Gear Toothing Machining with Fourier-Based Tool Wear Detection

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Solution Overview

Problem

Existing methods for machining workpieces with rotating tools face challenges in maintaining tool life and reliability, leading to potential errors in workpiece production due to tool wear, with current monitoring systems often detecting issues too late to prevent batch-wide defects.

Innovation Solution

A monitoring system that uses Fourier transformation of time signals from sensors to detect local tool wear, generating warning signals when thresholds are exceeded, allowing for timely tool changes and preventing further processing with worn tools, thereby reducing production errors and extending tool life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If tool life is maximized by using wear-increasing coatings and postponing tool replacement, then tool life is extended, but the risk of producing defective workpieces increases

Engineering Contradiction:
Improvetool lifeVSAvoidworkpiece quality reliability
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The monitoring system performs preliminary detection of tool wear by analyzing vibrations during machining operations. By detecting wear trends before they reach critical levels, the system enables proactive tool replacement decisions, extending tool life while preventing defective workpieces from being produced

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors machining vibrations and provides real-time feedback about tool condition. This feedback loop allows dynamic adjustment of machining parameters and timely tool replacement, resolving the contradiction between maximizing tool life and maintaining workpiece quality

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If tool changes are performed frequently to maintain high machining quality, then workpiece quality is maintained, but productivity decreases

Engineering Contradiction:
Improvetooth flank profile precisionVSAvoidaverage machining time per workpiece
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The monitoring system detects tool wear trends in advance, allowing tool replacement to be timed optimally. This prevents both premature replacement (which would reduce productivity) and delayed replacement (which would compromise precision), achieving the right balance between the two competing requirements

Inventive Principle:
Principle #10Preliminary action

3Reliability

If monitoring systems are implemented to detect tool wear, then workpiece quality reliability is improved, but device complexity increases

Engineering Contradiction:
Improveworkpiece quality reliabilityVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The monitoring system utilizes the machine's own vibration signals during normal operation, without requiring separate sensing systems or additional actuators. This self-service approach provides reliable tool wear detection while minimizing the addition of complex external monitoring hardware

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system replaces complex mechanical monitoring devices with signal processing of existing vibration data. By using Fourier transformation and spectral analysis of readily available vibration signals, the system achieves sophisticated tool condition monitoring without the complexity of dedicated mechanical sensors

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

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

The system effectively reduces the probability of workpiece errors by detecting tool wear early, allowing for immediate action to prevent machining errors and optimizing tool life, while minimizing follow-up efforts by ensuring tools are replaced before tolerance limits are breached.

Implementation Method 1

a sensor for detecting a time signal of vibrations occurring during the machining operation

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3956094B1Method for producing or machining toothing
Publication Date: 2024.11.20 GLEASON PFAUTER MASCHFAB
  • EP3956094B1 patent drawingFigure 1~2a
  • EP3956094B1 patent drawingFigure 2b~2c
  • EP3956094B1 patent drawingFigure 3~4

AI summary

The invention relates to a method for producing or machining toothing (2) on a workpiece (3), in which method the workpiece, which is rotationally driven about its axis of rotation (C), is brought into rolling machining engagement with tool toothing (5) rotating about an axis of rotation (C2) which is, in particular, at a non-null crossed-axes angle to the axis of rotation of the workpiece, wherein the machining operation is automatically monitored, using sensors to record same, already at the machining operation stage, for a recurring irregularity originating from tool wear (52), in particular higher wear of at least one tool tooth (51) compared to other tool teeth. The invention also relates to a gear cutting machine and a monitoring programme for same.