Short-Circuit Welding Wire Speed Control

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Solution Overview

Problem

In short-circuit welding processes, the variability in short circuit admission and release times leads to inconsistent welding frequency, resulting in reduced weld quality and potential splashes, especially with materials like chrome-nickel alloys or titanium, due to inadequate control over welding wire speeds.

Innovation Solution

A control and regulation system adjusts the first time duration of the backward promotion phase to ensure the welding wire does not exceed a reduced backward speed at the time of short circuit breakage, stabilizing the welding frequency by reducing the speed before the short circuit and maintaining a constant speed during material delivery, thus preventing splashes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the welding wire speed is increased to improve productivity, then the welding frequency increases, but weld spatter and quality defects occur due to excessive speed at material dispensing

Engineering Contradiction:
Improvewelding frequencyVSAvoidweld spatter
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent implements dynamic speed control of the welding wire through multiple conveying phases with different speeds. During the short-circuit phase, the wire is conveyed at a first reduced speed, then at a second higher speed, and finally at a third reduced speed before material dispensing. During the arc phase, similar dynamic speed adjustment is applied. This dynamic speed variation allows the system to maintain high average welding frequency while ensuring low speed at the critical moment of material dispensing, thereby preventing weld spatter.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The welding process is segmented into distinct phases (short-circuit phase and arc phase), with each phase further divided into multiple conveying sub-phases with different speed characteristics. This segmentation allows independent optimization of wire speed for each sub-phase, enabling high productivity during acceleration and deceleration phases while maintaining controlled speed during material dispensing.

Inventive Principle:
Principle #1Segmentation

2Object-generated harmful factors

If the welding wire speed is decreased to prevent weld spatter, then welding frequency and productivity are reduced

Engineering Contradiction:
Improveweld spatter preventionVSAvoidwelding frequency
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The system employs dynamic speed adjustment rather than maintaining a constantly low speed. The welding wire is accelerated to higher speeds during non-critical phases (after material dispensing and during arc phase) to maintain high productivity, while being decelerated to low speeds only during the critical short moments of material dispensing and short circuit occurrence. This dynamic approach prevents spatter without sacrificing overall welding frequency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The welding process utilizes periodic acceleration and deceleration cycles of the welding wire. Each welding cycle includes periods of high speed conveyance followed by controlled deceleration before material dispensing. This periodic action pattern allows the system to achieve high average productivity while ensuring low speed at critical moments, effectively preventing weld spatter.

Inventive Principle:
Principle #19Periodic action

3Ease of operation

If fixed speeds and times are used for welding wire conveyance, then the process is simple to control, but welding frequency becomes inconsistent due to variability in short circuit timing

Engineering Contradiction:
Improvecontrol simplicityVSAvoidwelding frequency consistency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control system monitors the actual timing of short circuit occurrence and uses this feedback information to dynamically adjust the welding wire speed profile. The system detects when the short circuit occurs and adapts the conveying phases accordingly, ensuring that the wire reaches the appropriate speed at the right moment. This feedback mechanism maintains consistent welding frequency despite variations in short circuit timing, while the automated control keeps the operation relatively simple.

Inventive Principle:
Principle #23Feedback

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 stabilizes the welding frequency and improves weld quality by ensuring consistent welding wire speeds, reducing the occurrence of splashes and irregularities, and enhancing the overall efficiency of the welding process.

Implementation Method 1

Conveying a consumable welding wire away from a workpiece during the short-circuit phase at a reverse speed so that material is transferred from the welding wire to the workpiece

Methodology Applied
Scientific EffectMaterial transfer:

Implementation Method 2

material is transferred from the welding wire to the workpiece and an arc is ignited

Methodology Applied
Scientific EffectArc ignition: Electric Arc

Implementation Method 3

During the arc phase, heat energy is introduced into the welding wire and the workpiece

Methodology Applied
Scientific EffectHeat energy introduction:

Implementation Method 4

conveying the welding wire towards the workpiece during the arc phase at a forward speed to bring the welding wire into contact with the workpiece and to create a short circuit between the welding wire and the workpiece

Methodology Applied
Scientific EffectShort circuit creation:

Data Source

PatentEP4370274B1Short-circuit welding method and welding device
Publication Date: 2025.02.12 FRONIUS INT GMBH
  • EP4370274B1 patent drawingFigure 1
  • EP4370274B1 patent drawingFigure 2
  • EP4370274B1 patent drawingFigure 3

AI summary

The invention relates to a welding device (1) and to a short-circuit welding method with successive welding cycles, each of which has an arc phase (6) and a short-circuit phase (7). The method has the following steps: conveying a welding wire (3) away from a workpiece (5), said welding wire (3) being brought to a final rearward speed (vre_max) in a first rearward conveying phase (13) and then being conveyed at the final rearward speed (vre_max) until a second rearward conveying phase (15) in which the rearward speed (-vd) of the welding wire (3) is reduced again; and conveying the welding wire (3) in the direction of the workpiece (5), said welding wire (3) being brought to a final forward speed (vv_max) in a first forward conveying phase (16) and being conveyed at the final forward speed until the beginning of a second forward conveying phase (18) in which the forward speed (vd) of the welding wire (3) is reduced again, wherein the first duration (T1) is adapted by means of a control and/or regulating system such that the welding wire (3) does not exceed a specified reduced rearward speed (vre_K) in the second rearward conveying phase (13) at the point in time at which the short-circuit is interrupted (12).