Pulse Welding Current Modulation to Reduce Spatter
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Solution Overview
Problem
In pulse welding, short circuits between the electrode and workpiece often result in undesirable spatter, leading to inefficiencies and the need for post-welding cleanup, as the molten metal explodes due to rapid current increases when the tethered connection breaks.
Innovation Solution
A pulse welding apparatus with a switching module that detects shorts and adjusts the welding current by opening and closing an electrical switch to reduce current flow through a resistive path, preventing excessive spatter by managing the current levels during short intervals and incorporating a plasma boost pulse to prevent immediate re-shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the welding current is rapidly increased to clear the short circuit, then the short is cleared and welding can continue, but excessive spatter is generated due to explosive separation of molten metal
Solution Approach 1:
The welding system applies periodic current modulation during the short interval, using a controlled sequence of current reduction followed by plasma boost pulse. This periodic action allows the short to clear gradually rather than through explosive rapid current increase, reducing spatter while maintaining short clearing effectiveness
Solution Approach 2:
The system dynamically changes the welding current parameter during the short interval by first reducing it to prevent explosive molten metal separation, then applying a plasma boost pulse to facilitate short clearing. This parameter change strategy controls the current profile to minimize spatter generation
2Object-generated harmful factors
If the welding current is reduced during short intervals to prevent spatter, then spatter is reduced, but the short circuit may not clear rapidly enough
Solution Approach 1:
The system applies a plasma boost pulse after the initial current reduction to preliminarily prepare for short clearing. This preliminary action ensures that when the short does clear, it does so rapidly and cleanly without causing explosive spatter, thus resolving the contradiction between slow clearing and spatter generation
Solution Approach 2:
The welding system maintains continuous useful action by seamlessly transitioning from current reduction to plasma boost pulse application. This continuous control ensures the short clears at the optimal moment without interruption, maintaining welding productivity while minimizing spatter
3Device complexity
If conventional pulse welding is used with single polarity, then the welding process is simple, but spatter control is poor and heat input cannot be optimized
Solution Approach 1:
The welding system dynamically switches between different polarities (DCEN and DCEP) during the welding cycle. This dynamic polarity change allows optimization of both spatter control and heat input without requiring complex additional hardware, maintaining relative simplicity while improving performance
Solution Approach 2:
The system employs periodic polarity reversal in conjunction with current modulation. This periodic action with dual polarity enables better spatter control and optimized heat distribution across the weld, enhancing the conventional pulse welding process without significantly increasing complexity
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
Significantly reduces spatter by lowering the welding output current during short intervals from 280 amps to around 40 amps, maintaining travel speeds and deposition rates, and preventing explosive separation of molten metal.
Implementation Method 1
In electric arc welding, a popular welding process is pulse welding which primarily uses a solid wire electrode with an outer shielding gas
Implementation Method 2
The power converter provides the welding waveform to an electrode and at least one workpiece to weld the at least one workpiece
Data Source
AI summary
A pulse welding welder is provided which provides a pulse welding waveform to a workpiece to be welded. The welding waveform has a plurality of welding cycles and each of the cycles has a droplet transfer peak pulse and a background portion with a first polarity and an opposite polarity portion which precedes the droplet transfer peak pulse and is after the background portion.