Wire EDM Coil Layout for Precise Electrode Deflection Sensing

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Solution Overview

Problem

Existing sensor arrangements for detecting wire electrode deflection in wire EDM machines are complex and require a dielectric for resistance measurement, limiting precision and accuracy.

Innovation Solution

A sensor arrangement with a coil element configuration that generates and detects an alternating magnetic field around the wire electrode, allowing for precise, contactless, two-dimensional detection of wire electrode deflection without the need for a dielectric, featuring a compact and simple structure with coil elements arranged in planes perpendicular to the reference axis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If four measuring electrodes are arranged in four main axis directions with a dielectric for resistance measurement, then the wire electrode deflection can be detected, but the device structure becomes complex and space-consuming

Engineering Contradiction:
Improvewire electrode deflection detection precisionVSAvoidsensor arrangement structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the electrical resistance measurement system (measuring electrodes and dielectric) with an electromagnetic detection system using coil elements that sense the alternating magnetic field generated by the wire electrode. This substitution eliminates the need for complex electrode arrangements and dielectric materials while achieving the same deflection detection function.

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

Solution Approach 2:

The patent transitions from a two-dimensional electrode arrangement in the XY plane to a three-dimensional coil element configuration with elements positioned at different heights (first and second planes spaced apart in the Y direction). This spatial distribution in multiple dimensions enables precise magnetic field sensing while simplifying the overall structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If four measuring electrodes and dielectric are used for resistance measurement, then wire electrode position can be detected, but the device occupies more space

Engineering Contradiction:
Improvewire electrode position detection accuracyVSAvoidsensor arrangement volume
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent replaces the bulky dielectric material and four measuring electrodes with compact coil elements that detect the magnetic field directly. This substitution significantly reduces the volume required for the sensor arrangement while maintaining detection precision.

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

Solution Approach 2:

The coil elements are arranged in a compact configuration where elements in the first plane and second plane are positioned close to each other, nesting the sensing structure within a smaller spatial envelope compared to the extended electrode arrangement.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Measurement precision

If resistance measurement with dielectric is used, then wire electrode deflection can be measured, but the device requires additional components and becomes less reliable

Engineering Contradiction:
Improvedeflection measurement accuracyVSAvoidsensor arrangement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the resistance measurement system (which requires dielectric material and multiple electrode connections) with a magnetic field sensing system using coil elements. This eliminates potential failure points related to dielectric breakdown, electrode contact issues, and connection reliability, thereby improving overall system reliability while maintaining measurement precision.

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

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

Enables high-accuracy detection of wire electrode deflection with reduced space requirements and eliminates the need for a dielectric, enhancing precision and reliability in wire EDM machine operations.

Implementation Method 1

The coil element arrangement has at least one first to fourth coil element arranged in the first measurement plane for detecting an alternating magnetic field generated by the wire electrode

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the wire electrode is designed in such a way that the alternating magnetic field to be detected is generated when the alternating current pulse is applied to it

Methodology Applied
Scientific EffectElectromagnetic field generation: Electromagnetic Induction

Data Source

PatentEP3764054B1Sensor arrangement for detecting a deflection of a wire electrode
Publication Date: 2022.07.13 DR JOHANNES HEIDENHAIN GMBH
  • EP3764054B1 patent drawingFigure 1
  • EP3764054B1 patent drawingFigure 2
  • EP3764054B1 patent drawingFigure 3~4

AI summary

The present invention relates to a sensor arrangement (10) for detecting a deflection (ΔX1, ΔY1) of a wire electrode (1) of a wire EDM machine with respect to a first reference point (O1) located on a reference axis (O) in a first measuring plane (T1). The sensor arrangement (10) comprises a coil element arrangement (18). The coil element arrangement (18) has at least one first to fourth coil element (20.1 to 20.4) arranged in the first measuring plane (T1). The first to fourth coil elements (20.1 to 20.4) are arranged in a first plane (A1) and in a second plane (A2) such that they are paired with respect to the first reference point (O1) in a first and second deflection direction (X, Y). The first plane (A1) and the second plane (A2) each extend parallel to the reference axis (O).The first and second planes (A1, A2) are spaced apart from each other and arranged opposite each other in the second deflection direction (Y) with respect to the first reference point (O1).