MIG welding wire speed controls penetration more than voltage

Most beginners adjust voltage to control the weld. In reality, wire feed speed (amperage) drives penetration depth, while voltage controls arc length and bead width. For thin material, reduce wire speed first. For thick material, increase wire speed. Voltage fine-tunes the arc character. The correct sequence: set wire speed for penetration, then adjust voltage for a smooth arc. Not the other way around.