Dual Contact Tip Wire Preheating for Stable Weld Starts

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Solution Overview

Problem

Current welding techniques lack effective strategies for ensuring a heated electrode wire at the initiation of welding operations, which can impact weld performance.

Innovation Solution

A wire preheating system and method that utilizes a welding torch with a contact tip assembly to provide preheating power through a second contact tip, allowing for controlled preheating of the electrode wire based on user input, adjusting preheating power in response to changes in weld penetration settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If welding is started with a cold electrode, then the welding system is simpler to operate, but weld performance deteriorates due to poor arc initiation and increased spatter

Engineering Contradiction:
Improveweld performanceVSAvoidoperational complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system applies preliminary heating action to the electrode wire before welding begins. A preheat circuit with separate contact tips heats the wire to an elevated temperature (below melting point) prior to arc initiation, ensuring reliable weld performance without requiring complex manual preheating procedures

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary preheat circuit between the power source and the welding arc. This separate heating circuit with dedicated contact tips acts as a mediator to prepare the electrode wire before the main welding process, improving arc initiation while maintaining operational simplicity through automated control

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If preheating power is increased to ensure heated electrode wire, then weld performance improves, but heat input to the workpiece increases excessively

Engineering Contradiction:
Improveweld performanceVSAvoidheat input
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the heating function into two separate circuits: a preheat circuit that heats the electrode wire to an elevated temperature (below melting point) and a welding circuit that provides the arc energy. This segmentation allows control of preheat power independently from welding power, ensuring adequate wire heating without excessive heat input to the workpiece

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The preheat circuit applies heat locally to the electrode wire at the contact tips rather than heating the entire welding system or workpiece. The separate contact tips concentrate preheat energy on the wire endpoint, achieving effective preheating with minimal overall heat input

Inventive Principle:
Principle #3Local quality

3Reliability

If a dual contact tip system is used for preheating, then electrode preheating capability is improved, but device complexity increases

Engineering Contradiction:
Improveelectrode preheating capabilityVSAvoidcontact tip configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses a single power source that serves dual functions: providing preheat power through the preheat circuit and welding power through the welding circuit. The control system automatically switches between preheat and welding modes, making the power source universal and reducing overall device complexity despite the dual contact tip configuration

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

Solution Approach 2:

The control system automatically manages the preheat and welding operations without requiring manual intervention. The system self-regulates by switching between preheat and welding circuits based on operational state, reducing the complexity of manual operation despite the enhanced dual-circuit hardware

Inventive Principle:
Principle #25Self-service

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

Improves weld performance by ensuring a heated electrode wire, reducing spatter and improving deposition rates, while allowing for precise control of heat input and penetration.

Implementation Method 1

An electrode preheating circuit is configured to provide preheating power through a first portion of the welding-type electrode via a second contact tip of the welding torch

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3624980B1Systems and methods to preheat welding wire
Publication Date: 2024.02.21 ILLINOIS TOOL WORKS INC
  • EP3624980B1 patent drawingFigure 1
  • EP3624980B1 patent drawingFigure 2A
  • EP3624980B1 patent drawingFigure 2B

AI summary

A contact tip assembly with a preheating tip comprises 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. The assembly also includes an electrode preheating circuit configured to provide preheating current through a portion of the welding-type electrode via a second contact tip of the welding torch, and a voltage sense circuit to monitor a voltage drop across the two contact tips, and the electrode preheating circuit adjusts at least one of the first current or the preheating current based on the voltage drop.