Auto Wire Feeding with Reversible Airflow in Wire EDM

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Solution Overview

Problem

The existing auto wire feeding systems in wire electrical discharge machines are inefficient due to the time required for the motor to reach rated torque during retry processes, leading to prolonged auto wire feeding times.

Innovation Solution

The system uses compressed air to randomly move the tip of the wire electrode, allowing for retry insertion without the need to drive the motor from starting torque to rated torque, thus reducing the time required for auto wire feeding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor is controlled to alternately repeat the rewinding and feeding of the wire electrode, then the wire electrode can be repositioned for retry insertion, but the time required for auto wire feeding increases due to motor torque buildup delay

Engineering Contradiction:
Improvewire electrode insertion successVSAvoidauto wire feeding time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical motor-driven wire feeding system with a pneumatic system. Compressed air is supplied to the wire electrode through a guide pipe to directly push and reposition the wire tip, eliminating the need for motor torque buildup and mechanical acceleration phases. This substitution of pneumatic force for mechanical drive resolves the time delay issue while maintaining the ability to retry insertion.

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

Solution Approach 2:

The patent introduces a pneumatic device that supplies compressed air to the wire electrode. The air flow is controlled to push the wire electrode forward or backward as needed, providing rapid response without the inertia and torque buildup characteristics of motor-driven systems. This pneumatic approach enables quick retry operations without the time penalty of mechanical system acceleration.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Ease of operation

If the motor is used to rewind and feed the wire electrode alternately, then the wire electrode can be repositioned, but the drive time from starting torque to rated torque prolongs the retry process

Engineering Contradiction:
Improvewire electrode repositioning capabilityVSAvoidmotor drive time
Core Design Contradiction:
Ease of operationVSDuration of action of moving object

Solution Approach 1:

The patent replaces the motor-driven mechanical system with a pneumatic system for wire electrode repositioning. The pneumatic device can instantly adjust wire position without the gradual torque buildup inherent in motor systems, eliminating the prolonged drive time while maintaining full repositioning capability.

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

Solution Approach 2:

The patent uses periodic pulses of compressed air to move the wire electrode in small increments. By controlling the timing and duration of air pulses, the system can precisely reposition the wire tip without requiring continuous motor operation, thereby reducing the overall duration of the repositioning action.

Inventive Principle:
Principle #19Periodic 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

This approach significantly shortens the auto wire feeding time by eliminating the delay associated with motor torque buildup, enabling more efficient wire electrode insertion and feeding.

Implementation Method 1

compressed air slightly moves the tip of the wire electrode in a random manner

Methodology Applied
Scientific EffectCompressed air flow: Fluid Spray

Data Source

PatentEP3505285B1Wire electrical discharge machine and auto wire feeding method of wire electrical discharge machine
Publication Date: 2025.01.29 FANUC LTD
  • EP3505285B1 patent drawingFigure 1
  • EP3505285B1 patent drawingFigure 2
  • EP3505285B1 patent drawingFigure 3

AI summary

A wire electrical discharge machine (10) includes: a guide pipe (22) as a guide member arranged on a path for feeding a wire electrode (12) from a feed roller (20) toward a workpiece (W) and having a passage hole (22a) through which the wire electrode (12) is passed; an airflow generator (42) for generating a flow of compressed air in the passage hole (22a) and switching a flow direction of compressed air flowing through the passage hole (22a) between a forward direction and a reverse direction; a deflection detector (44) for detecting a deflection of the wire electrode (12); and a control device (48) for controlling the airflow generator (42) so as to generate a flow of compressed air in the forward direction in the passage hole (22a) during auto wire feeding and, when the deflection detector (44) detects the deflection, change the flow direction of compressed air to the reverse direction and thereafter switch the flow direction of compressed air to the forward direction.