Rotational Molding Machines, Kinds and Its Use
Rotational molding machine is a kind of machine that is used to create or mold different kinds of things that has hallow in shapes usually made in plastic materials.
In the process, the heated hallow molds is filled with a charge or a shot weight of material before it is rotated in two perpendicular axes. This activity will cause the material to soften as well as it will go to stick to the walls of the molds.
The mold continues to rotate during the heating phase in order to maintain even thickness throughout the entire part. The mold will also continue to rotate during the cooling phase in order to avoid sagging or deformation.
The Rotational molding machines are usually made from a wide variety of sizes. Rotational molding machines are consists of the molds, a chamber for cooling, a mold spindle and an oven. The spindle in the rotational molding machines are usually mounted on a rotating axis, this design of the spindle will provide a uniform coating of the plastic inside each mold.
There are different kinds of rotational molding machines; the Rock and Roll rotational molding machine, the Clamshell rotatonal molding machine, the Vertical or Up and Over rotational molding machine, the Shuttle or Swing Arm rotational molding machine and the Carousel rotational molding machine.
The Rock and Roll rotational molding machine is a specialized single arm machine. This machine rolls the mold in about 360 degrees in a single direction. At the same time, it tips and rocks the mold in about 45 degrees either above or below horizontal in other direction. Most of the new versions of this machine have the feature of forcing hot air to heat the mold. These kinds of machines are said to be best for large parts that are having long length-to–width ratio. It also has small heating chambers that save heating cost.
The Clamshell rotational molding Machine is also a single arm rotational machine. The arm of the Clamshell rotational molding machine was designed to be supported with the other arms of the machine on both ends. The machine heats and cools in the same chamber.
The Vertical or Up and over rotational molding machine varies in sizes. The sizes of these machines vary from small size to medium as compared to the sizes of other rotational machines. It is energy sufficient because of the machines compact heating and cooling chambers. It has the same features with the Horizontal Carousel Multi-Arm rotational molding machine. Only it takes up lesser space.
The Shuttle or Swing arm rotational molding machine is a single arm turret machine. It moves back and fourth between the two chambers; the heating and the cooling chambers. It moves the mold in a linear direction into the heating and cooling chamber in an in and out manner.
The Carousel machine can have 6 arms in different range of sizes. This machine has two different models namely the fixed and the independent. The fixed carousel machine has 3 fixed arms that must move together. One of the arms is in the heating chamber; the other arm is in the cooling chamber while the third arm is in the loading and reloading area. The Independent Carousel machine has more arms that move separately from the others. This feature will allow for the different sizes of molds that have different heating and thickness specification