Pulsed Welding Current Decay Circuit for Spatter Reduction
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Solution Overview
Problem
Current pulsed welding processes experience poor performance due to the difficulty in transferring molten metal from the consumable electrode to the workpiece, leading to spatter issues, particularly in low wire feed speed stainless processes, where a long tether of molten metal can form and cause shorting and spatter.
Innovation Solution
A welding power source with a switching network and controller that generates welding output current pulses with an increased decay rate at the trailing edge, using an electrical switch and snubber to introduce impedance in the welding circuit path, effectively reducing spatter by ensuring the molten metal ball separates from the electrode before depositing on the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional pulsed welding current is used, then the welding process can be performed, but a long tether of molten metal forms causing spatter and shorting
Solution Approach 1:
The patent applies dynamics by making the circuit impedance variable rather than fixed. The switching network dynamically changes the impedance state between low and high impedance based on the pulse phase, allowing the system to adapt to different stages of the welding pulse and achieve rapid current decay at the trailing edge to prevent spatter
Solution Approach 2:
The patent changes the electrical parameter of circuit impedance from a constant value to a time-varying parameter. By switching between different impedance states (low impedance during pulse rise, high impedance during decay), the system achieves controlled current waveform shaping that prevents molten metal tether formation
2Object-affected harmful factors
If the decay rate of the trailing edge of welding output current pulse is increased, then spatter is reduced, but additional circuit components are required
Solution Approach 1:
The switching network operates periodically in synchronization with the pulsed welding current, switching between low and high impedance states at specific phases of each pulse cycle. This periodic action enables rapid current decay during the trailing edge phase while maintaining normal current flow during the pulse phase, achieving spatter reduction through rhythmic impedance modulation
Solution Approach 2:
The switching network acts as an intermediary component between the power source and welding circuit. It mediates the current flow by introducing controlled impedance variations, enabling rapid decay without requiring fundamental changes to the welding process or electrode configuration
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 solution significantly reduces spatter by ensuring the molten metal ball separates from the electrode before depositing on the workpiece, improving the overall pulsed arc welding process, especially in low wire feed speed stainless, nickel, and steel welding processes.
Implementation Method 1
introducing an impedance in the welding output circuit path over a predefined period of impeding time
Implementation Method 2
The electrical switch may include a high power transistor and the snubber may include a resistor in series with a capacitor
Implementation Method 3
the snubber may include a resistor in series with a capacitor
Data Source
AI summary
Embodiments of welding systems and methods for reducing spatter in pulsed welding are disclosed. A welding power source includes a first welding output stud to be electrically connected to a consumable welding electrode and a second welding output stud to be electrically connected to a workpiece. Power electronics generate welding output current pulses. A switching network is connected between the power electronics and the first welding output stud. A controller is connected between the power electronics and the switching network. The controller controls the timing of each welding output current pulse and switches the switching network back and forth between a first welding output current flowing state and a second welding output current impeding state based on the timing. An increase in a decay rate of a trailing edge of each welding output current pulse is effected during the second welding output current impeding state.