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Rotational Moulding |
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Overview
Rotational moulding (often referred to as Rotamoulding or Rotomoulding) is a process used for producing hollow plastic products. By using additional post-moulding operations, complex components can be produced enabling the process to compete effectively with other moulding and extrusion practices.
Rotational moulding differs from other processing methods in that the heating, melting, shaping, and cooling stages all occur after the polymer is placed in the mould, therefore no external pressure is applied during forming.
This provides the following advantages:
• Economically produced large products
• Minimum design constraints
• Stress-free products
• No polymer weld lines
• Comparatively low mould costs |
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The Process
The Rotational Moulding process is essentially split into four operations:
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Charging Mould
A pre-determined amount of polymer powder is placed in the mould. With the powder loaded, the mould is closed, locked and loaded into the oven. The powder can be pre-compounded to the desired colour. |
Heating & Fusion
Once inside the oven, the mould is rotated around two axis, tumbling the powder – the process is not a centrifugal one. The speed of rotation is relatively slow, less than 20 rev/min. The ovens are heated by convection, conduction and, in some cases, radiation. As the mould becomes hotter the powder begins to melt and stick to the inner walls of the mould. As the powder melts, it gradually builds up an even coating over the entire surface. |
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Cooling
When the melt has been consolidated to the desired level, the mould is cooled either by air, water or a combination of both. The polymer solidifies to the desired shape. |
To view a flash animation of this process please click above. |
Unloading/Demoulding
When the polymer has cooled sufficiently to retain its shape and be easily handled, the mould is opened and the product removed. At this point powder can once again be placed in the mould and the cycle repeated. |
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Typical Materials Used
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Typical Products Produced
| Manhole inspection chambers |
Rainwater tanks |
| Slides and climbing frames |
Diesel fuel tanks |
| Childrens playhouses |
Traffic cones |
| Canoes and kayaks |
Pallets | |
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A Profile of Balmoral Tanks
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Balmoral Tanks, a division of Balmoral Group Ltd, is the world's largest single source designer and manufacturer of liquid storage and treatment products. Covering the water, wastewater, chemical, civil, environmental and fuel sectors, the company provides rotationally moulded seamless products measuring up to 7m in height by 4m dia with capacities of 75,000 litres.
The vast majority of Balmoral Tanks products are accredited and approved by numerous agencies: BBA; IAB; IP; LPCB; OFTEC and WRAS to name but a few. In gaining these accreditations Balmoral has raised the integrity and standards of the tank industry around the world.
With an extensive computer aided design suite that includes 3D CAD, 3D solid modelling, finite element analysis applications and unrivalled manufacturing capacity, Balmoral Tanks’ products are in use around the world.
Contact
Balmoral Tanks, Balmoral Park, Loirston, Aberdeen, AB12 3GY, United Kingdom
Tel +44 (0)1224 859100 Fax +44 (0)1224 859123 E tanks@balmoral.co.uk
www.balmoraltanks.com | |
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Click Here for an idea of Processing Costs
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