In this process a slow continuous pressure is applied to the area to be forged. The pressure extends deep into the material. Press forging can be either cold or hot. Cold press forging is generally used on thin, annealed materials, while a hot press forging is done on works such as locomotive armor plating and heavy machinery. Cost wise, Press Forging is more economical than hammer forging (except when low production is required) and closer tolerances can be achieved. A greater quantity of the work done is passed on to the workpiece. This way it differs from the hammer forging operation, where most of the work is absorbed by the machine and foundation. This production process is ideally suited for larger forgings, as there is no limitation in the size of the machine.