Indexable Cutting Tool Positioning and Stress Relief

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Solution Overview

Problem

The existing indexable cutting tool structures face challenges in achieving precise positioning and stable securing of round inserts due to small contact areas and concentrated stress at the corners of the support seat, leading to poor seating and potential processing errors.

Innovation Solution

The indexable cutting tool incorporates a positioning section with recessed portions and ridges on the round insert and a restraining section with a restraining flute and protrusions on the support seat, allowing for 90-degree contact between the insert's side surfaces and the seat's side surfaces, along with a larger second relief portion to reduce stress concentration at the corners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If contact surfaces are formed at portions of the insert towards the bottom surface at the periphery of the round insert, then the insert can be positioned by contacting with seat side surfaces, but the contact area is small making it difficult to achieve precise positioning and stable securing

Engineering Contradiction:
Improvepositioning precisionVSAvoidcontact area
Core Design Contradiction:
Measurement precisionVSArea of moving object

Solution Approach 1:

The invention transitions from a single-point or small-area contact positioning method to a multi-dimensional positioning approach. The positioning section includes multiple contact points distributed around the periphery of the round insert, engaging with corresponding seat side surfaces at different angular positions. This multi-point contact system in multiple dimensions provides both precise positioning and stable securing, resolving the contradiction between small contact area and positioning precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If the area of seat side surfaces is ensured, then contact stability is improved, but thinned portions at corners of the support seat cannot be made large causing stress concentration

Engineering Contradiction:
Improveseating stabilityVSAvoidstress concentration at corners
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The invention segments the support seat structure by introducing relief portions that separate the seat side surfaces from the corner regions. These relief portions create a gradual transition zone that reduces stress concentration at the corners while preserving the full contact area of the seat side surfaces. The segmentation allows the seat side surfaces to maintain large area for stability while the corner regions are relieved of stress concentration through the introduced geometric features.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If flat contact surfaces are used for positioning, then the structure is simple, but processing errors make it very difficult to simultaneously closely contact two contact surfaces with two seat side surfaces

Engineering Contradiction:
Improvemounting structure complexityVSAvoidseating precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention changes the geometric parameters of the contact surfaces by introducing inclined surfaces that converge toward the center of the round insert. Instead of using flat contact surfaces that require precise parallelism, the inclined surfaces create a self-aligning effect where small variations in manufacturing do not significantly affect the final positioning. The angular parameters of the inclined surfaces are designed to compensate for typical manufacturing tolerances, achieving high seating precision without increasing structural complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2878405B1Indexable cutting tool
Publication Date: 2017.05.17 SUMITOMO ELECTRIC HARDMETAL CORP
  • EP2878405B1 patent drawingFigure 1~2
  • EP2878405B1 patent drawingFigure 3~4
  • EP2878405B1 patent drawingFigure 5~6

AI summary

A positioning section 16 that positions a cutting edge, used in cutting, at an indexed point is provided at a portion of a round insert 10 towards a bottom surface at a periphery of the round insert 10. A support seat 3, provided at a tool body 1, includes a first seat side surface 3b, a second seat side surface 3c, and a restraining section 5. The first seat side surface 3b and the second seat side surface 3c contact and support side surfaces of the round insert that are disposed 90 degrees apart from each other. The positioning section 16 is fitted to the restraining section 5 by bumpy portion fitting. Only one restraining section 5 is provided. A second relief portion 7 that is larger than a first relief portion 6 is provided at a corner at a side of the second seat side surface 3c.