Rotomolding, or
rotational molding, is a
manufacturing process in which a measured amount of
plastic resin is loaded into a
mold,
heated, and the
mold is
spun on at least one
axis until the
hot,
fluidized resin acquires the
shape of the
mold. At that point the
mold is
cooled and
despun, and the
finished part is removed from the
mold. The
mold can be used again for the
next part.
The resulting part has a number of useful and interesting properties. A greater amount of resin collects in corners and joints, where stresses may naturally be higher. This leads to a rugged, durable, seamless part requiring no assembly or bonding. The color will never crack or chip, since the resin can be colored before being loaded into the mold. It is possible to make the resin result in a 'marble' or 'woodgrain' finish on the part. The resulting part is corrosion-proof. The resins can be tailor-made to suit regulatory requirements, such as FDA regulations. The process is economical for both large- and small-volume production runs. In many cases, rotomolding can yield parts too complex or topologically difficult to mold by other conventional molding methods, such as injection molding. Also, since with rotomolding the molds do not have to withstand increased pressures of injection molding or blowmolding, they can be structurally thinner and cheaper.
Rotomolding is used to produce a wide variety of
commercial products. Among them are:
Plastic whitewater kayaks
Playground equipment
Vending machines
Highway barriers
Headrests
Air ducts
And much, much more...