Gas Tungsten Arc Welding (GTAW), also known as Tungsten Inert Gas (TIG) welding, is an open arc process is which a non consumable electrode is used to create and maintain the arc.  It is often used without any filler fire, in which case the process is called autonomous.

One common application for GTAW is in tube manufacture.  Meta's laser sensors are compact enough to fit in the tight spaces available and provide highly accurate tracking to compensate for tube rotation.