Spot Welding Electrode Surface Relief Patterns

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Solution Overview

Problem

Resistance spot welding electrodes often leave sharp imprints and unsightly deformations on metal surfaces, leading to undesirable whiskers or fingers, and existing methods for creating patterns on these electrodes are limited to axisymmetric designs centered on the weld face, which may not be suitable for complex or aesthetically pleasing patterns.

Innovation Solution

The method involves resurfacing the electrodes with specific patterns by selective material removal or displacement, using techniques such as abrasive processes with masks, electrical discharge machining, mechanical deformation, or composite materials with differential properties to create non-axisymmetric, recognizable images on the weld face, allowing for the formation of complex and attractive patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional spherical domed electrode faces are used, then the welding process is simple and efficient, but the electrode leaves sharp imprints and unsightly deformations on the metal surface

Engineering Contradiction:

Improveelectrode manufacturing simplicityVSAvoidsurface deformation and sharp imprints

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The electrode face is divided into different zones with distinct geometries: a central dome portion for effective welding and a peripheral flat portion with reduced curvature. This local differentiation allows the central area to maintain high welding efficiency while the peripheral area reduces surface deformation and eliminates sharp imprints on the workpiece.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The electrode face transitions from a completely symmetrical spherical dome to an asymmetric configuration where the peripheral region has a different curvature profile than the central region. This asymmetry in curvature distribution enables selective control over contact pressure and heat distribution, reducing unwanted surface deformation while maintaining welding quality.

Inventive Principle:

Principle #4Asymmetry

2Ease of manufacture

If axisymmetric patterns are used on electrode faces, then the manufacturing process is simple, but complex and aesthetically pleasing patterns cannot be achieved

Engineering Contradiction:

Improvepattern manufacturing simplicityVSAvoidpattern design flexibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The electrode face is segmented into multiple functional zones: a central dome portion and a peripheral flat portion, each capable of carrying different pattern geometries. This segmentation allows independent design and manufacturing of patterns in different regions, enabling complex non-axisymmetric patterns while using relatively simple manufacturing processes for each segment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention moves beyond two-dimensional axisymmetric patterns on a spherical surface to three-dimensional pattern integration across different surface zones (central dome and peripheral flat areas). This dimensional expansion allows complex spatial patterns and logos that cannot be achieved with conventional axisymmetric designs.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If the electrode face is reprofiled frequently to maintain pattern quality, then aesthetic appearance is maintained, but production time is lost and productivity decreases

Engineering Contradiction:

Improveweld pattern quality consistencyVSAvoidproduction throughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The electrode face is pre-configured with a dual-zone geometry (central dome and peripheral flat portions) that inherently maintains pattern integrity over extended use. The peripheral flat portion with reduced curvature is designed to minimize wear and pattern degradation, eliminating the need for frequent reprofiling and allowing continuous production without interruption.

Inventive Principle:

Principle #10Preliminary action

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 enables the creation of functional and aesthetically pleasing patterns on spot-welded surfaces, improving the quality of welds by maintaining consistent heat input, reducing electrical demand, and extending electrode life, while allowing for continuous production with minimal disruption.

Implementation Method 1

The method involves resurfacing the electrodes with specific patterns by selective material removal or displacement, using techniques such as abrasive processes with masks

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

using techniques such as abrasive processes with masks, electrical discharge machining, mechanical deformation

Methodology Applied

Scientific EffectElectrical discharge machining: Electrical Discharge Machining

Data Source

PatentUS8350179B2Application of surface relief to spot welding electrodes

Publication Date: 2013.01.08 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

The workpiece-contacting surface of the spot welding electrode may be suitably modified to incorporate a desired shape or form, generally comprising a depressed region outlining a recognizable shape, to form aesthetically-pleasing or functional features in the surface of a workpiece during resistance spot welding. Methods for creating the desired form in the spot welding electrode including abrasion, upsetting, and electrical discharge machining are disclosed. Preferably the electrode face is shaped and subsequently redressed during welding operations at the welding station.