Cupola is a continuous melting shaft furnace which has by its inherent design considerable advantages over batch type melters such as electric furnaces or rotary furnaces. A cupola can accept a wide range of raw materials including oily, wet and contaminated scrap. These materials are unsuitable for electric furnaces for safety reasons and because of the contamination their use is also often limited for metallurgical reasons. In cupola melting there is a degree of refining as the metal forms droplets during melting before collecting in the well. Many contaminants are lost or reduced in value in this process whereas when melting in electric furnaces or rotary furnaces whatever is in the charge material finishes up in the liquid.
Induction furnaces are refractory lined crucibles with a water-cooled induction coil installed behind the refractory. The coil is powered by alternating current, which induces eddy currents in the metallic charge that generate heat. Induction furnaces allow for closer control of the metal analysis since the chemistry can be analyzed and adjusted if necessary before being tapped from the furnace.