CO2 Arc Welding Current Waveform Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional carbon dioxide gas shielded arc welding methods experience irregular droplet formation and bead shape due to high current causing excessive repelled force, leading to vibration of the molten pool and decreased welding quality, especially at high speeds.
Innovation Solution
A welding device and method that control the power supply to output a high-level current with a waveform increasing and decreasing at constant frequency and amplitude during the arc period, and reduce short circuit current when a droplet constriction is detected, stabilizing droplet formation and improving welding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high current is used to increase welding speed, then productivity is improved, but droplet elevation occurs due to excessive repelled force causing irregular welding quality
Solution Approach 1:
The patent applies periodic action by superimposing an alternating current component on the high-level current during the arc period. This causes the current to periodically increase and decrease, which in turn periodically adjusts the repelled force on the droplet. The periodic variation prevents continuous excessive repelled force that would elevate the droplet, thereby maintaining stable droplet formation and welding quality even at high welding speeds.
2Productivity
If high current is used to increase welding speed, then productivity is improved, but molten pool vibration occurs leading to humping bead formation
Solution Approach 1:
The patent uses periodic action by superimposing an alternating current component that causes the current to periodically increase and decrease during the arc period. This periodic current variation modulates the repelled force on the molten pool, preventing continuous excessive force that would cause violent vibration and humping bead formation. The periodic adjustment stabilizes the molten pool while maintaining high welding speed.
3Productivity
If high current is used, then welding speed is increased, but short circuiting becomes irregular due to excessive repelled force
Solution Approach 1:
The patent applies periodic action by superimposing an alternating current component on the high-level current during the arc period. This creates a periodic variation in current and repelled force, which ensures that the droplet does not remain continuously elevated. The periodic adjustment allows the droplet to periodically approach and contact the molten pool, restoring regular short circuiting behavior even at high welding speeds.
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
Prevents droplet elevation by the repelled force, resulting in stable droplet formation and improved welding quality with reduced spatter and irregular bead shapes, enhancing productivity at higher welding speeds.
Implementation Method 1
a power supply circuit applying a voltage across a torch and a base metal
Implementation Method 2
the tip of the welding wire melts to form the droplet
Implementation Method 3
a high level current is generated having a waveform increasing and decreasing at a constant frequency and constant amplitude superimposed on the high level current
Implementation Method 4
a droplet will be elevated to the upper portion of the wire by the repelled force by the arc
Implementation Method 5
the wire feeds continuously toward an arc zone
Data Source
AI summary
A welding device includes a power supply circuit for applying a voltage across a torch and a base metal, and a power supply control device. The power supply control device controls the power supply circuit such that a high level current is output during a first arc period Ta1 that is the initial period of an arc period, and an arc current corresponding to a regulated welding voltage is output during a second arc period Ta2 that is the latter period of the arc period. The power supply control device controls the power supply circuit such that a high level current is generated having a waveform increasing and decreasing at a constant frequency and constant amplitude superimposed on the high level current. By superimposing the waveform, the elevation of a droplet caused by an repelled force by the arc can be prevented, allowing a droplet to be formed in stabilization.