Hybrid Pulse Welding Waveform for Stable High-Rate GMAW
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Solution Overview
Problem
In heavy fabrication welding, solid wire gas metal arc welding (GMAW) operations face instability and spatter issues at deposition rates above 16 Ib/hr, leading to unacceptable puddle behavior and arc instability, which limits productivity and requires manual intervention for control.
Innovation Solution
A hybrid pulse welding process that delivers a pulse waveform with interleaved current pulses and background portions, allowing for projected, streaming, and rotating spray transfer modes during each current pulse, stabilizing the arc and puddle by distributing pressure evenly across the weld pool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solid wire GMAW welding is performed at deposition rates above 16 Ib/hr, then productivity is improved, but arc/puddle instability and spatter increase
Solution Approach 1:
The patent applies periodic pulsed current instead of continuous current to the wire electrode. The pulsed waveform creates periodic cycles of high current (for droplet projection and deposition) followed by lower current intervals (for puddle stabilization and arc recovery). This periodic action enables high deposition rates while preventing arc and puddle instability that would occur with continuous high-current operation.
Solution Approach 2:
The patent changes the electrical current parameters by using a pulsed waveform with varying current levels and frequencies. By adjusting pulse amplitude, pulse width, and frequency, the system can achieve high deposition rates during pulse peaks while maintaining arc stability during troughs. This parameter modulation resolves the contradiction between high productivity and process stability.
2Ease of operation
If larger welding wires are used to increase arc cone size, then puddle control is improved, but device complexity and operation difficulty increase
Solution Approach 1:
Instead of changing wire physical dimensions, the patent changes the electrical parameters by applying pulsed current waveforms. This allows the arc cone to be effectively enlarged and improved in control through electrical modulation rather than mechanical wire size changes, avoiding the complexity of selecting and handling different wire diameters.
Solution Approach 2:
The patent replaces the mechanical approach of using larger wire diameters to control puddle size with an electrical approach using pulsed current waveforms. The electrical parameter modulation achieves the same puddle control effect without the mechanical complexity of wire size selection and adjustment.
3Productivity
If metal cored wires or flux cored wires are used to increase deposit rate, then productivity is improved, but fume rates and slag generation increase
Solution Approach 1:
The patent uses simple solid wire that can be consumed continuously without generating harmful byproducts. Unlike metal cored or flux cored wires that produce fume and slag, the solid wire with pulsed GMAW process achieves high deposition rates through controlled droplet transfer, eliminating the need for complex wire compositions that generate contamination.
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 hybrid pulse welding process enhances stability and control at high deposition rates, reducing spatter and puddle instability, allowing for consistent operation at or above 16 Ib/hr with a larger arc cone that covers more of the weld pool, improving operator ease and weld quality.
Implementation Method 1
an arc generation power supply operatively connected to the torch to deliver a pulse waveform to the wire electrode during a deposition operation
Implementation Method 2
During each current pulse a molten droplet is projected from a tip of the wire electrode followed by an axial spray of molten metal away from the tip of the wire electrode
Data Source
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AI summary
An arc welding or additive manufacturing system includes a wire feeder, a torch, a wire electrode driven through the torch by the wire feeder, and an arc generation power supply operatively connected to the torch to deliver a pulse waveform to the wire electrode during a deposition operation. The pulse waveform includes a series of current pulses and interleaved background current portions such that each current pulse is separated from a prior current pulse by a prior background current portion and separated from a subsequent current pulse by a subsequent background current portion. During each current pulse a molten droplet is projected from a tip of the wire electrode followed by an axial spray of molten metal away from the tip of the wire electrode before the subsequent background current portion occurs.