Cutting Tool Stress Splitter Reduces Pocket Corner Concentration

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Solution Overview

Problem

Conventional cutting tools experience high stress concentrations at the corner of the insert pocket during stress relief, leading to potential tool breakage, increased deflection, and reduced accuracy due to uneven distribution of metal in the cutter core.

Innovation Solution

A stress splitter is introduced on the tool body, intersecting the top surface and stress relief groove, which can take the form of a sharp peak, radiused peak, or protuberance, to redistribute stress and reduce maximum equivalent stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional tool body design with a stress relief groove is used, then the tool structure is simple and easy to manufacture, but high stress concentration occurs at the corner of the insert pocket leading to potential tool breakage

Engineering Contradiction:
Improvestress resistanceVSAvoidtool body structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The stress splitter modifies the local geometry of the tool body at the critical stress concentration zone (corner of insert pocket). By adding a localized protrusion or ridge feature to the top surface, the stress distribution is altered locally without changing the overall tool body structure, thereby reducing stress concentration while maintaining manufacturing simplicity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The stress splitter divides the stress path into multiple segments by creating a geometric feature that interrupts the direct stress flow. This segmentation of stress distribution prevents stress concentration at a single point and distributes it across multiple areas, reducing the risk of tool breakage

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If metal is uniformly distributed in the cutter core, then the tool body is easy to manufacture, but high bending moment causes excessive tool deflection reducing accuracy

Engineering Contradiction:
Improvetool accuracyVSAvoidmetal distribution
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The stress splitter creates a localized geometric feature that selectively adds material where it is most needed - at the corner of the insert pocket where stress concentration occurs. This non-uniform metal distribution targets the critical area without requiring complex overall redesign, thereby improving accuracy while maintaining ease of manufacture

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP1948408B1Cutting tool with stress splitter
Publication Date: 2012.09.05 KENNAMETAL INC
  • EP1948408B1 patent drawingFigure 1~2
  • EP1948408B1 patent drawingFigure 3
  • EP1948408B1 patent drawingFigure 4

AI summary

A cutting tool (10) includes a tool body (14) having a plurality of insert receiving pockets (20) and at least one cutting insert (12) mounted in each pocket. Each pocket (20) includes a pocket base wall (22), a side wall (26) and a stress relief groove (24). The tool body (14) also includes a top surface (34) including a first portion (28) and a second portion (29), and a stress splitter (36) that extends from the stress relief groove (24) and intersects the first and second portions (28, 29). The stress splitter (36) may be in the form of a sharp peak or ridge, a radiused peak, rounded mass or protuberance, and the like. The stress splitter (36) reduces a maximum amount of stress in an area of the stress relief groove (24) during a machining operation.