Indexable Cutting Insert Large Corner Radius Mounting
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Solution Overview
Problem
Designing small indexable cutting inserts with large corner radii poses a challenge in maintaining strength and providing sufficient surface space for mounting without compromising the insert's integrity, especially for double-sided inserts where a trade-off is needed between screw or bolt size and insert material.
Innovation Solution
The cutting insert features two opposing end surfaces with a central surface portion disposed at a greater distance from the hole's axis than the supporting surface portion, a peripheral side surface with curved portions between major and minor side surfaces, and a hole extending through the major side surfaces to facilitate alignment and clamping, ensuring proper mounting and indexing while maintaining strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the insert size is reduced for machining smaller items, then the insert can machine smaller workpieces, but the strength of the insert and the surface space for mounting are compromised
Solution Approach 1:
The patent positions the mounting hole through the major side surface rather than through the end surface or minor side surface. This dimensional change allows the hole to be larger without compromising the insert's structural integrity, as the hole passes through the thickest part of the insert where material is most abundant, thereby maintaining strength while enabling proper mounting of small inserts.
2Reliability
If the hole size is increased for proper screw mounting, then the mounting reliability is improved, but the insert material between the hole and working surfaces becomes more fragile
Solution Approach 1:
By repositioning the hole through the major side surface, the patent utilizes the maximum available material thickness in that dimension. This allows a larger hole diameter for reliable screw mounting while the hole passes through the region of greatest material abundance, preserving structural strength in the critical areas where material is thinnest.
3Productivity
If a large corner radius is provided for roughing operations, then the cutting performance is improved, but the insert requires more material and becomes more difficult to mount securely
Solution Approach 1:
The patent accommodates large corner radii by orienting the mounting hole through the major side surface, which provides the maximum material cross-section. This dimensional approach allows the insert to have large radii for effective roughing operations while still providing sufficient material around the hole location to ensure secure mounting.
4Productivity
If the insert is made double-sided to increase the number of usable edges, then the productivity is improved, but the trade-off between screw size and insert strength becomes more critical
Solution Approach 1:
For double-sided inserts, positioning the hole through the major side surface allows both sides of the insert to maintain adequate material thickness. This dimensional configuration enables the insert to be flipped and indexed while both the original and opposite sides have sufficient material to support the mounting hole and provide structural strength.
Data Source
Figure 1~2
Figure 3~6
Figure 7~9B
AI summary
A cutting insert (25; 125A; 125B) includes two opposing end surfaces (35, 41; 141A; 141B), each end surface having four corners and, in a center thereof, a central surface portion (39, 45; 145A; 145B), a peripheral side surface (47; 147A; 147B) extending between the two end surfaces, the peripheral side surface comprising two opposing major side surfaces (49a-b; 149Aa-b; 149Ba-b), two opposing minor side surfaces (53a-b; 153Aa-b; 153Ba-b), and two curved surface portions (67a-b; 167Aa-b; 167Ba-b), one curved surface portion of the two curved surface portions being disposed between each minor side surface and each major side surface, a hole (51; 151A; 151B) extending through the cutting insert (25; 125A; 125B) from one of the major side surfaces to the other of the major side surfaces; and at least one cutting edge (63a-b; 163A; 163B) defined by an intersection of the peripheral side surface with at least one of the two end surfaces. Each cutting edge includes a curved portion (175A, 175B), the curved portion for each cutting edge extending over more than one quarter of a width (W) of the cutting insert (25; 125A; 125B) between the two major side surfaces, and in that a portion (171A; 171B) of the peripheral side surface adjacent the cutting edge defines an obtuse angle (ΘA; ΘB) with a plane (PA; PB) of the end surfaces.