Dear GPSCHAHIL

A good 400amp thyristorised control rectifier power source with minimum 70% open circuit voltage output, would sound better, though it may be a bit higher in capacity than what you intend to use, but for the safer side considering in future your good self might come across using higher capacity in welding jobs. By the way, which country.???

For welding sheet metal, I would strongly recommend inverter technology. It has a much more stable output and provides better arc control for welding thin materials.

If you can afford the budget, I would recommend pulse mig welding systems to reduce heat input and reduced weld shrinkage and warping of material. It also allows better arc control and improves welding speed.

I would suggest .030 welding wire. ESAB manufactures a product that was called 87HP and was awesome for thin metal welding. It's more expensive but great product.

Good Luck

250 Amps Mig welding with a inverter power source is will be ideal for mass production and quality welding. If it is affordable, Pulse MIG welding is also better. But it is up to you.

MIG will give high productivity compared to SMAW and at a low cost per kg metal out put and equally good for your thickness range and beyond that ( then 400 Amps ) also. Further it will help to avoid distortion which is a common problem with thin sheet metal welding. You can still minimise it by using a Copper (or) Aluminum back up strip (12 -14 mm thick or so ) with proper clamping to dissipate the heat during welding. Use 0.8 / 1.2 mm filler wire (depending upon thickness use).

If possible mechanise the operation using travel carriage (or) simple oxy – fuel gas cutting machine minus its torch. It will help to achieve a travel speed, more than 75 - 90 cm / min speed ( twice the SMAW speed) and avoids warping to maximum extent.

Best of luck.

Sridhar - Advance Institute of Welding Technology, Chennai – India.

Good selection. MIG/MAG is semei-automatic arc welding system, and I prefer to get the brochures and catalogues from machine's manufacturers to differentiate between variety of machines and its capabilities.

Please consider the following

You need at least 400 amp power source, but the ultimate specification is the duty cycle factor at full power. This should be at least 85% to be sure you have a good and heavy duty power source.