What is Rotational Moulding, its types & Materials Used
Unleash the power of rotational molding! Craft strong, hollow plastic parts for less.
Discover different types & materials to bring your vision to life.
1. What is Rotational Moulding:
Rotational moulding is a manufacturing process used to produce hollow plastic parts. This technique involves heating a hollow mould filled with a powdered thermoplastic material, typically polyethylene, until the powder melts and coats the inner surface of the mould.
The mould is then rotated slowly and continuously in multiple axes, allowing the melted plastic to evenly distribute and adhere to the mould’s inner surface.
As the mould continues to rotate, the plastic gradually cools and solidifies, forming the desired shape of the final product.
Think of roto moulding as a captivating dance between heat, rotation, and plastic. The process unfolds in following steps:
1. Mould Loading: Plastic powder like LLDPE is loaded into a specially designed sheet metal mould
2. Heating & Rotation: The mould then rotates on two axes while heating up in an oven. This allows the plastic to melt and evenly coat the mould’s interior.
3. Cooling: Once melted, the mould is transferred to a cooling station where the plastic solidifies and takes the shape of the mould.
4. Demoulding: The finished part is ejected, ready for trimming and any finishing touches.
2. Beyond the Basics: Unveiling the Types of Rotational Moulding:
While the core process remains the same, roto moulding offers different machines / variations to suit specific needs:
· Open Flame Rotational Moulding: This method involves heating the mould using an open flame. The heat from the flame gradually melts the plastic powder inside the mould, allowing it to coat the inner surface evenly as the mould rotates. Like — Large water tanks, Kayaks and canoes, Playground slides, etc.
· Rock and Roll Rotational Moulding: In rock and roll rotational moulding, the mould is rocked and rotated simultaneously during the heating and cooling phases. Like — Playground equipment, Agricultural bins and containers, etc.
· Carousel Rotational Moulding: Carousel rotational moulding involves multiple moulds mounted on a rotating carousel. As one mould is being filled and rotated, another mould can be loaded or unloaded. This setup allows for continuous
production and increased efficiency. Like — Traffic barriers and cones, Outdoor furniture, Waste containers, etc.
· Shuttle Rotational Moulding: In shuttle rotational moulding, the mould moves back and forth between the heating and cooling stations. This method is
commonly used for smaller parts or when different moulds are required for different products. Like — Cooler boxes, Automotive fuel tanks, toys and play structures
Materials: There are many thermoplastics which theoretically can be rotationally moulded. However, only a few are used to make
commercial products. The below materials are the most widely used to make rotational moulded products:
A. LLDPE.
B. LDPE.
C. HDPE.
D. COPOLYMERS.
E. CROSS-LINKED POLYTHELENE .
F. RECYCLED POLYETHELENE.
G. NYLON and many more.
3. Embrace the Versatility: Why Choose Rotational Moulding?
Rotational moulding isn’t just a manufacturing technique; it’s a gateway to endless possibilities. With its diverse types, adaptable materials, and unique benefits, it caters to a spectrum of industries and applications.
So, the next time you encounter a seamless, hollow plastic part, remember the magic of rotational moulding at play, shaping the future one rotation at a time.
