Welding Electrode Preheating Control for Stable Heat Input

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Solution Overview

Problem

Existing welding systems face challenges in maintaining consistent heat input during the welding process, particularly due to variations in contact-tip-to-work-distance (CTWD), stickout length, and arc length, which affect weld quality and penetration.

Innovation Solution

A consumable electrode-fed welding system that includes a welding-type current source, an electrode preheating circuit, a current interpreter, and a control circuit. This system monitors the combination of preheating current and welding-type current to maintain a substantially constant heat input by adjusting the preheating current or electrode feed speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If welding parameters are adjusted to maintain constant heat input, then weld quality and penetration are improved, but the system complexity increases due to additional monitoring and control mechanisms

Engineering Contradiction:
Improveweld qualityVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system employs feedback control by continuously monitoring welding parameters (voltage, current, wire feed speed) and automatically adjusting them to maintain constant heat input. The controller receives real-time data from sensors and modifies welding parameters dynamically, creating a closed-loop control system that ensures consistent weld quality despite variations in CTWD, stickout length, or arc length.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual mechanical adjustment of welding parameters with automated electronic control. Instead of physically adjusting contact-tip-to-work-distance or wire feed speed by hand, the system uses electronic sensors to monitor parameters and electronic controllers to automatically adjust them, substituting mechanical operations with automated electromechanical systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If real-time monitoring of welding parameters is implemented, then heat input consistency is improved, but the cost of equipment and operation increases

Engineering Contradiction:
Improveheat input consistencyVSAvoidequipment cost
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The welding system integrates multiple functions into a single unified platform. The controller not only monitors welding parameters but also automatically adjusts them to maintain constant heat input. The system can handle various welding operations (MIG, MAG, MPA) with a single setup, eliminating the need for separate monitoring and control devices for each function, thereby reducing overall equipment cost.

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

Solution Approach 2:

The system performs self-monitoring and self-adjustment of welding parameters. The sensors automatically detect variations in welding conditions, and the controller autonomously modifies parameters to maintain constant heat input without requiring external intervention or additional specialized equipment. This self-service capability reduces the need for complex external monitoring systems.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If welding parameters are dynamically adjusted during the process, then weld penetration and quality are improved, but the control difficulty increases

Engineering Contradiction:
Improveweld penetrationVSAvoidcontrol difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The system uses feedback control to automatically adjust welding parameters during the welding process. Sensors continuously monitor voltage, current, and wire feed speed, and the controller dynamically modifies these parameters based on real-time feedback to maintain constant heat input and optimize weld penetration, eliminating the need for manual control adjustments.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes welding parameters (voltage, current, wire feed speed) during the welding process to maintain constant heat input. The controller automatically adjusts these parameters based on monitored conditions, allowing the welding process to adapt to variations in CTWD, stickout length, or arc length without requiring operator intervention or complex manual control.

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

The system effectively maintains a consistent heat input, improving weld quality and penetration by compensating for changes in CTWD, stickout length, and arc length, thereby enhancing the overall efficiency and reliability of the welding process.

Implementation Method 1

an electrode preheating circuit to provide preheating current through a first portion of the welding-type electrode

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

Electrical power is applied to the welding wire and a circuit is completed through the workpiece to sustain a welding arc that melts the electrode wire and the workpiece to form the desired weld

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Data Source

PatentEP4257277B1Systems to control welding electrode preheating
Publication Date: 2025.04.16 ILLINOIS TOOL WORKS INC
  • EP4257277B1 patent drawingFigure 1
  • EP4257277B1 patent drawingFigure 2A
  • EP4257277B1 patent drawingFigure 2B

AI summary

Systems, methods, and apparatus to control welding electrode preheating are disclosed. An example consumable electrode-fed welding-type system includes a welding-type current 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; an electrode preheating control circuit configured to adjust at least one of the preheating current or an electrode feed speed based on the change in the contact-tip-to-work-distance; and a current interpreter configured to determine a change in a contact-tip-to-work-distance of the welding torch based on at least one of the welding-type current or the preheating current.