Wire EDM Guide Position Correction for Precise Taper Machining

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Solution Overview

Problem

Existing wire electric discharge machining techniques face challenges in maintaining machining precision due to wire electrode bending from discharge heat, requiring external measurement instruments for taper angle correction, and are inconvenient for re-machining due to positional deviations when re-mounting the workpiece.

Innovation Solution

A wire electric discharge machine equipped with a contact detector that performs in-situ measurement and automatic calculation of correction values for wire support positions, eliminating the need for external measurement instruments and enabling precise taper angle correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wire support positions are measured using a jig before machining and correction values are calculated manually, then taper angle correction can be performed, but external measurement instruments are required and additional time is needed for measurement and calculation

Engineering Contradiction:
Improvetaper angle measurement precisionVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the measurement function and machining function into a single integrated system. The contact detector is mounted on the wire electric discharge machine itself, allowing measurement and correction to be performed without external instruments. This combines what were previously separate operations (external measurement + internal machining) into one unified system, eliminating the need for separate measurement devices and manual calculation processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The wire electric discharge machine performs self-measurement and self-correction through the integrated contact detector system. The machine automatically detects wire support positions, calculates correction values, and adjusts wire guide positions without requiring external measurement instruments or manual intervention. This self-service capability eliminates dependency on external equipment and reduces operational complexity.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If workpiece is removed from the machine for measurement and then remounted, then measurement can be performed, but positional deviation occurs between mounting positions making re-machining difficult

Engineering Contradiction:
Improveworkpiece measurement accuracyVSAvoidre-machining reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent combines measurement and machining operations in-situ on the same workpiece mounting position. The contact detector measures workpiece dimensions directly on the machine table without removal, and the wire electric discharge machine performs correction machining at the same position. This eliminates the remove-measure-remount cycle that causes positional deviations, ensuring consistent reference positions for both measurement and machining operations.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If measurement and correction are performed manually with external instruments, then correction values can be calculated, but additional man-hours are required and productivity decreases

Engineering Contradiction:
Improvetaper angle correction precisionVSAvoidcorrection process efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system performs automatic self-measurement and self-correction without manual intervention. The contact detector automatically measures wire support positions and workpiece dimensions, the control unit automatically calculates correction values based on measured data, and the system automatically adjusts wire guide positions. This eliminates manual measurement, calculation, and adjustment operations, significantly reducing man-hours while maintaining high correction precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements a closed-loop feedback mechanism where measurement results are immediately used to calculate and apply correction values. The contact detector continuously monitors wire support positions and workpiece dimensions, feeds this information to the control unit for real-time calculation of correction values, and automatically adjusts the wire guide positions accordingly. This automated feedback loop eliminates manual intervention and accelerates the correction process while maintaining precision.

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 solution allows for accurate and automatic correction of taper angles and dimensions without external measurement tools, reducing man-hours and preventing positional deviations, enabling continuous and precise machining.

Implementation Method 1

the wire support positions of the upper and lower wire guides for supporting the wire electrode are measured by a jig or the like through short-circuit detection of the wire electrode

Methodology Applied
Scientific EffectElectrical contact detection: Conduction (electrical)

Implementation Method 2

When a taper machining is performed on a workpiece by a wire electric discharge machine, the wire support positions of the upper and lower wire guides for supporting the wire electrode are measured

Methodology Applied
Scientific EffectElectric discharge machining: Electrical Discharge Machining

Data Source

PatentEP2767360B1Wire electric discharge machine and calculation method for wire support positions of wire electric discharge machine
Publication Date: 2023.05.10 FANUC LTD
  • EP2767360B1 patent drawingFigure 1
  • EP2767360B1 patent drawingFigure 2
  • EP2767360B1 patent drawingFigure 3

AI summary

One arbitrary point on an upper surface of a workpiece and two points at arbitrary heights on a tapered section of the workpiece are measured using a contact detector disposed on an upper wire guide of a wire electric discharge machine to calculate the shape accuracy and tapered angle. Based on the calculated data, the upper and lower wire guide support positions of the upper and lower wire guides are calculated. Using the calculated upper and lower wire guide support positions, electric discharge machining is performed on the workpiece.