Final answer:
The statement is false because SMAW uses constant current machines, while GMAW uses constant voltage machines.
Step-by-step explanation:
The statement that SMAW and GMAW use constant current arc welding machines is false. SMAW (Shielded Metal Arc Welding) typically uses a constant current (CC) welding machine, which provides a consistent current regardless of length changes in the arc. On the other hand, GMAW (Gas Metal Arc Welding), also known as MIG (Metal Inert Gas) welding, usually uses a constant voltage (CV) welding machine that keeps the voltage constant but allows the current to fluctuate depending on the arc distance and wire feed speed.