
Cutting inserts with acute angle corners face durability issues when the internal angle is small, necessitating control measures like reducing feed rates to maintain efficiency in cutting processes.
Innovation Solution
A cutting insert design featuring a convex curvilinear first corner and a rake surface with a varying rake angle, which enhances durability and efficiency by optimizing the cutting edge geometry and chip flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the internal angle of the acute angle corner is made small to achieve sharp cutting edges, then cutting precision is improved, but durability of the cutting edge decreases
Solution Approach 1:
The patent applies local quality by differentiating the rake angle across different regions of the cutting insert. The first region (near the acute angle corner) has a smaller rake angle to enhance durability, while the second region has a larger rake angle to maintain cutting precision and chip flow efficiency. This spatial variation in geometric properties resolves the contradiction between sharpness and durability.
Solution Approach 2:
The rake surface is segmented into multiple regions with different rake angles. The first region adjacent to the acute angle corner has a first rake angle optimized for durability, while the second region has a second rake angle optimized for cutting performance. This segmentation allows each region to independently optimize its function without compromising the other.
2Reliability
If feed rate is decreased to maintain cutting edge durability, then durability is improved, but productivity of the cutting process decreases
Solution Approach 1:
By implementing different rake angles in different regions, the patent enables the cutting insert to maintain high durability at the critical acute angle corner while preserving efficient chip flow and cutting performance in other regions. This allows sustained high feed rates without premature edge failure.
3Object-generated harmful factors
If rake angle is increased to improve chip flow, then chip discharge performance is improved, but durability of the acute angle corner decreases
Solution Approach 1:
The patent strategically places a smaller rake angle in the first region adjacent to the acute angle corner to maximize durability, while implementing a larger rake angle in the second region to optimize chip flow and discharge performance. This localized differentiation resolves the contradiction between edge strength and chip evacuation efficiency.
Data Source
AI summary
A cutting insert may include an upper surface, a lower surface, a lateral surface and a cutting edge. The upper surface may include a first corner, a first side, a second side and a rake surface. The cutting edge may include a first cutting edge located on the first corner, and a second cutting edge located on the first side. The first cutting edge may include a first part. The first part may be located between a midportion of the first corner and the first side, and may come closer to a reference plane as going away from the first side. The rake surface may include a first region located along the first part. A rake angle in the first region may become smaller as coming closer to the midportion of the first corner.