is Rotational Molding?
Rotational molding is a process whereby
a hollow mold is filled with a powder resin and then
rotated bi-axially in an oven until the resin coats
the inside of the mold and cures.
The mold is then cooled and the part
removed. There are many advantages to this process.
A primary advantage over other processes is size, some
of the largest ovens now incorporate a 5.5m swing.
Entire boat hulls and automobile bodies
are being rotomolded in one piece. On the small part
end, many small PVC parts such as ear syringes and face
masks are rotationally molded.
Another advantage is unrestricted
deign. Complex geometry is easy to incorporate into
a one-piece product design. The application of solid
modeling and CNC tools enables the molder to produce
virtually any design.
Rotational molding is a very cost
effective method of redesigning four or five thermoformed
or sheet metal pieces into one hollow plastic product.
Rotationally molded products are recognized for their
strength and durability.
In this no-stress process, material
tends to collect in corners and ribs making these areas
thicker and thus stronger. The material does not thin
out in corners as with other processes.
Finally, ease in prototyping. One
of the reasons that Rotational molding is a cost effective
alternative to other processes is the low cost of the
tooling used in this process. Since Rotational molding
is a stress free process, tools are primarily a thin
hollow shell and can be produced from aluminum, stainless
steel, mild steel and nickel.
The product forms on the inside of
the mold therefore tools do not require internal cores.
Tooling can be produced quickly and relatively inexpensive
to other processes.