Welding Arc Start Control With Intermediate Wire Feed Ramp

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Solution Overview

Problem

Conventional welding systems face challenges during the arc starting transient due to high wire feed speeds, leading to variable start conditions, potential electrode extension breakage, excessive spatter, and arc extinguishment, as the arc current can reach maximum output, causing instability in the welding process.

Innovation Solution

The system employs a predetermined intermediate wire feed speed to stabilize the wire temperature profile before ramping to the target speed, controlling the arc current and wire feed speed to maintain a consistent arc starting process, reducing variability and preventing excessive spatter and arc extinguishment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high wire feed speed is used during arc starting, then productivity is improved, but welding process stability deteriorates causing spatter and arc extinguishment

Engineering Contradiction:
Improvewire feed speedVSAvoidwelding process stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary heating of the welding wire using resistive heating from the power source before initiating the welding arc. This preheating action stabilizes the wire temperature profile at the contact tip, preventing excessive spatter and arc extinguishment when high wire feed speeds are subsequently used during welding operations.

Inventive Principle:
Principle #10Preliminary action

2Power

If maximum arc current is applied during arc starting, then arc ignition is achieved, but wire temperature instability increases leading to electrode breakage

Engineering Contradiction:
Improvearc currentVSAvoidwire temperature profile
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The system applies resistive heating current through the wire before arc ignition to preheat and stabilize the wire temperature profile. This preliminary thermal conditioning prevents thermal shock and temperature instability when maximum arc current is subsequently applied, eliminating electrode breakage at the contact tip.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The power source continuously supplies controlled current through the wire during the preheating phase to maintain a stable temperature profile. This continuous thermal action ensures the wire remains at optimal temperature throughout the arc starting transient, preventing interruption from electrode breakage.

Inventive Principle:
Principle #20Continuity of useful 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

This approach ensures a stable wire temperature profile, reducing spatter and arc extinguishment, while maintaining process stability and consistency across different wire feed speed settings, thereby improving the reliability of the welding process.

Implementation Method 1

the arc current can reach maximum output, causing instability in the welding process

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Implementation Method 2

igniting an arc and an arc-stabilizing phase comprising at least one initial sub-phase

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Data Source

PatentEP4112216B1Systems and methods to start a welding process
Publication Date: 2024.07.31 ILLINOIS TOOL WORKS INC
  • EP4112216B1 patent drawingFigure 1A
  • EP4112216B1 patent drawingFigure 1B
  • EP4112216B1 patent drawingFigure 2

AI summary

An example welding system includes: a welding power supply configured to convert input power to welding power; a wire feeder configured to feed welding wire to a welding torch; and control circuitry configured to: in response to an initiation of a welding process, control the wire feeder to feed the welding wire at a first rate while controlling the welding power supply to output the welding power to initiate a welding arc; in response to initiation of the welding arc, control the wire feeder to increase a feed rate of the wire feeder from the first rate to a second rate; and in response to determining that a temperature profile of a heated portion of the welding wire has stabilized, control the wire feeder to change the feed rate of the wire feeder from the second rate to a target wire feed speed.