Wire EDM Contact Detection for Workpiece Conductivity Assessment

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Solution Overview

Problem

It is challenging for general users to determine whether electrical discharge machining can be performed on workpieces with varying electrical conductivity, as the threshold for successful machining depends on the power supply characteristics, and existing methods require separate measuring instruments, making the process cumbersome.

Innovation Solution

A wire electric discharge machine equipped with a contact detection unit, breaking detection unit, and display unit that determines the feasibility of electrical discharge machining by detecting contact or tension between a wire electrode and a workpiece, eliminating the need for external measuring instruments and simplifying the determination process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a measuring instrument such as a tester is used to measure resistance value or electrical conductivity, then the determination of whether electrical discharge machining can be performed becomes possible, but the work process becomes cumbersome and requires separate preparation of measuring instruments

Engineering Contradiction:
Improvedetermination accuracyVSAvoidprocess complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the measuring instrument functionality directly into the wire electric discharge machine by integrating a resistance value measurement unit. This allows the machine to both measure the resistance value of the workpiece and perform electrical discharge machining using the same device, eliminating the need for separate tester preparation and reducing process complexity while maintaining determination accuracy

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If a fixed threshold of resistance value is used to determine whether electrical discharge machining can be performed, then the determination process becomes simple, but the determination becomes inaccurate because the threshold varies depending on power supply characteristics

Engineering Contradiction:
Improvedetermination simplicityVSAvoiddetermination accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the parameter used for determination from a fixed resistance value threshold to a dynamic threshold based on the actual power supply characteristics. The determination unit compares the measured resistance value against a threshold that adapts to the specific wire electric discharge machine's power supply, ensuring accurate determination while maintaining operational simplicity through automated comparison

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the wire electrode is moved toward the workpiece to detect contact, then the determination can be performed using the machine's own components, but the wire electrode may break if the workpiece has insufficient electrical conductivity

Engineering Contradiction:
Improvedevice integrationVSAvoidwire electrode integrity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent performs preliminary measurement of the resistance value before moving the wire electrode toward the workpiece. By measuring the resistance value in advance and comparing it against the threshold determined from power supply characteristics, the system identifies unsuitable workpieces beforehand, preventing wire electrode breaking by avoiding contact with materials that have insufficient electrical conductivity

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

Enables easy determination of whether electrical discharge machining can be performed on workpieces without requiring additional measuring instruments, even when the resistance value threshold is unclear due to differences in power supply performance, thereby streamlining the machining process.

Implementation Method 1

a contact detection unit configured to detect the contact between the wire electrode and the workpiece by applying a predetermined voltage to the wire electrode

Methodology Applied
Scientific EffectElectrical conductivity: Conduction (electrical)

Data Source

PatentEP2985105B1Wire electric discharge machine determining whether or not electrical discharge machining of workpiece can be perfomed
Publication Date: 2018.09.26 FANUC LTD
  • EP2985105B1 patent drawingFigure 1
  • EP2985105B1 patent drawingFigure 2~3
  • EP2985105B1 patent drawingFigure 4~5

AI summary

A wire electric discharge machine, configured to determine whether or not electrical discharge machining of a workpiece can be performed, includes a determination unit for determining that wire electrical discharge machining of the workpiece can be performed when a wire electrode is moved toward the workpiece and a contact detection unit detects contact, and for determining that the wire electrical discharge machining of the workpiece cannot be performed when a breaking detection unit detects the breaking of the wire electrode before the contact detection unit detects the contact.