MMA welding machines bring low cost and high versatility to site welding, off-shore, maintenance and repair and many more industries - And you won't go wrong with a Migatronic welding machine.
Also known as shielded metal arc welding (SMAW) or simply stick welding, MMA is an inexpensive welding process. Using a consumable, flux-covered electrode and a ground clamp, a short-circuit is intentially made on the weld piece. An electric arc forms between electrode and workpiece, which heats up enough to melt both. As the electrode melts, the flux coating on the electrode develops gas and slag, which help protect the weld pool. The gas keeps air and other pollutants away, while slag forms on top of the weld pool to protect the weld seam. The slag cools down and solidifies rapidly, protecting the weld area after the gas has disappeared. This combination makes MMA welding ideal for windy conditions (outdoor use) which might effect other welding processes.
Stick welding is an older type of welding, but still in wide-spread use for its versatility, low price and strong welds. Furthermore, MMA inverter welding machines are often portable since you don't need gas containers and wire feed units, but simply a power supply. However, MMA welding produces spatter, which increases post-treatment time and reduces productivity. Also, electrodes have to be changed frequently. Usually used for cast iron and steel.
The position you are welding affects the type of electrode you have to use. For instance, you need a stainless steel electrode with the correct chemical flux composition for vertical down welding on a stainless steel pipe. Electrodes can be sorted into three different groups:
Suited for vertical down welding, this type of electrode features a higher concentration of cellulose, resulting in rapid burn-off rate and deep penetration. Downsides are coarse weld deposit, which makes deslagging difficult.
A general purpose electrode, with high proportion of titanium oxide in the flux coating. Makes for an easy arc ignition, low spatter and smoother arc control which contributes to a good bead profile. AC and DC compatible, these electrodes can be used in all positions, and are especially suited for welding fillet joints in horizontal/vertical position.
Containing a high proportion of calcium carbonate and calcium fluoride, this electrode makes the slag more fluid and fast-freezing. This is ideal for vertical and overhead welding position. These electrodes produce a higher quality weld with good mechanical properties and cracking resistance, and as such are used for heavy fabrication.
Newer manual metal arc welding machines have an inverter power source, with the added benefit of smaller weight and size. This makes site welding easier, as transport is less cumbersome. These power sources come in AC or DC or AC/DC. AC electrodes can be used in either, but some DC electrodes cannot be used in AC mode.