Lathe Turning Insert Mounting Structure for Stable Clamping

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Solution Overview

Problem

Existing lathe turning tools face issues with insufficient clamping force leading to insert damage, increased component count and cost, and excessive force on the tool holder due to press-fitting, which can result in deformation and screw damage.

Innovation Solution

A lathe turning tool design that stabilizes the cutting insert using a non-circular concave portion and a second portion with a parallel side surface, eliminating the need for a collet and reducing radial force on the tool holder, while a cutting insert with a polygonal or rounded cutting edge and grooves for coolant flow enhances clamping and reduces wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a collet is used to fix the cutting insert, then the insert can be held in position, but the clamping force is insufficient leading to insert damage and the number of components increases

Engineering Contradiction:
Improveclamping forceVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the collet component from the tool assembly. Instead of using a separate collet to hold the cutting insert, the insert is directly mounted in a recess of the tool holder with its side surface abutting the holder's side surface, thereby reducing component count while maintaining secure positioning.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the functions of the collet and tool holder into a single integrated structure. The tool holder directly provides both the recess for the insert and the side surface for abutting, combining what were previously separate components into one unified element.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If press-fitting is used to attach the cutting insert, then the insert can be fixed, but excessive force is exerted on the tool holder causing deformation and screw damage

Engineering Contradiction:
Improveinsert fixationVSAvoidtool holder integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention employs asymmetric force distribution in the insert attachment structure. The insert is positioned such that cutting forces are distributed between the recess walls and the abutting side surface, creating an asymmetric load path that prevents excessive concentrated force on any single point of the tool holder.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention segments the force transmission path into multiple independent contact points: the recess walls provide radial support while the abutting side surface provides axial support. This segmentation distributes the cutting forces across multiple locations, preventing excessive force concentration that would cause holder deformation.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If the cutting insert is allowed to rotate freely, then the tool structure is simpler, but the insert position becomes unstable during processing

Engineering Contradiction:
Improvetool structureVSAvoidinsert position stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The invention uses asymmetric geometric constraints to prevent insert rotation. The non-circular recess and the abutting side surface create an asymmetric fit that inherently prevents rotational movement of the insert, eliminating the need for additional anti-rotation mechanisms while maintaining positional stability.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP2883636B1Lathe turning tool
Publication Date: 2023.08.02 SUMITOMO ELECTRIC HARDMETAL CORP
  • EP2883636B1 patent drawingFigure 1~2
  • EP2883636B1 patent drawingFigure 3~5
  • EP2883636B1 patent drawingFigure 6~7

AI summary

A cutting insert (10) is configured to include: a first portion (11) having a rake face (14), a flank face (15), a cutting edge (16), and a face (17) facing an insert attachment portion (3) at an end of a tool main body (1); and a second portion (12) having a side surface (12a) including at least one flat plane that is parallel to a center line (C) of a tool or inclined at a prescribed angle to the center line (C). The second portion (12) extends continuously to a region surrounded by the face (17) of the first portion. The second portion (12) is fitted into the tool main body (1) to position the cutting insert (10) and to prevent the cutting insert (10) from rotating.