Discontinuous Electrode Feeding for Precise Droplet Transfer
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Solution Overview
Problem
Conventional arc welding processes face issues with excessive metal buildup and voids along weld joints due to improper control of droplet size and transfer frequency, particularly in metal additive manufacturing.
Innovation Solution
A welding system with a driven consumable electrode that utilizes a series of welding waveforms including pinch and arcing current portions, with arc suppression phases, to control droplet deposition and transfer frequency by detecting short circuits and adjusting wire feeder operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional arc welding processes are used with continuous wire feeding, then productivity is maintained, but manufacturing precision deteriorates due to excessive metal buildup and voids along weld joints
Solution Approach 1:
The wire feeder operates periodically by stopping wire feeding during the arc suppression portion and restarting during the arcing current portion. This periodic action allows precise control of droplet deposition timing and spacing, eliminating excessive metal buildup while maintaining controlled deposition rates through rhythmic feed cycles synchronized with the welding waveform.
Solution Approach 2:
The system dynamically adjusts wire feeding speed by transitioning between stopped and moving states based on the welding process phase. The wire feeder responds to real-time detection of short circuits and waveform stages, creating adaptive control that optimizes both precision (during suppression) and productivity (during arcing portions).
2Manufacturing precision
If the electric arc is continuously maintained during wire feeding, then productivity is improved, but manufacturing precision deteriorates due to inability to control droplet transfer frequency
Solution Approach 1:
The welding process uses periodic arc suppression and re-ignition cycles. During the arc suppression portion, wire feeding is stopped to allow precise droplet formation and transfer. During the arcing current portion, wire feeding restarts to maintain deposition. This periodic rhythm enables precise control of droplet transfer frequency while maintaining overall productivity through efficient use of arc time.
Solution Approach 2:
The welding waveform is segmented into distinct portions (arc suppression, pinch current, arcing current) with corresponding wire feeder states. This segmentation allows independent optimization of droplet transfer control during suppression phases and deposition efficiency during arcing phases, resolving the contradiction between precision and productivity.
3Manufacturing precision
If wire feeding is stopped during short circuit detection, then manufacturing precision is improved by controlling droplet size, but productivity decreases due to feeding interruptions
Solution Approach 1:
Wire feeding interruptions are converted into a periodic control strategy synchronized with the welding waveform. The wire feeder stops during arc suppression portions (which are brief and timed) to control droplet size, then restarts during arcing portions to maintain productivity. This rhythmic stop-start pattern minimizes total stop time while achieving precise droplet control.
Solution Approach 2:
The system maintains continuous useful action by coordinating wire feeding stops with natural arc suppression phases in the welding cycle. Rather than arbitrary stops that waste time, the feeding interruptions are timed to coincide with necessary arc-off periods for droplet control, ensuring that stop time does not extend beyond what is already required for precise manufacturing.
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
Accurately controls droplet size and spacing, reduces metal buildup, and enhances precision in welding and additive manufacturing by suppressing the arc between droplet transfers, facilitating stable and controlled deposition.
Implementation Method 1
a welding power supply operatively connected to the wire feeder and the torch. The welding power supply is configured to provide a plurality of welding waveforms to the torch to generate a welding current in the consumable electrode. Each of the plurality of welding waveforms includes a pinch current portion followed by an arcing current portion
Implementation Method 2
The welding power supply is configured to detect a short circuit between the consumable electrode and workpiece and generate the pinch current portion when the short circuit is detected
Data Source
AI summary
A welding system includes a consumable electrode, torch, wire feeder, and power supply. The power supply is configured to provide a plurality of waveforms to the torch to generate a welding current in the electrode. Each of the plurality of waveforms includes a pinch current portion followed by an arcing current portion, and the pinch current portion is preceded by a first arc suppression portion and the arcing current portion is followed by a second arc suppression portion. An arc exists between the electrode and a workpiece during the arcing current portion, and an air gap without an arc exists between the consumable electrode and the workpiece during the arc suppression portions. The power supply is configured to detect a short between the electrode and workpiece and generate the pinch current portion when the short is detected, and the wire feeder stops feeding the electrode when the short is detected and restarts feeding the electrode after the short is clear.