Aluminium is normally welded at higher travel speeds than when welding steels, particularly when using the MIG process. The implication of this is that abrupt changes of direction are to be avoided. It is, for example, impossible to weld around a 90° corner as the MIG torch cannot be moved rapidly enough to keep the correct lead angle. It is also difficult to weld around small diameter bosses fixed in position. In this sort of application the boss needs to be rotated with the torch held stationary. Such comments do not necessarily apply when fully mechanised or robotic equipment is used.
Automation or the use of robots enables torch positioning and motion to be controlled with the precision required for the production of quality welds.