Wire EDM Breakage Position Control for Selective Condition Adjustment

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Solution Overview

Problem

Unnecessary adjustments to machining conditions in wire electrical discharge machines can lead to a decrease in production efficiency due to incorrect identification of the cause of wire breakage, such as wear of parts or temporary disturbances in the wire traveling system.

Innovation Solution

A wire electrical discharge machine equipped with a control device that includes a tension detector, tip detection electrode, and motors to accurately detect wire breakage and adjust machining conditions only when the breakage is attributed to machining conditions, by extending the voltage pulse pause time, raising the servo voltage, or lowering the feed rate of the workpiece.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If machining conditions are adjusted when wire breakage occurs, then wire breakage is suppressed, but production efficiency decreases due to unnecessary adjustments

Engineering Contradiction:
Improvewire breakage suppressionVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system changes machining parameters (voltage pulse pause time, servo voltage, feed rate) dynamically based on detected wire breakage patterns. When breakages are detected within a predetermined number of times, the system adjusts these parameters to suppress further breakages while avoiding unnecessary adjustments when breakages exceed the threshold, thus resolving the contradiction between reliability and productivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control device continuously monitors wire breakage occurrences and uses this feedback to determine whether adjustment is necessary. By comparing the actual breakage count against the predetermined threshold, the system provides conditional feedback control that activates adjustments only when needed, preventing efficiency loss from unnecessary interventions

Inventive Principle:
Principle #23Feedback

2Reliability

If machining conditions are adjusted frequently, then wire breakage is suppressed, but machining speed decreases

Engineering Contradiction:
Improvewire breakage suppressionVSAvoidmachining speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The system applies adjustment actions partially rather than continuously. By setting a predetermined threshold for wire breakage occurrences, the system performs adjustments only when the breakage count reaches this threshold, avoiding excessive adjustments that would unnecessarily reduce machining speed while still effectively suppressing wire breakages

Inventive Principle:
Principle #16Partial or excessive 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

Prevents efficiency decreases by accurately identifying the cause of wire breakage and only adjusting machining conditions when necessary, thereby minimizing unnecessary adjustments and maintaining production efficiency.

Implementation Method 1

a tension detector (breakage detector) 34 for detecting the tension of the wire electrode 12

Methodology Applied
Scientific EffectTension detection: Tension

Implementation Method 2

wire electrical discharge machine that performs electrical discharge machining on a workpiece

Methodology Applied
Scientific EffectElectrical discharge machining: Electrical Discharge Machining

Data Source

PatentEP3581311B1Wire electrical discharge machine and machining condition adjustment method
Publication Date: 2024.12.04 FANUC LTD
  • EP3581311B1 patent drawingFigure 1
  • EP3581311B1 patent drawingFigure 2
  • EP3581311B1 patent drawingFigure 3

AI summary

A wire electrical discharge machine (10) for performing electrical discharge machining on a workpiece (W) to be machined by applying voltage to an electrode gap formed between a wire electrode (12) and the workpiece (W) to generate electrical discharge at the electrode gap under predetermined machining conditions while conveying the wire electrode (12) along a transfer path (C), includes: a wire breakage detector (34) for detecting a breakage of the wire electrode (12); a position calculator (74) for calculating the breakage position of the wire electrode (12) in the transfer path (C); and an adjustment unit (78) for adjusting the machining conditions when the breakage position is in a predetermined section of the transfer path (C) .