Electrical Discharge Machine Precision Prediction via Process Signal Analysis

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Solution Overview

Problem

Conventional electrical discharge machines lack the ability to predict workpiece quality in real-time, relying on post-processing metrology, which is time-consuming and inefficient, due to the absence of a predictive system for quality assessment during processing.

Innovation Solution

A method is developed to establish key features from process data, including discharge voltage and current signals, using correlation analysis and distribution fitting, to build a predictive model that forecasts the precision of the electrical discharge machine, enabling real-time quality prediction and adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If post-processing metrology is used to measure workpiece quality, then measurement accuracy is ensured, but production time is significantly increased

Engineering Contradiction:
Improveworkpiece quality measurement accuracyVSAvoidproduction time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical metrology measurement system with an electrical discharge process monitoring system. By capturing and analyzing discharge current and voltage signals during the machining process, the system predicts workpiece quality without requiring physical measurement tools, thus eliminating the time delay between machining and quality assessment.

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

Solution Approach 2:

The patent introduces process signals (discharge current and voltage) as intermediary indicators that correlate with final workpiece quality. These signals serve as mediators between the machining process and quality outcome, allowing real-time quality prediction through signal analysis rather than direct physical measurement of the workpiece.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If comprehensive process data is collected during electrical discharge machining, then quality prediction accuracy is improved, but data processing complexity increases

Engineering Contradiction:
Improvequality prediction accuracyVSAvoiddata processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the critical process signals (discharge current and voltage) from the comprehensive process data that have the strongest correlation with workpiece quality. By focusing on these key extracted features rather than processing all available data, the system maintains high prediction accuracy while reducing processing complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary analysis to identify which process signals correlate most strongly with quality outcomes before building the prediction model. This preliminary action of selecting key features in advance simplifies the subsequent data processing while maintaining prediction accuracy.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10413984B2Method for predicting precision of electrical discharge machine
Publication Date: 2019.09.17 METAL INDS RES & DEV CENT
  • US10413984B2 patent drawing
  • US10413984B2 patent drawing
  • US10413984B2 patent drawing

AI summary

A method for predicting precision of an electrical discharge machine is provided. In the method, plural sets of process data are obtained while the electrical discharge machine processes workpiece samples. Process features are established based on the process data. Each of the workpiece samples with respect to each of at least one measurement item is measured by using a metrology tool, thereby obtaining measurement values of the workpiece samples with respect to each measurement item. A correlation analysis operation is performed to obtain correlation coefficients. At least one key feature is selected from the process features as representative according to the correlation coefficients. The measurement values of the workpiece samples with respect to each measurement item, and the sets of process data corresponding to the key features are used to build a predictive model for predicting the precision of the electrical discharge machine.