Basics of Orbital Welding Systems
A basic orbital welding system is comprised of a gas delivery system, a power source or arc machine, and a weld head. The gas delivery system feeds gas to the weld head that contains a tungsten electrode. The electrode transmits electricity through a channel of conductive gas that is surrounded by field gas in order to create a consistently-sized arc that can be rotated around the weld head – as though it were in orbit – which is tightly affixed to the weld joint-to-be so as not to let atmospheric gas contaminate the field gas.
For gas delivery, many industrial welders choose to employ automatic gas cabinets, which safely and efficiently manage the delivery of expensive and volatile industrial gases, as well as simple inert gases used for purging and/or shielding like argon. The cabinet can mechanically operate a panel and is often programmable by an on-board touch-screen computer interface that can manage a number of different processes and easily transition between process as required for different batches.
As far as providing current to the weld head, an arc machine is necessary to ensure consistent arc length and temperature. Different mixtures of gasses used in TIG welding respond differently to different configurations of current delivery. The current delivered by arc machines is easily programmed to provide whatever is necessary for a specific process as far as arc length and intensity for any number of conductive gasses.
The gas delivery system for orbital welding is generally anchored in an automatic gas cabinet that manages purging and delivery. A touch screen interface allows for the management of gas flow and purge cycles, and the panel can easily integrate an MFC internally, or an MFC can otherwise be placed at the process site as an intermediate step to the weld head for applications that require precise amounts of gas, the output of which can often be measured in flow of mere molecules per millisecond.
For GTAW process welding, all three main elements – the delivery system, the power source, and the weld head – must work in concert to achieve the desired results. Buyers of welding equipment are well served by consulting with the same vendor for all three components, since certain configurations are best suited to certain processes. Since many OEMs specialize in just one component of the welding process, a vendor that deals in all aspects is well worth a slight value-added premium because significant cost savings can be realized from the selection of the perfect part for the process.