MMA WeldingManual Metal Arc (MMA) welding, also known as Shielded Metal Arc Welding (SMAW), Manual Metal Arc Welding (MMAW) or commonly, 'stick-welding' or 'electrode welding', is an electric arc welding process in which the arc is struck between a covered metal electrode and the workpiece. The central metal electrode or core wire is consumable to provide the filler metal for the weld. Shielding of the weld pool is provided by the decomposition of some components of the electrode covering. The MMA process was probably the most significant development in welding technology, and was developed by a Swedish engineer Oscar Kjellberg and patented in 1908, by the '30's had become well established. The development of a wide range of electrode types and alloy compositions meant it could be used to weld all sorts of components. By using engine-driven generators it could be used 'in the field' as well as in the workshop, and in remote areas were mains power wasn't available, so extending its versatility. The main drawback with MMA is that only a limited amount of weld metal can be deposited from one electrode, so electrodes have to be replaced quite frequently, making it a low productivity process.
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