Arc Welding Wire Feed Cycling for Stable Short-Circuit Transfer

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Solution Overview

Problem

The existing arc welding methods using constant feeding rates become unstable when the welding speed or wire deposition amount per unit length changes, leading to inconsistent welding states.

Innovation Solution

An arc welding control method that alternates the feeding of the welding wire between forward and reverse feeding with a predetermined cycle and amplitude, generating short-circuiting and arc periods to maintain a stable welding state by adjusting the cycle and amplitude based on welding speed or wire deposition amount.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a constant feeding rate is used in consumable electrode arc welding, then the welding process is simple to control, but the welding state becomes unstable when welding speed or wire deposition amount changes

Engineering Contradiction:
Improvecontrol simplicityVSAvoidwelding state stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies dynamics by transitioning from a constant feeding rate to a dynamically varying feeding rate that alternates between forward and reverse directions. The feeding rate is modified to include a sinusoidal component that changes over time, allowing the system to adapt to different welding conditions while maintaining stability. This dynamic adjustment enables the welding process to remain reliable despite changes in welding speed or wire deposition amount.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements periodic action by introducing a cyclic alternation between forward feeding and reverse feeding of the welding wire. The feeding rate follows a periodic pattern defined by a cycle time Tf and amplitude Wf, creating regular short-circuiting periods and arc periods. This periodic modulation stabilizes the welding state by ensuring consistent repetition of welding phases, thereby resolving the instability issue while maintaining operational simplicity through standardized cycle parameters.

Inventive Principle:
Principle #19Periodic action

2Reliability

If the feeding rate is alternated between forward and reverse feeding periodically, then the welding state stability is improved, but the control complexity increases

Engineering Contradiction:
Improvewelding state stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the feeding rate parameters (cycle time Tf and amplitude Wf) based on welding conditions such as welding speed and wire deposition amount. The control system adjusts these parameters dynamically to maintain optimal welding state stability. This approach allows the system to adapt to different welding scenarios without requiring complex control logic, as the parameter adjustments follow predetermined relationships with welding conditions.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the cycle and amplitude of feeding rate are fixed, then the control is simple, but the welding quality varies when welding speed or wire deposition amount changes

Engineering Contradiction:
Improvecontrol simplicityVSAvoidwelding quality consistency
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent resolves this contradiction by making the feeding rate parameters dynamic rather than fixed. The cycle time Tf and amplitude Wf are adjusted based on welding speed and wire deposition amount, allowing the system to maintain consistent welding quality across different operating conditions. This dynamic adaptation ensures that the welding process remains precise while preserving the simplicity of the control approach through standardized adjustment rules.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by systematically varying the feeding rate parameters (Tf and Wf) in response to changes in welding speed and wire deposition amount. This ensures that the welding quality remains consistent across different production scenarios. The control system maintains simplicity by using predetermined parameter relationships, avoiding the need for complex real-time optimization while achieving precise and consistent welding results.

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 method ensures a stable welding state by dynamically adjusting the feeding rate cycle and amplitude, maintaining stability even when welding speed or wire deposition amount changes, thereby improving welding quality and reducing spatter generation.

Implementation Method 1

generating an arc between the welding wire and base material

Methodology Applied
Scientific EffectArc: Electric Arc

Implementation Method 2

both the welding wire and the base material are mostly placed in a welding state in which a short-circuiting period and an arc period are alternately repeated

Methodology Applied
Scientific EffectShort-circuiting: Conduction (thermal)

Data Source

PatentEP3120963B1Arc welding control method
Publication Date: 2024.05.01 DAIHEN CORP
  • EP3120963B1 patent drawingFigure 1
  • EP3120963B1 patent drawingFigure 2
  • EP3120963B1 patent drawingFigure 3

AI summary

The purpose of the present invention is to improve the stability of arc welding carried out by cyclical repetition of forward feed and reverse feed of a weld wire (1). Provided is an arc welding control method involving repeated forward feed and reverse feed at a weld wire (1) feed rate (Fw), according to a prescribed cycle (Tf) and a prescribed amplitude (Wf), and generation of short-circuit time intervals and arc time intervals to carry out welding, wherein the feed rate (Fw) cycle (Tf) and/or the amplitude (Wf) are set automatically on the basis of the average feed rate (Far) and the welding rate (Wsr), or the wire deposition amount (Md) per unit of weld length. Further, in the event that the amplitude (Wf) has changed, feedback control of the forward feed-side shift amount (Sf) is carried out in such a way that the average value of the feed rate (Fw) is constant. In so doing, the feed rate (Fw) cycle (Tf) and amplitude (Wf) are always set to optimal values, and stable welding conditions can be maintained.