AC Welding Waveform Switching for Short-Circuit Spatter Control
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Solution Overview
Problem
In electric arc welding, short circuits occurring in an electrode negative state can lead to arc instability and spatter, causing inefficiencies and requiring removal of molten metal from the workpiece, which is undesirable.
Innovation Solution
A welding system with a switching module that modifies the welding waveform by opening and closing an electrical switch in the welding current return path to reduce current during short circuits, preventing spatter by managing the short circuit clearance process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If short circuit is cleared using negative polarity, then short circuit is cleared, but arc instability or spatter event occurs
Solution Approach 1:
The patent applies polarity inversion by switching from negative polarity to positive polarity when clearing a short circuit. During normal welding, negative polarity is used, but when a short circuit is detected, the system inverts the polarity to positive to clear the short. This inversion allows the short to be cleared without causing spatter, as the positive polarity creates a more stable arc during the clearing process. After clearing, the polarity returns to negative for continued welding.
2Productivity
If molten metal contacts workpiece before release, then welding progresses, but short circuit occurs
Solution Approach 1:
The system employs feedback by continuously monitoring the welding circuit to detect short circuit conditions. When a short is detected (when molten metal contacts the workpiece), the system responds by inverting the polarity to positive, which stabilizes the arc and clears the short. This feedback mechanism allows the welding process to continue progressing while automatically correcting short circuit events, maintaining both productivity and reliability.
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 controlling the welding current during short circuit clearance, maintaining travel speeds and deposition rates, and minimizing heat input.
Implementation Method 1
In electric arc welding, it is generally known that welding in an electrode negative state can result in a lower overall heat input during a welding operation.
Data Source
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AI summary
A welder power supply and welding method are provided which utilizes a short arc welding method in which the waveforms have a positive polarity portion and negative portion to optimize heat input and provide heat and current control.