Machining Tool Clamping Surface Relocation for Stability

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Solution Overview

Problem

Tools for axial plunge turning face stability issues, particularly with small radii and large plunge depths, due to the trade-off between clamping force and support stability, limiting their range of applications and economic efficiency.

Innovation Solution

The tool design features a configuration where the upper clamping surface is set back within the base body, distributing the clamping force directly into the base body rather than the lower clamping finger, reducing the load on the support and allowing for smaller radii and deeper plunges without stability issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the upper clamping surface is arranged over the protruding part of the lower clamping finger to achieve a tight fit of the cutting insert, then the clamping force is sufficiently strong, but the lower clamping finger becomes unstable and cannot absorb the clamping force

Engineering Contradiction:
Improveclamping forceVSAvoidsupport stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The upper clamping surface is relocated from the protruding part of the lower clamping finger to the base body, changing the spatial dimension of force application. This dimensional shift allows the clamping force to be applied at a location that does not compromise the stability of the protruding support structure.

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

Solution Approach 2:

The clamping function is separated from the support function. The base body performs the clamping function through the upper clamping surface, while the protruding lower clamping finger performs only the support function. This segmentation allows each component to be optimized for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the lower clamping finger is designed with a large dimension to provide stable support, then the support stability is sufficient, but the tool cannot achieve small radii and large plunge depths

Engineering Contradiction:
Improvesupport stabilityVSAvoidrange of applications
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

By moving the upper clamping surface to the base body, the protruding lower clamping finger can be minimized in dimension while maintaining stability. This enables the tool to accommodate small radii and large plunge depths that would be impossible with a traditionally sized support structure.

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

3Strength

If the clamping force is increased to ensure a tight fit of the cutting insert, then the cutting insert is securely held, but the tool vibrates and stability problems occur

Engineering Contradiction:
Improveclamping forceVSAvoidtool stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The clamping force is applied through the base body rather than through the protruding lower clamping finger. This segmentation isolates the high clamping forces from the delicate support structure, allowing strong clamping without inducing vibrations or stability problems in the tool.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3107674B1Tool for machining a workpiece
Publication Date: 2018.03.07 HARTMETALL WERKZEUGFAB PAUL HORN
  • EP3107674B1 patent drawingFigure 1~2
  • EP3107674B1 patent drawingFigure 3
  • EP3107674B1 patent drawingFigure 4~5

AI summary

The invention relates to a tool (10) for machining a workpiece, comprising a cutting insert (12) and a tool holder (14), which has a main body (15), an upper clamping finger (16), and a lower clamping finger (18). The main body (15) extends predominantly along a longitudinal direction (x) from an end (22) on the holder side to an end (24) on the workpiece side. At least one part of the lower clamping finger (18) projects over the end (24) of the main body (15) on the workpiece side. The upper clamping finger (16) and the lower clamping finger (18) together form a receptacle for the cutting insert (12), in which the cutting insert (12) can be secured by means of an actuating element (20) in such a way that the upper clamping finger (16) exerts a clamping force on the cutting insert (12) via an upper clamping surface (30) disposed on the upper clamping finger. At least one part of the upper clamping surface (30) when viewed in the longitudinal direction (x) is disposed between the end (24) of the main body (15) on the workpiece side and the end (22) on the holder side, and a resulting force vector (44) of the clamping force acts in a region which when viewed in the longitudinal direction is located between the end (24) of the main body (15) on the workpiece side and the end (22) on the holder side. The projecting part of the lower clamping finger (18) has a substantially crescent-shaped or arcuate cross-section.