Asymmetric Polygonal Cutting Insert Corner Changing
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Solution Overview
Problem
Cutting tools with regular polygonal cutting inserts having five or more corners face increased cutting force and reduced machining stability and accuracy due to the need for nose-radius formation and decreased side cutting edge angles when used for turning operations.
Innovation Solution
A negative-type cutting insert with a regular polygonal shape (five to eight corners) is attached to a tool holder, where one side serves as a rake face with a negative rake angle, and the other side as a front flank face, allowing corner changing and eliminating the need for nose-radius formation, with ridge portions reinforced by chamfering or honing for increased rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cutting insert with five or more corners is used to increase the number of usable corners and reduce cost, then cost-effectiveness improves, but cutting force increases and machining stability decreases
Solution Approach 1:
The cutting insert uses an asymmetric orientation where one side serves as the rake face and the adjacent side serves as the front flank face, creating an asymmetric cutting configuration that maintains high side cutting edge angles even with five or more corners, thereby reducing cutting force while preserving cost-effectiveness
Solution Approach 2:
The invention changes the geometric parameters by specifying that the side cutting edge angle should be 75 degrees or more, which fundamentally alters the cutting mechanics to reduce cutting force while maintaining the economic advantage of having five or more usable corners on the cutting insert
2Adaptability or versatility
If a cutting insert with five or more corners is used to increase the number of usable corners, then cost-effectiveness improves, but machining accuracy decreases
Solution Approach 1:
By establishing an asymmetric configuration where specific sides serve as rake and flank faces, the invention maintains consistent cutting geometry across multiple corners, ensuring high machining accuracy is preserved even when using cutting inserts with five or more corners for extended tool life and cost-effectiveness
3Adaptability or versatility
If a cutting insert with five or more corners is used to increase the number of usable corners, then cost-effectiveness improves, but cutting insert life decreases
Solution Approach 1:
By changing the side cutting edge angle parameter to 75 degrees or more, the invention reduces cutting force and improves cutting conditions, which directly extends cutting insert life while maintaining the cost-effectiveness advantage of having five or more usable corners
4Force
If the side cutting edge angle is increased to reduce cutting force, then cutting force decreases, but the number of usable corners is reduced
Solution Approach 1:
The asymmetric configuration allows the cutting insert to maintain a high side cutting edge angle of 75 degrees or more while preserving five or more usable corners, as the asymmetric orientation optimizes the cutting geometry to simultaneously achieve both force reduction and corner multiplicity
Data Source
Figure 1~2
Figure 3~4
Figure 5(a)~5(f)
AI summary
An object is to provide a cutting tool including a cutting insert for which corner changing can be performed, the cutting tool having a large number of usable corners and thereby being cost effective, reducing cutting force during machining, and ensuring high rigidity. A negative-type cutting insert (2) having a regular polygonal shape with five to eight corners is attached to an end of a tool holder (3) such that one of two adjacent sides of an outer peripheral surface (2c) serves as a rake face having a negative rake angle, the other of the two adjacent sides serves as a front flank face, a ridge between the two adjacent sides of the outer peripheral surface serves as an end cutting edge (7), and a ridge between the side that serves as the rake face and one of top and bottom surfaces serves as a side cutting edge (6), and such that corner changing can be performed.