Modes of Operation on a Welding Machine

Video Transcript

" Hello! My name is Mac and on behalf of expertvillage.com I am here to discuss MIG welding. Many MIG machines have three different kinds of modes of metal transfer. That is the arc characteristic that deposits the weld metal in the arc welding puddle. In the bottom one third of the machine’s range of capability you will find that the mode of metal transfer is called short arc. Short arc is distinguished by the fact that they are, the advancing electrode must touch the puddle and the piece be shorted off or actually a short circuit occurs that melts off a little puddle of weld metal. In the middle range of the machine’s capability you will have globular transfer. And now, when that advancing electrode touches the weld puddle it melts off a piece and establishes an electric arc. The advancing wire actually melts off in the arc and globs of metal are transferred across the ark into the weld puddle. Globular transfer has a nasty habit of causing an awful lot of spatter, it fuses to the area around the weld puddle. So it is not used all that much. The top one third of the machine’s capability is called spray arc. So with the proper gas mixture and the proper machine you can achieve a very high rate of metal deposit. The characteristics of spray arc are the globs of metal that melt off the end of the work wire and go through the arc are all the same size. They follow one another evenly spaced across the arc almost like box cutters in a train and they travel at a very high rate of speed and true spray arc is almost soundless, there is very little crackling noise and the weld is actually very smooth, there is a very good cosmetic appearance to it. Spray arc is widely used in industry to weld the things and weld metal together."