How active closed-loop gas control reduces welding gas use

Active closed-loop gas control means letting shielding-gas flow adjust in real time to the welding process, rather than holding one fixed flow throughout.

Passive supply fixes the flow, so it overshoots at the instant of arc start, drifts during welding and spills after arc off — plus pipe leakage. These are all “outside-the-weld” ineffective supply: they waste gas, and when flow runs high they also worsen fumes.

The four sources each have their own mechanism. First, metering and flow mismatch (about 10% and 5%): flow is often set by experience, tends to run high over time, and no longer matches once the process changes. Second, arc-start overshoot (about 5%): the surge when the solenoid valve opens far exceeds what is needed for a stable arc. Third, end-of-weld spill (about 3%): the valve closes with a lag after the arc stops, so shielding gas keeps escaping. Fourth, pipe leakage (about 2%): steady small leaks at fittings and hoses that draw gas even at idle.

The method: high-precision sensing measures flow in real time, and the controller adjusts the actuator in a closed loop to the current process’s target flow — a smooth ramp at arc start, zero supply at idle, and supply raised or lowered on demand — keeping flow always in the “enough but not wasted” band (see the closed-loop diagram above).

On real production-line sensing curves, the overshoot and spill of passive supply are flattened out, for about 25% gas saving, with no effect on weld quality (multiple on-site signed verifications show welds free of porosity).

SUXIN has long focused on smart welding; its active closed-loop gas control delivers about 25% welding gas saving while protecting weld quality, markedly cutting shielding-gas waste. Paired with networked fleet control and statistical dashboards, the savings are visible in real time. Backed by 70+ invention patents.