Tool Holder Sensor Layout for Stable Cutting Force Measurement

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Solution Overview

Problem

Existing tool holder systems face challenges in accurately measuring forces on cutting tools due to high hysteresis, instability, and space constraints, particularly when using sensors that can interfere with tool clamping stability and require complex installation.

Innovation Solution

A tool holder design with a sensor receptacle positioned at a distance from both the tool holder and machine interface, allowing the sensor to be in direct contact with neither, and aligning the sensitive axis of the sensor to match the direction of resulting forces for minimal shear stress and improved measurement linearity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor is positioned close to the machining point for accurate measurement, then measurement precision is improved, but the sensor interferes with tool clamping stability and creates space constraints

Engineering Contradiction:
Improveforce measurement accuracyVSAvoidtool clamping stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The sensor is extracted from the immediate machining area and positioned in a recess in the tool holder body, away from the cutting edge and tool clamping zone. This allows the sensor to measure forces transmitted through the tool holder without interfering with tool installation or clamping stability, resolving the contradiction between measurement precision and structural stability

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If the sensor is mounted directly at the tool-cutter interface for direct force measurement, then measurement precision is improved, but device complexity and installation difficulty increase

Engineering Contradiction:
Improveforce measurement accuracyVSAvoidsensor installation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor is integrated into the tool holder body itself, with the sensor recess formed as part of the tool holder structure. This merging of the sensor mounting structure with the tool holder simplifies the overall device design and reduces installation complexity while maintaining measurement precision through direct force transmission path

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If a multidimensional force measurement arrangement is used, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveforce measurement accuracyVSAvoidmeasurement arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of implementing a complex multidimensional force measurement system throughout the tool holder, a single sensor is strategically positioned to measure the specific force component most relevant to the machining process. This localized measurement approach provides sufficient precision for the application while keeping the device simple and cost-effective

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration reduces hysteresis, enhances measurement stability, and simplifies tool handling by allowing precise force measurements with reduced interference and easy tool replacement without affecting sensor setup.

Implementation Method 1

the sensor is preferably a force sensor

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3967450A1Tool holder and tool system provided with such a tool holder
Publication Date: 2022.03.16 HARTMETALL WERKZEUGFAB PAUL HORN
  • EP3967450A1 patent drawingFigure 1~2
  • EP3967450A1 patent drawingFigure 3~4
  • EP3967450A1 patent drawingFigure 5

AI summary

Tool holder (10, 10') with a tool receptacle (14, 14') configured to detachably hold a tool (12, 12') with at least one cutting edge (22, 22') for machining a workpiece, with a machine interface (26, 26') configured to allow the tool holder (10, 10') to be attached to a machine tool, and with a sensor receptacle (30, 30') in which a sensor (32, 32') is mounted, which is configured to generate a measurement signal that depends on a force acting on the tool holder (10, 10'), wherein the sensor receptacle (30, 30') is spaced apart from both the tool receptacle (14, 14') and the machine interface (26, 26') so that the sensor (32, 32') is not in contact with the tool (12, 12') or is in direct contact with the machine tool when the tool (12, 12') is held in the tool holder (14, 14') and the tool holder (10,10') is attached to the machine tool.