Welding Wire Preheating Circuit for Stable Arc Initiation

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Solution Overview

Problem

Current welding techniques lack effective methods for ensuring a heated electrode wire at the start of the welding process, which can affect the initiation and quality of welds, particularly in continuous welding operations where electrode preheating is not standardized.

Innovation Solution

A consumable electrode-fed welding system with a preheating circuit and control system that heats the electrode wire before welding, using a contact tip assembly with separate power supplies for preheating and welding, and a switching circuit to manage current flow, ensuring the electrode wire is preheated to an optimal temperature for improved arc initiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a cold electrode start is used, then the welding system is simpler to operate, but the weld initiation quality deteriorates

Engineering Contradiction:
Improveease of operationVSAvoidweld initiation quality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system applies preliminary heating action to the electrode wire before welding begins. A preheating circuit with separate contact tips heats the wire to an optimal temperature range (100-500°C) before arc initiation, ensuring consistent weld quality without complicating the operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The contact tip assembly is segmented into separate preheating contact tips and welding contact tips. This segmentation allows independent control of preheating and welding functions, enabling the system to maintain ease of operation while improving weld initiation quality through controlled preheating.

Inventive Principle:
Principle #1Segmentation

2Reliability

If electrode preheating is implemented, then weld performance improves, but device complexity increases

Engineering Contradiction:
Improveweld performanceVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The preheating circuit and welding power source are merged into a single integrated system. The preheating contact tips and welding contact tips share the same power source and control circuitry, reducing overall device complexity while maintaining improved weld performance through controlled preheating.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The welding power source is designed with multi-functionality, serving both as a preheating power source and a welding power source. This universal design eliminates the need for separate preheating equipment, improving weld performance without significantly increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If preheating current is applied through the same contact tip, then the system is simpler, but wire temperature control precision deteriorates

Engineering Contradiction:
Improvesystem simplicityVSAvoidwire temperature control precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The contact tip assembly is segmented into separate preheating contact tips and welding contact tips positioned at different locations along the wire. This spatial segmentation enables precise temperature control at the wire entry point while maintaining relative system simplicity through integrated control circuitry.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The separate preheating contact tips act as intermediaries between the power source and the wire. They provide controlled electrical contact for preheating without the mechanical wear and temperature interference associated with using the primary welding contact tip, thereby improving temperature control precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If electrode preheating is implemented, then spatter and material transfer improve, but energy consumption increases

Engineering Contradiction:
Improvematerial transfer qualityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system applies preliminary heating action to the electrode wire before welding begins. By heating the wire to an optimal temperature range (100-500°C) in advance, the system improves material transfer quality and reduces spatter during welding, while the total energy consumption is managed through controlled preheating duration and intensity.

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

The system enhances weld performance by consistently preheating the electrode wire, reducing spatter, improving material transfer, and maintaining a stable arc, leading to higher deposition rates and better weld quality across various welding processes.

Implementation Method 1

A consumable electrode-fed welding system with a preheating circuit and control system that heats the electrode wire before welding

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3774151B1Systems, methods, and apparatus to preheat welding wire
Publication Date: 2023.01.11 ILLINOIS TOOL WORKS INC
  • EP3774151B1 patent drawingFigure 1
  • EP3774151B1 patent drawingFigure 2A
  • EP3774151B1 patent drawingFigure 2B

AI summary

An example welding-type system includes: a welding-type power source configured to provide welding-type current to a welding-type circuit, the welding-type circuit comprising a welding-type electrode and a first contact tip of a welding torch; an electrode preheating circuit configured to provide preheating current through a first portion of the welding-type electrode via a second contact tip of the welding torch; a switching circuit configured to control a current flow between the welding-type power source and the first contact tip; and a preheat control circuit configured to control the switching circuit to: selectively direct current from the welding-type power source to the second contact tip; and selectively divert current from the electrode preheating circuit to the first contact tip.