Cutting Insert Clamping Recess Design for Secure Fastening

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Solution Overview

Problem

Existing turning tools with cutting inserts face challenges in secure clamping and easy replacement, often resulting in weakened inserts due to through holes and inefficient clamping mechanisms that hinder chip flow and increase friction.

Innovation Solution

A cutting tool design featuring a holder with an insert pocket and a clamping member that securely clamps a cutting insert without through holes, utilizing a screw with a non-round opening clamping recess and a washer for reduced wear, allowing for efficient clamping and easy replacement of the insert.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a clamping member with through holes is used to secure the cutting insert, then the clamping force is enhanced, but the cutting insert is weakened due to the through holes

Engineering Contradiction:
Improveclamping forceVSAvoidinsert strength
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The clamping recess is segmented into two parts: a first clamping recess extending from the front surface and a second clamping recess extending from the rear surface. This segmentation allows the clamping member to apply clamping force without requiring through holes that would weaken the entire insert, as each recess is localized and non-through.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clamping mechanism transitions from a single-dimensional through-hole approach to a multi-dimensional configuration with recesses extending from both front and rear surfaces. This dimensional change enables effective clamping while avoiding the creation of complete through holes that would compromise insert strength.

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

2Reliability

If a conventional clamping mechanism is used, then the cutting insert is securely clamped, but chip flow is hindered and friction is increased

Engineering Contradiction:
Improveclamping securityVSAvoidchip flow restriction and friction
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The clamping recesses are designed with specific local geometries that optimize both clamping security and chip flow. The first recess has a geometry that accommodates the clamping member from the front surface while maintaining chip flow paths, and the second recess similarly accommodates the clamping member from the rear surface without creating harmful friction zones.

Inventive Principle:
Principle #3Local quality

3Device complexity

If through holes are drilled in the cutting insert for clamping, then the clamping mechanism is simplified, but the insert structure is weakened

Engineering Contradiction:
Improveclamping mechanism complexityVSAvoidinsert structural strength
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

Instead of using simple through holes, the clamping mechanism is segmented into two separate non-through recesses positioned at different surfaces. This segmentation maintains structural integrity by avoiding complete penetration while still providing effective clamping locations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clamping member acts as an intermediary element that engages with the recesses without requiring direct through-hole penetration. This intermediary approach allows the clamping force to be transmitted effectively while the insert material remains continuous and strong.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2678127B1Cutting tool and cutting insert having clamping recess therefor
Publication Date: 2017.08.23 ISCAR LTD
  • EP2678127B1 patent drawingFigure 1~2
  • EP2678127B1 patent drawingFigure 3~5

AI summary

A cutting insert includes opposing first and second major surfaces and two side surfaces extending therebetween, two side abutment surfaces, each located on a respective side surface and a clamping recess which opens out to the second major surface and/or to the insert front surface. The side abutment surfaces converge towards the first major surface and the side surfaces converge in a direction away from an insert front surface which extends between the major surfaces and the side surfaces. The clamping recess does not extend beyond a mid plane, which is located midway between the first and second surfaces.