Asymmetric Milling Insert Geometry for Secure Pocket Retention

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Solution Overview

Problem

Existing cutting inserts for milling operations lack stability and effective retention in insert receiving pockets, particularly in configurations where cutting edges do not overlap axially, leading to suboptimal performance and security during machining.

Innovation Solution

A cutting insert with non-identical, opposing front and back end surfaces, featuring a concave front and convex back shape in cross-section, and a unique geometry that includes specific axes and planes, allowing for secure removability and stability within a cutting tool's insert receiving pocket, with a clamping mechanism that distributes forces effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cutting inserts with identical rectangular end surfaces are used, then manufacturing is simple, but stability and retention in insert receiving pockets is insufficient

Engineering Contradiction:
Improvestability and retention in insert receiving pocketVSAvoidinsert geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cutting insert employs non-identical opposing end surfaces where the front end surface has a concave cross-sectional shape and the back end surface has a convex cross-sectional shape. This asymmetric geometry creates complementary mating surfaces that engage with corresponding features in the insert receiving pocket, providing positive location and enhanced retention while maintaining manufacturing feasibility through standard forming processes.

Inventive Principle:
Principle #4Asymmetry

2Force

If conventional cutting inserts are used, then device complexity is low, but axial and tangential cutting forces on clamping screw are high

Engineering Contradiction:
Improvecutting forces on clamping screwVSAvoidinsert geometry complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The asymmetric concave-convex geometry distributes clamping forces more evenly across the insert-body interface. The concave front surface and convex back surface create natural force distribution paths that reduce peak stresses on the clamping screw while maintaining secure retention during milling operations.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3618992B1Cutting insert having non-identical rectangular end surfaces with raised and lowered corner portions and cutting tool
Publication Date: 2021.09.01 INGERSOLL CUTTING TOOL CO
  • EP3618992B1 patent drawingFigure 1~2
  • EP3618992B1 patent drawingFigure 3~4
  • EP3618992B1 patent drawingFigure 5~6

AI summary

A cutting insert has opposing front and back end surfaces with a peripheral side surface extending therebetween and a first axis extending therethrough, and a median plane perpendicular to the first axis located between the front and back end surfaces. Each of the front and back end surfaces has a rectangular shape in a respective end view thereof, and two diagonally opposed raised corners and two diagonally opposed lowered corners with respect to the median plane. The front end surface has a front major cutting edge associated therewith, and in a cross-section taken in a first plane containing the first axis, the front end surface has a concave shape and the back end surface has a convex shape. The cutting insert is removably secured in an insert receiving pocket of a cutting tool with the peripheral side surface and back end surface making contact with pocket support walls.