Arc Welding Mode Switching Without Droplet Transfer Spatter

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Solution Overview

Problem

Conventional arc welding methods experience instability and spatter generation when switching between pulse arc welding and short-circuit transfer arc welding, due to the transfer of molten droplets during the switching process.

Innovation Solution

An arc welding method that alternates between pulse arc welding and short-circuit transfer arc welding by ensuring no transfer of molten droplets during the final pulse cycle, with increased wire feeding speed to a forward-feeding peak value at the start of the short-circuit transfer arc welding period, and switching to pulse arc welding during the arc period of short-circuit transfer arc welding when arcing reoccurs at a low current level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If switching between pulse arc welding and short-circuit transfer arc welding is performed by changing droplet transfer modes, then welding process control is achieved, but spatters are generated and welding state becomes unstable

Engineering Contradiction:
Improvewelding process controlVSAvoidwelding state stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by preventing droplet transfer during the final pulse cycle before switching to short-circuit transfer arc welding. This is achieved by controlling the pulse timing and duration to ensure no droplet is in the transfer phase when the welding mode changes, thereby eliminating spatter generation and maintaining welding state stability during transitions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by adjusting pulse width, frequency, and current levels to control droplet formation and transfer timing. By modifying these parameters during the final pulse cycle, the system ensures droplet transfer is suppressed or completed before mode switching occurs, resolving the contradiction between process control and stability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If droplet transfer is allowed during pulse arc welding, then welding progress is maintained, but switching to short-circuit transfer arc welding becomes unstable

Engineering Contradiction:
Improvewelding progressVSAvoidswitching stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by preparing the welding system in advance for mode switching. During the final pulse cycle of pulse arc welding, the system preemptively suppresses droplet transfer initiation, ensuring that when short-circuit transfer arc welding begins, no droplet transfer is in progress, thereby maintaining switching stability without significantly impacting overall welding progress.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses periodic action by implementing cyclic pulse welding with controlled intervals. The pulse frequency and duty cycle are adjusted so that droplet transfer occurs during designated pulse periods but is suppressed during transition periods, allowing regular welding progress while ensuring stable mode switching when needed.

Inventive Principle:
Principle #19Periodic 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 stabilizes the welding state, prevents spatter generation, and ensures smooth switching between welding modes, maintaining a consistent bead appearance and heat input.

Implementation Method 1

arc welding method comprising: performing pulse arc welding with a welding wire being fed in a forward direction during a first period; performing short-circuit transfer arc welding with the welding wire being fed in the forward direction and a reverse direction during a second period

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Implementation Method 2

no transfer of a molten droplet of the welding wire occurs during a final pulse cycle of the first period

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3695929B1Arc welding method
Publication Date: 2023.11.15 DAIHEN CORP
  • EP3695929B1 patent drawingFigure 1
  • EP3695929B1 patent drawingFigure 2(A)~2(G)
  • EP3695929B1 patent drawingFigure 3(A)~3(F)

AI summary

An arc welding method includes the following steps. Pulse arc welding is performed with the welding wire being fed in a forward direction during a first period. Short-circuit transfer arc welding is performed with the welding wire being fed in the forward direction and the reverse direction during a second period. The first period and the second period are alternately switched. The switching of the first period to the second period is performed in a manner such that no transfer of a molten droplet of the welding wire occurs during the final pulse cycle of the first period.