Welding Torch Electrode Geometry for Repeatable Coaxial Alignment

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Solution Overview

Problem

Tungsten electrodes in TIG and plasma welding systems face issues with repeatable alignment and retention, leading to time-consuming recalibration and potential contamination due to chipped threads, and high scrap metal rates, especially when welding sheet metal workpieces.

Innovation Solution

The development of electrodes with a 55° threaded angle and dual material construction, featuring a tungsten shank with a copper or silver alloy head, which improves retention and reduces material waste, along with a radiused working end surface for enhanced stability and coaxial repeatability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a threaded portion with 60° thread angle is used to secure the electrode to the welding torch, then the electrode can be retained in the welding torch, but thread chipping occurs which affects installation and reduces reliability

Engineering Contradiction:
Improveelectrode retentionVSAvoidthread chipping
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the thread angle parameter from the conventional 60° to 55°. This parameter modification reduces thread chipping during installation while maintaining adequate electrode retention in the welding torch, directly resolving the contradiction between reliable retention and thread damage prevention

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the electrode is removed from the welding torch for replacement, then a new electrode can be installed, but recalibration is required which consumes time

Engineering Contradiction:
Improveelectrode replacementVSAvoidrecalibration time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent incorporates a positioning feature on the electrode that pre-establishes alignment with the welding torch axis. This preliminary alignment feature ensures that when a new electrode is installed, it automatically maintains the correct coaxial position without requiring time-consuming recalibration, thus enabling easy replacement while minimizing time loss

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If a radiused working end surface is provided on the electrode, then coaxial repeatability and stability are improved, but manufacturing complexity increases

Engineering Contradiction:
Improvecoaxial repeatabilityVSAvoidelectrode geometry
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies a radius to the working end surface of the electrode, transitioning from a flat surface to a curved one. This curvature improves coaxial repeatability and positional stability during welding operations. While it adds some manufacturing complexity, the modification is a simple geometric change that can be achieved through standard machining or forming processes

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP3397422B1Electrode of a welding torch
Publication Date: 2021.08.04 CAMARC LLC
  • EP3397422B1 patent drawingFigure 1~2
  • EP3397422B1 patent drawingFigure 3~6
  • EP3397422B1 patent drawingFigure 7~8

AI summary

An electrode includes a working end portion defining a first truncated cone. A seating end portion defines a second truncated cone and including a threaded portion having a plurality of threads with a thread angle of 55°. An elongated body defines a longitudinal axis. The elongated body is located between the seating end portion and the working end portion. A method is also disclosed.