Asynchronous Hot-Wire Preheating to Eliminate GTAW Arc Blow
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Solution Overview
Problem
Welding processes face challenges with arc blow, which is caused by the interaction of electromagnetic forces from preheat power in hot-wire GTAW systems, leading to a less focused welding arc and lower quality welds, particularly in manual operations where precise control is difficult.
Innovation Solution
A welding system with a power conversion circuit that asynchronously switches between welding-type power and preheat power, using a single contact tip and the work cable as the return conductor, to eliminate arc blow without additional hardware, allowing for focused and coaxial welding arcs during both manual and automated operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If preheat power is applied to heat filler material in hot-wire GTAW systems, then filler material temperature is improved, but arc blow occurs causing welding arc to become less focused
Solution Approach 1:
The patent applies periodic action by switching preheat power on and off in synchronization with the welding arc cycle. During the arc-off portion of the cycle, preheat power is applied to heat the filler material; during the arc-on portion, preheat power is eliminated to prevent electromagnetic interference with arc focus. This periodic application resolves the contradiction by providing thermal benefit without continuous electromagnetic disruption.
Solution Approach 2:
The patent uses preliminary action by preheating the filler material during the arc-off portion of the welding cycle before the arc is struck. This allows the filler material to reach an elevated temperature in advance, reducing the energy required during actual welding while avoiding electromagnetic interference during the critical arc formation phase.
2Temperature
If preheat power is applied continuously, then filler material heating is improved, but electromagnetic forces cause arc blow and reduce weld quality
Solution Approach 1:
The system implements periodic action by synchronizing preheat power application with the welding arc cycle. Preheat power is applied only during the arc-off portion of the cycle when electromagnetic interference would not affect weld quality, while still providing continuous heating over time through repeated cycles. This maintains filler material temperature elevation without compromising weld reliability.
3Manufacturing precision
If additional hardware is added to eliminate arc blow, then welding arc focus is improved, but device complexity increases
Solution Approach 1:
The patent eliminates the need for additional hardware by using periodic action on the existing preheat power circuitry. By simply synchronizing the on/off timing of preheat power with the welding arc cycle through control circuitry, the system achieves arc focus improvement without adding physical components like magnetic shields or additional contact tips, thus avoiding increased device complexity.
Solution Approach 2:
The system applies self-service by using the existing preheat power infrastructure and control capabilities to solve the arc blow problem. The control circuitry that already manages the welding power supply is extended to also control preheat power timing, allowing the system to eliminate arc blow using its own existing resources rather than requiring external hardware additions.
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 asynchronous switching technique maintains a focused, coaxial welding arc, eliminating arc blow and enabling precise control of filler material deposition, even in manual operations, while reducing the need for additional hardware and improving welding quality.
Implementation Method 1
preheat circuitry configured to provide preheat power to heat a filler material
Implementation Method 2
welding circuitry configured to provide welding-type power to an electrode of a welding torch to generate a welding arc between a welding work piece and the electrode to form a weld pool
Data Source
Figure 1a
Figure 1b~1c
Figure 2a~2b
AI summary
A welding system configured to eliminate effects of arc blow in a welding operation. The welding system comprises welding circuitry, preheat circuitry, and control circuitry configured to switch the welding circuitry and the preheat circuitry between power levels asynchronously during the welding operation. The control circuitry configured to switch the welding circuitry and the preheat circuitry between power levels asynchronously such that the preheat circuitry is switched to the second preheat power level when the welding circuitry is switched to the first welding power level and the preheat circuitry is switched to the first preheat power level when the welding circuitry is switched to the second welding power level.