Welding Wire Surface Scanning With Wear Error Detection

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Solution Overview

Problem

Conventional scanning systems for metallic workpieces experience high acceleration forces and surface wear of the welding wire, leading to measurement inaccuracies and slippage due to mechanical movement, which impairs the precision of scanning results.

Innovation Solution

A method and device that use a welding torch with a welding wire electrode to scan the workpiece surface by moving the wire end towards and away from the surface, with adjustable movement profiles and frequencies, and detect surface wear through motor speed and current signals to adjust the scanning process and reduce measurement errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the wire end is repeatedly moved towards and away from the workpiece surface using drive rollers, then the scanning measurement can be performed, but high acceleration forces and surface wear occur causing measurement inaccuracies

Engineering Contradiction:
Improvescanning measurement accuracyVSAvoidwire surface condition
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical contact-based scanning system with an optical measurement system. Instead of using drive rollers to physically move the wire against the workpiece surface, the invention uses optical sensors and cameras to detect surface geometry and features. This eliminates mechanical wear, acceleration forces, and contact-related measurement errors while maintaining scanning functionality.

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

Solution Approach 2:

The patent introduces an optical field as an intermediary between the measurement system and the workpiece surface. Optical sensors and lighting systems serve as mediators to capture surface information without direct mechanical contact. This intermediary approach allows accurate scanning measurement without the harmful mechanical interactions that cause wire wear and slippage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If drive rollers are used to convey the welding wire electrode, then the wire can be positioned for scanning, but slippage occurs between the wire and rollers impairing measurement results

Engineering Contradiction:
Improvewire positioningVSAvoidscanning measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent eliminates the mechanical drive roller system entirely by replacing it with an optical measurement approach. The welding wire electrode is no longer used as a mechanical scanning probe, so there is no contact between the wire and drive rollers that could cause slippage. Optical sensors directly measure surface features without requiring mechanical wire conveyance.

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

Solution Approach 2:

The patent creates an optical copy or representation of the workpiece surface geometry through photogrammetry and image processing. Instead of physically contacting the surface with a wire, the system captures multiple images from different angles and reconstructs the surface topology digitally. This copying approach achieves accurate measurement without mechanical slippage.

Inventive Principle:
Principle #26Copying

3Measurement precision

If the wire end strikes the workpiece surface with high acceleration, then contact detection is achieved, but wear on the wire surface distorts measurement results

Engineering Contradiction:
Improvecontact detection accuracyVSAvoidwire material wear
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The patent replaces mechanical impact-based contact detection with optical detection methods. Instead of relying on the wire end striking the surface to detect contact points, the system uses optical sensors to identify surface features and geometry. This eliminates wire material wear while maintaining accurate contact and surface detection capabilities.

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

Solution Approach 2:

The patent converts the potential harm of wire wear into a benefit by using the wire's known geometry and position in the optical field as a reference. The optical system captures images of the wire itself along with the workpiece surface, and through image processing, separates wire features from surface features. This allows the wire to serve as both the measurement tool and the reference object, turning the wear issue into a self-calibrating system.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 enhances scanning accuracy by minimizing mechanical slippage and surface wear, allowing for precise determination of scanning measurement errors and improving the reliability of scanning results.

Implementation Method 1

contact of one end of the wire with the workpiece surface is detected

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the drive rollers provided for conveying the welding wire electrode are driven by an electric motor

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP3645202B1Method and device for sampling a workpiece surface of a metallic workpiece
Publication Date: 2021.08.04 FRONIUS INT GMBH
  • EP3645202B1 patent drawingFigure 1
  • EP3645202B1 patent drawingFigure 2
  • EP3645202B1 patent drawingFigure 3~4

AI summary

The invention relates to a device and to a method for scanning a workpiece surface (2A) of a metal workpiece (2), in which method a welding torch (3) having a welding wire electrode (4) is moved relative to the workpiece surface (2A) in order to determine scanning values and a wire end (4A) of the welding wire electrode (4) is moved toward the workpiece surface (2A) in a recurring manner until contact with the metal workpiece (2) is detected at the scanning position (P) in question on the workpiece surface (2A) of the metal workpiece (2) and subsequently the wire end (4A) of the welding wire electrode (4) is moved back, scanning values (d) being sensed multiple times at some scanning positions (P) by means of the welding torch (3) in order to determine scanning measurement errors.