Rotational moulding process

About rotational moulding

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  • Rotational moulding is the process of manufacturing hollow plastic parts or products such as garden planters, storage tanks, water butts or canoes.

    Rotational moulding produces strong, durable products which are weather resistant and will last many years.

    The process involves using high temperatures to melt Medium Density Polyethylene (MDPE) so that it can be moulded to any shape. This process is the same for all our rotational moulding machines accept that the de-moulding

    Stage 1 - Charging the mould

    A predetermined amount of powdered plastic is poured into a hollow metal mould which is made from either steel or aluminium.  The amount of plastic used in the mould is equivalent to the weight of the finished product.  Rotational moulding has the advantage of producing no waste; all the plastic poured into the mould is used.

    Stage 2 - Turning up the heat

    Once the powdered plastic has been poured into the mould, the second half of the mould is securely clamped into position.  The mould is then moved into the oven where the rotation starts.  Rotations are normally around 10-12 rev min so that all the plastic is dispersed equally.  Also, as well as rotating, the mould will start to tilt on its second axis.

    By changing the speed of revolutions and tilts, it is possible to control the wall thickness of the end product.

    Stage 3 - Cooling down

    After the heating cycling is complete, the mould is removed from the oven and the cooling cycle begins.  This involves using fans and/or a fine mist of water to slowly cool the mould.  If the mould is cooled too quickly the product may become distorted.

    When the product is cooling, it starts to shrink away from the mould.  Once cooled, the product can be removed from the mould.  Release agents are used to facilitate this process.

    Contact us

    Rotational Mouldings
    Etills Ltd 
    Unit 1
    Whiting Way, Melbourn
    Hertfordshire, SG8 6NA
    United Kingdom

    Phone: 01763 261781
    Fax: 01763 268409
    Etills Ltd VAT Number: 895 3143 00
    Company No. 06006123

    Opening Times
    Mon - Fri: 8:00am - 5:00pm
    Sat: Closed
    Sun: Closed.