AC Welding Waveform for High-Speed Galvanized Workpiece Joining
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Solution Overview
Problem
Conventional welding methods for galvanized workpieces are slow and inefficient due to the need to prevent contamination from the corrosion-resistant coating, leading to increased heat input and porosity issues, especially in thin workpieces.
Innovation Solution
A welding system using an AC welding waveform in combination with a hot wire system, which allows for high-speed welding of coated materials with minimal porosity and spatter by precisely controlling the weld puddle formation and filler wire deposition without the need for shielding gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional welding methods are used to prevent coating contamination, then weld quality is maintained, but welding speed decreases and heat input increases
Solution Approach 1:
The patent applies parameter changes by using AC welding current with specific waveform characteristics (peak current, valley current, frequency) to control the welding process. The AC waveform creates periodic arc extinction and reignition that prevents zinc vapor entrapment while maintaining welding speed, resolving the contradiction between weld quality and productivity
Solution Approach 2:
The patent utilizes periodic action through AC current cycles that repeatedly extinguish and reignite the arc. This periodic arc behavior creates controlled weld pool oscillation that prevents coating contamination entrapment while maintaining high welding speeds, thereby improving both weld quality and productivity simultaneously
2Productivity
If welding speed is increased for higher productivity, then production efficiency improves, but porosity increases due to coating contamination
Solution Approach 1:
The patent changes welding parameters by using AC current with optimized peak current (100-500A), valley current (0-100A), and frequency (1-10Hz) to enable high-speed welding while preventing porosity. The parameter optimization allows fast welding speeds without sacrificing weld quality
Solution Approach 2:
The periodic AC arc extinction and reignition creates controlled weld pool dynamics that prevent zinc vapor entrapment even at high welding speeds. This periodic action mechanism enables the patent to achieve both high productivity and high weld quality without the porosity issues that normally accompany fast welding
3Productivity
If heat input is increased to maintain welding speed on thin workpieces, then productivity is maintained, but coating contamination and porosity worsen
Solution Approach 1:
The patent optimizes heat input parameters by controlling AC current peak and valley levels, allowing maintenance of welding speed on thin workpieces while limiting excessive heat input. The parameter control prevents coating vaporization and contamination, resolving the contradiction between productivity and harmful effects
Solution Approach 2:
The periodic AC arc creates intermittent heating cycles that prevent continuous high heat input into thin workpieces. This periodic heating maintains welding speed while allowing heat dissipation between cycles, preventing coating contamination and porosity that would otherwise occur with continuous high heat input
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
Enables high-speed welding of coated materials with reduced heat input, minimizing porosity and spatter, and allowing for the use of thinner workpieces without the need for pre-coating removal or shielding gases, thereby improving production efficiency and weld quality.
Implementation Method 1
uses a welding current having an AC current portion to build a droplet for transfer to the workpiece
Data Source
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AI summary
Embodiments of the present invention comprise a system (100, 1200, 2000) and method to weld or join coated materials using an arc welding system alone, or in combination with a hot wire system, where the arc welding system uses a welding current having an AC current portion to build a droplet (D) for transfer to the workpiece (115). In further embodiments, the workpiece (115) is coated with a material, such as zinc, and the arc welding system uses an AC welding waveform which is capable of welding coated workpieces (115) with little or no porosity or spatter and can achieve enhanced performance. Additional embodiments use an enhanced electrode to provide optimum porosity performance. Such embodiments allow for the welding of coated material with little or no porosity and spatter, and at a high welding rate.