Cutting Insert Asymmetric Rake Projections for Ductile Chip Control
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Solution Overview
Problem
Cutting inserts used for grooving in metal materials with excellent ductility face challenges in chip discharge, leading to chip accumulation and damage to the machined surface and the cutting tool, as existing designs fail to effectively curl and break chips with high ductility materials.
Innovation Solution
A cutting insert with a rake face featuring three projections of different distances from the cutting edge, where the second projection's top is lower than an imaginary line connecting the first and third projections, and all have tangent points to an imaginary circular arc, facilitating stable chip curling and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cutting insert designs with linearly arranged projections are used, then chip breaking is achieved for normal materials, but chips of highly ductile materials slide through without curling and remain on the ascending portion
Solution Approach 1:
The patent applies asymmetry by positioning the top of the second projection lower than the imaginary straight line connecting the tops of the first and third projections. This asymmetric arrangement creates an effective curling path for chips that prevents sliding through, solving the problem of chip accumulation on the ascending portion when machining highly ductile materials.
Solution Approach 2:
The patent employs curvature by arranging all three projections to have tangent points to an imaginary circular arc. This circular arc configuration guides chips along a curved path, ensuring they are properly curled and directed away from the ascending portion, preventing chip accumulation and associated damage.
2Object-generated harmful factors
If chip curling is reduced to prevent chip remaining on the ascending portion, then chip accumulation is avoided, but chips in extended state graze the ascending portion and are caught by the cutting insert and holder
Solution Approach 1:
The asymmetric positioning of the second projection (lower than the imaginary straight line connecting first and third projections) creates an optimal chip curling geometry that ensures chips are properly contained and directed, preventing both accumulation on the ascending portion and extended-state grazing that would cause damage.
Solution Approach 2:
The circular arc arrangement of the three projections provides a smooth curved path for chip flow. This curvature ensures chips are guided along the rake face in a controlled manner, preventing them from remaining on the ascending portion while avoiding extended-state contact that would lead to damage of the machined surface and tool.
3Productivity
If three projections are arranged with tops on an imaginary straight line, then chip breaking is improved, but chips of ductile materials ride on the ascending portion without being curled
Solution Approach 1:
The patent modifies the linear arrangement by positioning the second projection's top lower than the imaginary straight line connecting the first and third projections. This asymmetric adjustment maintains chip breaking efficiency while adding the necessary curling action to reliably discharge chips, especially those from highly ductile materials.
Solution Approach 2:
By arranging projections along a circular arc rather than a straight line, the patent introduces curvature that actively curls chips during their path along the rake face. This curved arrangement maintains the chip breaking efficiency of multiple projections while ensuring stable chip discharge by preventing chips from riding on the ascending portion.
Data Source
AI summary
A cutting insert includes a rake face region located on an upper surface, a flank located on a front surface, and a cutting edge located at an intersection between the rake face region and the flank. At least three types of projections having different distances from the cutting edge are on the rake face region. When these three types of projections are arranged in the order of increasing distance from the cutting edge, namely, a first projection, a second projection and a third projection, the top of the second projection is lower than an imaginary straight line connecting the top of the first projection and the top of the third projection in the side view.