Asymmetric Cutting Insert Geometry for High-Feed Back-Turning
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Solution Overview
Problem
Conventional cutting inserts with small corner angles face challenges in secure chip discharge and stable mounting during both front-turning and back-turning, particularly in high feed back-turning, due to limited space for chip formation and increased load, leading to chip drooping and machining quality issues.
Innovation Solution
A double-sided cutting insert with a rhombus-shaped upper surface and mirror-symmetrical lower surface, featuring a major cutting edge for front-turning and a minor cutting edge for high feed back-turning, along with a unique rake surface and chip former design to ensure smooth chip generation and discharge, with corner angles between 66° and 75° to balance chip thickness and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the corner angle of the cutting insert is small, then the entering angle during back-turning is secured, but the upper and lower surfaces of the cutting insert become smaller, reducing space for chip former formation and inducing chip discharge
Solution Approach 1:
The cutting insert employs asymmetric surface area distribution with a large upper surface and a smaller lower surface. The upper surface has area Su and the lower surface has area Sl, where Su > Sl. This asymmetric design allows the upper surface to provide sufficient space for chip former formation and chip discharge, while the lower surface maintains adequate size for stable mounting. The asymmetric configuration resolves the contradiction by allocating surface area according to functional requirements rather than using equal areas.
Solution Approach 2:
The invention utilizes the vertical dimension by designing different surface areas for the upper and lower surfaces of the cutting insert. Instead of attempting to maximize both surfaces equally in the horizontal plane, the solution accepts that the lower surface can be smaller since it only needs to provide mounting stability, while the upper surface is enlarged to accommodate chip formation and discharge requirements. This dimensional approach allows the corner angle to be small for good entering angle while maintaining sufficient upper surface area.
2Manufacturing precision
If the corner angle of the cutting insert is small, then the entering angle during back-turning is improved, but the load during front-turning increases
Solution Approach 1:
The cutting insert applies the principle of local quality by providing different surface areas for different functions: the upper surface is designed with larger area to accommodate chip formation and discharge, while the lower surface has smaller area sufficient for mounting. This localized optimization allows the corner angle to be small (improving back-turning entering angle) while the upper surface provides adequate space for chip handling, indirectly supporting front-turning performance by ensuring proper chip discharge even under increased load conditions.
3Manufacturing precision
If the corner angle of the cutting insert is small, then the entering angle during back-turning is secured, but the length for chip former formation becomes very small, making it difficult to use for high feed back-turning
Solution Approach 1:
The cutting insert employs asymmetric surface area distribution with a large upper surface and a smaller lower surface. The upper surface has area Su and the lower surface has area Sl, where Su > Sl. This asymmetric design allows the upper surface to provide sufficient space for chip former formation and chip discharge, while the lower surface maintains adequate size for stable mounting. The asymmetric configuration resolves the contradiction by allocating surface area according to functional requirements rather than using equal areas.
4Manufacturing precision
If the corner angle of the cutting insert is small, then the entering angle during back-turning is improved, but the mounting surface area is reduced, affecting stable mounting
Solution Approach 1:
The cutting insert employs asymmetric surface area distribution with a large upper surface and a smaller lower surface. The upper surface has area Su and the lower surface has area Sl, where Su > Sl. This asymmetric design allows the upper surface to provide sufficient space for chip former formation and chip discharge, while the lower surface maintains adequate size for stable mounting. The asymmetric configuration resolves the contradiction by allocating surface area according to functional requirements rather than using equal areas.
Data Source
AI summary
A cutting insert capable of performing front-turning and high feed back-turning according to one embodiment includes: an upper surface; a lower surface opposite to the upper surface in a vertical direction; a side portion configured to connect the upper surface and the lower surface; a mounting hole extending through the upper surface and the lower surface; and a plurality of cutting edges formed at edges where the upper surface meets the side portion, wherein the upper surface has one or more cutting corners, the plurality of cutting edges include a major cutting edge and a minor cutting edge extending from the cutting corner, and a representative inclination of the minor cutting edge used for high feed back-turning is greater than a representative inclination of the major cutting edge used for front-turning with respect to a virtual reference plane perpendicular to the vertical direction.