Rotational Moulding - Bluejohn, · PDF fileThe advantages of rotational moulding ... the mould...

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Transcript of Rotational Moulding - Bluejohn, · PDF fileThe advantages of rotational moulding ... the mould...

  • Rotational Moulding

  • Established in 1978, Amber Plastics is one of Europes leading rotational moulders. Strategically located in Chesterfield, at the heart of the UK motorway network, alongside the London to Edinburgh rail link, and within 90 minutes drive of five international airports, Amber Plastics is ideally placed to fulfil even your most demanding delivery schedules.

    Taking a project from raw concept to finished product is what Amber Plastics does best. Our approach to project management is based on three fundamental beliefs. Firstly, no two projects are the same; there is no one size fits all solution. Secondly, each project is critical both in the eyes of the client, and to our future success. Thirdly, continuous and open communications are common to every successful project.

    You may want to simplify design complexity, reduce component weight, or investigate the possibilities of switching to plastics from metal. Your priority may be cost, quality or performance. Whatever you are seeking to achieve, Amber Plastics can deliver. Our mantra is Right first time, every time.

    Mission Statement:

    To create a world leading, project based, customer focussed rotational moulding business which produces niche volume, technically difficult mouldings delivering profit for Amber Plastics Limited and added value for our customers.

    Amber Plastics management team, Chris Jerromes and Paul Scholey

    Amber Plastics

    Telephone: +44 (0)1246 456525

  • Design FlexibilityRotational moulding can accommodate both simple and complex product shapes, from small to large sizes.

    Ideal for enclosed hollow products such as tanks, rotational moulding also excels in multi-wall applications. Structural foam injected into the parts or self foaming polyethylene offer excellent insulation and impact properties and are ideal for applications where impact and thermal stability are critical for insulated transport boxes.

    A product designer is limited only by their own imagination rotational moulding can accommodate logos, inserts, recesses, bosses, spouts and much more.

    Further added-value can be created for complex products through CNC finishing techniques.

    The advantages of rotational moulding

    The rotational moulding process offers a unique set of advantages which can generate significant benefits for your new product development projects. Furthermore, companies are switching to rotationally moulded thermoplastics as an alternative for existing products currently made out of metal or grp. In many cases, rotational moulding may provide a more cost-effective and technically superior manufacturing solution compared with injection, vacuum or blow moulding.

    For clarity and simplicity, the advantages have been grouped under three headings:

    lDesign FlexibilitylProduct PerformancelEconomics

    Structural foam

    CNC machining Ro



    l Mo



    Special double shot foam

    Telephone: +44 (0)1246 456525

  • There is a wide range of thermoplastic materials which you can use in the rotational moulding process; polyethylene, polypropylene, nylon-12 and cross-linked polyethylene to name just a few. Many thermoplastics come in a selection of colours which can add-value to your product and avoid the additional cost of painting or coating. Aesthetically, different surface finishes for example peening can be integrated at the mould tool design stage and you have the option of using mottled materials which produce a natural look.

    Product PerformanceThe rotational moulding process delivers single piece, seam-free products, ideal for situations demanding leakproof and weather-resistant solutions. Further performance benefits include high impact resistance, good load bearing properties, and no corrosion when compared with metals.

    For applications such as fuel tanks, rotationally moulded thermoplastics possess good chemical resistance and, depending on material selection, are able to operate in temperatures ranging from -30C to 120C with excellent UV stability.

    The relative lack of locked in stresses in your rotationally moulded products helps protect them from cracking and makes them more durable.

    EconomicsUnlike other moulding processes, rotational moulding does not involve pressure loading. Consequently the mould tools can use more cost-effective materials such as sheet steel and aluminium. Furthermore, rotational moulding tools are simpler to construct as they require only a female element and this can significantly reduce project lead times.

    These two factors make rotational moulding an ideal solution for your small to medium batch production requirements.

    Rotational moulding techniques allow wall thicknesses to be changed without having to invest in new tools. The ability to modify wall thickness can contribute to significant reductions

    in the amount of thermoplastic material required. This not only impacts on the cost of your product, but minimises its weight which can be a major benefit in

    some applications.

    Few processes use materials as cost-effectively or with as little environmental impact as rotational moulding. The exact amount of material required is added to the mould before the heating process and there is virtually zero waste. The vast majority of rotationally moulded products use thermoplastics such as polyethylene or polypropylene which can be recycled and re-used as well as enhancing your environmental policy.

    Metal inserts can be incorporated in rotationally moulded products. This allows design flexibility and can greatly reduce the amount of secondary machining and finishing required.

    The advantages of rotational moulding

    Element from modular playground equipment

    Material being added to the mould

    Telephone: +44 (0)1246 456525

  • Step OneThe mould tool is fixed to the moulding machine arm. Several tools can be attached to one arm, the optimum combination being determined by the need of all mould surfaces to receive the correct heat levels. Advanced mould coatings mean no release agents are required.

    Step-by-step guide to rotational moulding

    Step TwoA computer programme determines the exact amount of thermoplastic material to be added. Fuel tanks are manufactured in a wide-range of plastics from polyethylene and polypropylene, to high performance cross-linked polymers and nylon-12 for resistance to chemical attack and high operating temperatures.

    Step ThreeThe tool is clamped up and enters the oven.

    Inserts and fittings added to the mould

    Any inserts or fittings incorporated in the final moulding are placed in the mould at this stage.

    Telephone: +44 (0)1246 456525




    l Mo



    Tooling pictures provided courtesy of Persico S.p.A.

  • Step-by-step guide to rotational moulding

    Step FourIn the oven, the mould is slowly rotated around three axes no centrifugal force is used - to ensure that all surfaces are exposed to the heat source. Gradually the plastic material adheres to the surface of the mould and, over time, builds up a uniform wall thickness.

    Oven temperatures range from 230-360C. Mould rotation speeds vary from 2 to 20 rpm. Other factors influencing cycle times the time the mould spends in the oven and cooling phases include wall thickness and material used.

    Step FiveThe mould moves from the oven to the cooler. The arm continues to rotate and air or water is used to gradually reduce the mould temperature.

    Step SixThe product is carefully removed from the mould.

    Step SevenThe product receives a thorough visual inspection, a skilled task requiring concentration and experience. Great care is taken during the design and prototyping phases to eliminate potential problems and inspection can confirm that the correct parameters have been used.

    Full inspection of the product takes place in relation to the original specification agreed with the customer. Testing procedures can include water pressure to rule out leaks, ultrasound to verify wall thicknesses, and impact tests to confirm durability.

    Amber Plastics specialises in supplying complete product assembles. In the case of fuel tanks, this can include fitting filters, caps and electrical connections.

    Turnkey projects with full assembly ready to send to the customer are all part of the service.

    Step EightRotational moulding produces a hollow, seam-free product which frequently requires very little by way of finishing procedures. However, CNC machining can be used on more complex products to add additional features.

    Telephone: +44 (0)1246 456525

  • Tip OneUse surface detailing to enhance your product.

    Rotational moulding facilitates excellent external surface detail including textures, and mottled effects. The internal mould surface is smooth. You can add value to your product by a moulded in name or by using moulded in or post moulded full colour graphics.

    Key Design Tips

    Rotational moulding is an exceptionally flexible and cost-effective method for creating thermoplastic products and components. You may be considering switching to plastics from metal or grp, or choosing rotational moulding over injection, blow or vacuum forming. Whatever the scenario, the following design tips will help you make the most of the exciting opportunities which rotational moulding can offer.

    For further information see our page on the key benefits of rotational moulding.

    Tip TwoTake advantage of radiused corners.

    Wherever possible, incorporate generously radiused corners in to y