Rotational moulding

Rotational moulding – also known as rotomoulding or rotational sintering – is the most economical process for producing large hollow plastic parts. Polymer powder is placed in a closed mould that rotates around two axes inside an oven. The material melts and distributes evenly across the mould wall. The result is a seamless, stress-free hollow body with uniform wall thickness.

We have represented Polivinil Rotomachinery in Germany, Austria, Switzerland, the Benelux countries and Poland since 2006. Over these 20 years we have delivered more than 100 machines – from laboratory units to large-scale plants.

Your Polivinil partner for DACH, Benelux and Poland

If you are looking for a Polivinil rotational moulding machine in Central Europe, you will end up talking to us – and that works in your favour, because we are more than a sales channel.

GEPOC has been a polymer chemistry company since 1971. We know the machine, but we also know the material processed inside it and the processing aids that make the difference between a usable part and a good one. Machine, mould, compound and application support come from one source – and if something goes wrong, you have one contact instead of three.

More than 100 machines delivered since 2006 also means this: we have seen the typical mistakes before. In most cases we know in advance where the difficulties will be.

When rotational moulding pays off

Rotational moulding plays to its strengths where injection moulding and blow moulding reach their economic limits:

• quantities from 20 to 2,000 parts per year
• volumes of more than 10,000 litres
• wall thicknesses from 2 to 15 mm
• tooling costs far below those of injection moulding
• complex geometries with openings, through-connections and threads
• seamless, stress-free parts without welded joints

Tooling cost is the decisive lever. Because rotational moulding works without pressure, the moulds are simpler in construction and many times cheaper than injection moulding tools. That makes even a small series viable which would never pay for itself in injection moulding.

Where the process reaches its limits

Rotational moulding is not the right process for every task. At very high volumes, injection moulding wins on part cost, because rotational cycle times are considerably longer. Tight tolerances and wall thicknesses below 2 mm are borderline cases as well.

Where exactly the limit lies in your case depends on geometry, material and annual quantity. Talk to us – if another process suits you better, we will say so.

Typical applications

• tanks and cisterns for water, chemicals and fuels
• containers and transport containers for industry and logistics
• housings and technical components
• boat hulls and marine applications
• road and traffic infrastructure such as barriers and bollards
• rotolining – internal lining of vessels for corrosion protection
• play and leisure equipment

Machinery for every scale

From the Polivinil range we supply the right machine for every production size:

Independent arm machines produce several parts with different cycle times simultaneously, or multi-layer components. Carousel machines with fixed arms are designed for fast cycles of similar length. Shuttle machines handle large parts with up to four stations. Rock & roll machines with tilting ovens are built for very large, elongated bodies. For PVC and plastisol in high volumes there is the box oven line, and for material testing and process development the laboratory machines.

Complete material handling comes with it: pulverising, colouring, conveying and automatic dosing.

Polivinil Rotomachinery S.p.A. is part of the Rotomachinery Group and, with more than 1,600 installations in 100 countries, one of the leading manufacturers of rotational moulding machinery worldwide. The group has been manufacturing for over 50 years and is also represented in North America through STP Rotomachinery Inc.

The moulds to go with it

We supply the tooling as well: since 2016 we have represented BOCA S.r.l. and provide rotational moulds in aluminium and steel – machined, cast or as a prototype mould. Every mould is tested and accepted on our own machines before delivery.

More about our rotational moulds

Your next step

Whether rotational moulding makes sense for your part can usually be assessed quickly. Send us a drawing or a sketch, the planned annual quantity and the material you have in mind – you will get a sound first assessment.

We would also be glad to welcome you in person at the plant in Italy and show you the machines in operation.

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Phone: +49 2428 902028