Electrode Preheat Voltage Feedback for Welding Overheat Protection

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Solution Overview

Problem

Current welding techniques lack a systematic approach to ensure the electrode is preheated before initiating a welding operation, which can affect the consistency and efficiency of the welding process, particularly in cold electrode starts.

Innovation Solution

A welding system and method that includes a preheat voltage feedback mechanism, where a preheat power supply heats the electrode wire, and a control circuit monitors the preheat voltage, adjusting the power to maintain a valid range and preventing damage by reducing or disabling power in case of invalid voltage feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If preheating power is applied to the electrode wire, then the welding performance is improved by ensuring hot electrode start, but the risk of overheating and damage increases if the preheat voltage feedback is lost

Engineering Contradiction:
Improvewelding performanceVSAvoidoverheating damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a preheat voltage feedback mechanism where the control circuit continuously monitors the preheat voltage across the electrode wire. When the preheat voltage falls outside the valid range (indicating feedback loss), the control circuit automatically reduces or disables the preheating power. This feedback loop ensures that preheating power is only applied when the electrode wire is properly positioned and receiving power, preventing overheating while maintaining welding performance.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent prepares for potential feedback loss by establishing valid and invalid voltage ranges before welding begins. The control circuit is pre-programmed with threshold values to detect when preheat voltage becomes invalid, allowing it to respond preemptively by reducing power before overheating damage can occur. This beforehand preparation ensures rapid protection without requiring complex real-time analysis.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Stability of the object's composition

If preheating power is continuously applied to ensure adequate electrode heating, then the consistency of welding process is improved, but the energy consumption increases and risk of damage rises

Engineering Contradiction:
Improvewelding process consistencyVSAvoidenergy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The control circuit uses preheat voltage feedback to determine when preheating power should be applied or reduced. By monitoring whether the preheat voltage remains within the valid range, the system maintains consistent electrode heating only when necessary, rather than continuously applying power. This feedback-based approach ensures welding process consistency while avoiding unnecessary energy consumption.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the preheating power level based on real-time voltage feedback conditions. When voltage feedback is valid, the system maintains adequate preheating power for consistent welding. When voltage feedback becomes invalid, the system automatically reduces or disables power. This dynamic adjustment optimizes energy usage while maintaining process consistency when needed.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the preheat voltage monitoring range is expanded to detect all abnormal conditions, then the reliability of welding operation is improved, but the device complexity increases

Engineering Contradiction:
Improvewelding operation reliabilityVSAvoidcontrol circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control circuit implements voltage range monitoring by comparing the preheat voltage against predetermined valid and invalid ranges. This feedback mechanism detects abnormal conditions (such as lost voltage feedback or short circuits) by determining whether the measured voltage falls outside the acceptable range. The approach maintains high reliability through continuous monitoring while keeping the control logic relatively simple by using threshold-based detection rather than complex analysis.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent defines specific voltage threshold parameters (valid range and invalid range) that simplify the detection of abnormal conditions. By establishing clear parameter boundaries, the control circuit can reliably detect issues such as lost voltage feedback or short circuits through straightforward parameter comparison. This parameter-based approach enhances reliability without requiring complex diagnostic algorithms.

Inventive Principle:
Principle #35Parameter changes

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 solution ensures consistent electrode heating, improving welding performance by maintaining a valid preheat voltage range, reducing the risk of overheating, and enhancing the quality of welds by ensuring the electrode is adequately preheated before welding.

Implementation Method 1

a preheat power supply is configured to heat the electrode wire

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Data Source

PatentEP3612338B1System and method to provide preheat voltage feedback loss protection
Publication Date: 2022.06.29 ILLINOIS TOOL WORKS INC
  • EP3612338B1 patent drawingFigure 1
  • EP3612338B1 patent drawingFigure 2A
  • EP3612338B1 patent drawingFigure 2B

AI summary

Systems, methods, and apparatus to provide preheat voltage feedback loss protection are disclosed. An example welding-type system includes a welding-type power source configured to provide welding-type power 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 power through a first portion of the welding-type electrode via a second contact tip of the welding torch; a preheat feedback circuit configured to measure a preheat voltage; and an electrode preheat control circuit configured to: control the preheating power based on the preheating voltage; and control the electrode preheating circuit to reduce the preheating power in response to detecting an invalid preheat voltage measured by the preheat feedback circuit.