Introduction to Rotational Moulding Pt 1: Process, Plastics and Potential
Understanding the Rotational Moulding Process, Its Benefits, and Real-World Applications
What is Rotational Moulding?
Rotational moulding, also known as rotomoulding, is a versatile plastic manufacturing process used to produce large, hollow plastic parts. Unlike injection moulding or blow moulding, this method uses finely powdered plastic resin that is heated and rotated in a mould to coat its interior evenly.
The process takes place on a rotational moulding machine, with the most common type being the carousel machine. These machines enable efficient production and are ideal for custom plastic moulding, such as the specialised components manufactured by Contact Plastics.
Why Use Rotational Moulding?
Rotational moulding sits in the middle of the plastic manufacturing spectrum in terms of cost and production volume. Here's why it is a popular choice for many industries:
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Moderate mould costs – Cheaper than injection moulding but more expensive than compression or dip moulding.
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Mid-range production output – Typically around 20 moulded parts per 24 hours per mould.
- Ideal for low- and medium-volume production – Making it perfect for custom or specialised plastic components.
Key Advantages of Rotational Moulding
Rotational moulding offers several unique benefits, making it ideal for manufacturing tough, durable plastic products:
1. High-Quality, UV-Stable Parts
Rotomoulded parts typically have thicker walls than injection or blow-moulded parts. This gives them excellent UV resistance. For example, Contact Plastics manufactures rotomoulded water barriers that withstand harsh South African weather and remain intact after 8+ years on the road.
2. Ability to Create Large, Organic Shapes
Unlike injection moulding, rotomoulding allows for complex, hollow shapes. A good example is the Contact Plastics hose reel cabinet, which features a 4mm thick wall and a large hollow body – a design not feasible with injection moulding.
3. Flexibility for Secondary Processes
Rotomoulded parts can undergo post-production processes like:
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Drilling
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Assembly
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Printing
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Lacquering
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Foam filling for added strength
This flexibility makes it ideal for custom and functional designs.
What’s Next in the Rotational Moulding Series?
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