Casting materials is done in a variety of ways, though the most common method is done with a die, where the material to be molded is poured into the die and the die then presses the material into its intended shape. Another means manufacturers will use to cast metal is the rotational molding method.The way rotational molding works is rather simple: the mold is filled with the material it will shape, such as aluminum, and then it rotates. The mold itself is heated, so over the duration of the slow rotations, the metal heats up and begins pressing into the shape of the mold. While not as popular as other casting methods such as injection molding, rotational molding companies employ the rotational molding method because it does have certain advantages over more commonly used molding processes.
The most obvious advantage rotational molding has over other means of molding is that it can maintain certain metals at higher temperatures. Doing this keeps the metal more malleable for a longer time, thereby making sure a higher amount of the metal adheres to the mold. The longer the metal stays in contact with the mold, the less waste there is when the metal cools. Additionally, there is less wasted metal because the rotational molding method does not press the metal into the die to shape it. All of the metal remains within the mold, unlike with other means of molding where there is always excess metal pushed out of the die.
There are many styles of rotational molding machines, and depending on the needs of rotational molding companies, their desired machine may differ from those others use. The most popular varieties of rotational molding machines are the clamshell, the carousel, the rock and roll machine, the shuttle, and the vertical machine. Though differently engineered, each type of machine is meant to process materials in the same way.