Rhombus Reversible Cutting Insert for Stable Turning and Chip Flow

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Solution Overview

Problem

Existing reversible cutting inserts for metal cutting processes, particularly in turning operations, lack optimal design features that enhance stability, chip management, and force transmission, leading to inefficiencies and potential damage during machining.

Innovation Solution

A generally rhombus-shaped reversible cutting insert with alternating obtuse and acute corner surfaces, a median plane, and strategically located abutment surfaces, allowing for indexable rotation and efficient contact with a support seat, which ensures stable retention and effective force transmission, while the design promotes positive rake angles and improved chip flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional reversible cutting inserts are used with abutment surfaces lower than corner cutting edges, then the insert can be retained in the tool holder, but the stability and positional accuracy are insufficient

Engineering Contradiction:
Improveinsert stabilityVSAvoidpositional accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The cutting insert employs an asymmetric rhombus-shaped configuration where the abutment surfaces are positioned at different elevations relative to the corner cutting edges. Specifically, the first abutment surface is lower than the first corner cutting edge while the second abutment surface is higher than the second corner cutting edge, creating an asymmetric geometry that simultaneously enhances stability and positional accuracy through selective contact points with the support seat

Inventive Principle:
Principle #4Asymmetry

2Productivity

If the cutting insert design does not include strategic abutment surface positioning, then the structure is simpler, but the force transmission and chip management are inefficient

Engineering Contradiction:
Improvecutting efficiencyVSAvoidinsert structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The cutting insert features locally differentiated abutment surfaces with specific elevations relative to the corner cutting edges. The first abutment surface is positioned lower than the first corner cutting edge to optimize force transmission in one direction, while the second abutment surface is positioned higher than the second corner cutting edge to improve chip management in the opposite direction, creating locally optimized contact zones that enhance overall cutting efficiency

Inventive Principle:
Principle #3Local quality

3Ease of operation

If all abutment surfaces are positioned symmetrically, then the manufacturing is easier, but the chip flow and cutting forces are not optimized

Engineering Contradiction:
Improvechip flowVSAvoidinsert design
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The cutting insert employs an asymmetric rhombus-shaped configuration where the abutment surfaces are positioned at different elevations relative to the corner cutting edges. Specifically, the first abutment surface is lower than the first corner cutting edge while the second abutment surface is higher than the second corner cutting edge, creating an asymmetric geometry that simultaneously enhances stability and positional accuracy through selective contact points with the support seat

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3310511B1A rhombus-shaped reversible cutting insert
Publication Date: 2024.04.03 ISCAR LTD
  • EP3310511B1 patent drawingFigure 1~2
  • EP3310511B1 patent drawingFigure 3~4
  • EP3310511B1 patent drawingFigure 5~6

AI summary

An assembly (20) of a generally rhombus-shaped reversible (i.e. double-sided) cutting insert (22) and a support seat (24). Each end surface (26) of the cutting insert (22) has a corner abutment surface (38) adjacent each nose cutting edge (36), at least one inner abutment surface (40a, 40b) on one side of a lateral plane (P2), and at least one inner abutment surface (40a, 40b) on the opposite side of the lateral plane (P2), and each corner abutment surface (38) is located closer to a median plane (M) than its adjacent nose cutting edge (36). In each index position of the cutting insert (22) on the support seat (24), only one corner abutment surface (38) is in operative contact with one (44a) of a plurality of protruding supporting members (44a, 44b, 44c) of the support seat (24), and only the at least one inner abutment surface (40a, 40b) located on the opposite side of the lateral plane (P) from the operative corner abutment surface (38) is in contact with the at least one remaining supporting member (44b, 44c).