Cutting Insert With Rearward Offset Edge

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Solution Overview

Problem

Conventional cutting inserts in metalworking operations experience rotational displacement due to torque, leading to instability and potential detachment from the insert holder, as the cutting force applied generates a torque that urges the insert away from the holder.

Innovation Solution

A cutting insert design featuring a rearwardly offset cutting edge and strategically positioned abutment surfaces forming an obtuse angle, which opposes the rotational direction of the torque, ensuring the insert is urged towards the holder, along with a holder pocket system providing stable abutment surfaces for secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cutting edge is positioned at the forwardmost point of the insert, then the cutting insert can be securely retained against rotational displacement by the insert holder, but the torque generated by the cutting force causes the insert to rotate and urges the lower abutment surface away from the holder, leading to instability and potential detachment

Engineering Contradiction:
Improvesecure retention of cutting insertVSAvoidrotational stability of cutting insert
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent inverts the conventional cutting edge position by placing it at the rearwardmost point of the insert rather than the forwardmost point. This reversal changes the direction of the torque generated by the cutting force, so that instead of urging the insert away from the holder, the torque now urges the lower abutment surface towards the holder, thereby improving rotational stability and preventing detachment

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the geometric parameter of the cutting edge position along the longitudinal axis of the insert. By offsetting the cutting edge rearwardly, the moment arm of the cutting force is altered, which changes the direction and magnitude of the torque. This parameter change transforms the harmful rotational effect into a stabilizing effect that presses the insert against the holder

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the cutting edge is offset rearwardly, then the torque has an opposite rotational direction that urges the lower abutment surface towards the holder, but this requires a specific geometric configuration with obtuse abutment angles and precise positioning

Engineering Contradiction:
Improverotational stability of cutting insertVSAvoidgeometric configuration complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent employs asymmetric geometry in the insert design, particularly with the obtuse abutment angle between the lower and rear abutment surfaces. This asymmetric configuration is specifically tailored to work with the rearwardly offset cutting edge position, creating a coordinated geometric system that maximizes stability while maintaining manufacturability

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP2999563B1Cutting insert having a rearwardly offset cutting edge and cutting tool
Publication Date: 2017.06.21 ISCAR LTD
  • EP2999563B1 patent drawingFigure 1~2
  • EP2999563B1 patent drawingFigure 3~4
  • EP2999563B1 patent drawingFigure 5~6

AI summary

A cutting insert (22) includes opposing forward and rear surfaces (34,36) and a peripheral surface (28) extending therebetween. The peripheral surface (28) includes opposing side surfaces (26) and opposing upper and lower surfaces (38,40). The upper surface (38) and the forward surface (34) intersect to form a main cutting edge (42) having an associated relief surface (44) that extends therefrom in the forward surface. One of the side surfaces (26) comprises an insert side abutment surface (60). The rear surface (36) comprises an insert rear abutment surface (50). The lower surface (40) comprises an insert lower abutment surface (52). The insert rear and insert lower abutment surfaces (50,52) form an obtuse abutment angle with respect to each other. In a side view along a side axis, a relief surface (44) line tangent to the relief surface intersects the insert lower abutment surface.