Rotational molding technique

Rotational moulding is a technological process that allows the production of hollow bodies in one piece without any welding. This technology allows the manufacture of pieces uniform in thickness and without any internal strains.

Large dimension and complex profile items can be moulded with several finishes -synthetic leather, embossing, etc. Co-moulded inserts could be also added.

Continuous search for new moulding materials and technologies enlarge every year the range of polymers efficiently used in the rotational process.

Today, most of production is made of linear top quality polyethylene. It is selected and supplied by only the best firms highly-qualified in raw materials provision.

The distinguishing feature of rotational moulding technology is the mould rotation around two perpendicular axes, a fixed direction primary axis and a secondary axis with variable direction.

Throughout the process (excluding the loading and unloading phases) the mould slowly and ceaselessly continues to rotate.

The mould rotation around two axes causes the softened polymer to disperse and stick to the internal walls of the mould. The finished piece is formed by depositing alternating layers of polymer fully melt.

Due to the slow rotational speed, the polymer doesn’t stick because of the rotating centrifugal force but being coalesced and adhering to the mould wall.

Advantages of rotational molding:

  • hollow bodies in one piece without any welding lines or junctions.
  • pieces without any internal strains
  • short manufacture delay for moulds
  • fair uniform thicknesses of walls over other "free surface" moulding processes e.g. blow moulding
  • variable thicknesses in the walls of the product without modifying the mould
  • economic feasibility of limited quantities production
  • lack of swarf since the whole material charge is generally consumed for the item manufacturing
  • multilayer pieces, including products made from expanded plastics
  • chance to print different items simultaneously onto a single machine
  • ease of co-moulding inserts within the item
  • chance of co-moulded high quality graphics on the item