For customized shapes as well as sizes, rotational moulding process, rotocasting, or rotomoulding is a trusted method. There are other moulding methods for creating custom shapes and sizes. However, for creating hollowed objects, these methods do not provide apt support. Owing to this, rotational moulding becomes a better option for the same. Many companies, in the manufacturing sector, prefer rotational moulding for creating custom shapes and sizes.

Although, plastic injection moulding is known for providing effective results for customized sizes and shapes. The problem arises in the case of hollow objects. This gives rotocasting an edge over plastic injection moulding.

What is Rotational Moulding?

As the name suggests, rotational moulding or rotocasting involves moulds rotating on their own axis. The rotational moulding process requires adding up the raw material in the cavity of the moulds. These moulds are heated up to melt and distribute the material for casting.
As the rotation of the moulds begins, the molten part starts to stick to the walls of the cavity. The controlled movement of the moulds keeps the distribution of the material uniform and even. Therefore, there is no scope for any unevenness across the walls of the moulds. It, thus, creates a hollowed object in an accurate shape and size.

How rotocasting takes place?

Rotocasting supports the manufacturing of objects under a limited number. Therefore, the process is more useful for emerging businesses.

The rotational moulding process can be understood in a few simple steps.

  • Plastic granules are filled into the cavities of a mould.
  • The mould, which starts to rotate, is conveyed into an oven.
  • As the granules begin to melt, they are coated onto the walls inside the mould. It is due to the rotational movement of the moulds.
  • When the mould starts to cool, the molten material begins to take the shape as required and becomes stiff.
  • The rotation stops when the finished product is ready to be removed from the moulds.

The mould tooling requires to be made up of a material that is highly resistant to extreme heat. Therefore, a rotomould, the mould for rotational moulding, is designed in aluminum. The resin that is used for moulding is, usually, polyethylene. Its low chemical degradation feature makes it a suitable material for rotomoulding. The add-ons like undercuts and inserts can be used in the process of rotational moulding.

Why rotation moulding is used?

As rotation moulding is essential for creating single-piece, large, and hollowed objects or double-walled open containers, it becomes an economical method of production. The process is more suitable for businesses that are new in the league.

Apart from packaging, the rotational moulding process is used for making a variety of products in the industry. The most common ones are-

  • Toys for kids such as ping-pong balls
  • Kayaks for water sports
  • Baby cribs
  • Containers or bins.

The process of rotation moulding is highly useful for manufacturing objects with the requirements of enhanced stability, seamless finishing, and even thickness of walls. It can equip the direct integration of spin weld attachments and inserts in the rotomould.

The pinch-off seams or the weld lines are not produced during the process of rotation moulding. Therefore, there is no requirement for further phases of processing as the initial process provides a well-finished product. All such features make rotocasting a better option in comparison to other competitive moulding processes such as blow moulding.

Advantages and Disadvantages of Rotational Moulding

There is a reason behind rotational moulding is considered better than some conventional processes of moulding. However, there are certain loopholes that can restrict the spread of the process across the industry.


  • Low-cost metal tooling makes it more economical
  • No secondary processing like joint fabrication or welding is required
  • Product thickness remains consistent due to uniform coating
  • Greater object strength due to thicker corners created in rotocasting.


  • More time consuming
  • Options for raw materials are confined
  • Repeated use of moulds is restricted to up to 3000 cycles.
  • Labor costs are high for rotomoulding due to a lack of mechanization and automation.


Rotation moulding is more useful in creating larger parts of different products. It saves a great chunk on the cost of the raw material and other inputs. However, certain loopholes of time constraints, durability, and labor costs are needed to be addressed to make it far more effective.

Acme Drinktec Solutions is known for providing leading-edge molds for the process of one-step molding. With a legacy of over 2 decades, ADS is known for its outstanding performance in the industry of ASB Molds.