Indexable Cutting Insert Geometry for Higher Edge Strength
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Solution Overview
Problem
Conventional substantially circular cutting inserts have weak strength due to the proximity of the cutting edge to the mounting hole, leading to insufficient strength against load, and the provision of recessed parts for indexing reduces the insert's thickness and strength, making it prone to damage.
Innovation Solution
A cutting insert with a shape featuring a substantially rounded quadrangular shape in plan view, comprising semicircular and linear portions, with cutting edges on both sides, allowing for increased strength and reduced risk of damage, and an indexable rotary cutting tool design that maintains strength without the need for recessed parts for indexing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a substantially circular cutting insert is used, then the indexing of cutting edge portions is facilitated, but the strength of the cutting insert is weak due to the proximity of the cutting edge to the mounting hole
Solution Approach 1:
The cutting insert is divided into a quadrangular portion and two semicircular portions, creating distinct functional zones. The quadrangular portion provides structural strength and mounting stability, while the semicircular portions provide cutting edges and indexing capability. This segmentation allows each portion to optimize its specific function without compromising the other.
Solution Approach 2:
The cutting insert employs an asymmetric shape combining quadrangular and semicircular portions rather than a purely circular or quadrangular form. This asymmetric design allows the insert to achieve both the indexing benefits of circular shapes and the strength advantages of quadrangular shapes with larger distances from mounting holes to cutting edges.
2Ease of operation
If recessed parts are provided on the peripheral side surface for indexing, then the indexing of cutting edge portions is facilitated, but the strength of the cutting insert is reduced due to the reduction in thickness
Solution Approach 1:
The indexing function is built into the overall shape of the cutting insert through the combination of quadrangular and semicircular portions, rather than requiring preliminary recessed parts to be created. The shape itself provides the indexing capability, eliminating the need for additional material removal and preserving strength.
Data Source
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AI summary
A cutting insert with remarkably high strength is provided despite such cutting insert having cutting edges which each have substantially the same shape as that of a conventional substantially circular cutting insert and which are substantially equal in number to those thereof. The present invention provides a cutting insert 1 comprising a first end surface 2, a second end surface 3 and a peripheral side surface 4 extending therebetween. The first end surface 2 and the second end surface 3 each have a shape comprised of one substantially quadrangular portion 8 and two substantially semicircular portions 9 which are respectively joined to two opposing sides of the substantially quadrangular portion 8. An intersecting edge between each of the first end surface 2 and the second end surface 3 and the peripheral side surface 4 is provided with a cutting edge 5. The cutting edge 5 is formed in at least part of the substantially semicircular portion 9. A mounting hole 7 is formed so as to penetrate substantially respective centers of the first end surface 2 and the second end surface 3. At least part of a portion of the peripheral side surface 4 which is adjacent to the substantially quadrangular portion 8 of each of the first end surface 2 and the second end surface 3, and at least part of a portion of the peripheral side surface 4 which is adjacent to the substantially semicircular portion 9, each have a function of coming into contact with an insert seat.