Subtractive Machining Tool Wear Inference Using Multi-Variable Neural Networks

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Solution Overview

Problem

Current methods for evaluating tool wear during subtractive machining are unreliable and often result in either premature tool replacement or continued use of worn-out tools, leading to increased costs and reduced component quality.

Innovation Solution

A method and system that utilize multiple process variables, including tool shape, operating current, voltage, maintenance, and interruption information, which are detected and analyzed using neural networks to accurately infer tool wear, allowing for timely tool swapping and minimizing machining time and tool wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If a worn-out tool is used further to reduce tool costs, then tool costs decrease, but component quality falls and cutting power drops drastically

Engineering Contradiction:
Improvetool costsVSAvoidcomponent quality
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The system continuously monitors multiple process variables (vibration, acoustic emissions, cutting forces, temperature) during machining and provides real-time feedback on tool wear status. This feedback loop enables dynamic adjustment of machining parameters or tool replacement decisions based on actual tool condition, preventing quality degradation while optimizing tool utilization.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual tool wear assessment with an automated sensor-based monitoring system using vibration sensors, acoustic emission sensors, and force sensors. This substitution of mechanical/manual evaluation with electronic sensing and signal processing enables precise, objective tool wear detection that directly correlates with component quality metrics.

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

2Manufacturing precision

If a tool is swapped out too soon to maintain quality, then component quality is maintained, but tool costs rise due to unused tool use time

Engineering Contradiction:
Improvecomponent qualityVSAvoidtool costs
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The real-time monitoring system provides continuous feedback on actual tool wear levels, enabling extension of tool life beyond conservative replacement schedules. By accurately measuring tool degradation through multiple sensors, the system allows tools to be used until their actual wear threshold is reached, maximizing tool utilization while maintaining quality standards.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system enables the tool to essentially monitor its own condition through integrated sensing of vibration, acoustic emissions, and cutting forces. This self-diagnosis capability eliminates the need for external inspection or conservative scheduling, allowing tools to operate autonomously until genuine wear impacts performance.

Inventive Principle:
Principle #25Self-service

3Device complexity

If manual tool wear evaluation methods are used, then implementation is simple, but reliability of wear assessment is poor

Engineering Contradiction:
Improveevaluation system complexityVSAvoidwear assessment reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system replaces unreliable manual or visual tool wear assessment with an automated electronic monitoring system using vibration sensors, acoustic emission sensors, and force sensors. This substitution transforms subjective, imprecise evaluation into objective, quantifiable measurements that reliably indicate actual tool wear and its impact on machining quality.

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

Solution Approach 2:

The patent shifts from assessing tool wear based on physical inspection of the tool itself to monitoring changes in machining process parameters (vibration amplitude, acoustic emission frequency, cutting force magnitude). These parameter changes provide indirect but reliable indicators of tool wear that correlate with component quality, enabling assessment without direct tool examination.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If multiple process variables are monitored using neural networks, then wear assessment accuracy improves, but system complexity increases

Engineering Contradiction:
Improvewear assessment accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system merges multiple monitoring functions (vibration analysis, acoustic emission detection, force measurement) into a unified neural network-based assessment platform. By combining these different process variables and processing them through integrated machine learning models, the system achieves superior wear assessment accuracy that exceeds the capability of any single sensor or method alone.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The neural network acts as an intermediary layer that processes raw sensor data from multiple sources and transforms it into meaningful wear assessments. This intermediary processing layer handles the complexity of multi-variable analysis, pattern recognition, and decision-making, shielding the user from the underlying system complexity while delivering high-accuracy results.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS20230251614A1Method for the Subtractive Machining of a Workpiece and Machining System
Publication Date: 2023.08.10 SIEMENS AG
  • US20230251614A1 patent drawing

AI summary

Various embodiments of the teachings herein include a method for subtractive machining of a workpiece using a tool. The method may include: detecting at least two process variables of a machining process; and using the process variables to infer a wear on the tool. The process variables are passed on to a neural network which assigns each process variable a respective degree of wear independently of the other. The wear is inferred by means of a logic on the basis of the respective degrees of wear. The process variables are each selected from the group consisting of: a shape of the tool, an operating current, an operating voltage, maintenance and servicing information, and interruption information of the machining. Detecting the shape of the tool includes imaging using a camera and/or a scanner.