Asymmetric Indexable Cutting Insert for Stable Grooving Positioning

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Solution Overview

Problem

Conventional indexable inserts for grooving or parting suffer from unfavorable lever ratios and imprecise cutting edge positioning due to the design of contact and support surfaces, leading to potential dislodgment during use.

Innovation Solution

The combination of an indexable insert and holder with a quadrilateral shape featuring unequal long and short sides, where cutting edges are circumferentially oppositely oriented, and a positioning notch system, allowing for more favorable leverage ratios and precise positioning through a cylindrical support element and contact surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the cutting edge protrudes further from the insert holder to penetrate the workpiece surface, then the cutting capability is improved, but the lever ratio worsens causing the insert to lever out or shift position

Engineering Contradiction:
Improveprotrusion length of cutting edgeVSAvoidpositioning stability of cutting insert
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent applies asymmetry by providing contact surfaces of different lengths on the insert holder. The first contact surface has a first length while the second contact surface has a second length that is different from the first length. This asymmetric design creates different lever arms for the clamping forces, optimizing the lever ratio to prevent insert dislodgment while allowing sufficient cutting edge protrusion for effective workpiece penetration.

Inventive Principle:
Principle #4Asymmetry

2Measurement precision

If the contact surfaces are positioned to support the cutting edge, then the positioning accuracy is improved, but the lever ratio worsens tending to force the insert out of its seat

Engineering Contradiction:
Improvecutting edge position accuracyVSAvoidclamping force stability
Core Design Contradiction:
Measurement precisionVSForce

Solution Approach 1:

The asymmetric contact surface design allows precise positioning of both contact surfaces to define the cutting edge location accurately, while simultaneously creating optimized lever arms that distribute clamping forces effectively. The different lengths of the contact surfaces prevent the insert from being forced out of its seat by maintaining favorable moment balance.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If the cutting insert is fixed with favorable leverage ratios, then the positioning stability is improved, but the cutting edge position accuracy may be compromised

Engineering Contradiction:
Improveinsert fixation stabilityVSAvoidcutting edge position definition
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The asymmetric contact surface configuration achieves both favorable leverage ratios for stable insert fixation and precise cutting edge position definition. The specific different lengths of the contact surfaces are designed to simultaneously optimize the mechanical leverage for preventing insert dislodgment and maintain accurate cutting edge positioning relative to the workpiece.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP2694236B1Indexable cutting insert and indexable insert holder
Publication Date: 2021.01.27 WALTER AG
  • EP2694236B1 patent drawingFigure 1(a)~1(b)
  • EP2694236B1 patent drawingFigure 2
  • EP2694236B1 patent drawingFigure 3(a)~3(b)

AI summary

The present invention relates to an indexable cutting insert (10) for grooving or parting, consisting of a plate-like main body having two parallel main surfaces (2a, b) and a peripheral surface (16 a-d) that connects the two main surfaces and consists of a plurality of sections that are angled with respect to one another, wherein four cutting edges (4 a-d) that extend transversely to the main surfaces are provided on the peripheral surface (16 a-d) at the transition to sections, that are angled with respect to one another, of the peripheral surface, and wherein the position of the cutting edges defines a quadrilateral in the plan view of the main surfaces. In order to provide an indexable cutting insert and an associated indexable cutting insert holder, in which fixing with more favourable leverages is possible and which furthermore allow permanently more precise positioning of the cutting edges, it is proposed according to the invention that the quadrilateral has in each case two short and two long sides (13, 14) and that the cutting edges (4 a-d) are oriented in each case in opposite directions in the peripheral direction at adjacent corners and are oriented in each case in the same direction at diagonally opposite corners of the quadrilateral.