Machine Tool Clamping Detection Using Axis Drive Vibration

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Solution Overview

Problem

Existing machine tools lack an effective method to monitor and ensure proper clamping conditions of tools or workpieces, which can lead to inadequate processing results and potential damage to the machine.

Innovation Solution

A machine tool control system that monitors and checks the tension state of tool or workpiece clamping by evaluating parameters of the drive axis, such as vibration behavior and frequency-dependent parameters, without the need for additional sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If no additional sensors are used for clamping force measurement, then device complexity is reduced, but the ability to directly measure and monitor clamping force is lost

Engineering Contradiction:
Improvedevice complexityVSAvoidclamping force measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent uses drive parameters (current, power, vibration) as intermediary indicators to indirectly assess clamping force. Instead of directly measuring clamping force with sensors, the system monitors parameters that change in response to clamping conditions, such as drive current during acceleration and vibration characteristics during operation. This intermediary approach resolves the contradiction by providing measurement capability without adding direct measurement sensors.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical measurement systems (sensors, transducers) with electrical and control system-based monitoring. By using the existing drive system's electrical parameters and control data to infer mechanical clamping state, the invention substitutes a mechanical measurement approach with an electrical/control-based approach, reducing device complexity while maintaining monitoring capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If manual clamping systems are used, then ease of operation is improved, but the ability to monitor clamping state is worsened

Engineering Contradiction:
Improveease of operationVSAvoidclamping state monitoring
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements feedback monitoring by continuously evaluating drive parameters and comparing them against expected ranges for proper clamping. The control system receives feedback from the drive system about actual clamping conditions and can alert operators or automatically adjust parameters. This feedback mechanism resolves the contradiction by providing monitoring capability for manual systems without interfering with their ease of operation.

Inventive Principle:
Principle #23Feedback

3Device complexity

If clamping state monitoring is not implemented, then device complexity is reduced, but manufacturing precision and reliability deteriorate

Engineering Contradiction:
Improvedevice complexityVSAvoidmachining results
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent performs preliminary monitoring and detection of clamping state before machining operations begin. By evaluating drive parameters during tool mounting and before production starts, the system ensures proper clamping is established in advance. This preliminary action prevents precision issues during machining without requiring complex continuous monitoring systems throughout the entire process.

Inventive Principle:
Principle #10Preliminary action

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 solution allows for the reliable detection of inadequate clamping states, preventing processing errors and machine damage by automatically recognizing and addressing insufficient clamping conditions.

Implementation Method 1

the function determines and evaluates a parameter of the vibration behavior of the axis in order to detect an insufficient clamping state

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP4530770A1Machine tool, in particular gear cutting machine
Publication Date: 2025.04.02 LIEBHER VERZAHNTECHNIK GMBH
  • EP4530770A1 patent drawingFigure 1
  • EP4530770A1 patent drawingFigure 2
  • EP4530770A1 patent drawingFigure 3

AI summary

The present invention relates to a machine tool, in particular a gear cutting machine, with a rotary axis which has a receptacle in which a tool or workpiece can be clamped, wherein the axis is driven by a drive, and wherein the machine tool has a control unit for controlling the drive. It is provided that the control unit has a function for monitoring and/or checking the clamping state of the tool or workpiece receptacle, wherein the checking and/or monitoring is carried out by determining and evaluating at least one parameter of the axis drive.