Wire EDM Path Compensation Using Protrusions at Workpiece Steps

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Solution Overview

Problem

Electrical discharge machining by wire electrical discharge machines faces accuracy issues and flaw generation around steps in workpieces due to abrupt changes in removal amounts caused by thickness changes, leading to disconnection of the wire electrode and streak-like flaws on the workpiece surface.

Innovation Solution

The implementation of a wire electrical discharge machine and machining program editor that compensates the machining path by forming protrusions in thin portions over predetermined distances, thereby stabilizing the removal amount per unit time and preventing sudden changes, using a path compensator to adjust the machining path to include protrusions that gradually change the removal rate, ensuring consistent machining accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the machining condition is automatically changed at the position of steps, then the accuracy of electrical discharge machining at the step is improved, but the removal amount changes abruptly causing streak-like flaws on the workpiece surface

Engineering Contradiction:
Improvemachining accuracy at stepVSAvoidstreak-like flaws on surface
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The machining path is compensated in advance by adding protrusions in thin portions before machining reaches the step position. This preliminary path modification ensures that the wire electrode gradually approaches the step rather than encountering it abruptly, preventing sudden removal amount changes and streak-like flaws while maintaining machining accuracy at the step position.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the machining condition is changed during electrical discharge machining, then the machining suitability for step positions is improved, but the removal amount changes abruptly due to the setting change

Engineering Contradiction:
Improvemachining condition suitabilityVSAvoidremoval amount stability
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The machining path is locally modified by adding protrusions specifically in thin portions near step positions, while leaving the rest of the machining path unchanged. This localized path compensation allows the system to adapt to step positions without globally changing machining conditions, thereby maintaining stable removal amounts and productivity throughout the overall machining process.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If the wire electrode relatively moves along the machining path, then the workpiece can be machined into the desired shape, but disconnection of the wire electrode occurs at the step

Engineering Contradiction:
Improveworkpiece shape accuracyVSAvoidwire electrode continuity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The machining path is compensated in advance by adding protrusions in thin portions before the wire electrode reaches the step position. This preliminary modification creates a gradual transition that prevents abrupt thickness changes, thereby maintaining wire electrode tension and preventing disconnection while still achieving the desired workpiece shape.

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

This approach effectively suppresses the generation of flaws around stepped portions of the workpiece by maintaining consistent removal rates, enhancing machining accuracy and preventing disconnection of the wire electrode during electrical discharge machining.

Implementation Method 1

A wire electrical discharge machine performs electrical discharge machining on a workpiece by generating discharge sparks between a wire electrode and the workpiece

Methodology Applied
Scientific EffectElectrical discharge machining: Electrical Discharge Machining

Data Source

PatentEP3708286B1Wire electrical discharge machine and machining program editor
Publication Date: 2023.04.05 FANUC LTD
  • EP3708286B1 patent drawingFigure 1
  • EP3708286B1 patent drawingFigure 2
  • EP3708286B1 patent drawingFigure 3

AI summary

A wire electrical discharge machine (10) includes: a drive control unit (58) for moving a wire electrode (12) relative to a workpiece (14) along a machining path (16); a path determination unit (64) for determining whether or not the machining path (16) includes a linear path section that crosses a boundary line (68) between a thick portion (70) and a thin portion (72) of the workpiece (14); and a path compensator (66) for compensating the machining path (16) so as to form, in the thin portion (72), a protrusion (74) projecting outward from the boundary line (68) when the path determination unit determines that the linear path section is included.