... digital welding machine contain 8 single welding methods: MMA, DC-argon arc welding, pulsed-argon arc welding, argon arc spot welding, GMAW ... with the traditional simulating-control circuit welding machine, the digital welding machine is insensitive to the change of temperature ... The user can add other welding functions to welding machine, and improve the welding performance by software upgrade. 8. ...