less waste, more economical,
better for the environment.
molding or moulding is a versatile process for creating many kinds of
mostly hollow plastic parts. The phrase is often shortened to
rotomolding or rotomoulding.
The process was developed
in the 1940s but in early years was used little because it was a slow
process restricted to a small number of plastics. Over the past two
decades, improvements in process control and developments with plastic
powders have resulted in a significant increase in usage.
The rotational molding process is a high temperature, low pressure
plastic forming process that uses heat and biaxial rotation (i.e.
rotation on two axes) to produce hollow, one piece parts.
The process does have distinct advantages. Manufacturing large, hollow
parts such as the ROTOSPA Tub is much easier by rotational molding than
any other method. Rotational molds are significantly more cost
effective than other types of mold. Very little material
is wasted using this process, and excess material can
often be re-used, making it a very
economically and environmentally viable
- Loading a measured quantity of
polymer (usually in powder form) into the mold.
the mold in an oven whilst it rotates, until all the polymer has melted
and adhered to the mold wall. The length of time the mold spends in the
oven is critical.
the mold, usually by fan. This stage of the cycle can be quite lengthy.
The polymer must be cooled so that it solidifies and can be handled
safely by the operator. This typically takes tens of minutes. The part
will shrink on cooling, coming away from the mold, and facilitating
easy removal of the tub.
- Removal of the tub.