Short-Arc Welding Current Transition Control to Reduce Spatter
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Solution Overview
Problem
Existing welding systems for short arc welding experience significant spatter due to rapid current increases during the transition from short to arc states, which existing control methods have been unable to effectively mitigate, leading to inefficiencies and increased costs.
Innovation Solution
A controller-based system that includes modules for peak short current detection, arc/short state detection, short time detection, dive module, and post dive module, which dynamically adjust the output current to reduce spatter by decreasing the current at a dive rate exceeding the normal rate and then maintaining it at a steady rate, thereby controlling the welding process to minimize spatter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional voltage-controlled welding systems are used for short arc welding, then the system can maintain stable arc voltage, but significant spatter occurs due to rapid current increases during transition from short to arc states
Solution Approach 1:
The controller predicts when the arc will form based on the rate of change of output power (dp/dt) before the actual transition occurs. This prediction provides advance time to reduce the current command before the arc forms, preventing the rapid current increase that causes spatter. The system takes preliminary action by adjusting current before the harmful transition happens.
Solution Approach 2:
The system dynamically adjusts the current command based on real-time detection of arc/short state transitions. The controller modifies the current waveform dynamically by reducing current before arc formation and controlling the transition characteristics, making the system adaptable to the changing welding state rather than using fixed current control.
2Object-affected harmful factors
If predictive control based on dp/dt is used to reduce spatter, then spatter is greatly reduced, but the control scheme becomes sophisticated and inconsistent with low cost welders
Solution Approach 1:
The system uses feedback from voltage and current sensors to detect arc/short state transitions and the rate of change of output power. This feedback information is processed by the controller to determine when to reduce current and by how much, creating a closed-loop control system that achieves spatter reduction through relatively simple feedback mechanisms rather than complex predictive algorithms.
3Object-affected harmful factors
If mechanical control of wire retraction is used to create arcs at known times, then spatter is reduced by lowering current before arc formation, but a wire feed motor close to the arc is required which adds cost and complexity
Solution Approach 1:
The system replaces mechanical wire retraction control with electrical current control. Instead of using a wire feed motor to physically retract the wire at precise moments, the system uses the controller to electrically adjust the current command based on detected arc/short transitions. This substitution eliminates the need for additional mechanical components near the arc while achieving the same spatter reduction effect through electrical means.
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
The system effectively reduces spatter by precisely managing the current transition from short to arc states, improving the efficiency and consistency of the welding process while minimizing the risk of tripping circuit breakers and maintaining wire feed speed.
Implementation Method 1
the rate of increase is set by the system inductance (or the apparent inductance set by the wave shape). As the current increases the wire melts faster
Implementation Method 2
electrical power is converted to a form useful for a welding process, and the power provides voltage and current necessary to establish and maintain arcs between an electrode and a workpiece
Data Source
AI summary
A method and apparatus for providing short arc welding-type power is disclosed. The system includes a power supply, a wire feeder, and a controller. The output current is decreased at dive rate when the arc forms. The dive rate is maintained until the currents drops to a threshold, preferably a function of the peak short current in that cycle. Then the current is held steady for a length of time that is a percentage of the short time for that cycle. Then the current is decreased at the normal rate until the short reforms, and the current begins increasing at the normal rate. The holding steady portion can be omitted.