At present, there are mainly two methods to produce parts, and they are forging and pressing method and rolling method.
 
Forging and pressing is the total name for forging and pressing. Forging is a common forming method used in machinery manufacturing, and it makes use of forging equipment like metal fork toe to put pressure on metal blank, making it have permanent deformation in order to produce forging parts with certain shape and size. Pressing makes use of press and mould to perform pressure on boards, strip and tubing and so on to make them have deformation because of the change of the space location. Therefore, in forging industry, forging and pressing are very popular to gain parts, and along with the development of the forging technology, forging process has been improved a lot and lot.
 
However, rolling is a processing method to make use of gaps in different shapes between a pair of rotary roller, making the metal blank get reduced in section and increased in length because of the compression coming from the roller. Rolling is the most common method to manufacture steels.
 
Though both forging and pressing method and rolling method belong to plastic forming category, they are different on the forming method. Loader crane parts are integral, and they are formed interruptedly, but rolling parts are local, and they are formed continuously.
 
Besides, rolling is local shaping, and its working load is only a small percentage of the whole forging, so the rolling equipment is much smaller than forging equipment, and the cost is much lower as well. Rolling takes continuous forming method, and it has high production efficiency, and it is easy to realize mechanization and automation.
 
At present, part rolling has become a new field for metallurgy rolling. Thanks to high efficiency of this process, stem cam has been widely used at many small and medium industries, and some industries even use rolling method to replace forging and pressing method to produce machinery parts.
 
In a word, forming, pressing and rolling are all processes to produce machinery parts. Though forging and pressing process and sand casting parts gain parts by means of plastic forming range, they still differ from each other at some aspects, for example, they are different on forming method. Anyway, forging and pressing process and rolling process are very popular among machinery industries, and they are suitable for machinery parts in different types, so we should choose right process based on our demand.