How does rotomolding works?

The rotational molding is a process of plastic molding by rotation in a specific recipe for each product.

Pulverizing

After pulverizing of plastic pellets into a powder, it is mixed with the chosen color.

Melting Plastic

This mixture is introduced into a mold that will enter into an high temperature oven. The mold rotates on two axes to provide an uniform coat of plastic inside the mold.

Cooling

Subsequently, the mold is get out of the oven to cooling the plastic that it can solidify.

Demolding

Once the room is cooled, the mold is opened and the room is closed.

Comparing with others plastic molding process:

Here is a table comparing the rotational molding process with other plastic molding process:
FEATUREs ROTOMOLDING INJECTION  MOLDING THERMOFORMING
Development Short Medium to long Medium Short
Mold cost Very low because it does not need to support pressure High because it needs to support a lot of pressure Moderate Low
Parts Size Small to very large Small to Medium Small to very large Small to very large
Parts Hollow Solid Hollow Solid
Parts shape Complex Complex Average Simple
Parts Joint or welding No No No Yes
Production Volume Small or large Large Large Small or large
Cooling Air (energy free) Water Water Air / Water
Production Waste Very little Very little Average High

Rotomolding advantages

  • – Control of wall thickness
  • – Single or double wall
  • – Several surface finishes
  • – Unlimited choice of color
  • – Recycling of plastic
  • – Openings at specific location in parts
  • – Include metallic inserts
  • – Relief printing on the plastic

The stages of a rotomolding project

Rotational molding is a process of plastic molding by rotation in a specific recipe for each product.