Rotational Moulding
The rotational moulding is a technological process that allows to produce hollow cavities in one piece without weldings.
This technology makes it possible to obtain items without internal deflections and with uniform thickness.
Articles can be printed with very large and complicated outlines in various colors and materials.
You can print different types of inserts at the same time and get the final product with different types of surface finishings.
The investment costs in equipment are less expensive than other production technologies concerning plastic products.
Currently most of production is made with linear and crosslinked polyethylene such as pvc, polipropilene, poliammide, policarbonato.
The particularity of this technology lies in the handling of the mould on two axes: a primary one , at a fixed direction, and a secondary one, at variable directions.
Thanks to the two movements polymer invests all internal surfaces of the mould, which once warmed in the oven, melt the polymer that adheres above.
In doing so, all the polymer is melted as a powder and the finished piece is created.
Due to its slow rotation, the polymer doesn’t cover the mould due to the centrifugal force generated by the rotation,
but only because it is melted when it comes into contact with the hot walls of the mould.
The rotational molding cycle is easily explicable four stages:
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1 - the mould is loaded with the chosen desired powder color quantity. |
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2 - the mould is heated for about 20 minutes to about 250°, turning as to the planned primary and secondary rotations. |
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3 - the mould is cooled for about 20 minutes by air and water, always turning as to the planned primary and secondary rotations. |
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4 - the mould is opened, we extract the product and go back to stage 1 again. |
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