Wire EDM Feed Rate Control During Entry and Exit Travel

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Solution Overview

Problem

In wire electrical discharge machines, the wire electrode is continuously fed during non-machining periods, leading to waste and increased motor load, as the processing start and end positions are often distant from the workpiece.

Innovation Solution

Implementing a motor control unit that adjusts the wire electrode feed rate to zero or a lower rate during non-machining periods, based on voltage sensor feedback, to reduce unnecessary wire feed and motor load, while maintaining efficient machining during machining periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wire electrode is continuously fed during non-machining periods, then the wire electrode is always ready for machining, but wire electrode waste increases and motor load increases

Engineering Contradiction:
Improvereadiness of wire electrode for machiningVSAvoidwire electrode waste
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies dynamics by making the wire electrode feed rate variable rather than constant. The feed rate is dynamically adjusted based on the machining state: during machining periods, the wire electrode is fed at a normal feed rate to maintain machining continuity; during non-machining periods, the feed rate is reduced or stopped to prevent waste. This dynamic adjustment resolves the contradiction between maintaining readiness and reducing waste.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of wire electrode feed rate based on different operational phases. By detecting whether the wire electrode is in contact with the workpiece (machining period) or not (non-machining period), the system adjusts the feed rate parameter accordingly. This parameter change allows the system to maintain reliability during machining while reducing substance loss during non-machining periods.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the wire electrode is continuously fed during non-machining periods, then the wire electrode positioning is maintained, but motor load increases unnecessarily

Engineering Contradiction:
Improvewire electrode positioningVSAvoidmotor load
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The motor control is made dynamic by adjusting the feed rate based on machining detection. During non-machining periods when positioning is not critical, the motor load is reduced by lowering or stopping the feed rate. During machining periods, the motor operates at normal load to maintain positioning and feeding. This dynamic control resolves the contradiction between maintaining positioning and reducing energy consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent extracts the unnecessary motor load during non-machining periods by detecting the machining state and adjusting the feed rate accordingly. By separating the feeding operation into machining-related and non-machining-related components, the system eliminates energy waste during periods when wire electrode feeding is not required for machining operations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the processing start and end positions are located away from the workpiece, then the wire electrode can be automatically fed to positioning points, but wire electrode waste and motor load increase during non-machining periods

Engineering Contradiction:
Improveautomatic wire electrode feedingVSAvoidwire electrode waste
Core Design Contradiction:
Ease of operationVSLoss of substance

Solution Approach 1:

The patent applies dynamics by adjusting the wire electrode feed rate based on whether the system is in a machining period or non-machining period. During automatic feeding to positioning points (non-machining periods), the feed rate is reduced or stopped to minimize waste. During actual machining operations, the normal feed rate is maintained. This dynamic adjustment resolves the contradiction between ease of automatic operation and reduction of substance loss.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses feedback by detecting whether the wire electrode is in contact with the workpiece to determine the machining state. This feedback information is used to control the motor feed rate, creating a closed-loop system that automatically adjusts feeding behavior. The feedback mechanism enables the system to distinguish between necessary feeding (during machining) and unnecessary feeding (during positioning), thereby reducing waste while maintaining automatic operation capability.

Inventive Principle:
Principle #23Feedback

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

This approach reduces wire electrode waste and motor load during non-machining periods, enhancing overall machining efficiency by optimizing feed rates during these periods.

Implementation Method 1

generates electrical discharge by applying voltage at an electrode gap between a workpiece and a wire electrode

Methodology Applied
Scientific EffectElectrical discharge: Electric Spark

Data Source

PatentEP3785836A1Wire electrical discharge machine and control method
Publication Date: 2021.03.03 FANUC LTD
  • EP3785836A1 patent drawingFigure 1
  • EP3785836A1 patent drawingFigure 2
  • EP3785836A1 patent drawingFigure 3

AI summary

A wire electrical discharge machine (10) controls a second motor unit (56) including motors for feeding a wire electrode (12) in a wire running direction in which the wire electrode (12) extends, so as to feed the wire electrode (12) at a set feed rate during a machining period from a first time point (T1) at which the wire electrode (12) moving relative to a workpiece (W) in a direction intersecting the wire running direction is estimated to enter the workpiece (W), to a second time point (T2) at which the wire electrode (12) is estimated to exit the workpiece (W). The second motor unit (56) is controlled so as to feed the wire electrode (12) at a feed rate lower than the set feed rate during at least one of a first non-machining period (r1) from a processing start time point (T0) to the first time point (T1) and a second non-machining period (r2) from the second time point (T2) to a processing end time point (T3).