Wire EDM Coordinate Calibration Using Reference Piece Contact

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing wire electrical discharge machining systems face challenges in calculating the relative positional relationship between the coordinate system of a wire electrical discharge machine and an articulated robot without using imaging devices or probes, limiting machining accuracy and increasing costs.

Innovation Solution

A wire electrical discharge machining system that includes a reference piece with a predetermined shape attached to the articulated robot, allowing the wire electrode to be moved parallel or inclined relative to the Z-axis to detect contact and calculate positional relationships using an electrode position acquiring unit and a relative positional relationship calculator, eliminating the need for imaging devices or probes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a contact position detecting function using a wire electrode is utilized, then the need for imaging devices or probes is eliminated, but the ability to detect contact position in the Z-direction is lost

Engineering Contradiction:
Improvesystem complexityVSAvoidcontact position detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transforms a 2D contact detection problem into a 3D solution by utilizing the wire electrode's ability to detect contact positions not only in the XY-plane but also by inferring Z-direction information through multiple contact detections. By moving the wire electrode to multiple positions and detecting contact points, the system reconstructs three-dimensional contact position information from two-dimensional detection data, thereby achieving full spatial measurement precision without adding complex imaging devices or probes.

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

2Measurement precision

If imaging devices or probes are used to calculate relative positional relationship, then measurement accuracy is improved, but system cost and complexity increase

Engineering Contradiction:
Improverelative positional relationship calculation accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables the wire electrode to serve dual functions: both performing electrical discharge machining and detecting contact positions for coordinate system calibration. By utilizing the wire electrode's inherent contact detection capability and processing multiple contact detection results through mathematical calculations, the system achieves self-calibration without requiring external imaging devices or probes, thereby maintaining high measurement precision while reducing system complexity and cost.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the wire electrode is moved only in the XY-plane, then the contact position detecting function works, but the Z-direction position cannot be detected

Engineering Contradiction:
Improveoperation simplicityVSAvoidcontact position detection precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent achieves three-dimensional contact position detection by performing multiple two-dimensional contact detections at different wire electrode positions. By systematically moving the wire electrode to multiple XY-plane locations and detecting contact points, the system reconstructs Z-direction information through mathematical processing, thereby achieving full 3D measurement precision while maintaining the operational simplicity of XY-plane movement.

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

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 accurate calculation of the coordinate system relative positional relationship between the wire electrical discharge machine and the articulated robot, reducing costs and improving machining precision by avoiding the use of imaging devices or probes.

Implementation Method 1

a contact position detecting function for detecting the position of contact between the wire electrode and an object by bringing the wire into contact with the object

Methodology Applied
Scientific EffectElectrical contact detection: Conduction (electrical)

Implementation Method 2

a wire electrical discharge machine configured to perform electrical discharge machining on a workpiece while feeding a wire electrode

Methodology Applied
Scientific EffectElectrical discharge machining: Electrical Discharge Machining

Data Source

PatentEP3418838B1Wire electrical discharge machining system and relative positional relationship calculating method
Publication Date: 2021.06.09 FANUC LTD
  • EP3418838B1 patent drawingFigure 1
  • EP3418838B1 patent drawingFigure 2
  • EP3418838B1 patent drawingFigure 3

AI summary

A wire electrical discharge machining system (10) includes: an electrode motion control unit (64) for moving a wire electrode (20) while keeping the wire electrode (20) parallel to Z1-axis and bring the wire electrode (20) into contact with a reference piece (36), and moving the wire electrode (20) while keeping the wire electrode inclined with respect to the Z1-axis and bring the wire electrode into contact with the reference piece; an electrode position acquiring unit (66) for acquiring a position of the wire electrode (20) in an X1Y1Z1 orthogonal coordinate system when the wire electrode (20) touches the reference piece (36); a piece position acquiring unit (62) for acquiring a piece position of the reference piece (36) in an X2Y2Z2 orthogonal coordinate system when the wire electrode (20) touches the reference piece (36); and a relative positional relationship calculator (68) for calculating a coordinate system relative positional relationship, based on the acquired positions.