Wire EDM Probe Offset Control for Accurate Start Positioning

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Solution Overview

Problem

Conventional wire electrical discharge machines do not utilize measurement results from contact-type probes to accurately position the wire electrode at the start of machining on a workpiece supported on a table, leading to potential inaccuracies in machining.

Innovation Solution

A wire electrical discharge machine that includes an upper wire guide, a lower wire guide, a probe for contact detection, an offset storage unit, a position shift drive unit, and a machining start position calculator to determine and adjust the wire electrode's position based on contact points and offset amounts, ensuring precise positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a contact-type probe is used to measure the workpiece shape, then measurement capability is improved, but the measurement result is not utilized to determine the wire electrode position, leading to positioning inaccuracy

Engineering Contradiction:

Improveworkpiece measurement capabilityVSAvoidwire electrode positioning accuracy

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The system uses the probe measurement results as feedback to automatically determine and adjust the wire electrode starting position. The control unit calculates the workpiece dimensions from probe measurements and sets the wire electrode position based on this feedback information, creating a closed-loop system that improves positioning accuracy.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The probe performs preliminary measurement of the workpiece before wire electrode machining begins. This preliminary action captures workpiece dimensional information that is then used to set the appropriate starting position for the wire electrode, ensuring accurate positioning before the actual machining process.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the wire electrode position is not adjusted based on measurement results, then the machining process is simple, but machining accuracy deteriorates

Engineering Contradiction:

Improvemachining process simplicityVSAvoidmachining accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The system performs automatic positioning of the wire electrode based on probe measurements without requiring manual intervention. The control unit automatically calculates dimensions from probe data and determines the wire electrode starting position, making the system self-adjusting and maintaining simplicity while improving accuracy.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If the probe is positioned far from the wire guide, then measurement freedom is improved, but positioning accuracy deteriorates due to offset errors

Engineering Contradiction:

Improveprobe measurement freedomVSAvoidpositioning accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system introduces an offset amount as an intermediary parameter that connects the probe position and wire guide position. By measuring and compensating for the offset between these two components, the system allows the probe to be positioned for measurement freedom while maintaining positioning accuracy through offset compensation calculations.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 the wire electrode to be accurately positioned at the machining start relative to the workpiece, enhancing machining accuracy and preventing accidental contact, thereby improving the overall machining process.

Implementation Method 1

a probe configured to detect contact with an object

Methodology Applied

Scientific EffectContact detection:

Implementation Method 2

applying a voltage across a gap between a wire electrode and the workpiece to generate electric discharge at the gap

Methodology Applied

Scientific EffectElectric discharge: Electrical Discharge Machining

Data Source

PatentUS11458555B2Wire electrical discharge machine

Publication Date: 2022.10.04 FANUC LTD

AI summary

A wire electrical discharge machine includes an upper wire guide and a lower wire guide supporting a wire electrode, a probe provided on an upper guide block having the upper wire guide, an offset storage unit for storing an offset amount from the upper wire guide to the probe, a position shift drive unit for changing the relative position between the table, and the upper and lower wire guides, a drive controller for controlling the position shift drive unit, a contact position calculator for calculating a contact position that is a position of the probe when it comes in contact, and a machining start position calculator for calculating a machining start position of the wire electrode, based on at least two contact positions and the offset amount. The drive controller controls the position shift drive unit so that the position of the wire electrode becomes the machining start position.