Wire EDM Voltage Filtering for Noise-Response Balance

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Solution Overview

Problem

Existing wire electrical discharge machines face instability and reduced accuracy due to noise in machining voltage detection values, which affects the stability and precision of electrical discharge machining.

Innovation Solution

A control device and method that utilize a digital low-pass filter to compensate machining voltage detection values by removing noise, with adjustments based on determinations of noise removal and response delay to stabilize the machining process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a digital low pass filter is used to remove noise from machining voltage detection values, then measurement precision is improved, but response delay increases

Engineering Contradiction:
Improvenoise removal accuracyVSAvoidresponse delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the filter parameter adjustment dynamic rather than static. The determination unit continuously monitors the relationship between detection values and compensated values, and the adjustment unit dynamically modifies the digital low pass filter parameters based on real-time machining conditions. This allows the system to adapt the noise removal strength and response delay characteristics according to the actual machining state, resolving the contradiction between measurement precision and response speed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback control where the determination unit compares detection values with compensated values to assess filter performance. Based on this feedback, the adjustment unit modifies the digital low pass filter parameters to optimize the balance between noise removal effectiveness and response delay. This closed-loop feedback mechanism ensures that the filter adapts to changing machining conditions while maintaining optimal performance.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If filter parameters are adjusted to increase noise removal degree, then measurement precision is improved, but stability of machining process deteriorates

Engineering Contradiction:
Improvenoise removal degreeVSAvoidmachining process stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The system dynamically adjusts filter parameters based on real-time determination of machining conditions. Rather than applying a fixed strong filter that would destabilize the process, the adjustment unit modifies the filter strength according to the actual noise levels and machining state detected by the determination unit. This dynamic adaptation prevents excessive noise removal that could interfere with the natural stability of the machining process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameters of the digital low pass filter based on determined machining conditions. The adjustment unit modifies filter parameters such as cutoff frequency or smoothing coefficient according to the relationship between detection values and compensated values. This parameter adaptation allows the system to achieve adequate noise removal without applying excessive filtering that would disrupt the stability of the electrical discharge machining process.

Inventive Principle:
Principle #35Parameter changes

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

Stabilizes electrical discharge machining and maintains high machining accuracy by effectively reducing noise and adjusting filter parameters to ensure precise control of machining parameters.

Implementation Method 1

a digital low pass filter configured to output a compensated value obtained by compensating the detection value by removing noise from the detection value

Methodology Applied
Scientific EffectDigital low pass filter: Filter (electronic)

Implementation Method 2

an acquisition unit configured to acquire a detection value of the machining voltage from a voltage sensor configured to detect the machining voltage

Methodology Applied
Scientific EffectVoltage detection: Ohmmeter

Data Source

PatentEP4599971A1Device and method for controlling wire electrical discharge machine
Publication Date: 2025.08.13 FANUC LTD
  • EP4599971A1 patent drawingFigure 1
  • EP4599971A1 patent drawingFigure 2
  • EP4599971A1 patent drawingFigure 3

AI summary

According to an aspect of the present disclosure, a device for controlling a wire electrical discharge machine comprises: an acquisition unit that acquires a detected value of a machining voltage; a digital low-pass filter that outputs a corrected value by removing noise from the detected value; a determination unit that makes at least one of a first determination and a second determination on the basis of the detected value and the corrected value, the first determination determining the degree of noise removal by the digital low-pass filter, the second determination determining a response lag of the digital low-pass filter; an adjustment unit that adjusts a parameter of the digital low-pass filter; and a machining control unit that controls electrical discharge machining on the basis of the corrected value.