rotational moulding - bluejohn, marketing · the advantages of rotational moulding ... the mould is...

Rotational Moulding

Established in 1978, Amber Plastics is one of Europe’s 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 www.amberplastics.co.uk

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

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Special double shot foam


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 -30°C to 120°C 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


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.


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Tooling pictures provided courtesy of Persico S.p.A. www.persico.com

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 230-360°C. 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.


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 your designs. Radiused corners dissipate stresses and can add a ‘health and safety’ benefit to your product. Aim to incorporate a minimum 2mm radius on each internal and external corner, and when designing twin wall products use five times the wall thickness for the void space.

Tip ThreeYou can design increased strength in to your product and reduce material at the same time.

In all moulding processes, large flat areas of plastic are prone to deflection. The temptation is to increase the nominal wall thickness to increase rigidity. A far more positive solution is to incorporate ribbing or cores in to your design. These both strengthen the finished product and minimise the volume of thermoplastic material required.


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Twin wall and radiused corners

Key Design Tips

Tip FiveYou can minimise secondary manufacturing operations by incorporating metal inserts as part of the rotational moulding process.

These photographs highlight just a fraction of the inserts you could ‘mould’ in to your finished product. Amber Plastics can also supply fully-assembled products. For example, many tanks are delivered complete with filters, caps and depth gauges.

Tip SixThe Amber Plastics enquiry form acts as a check list to help you cover all the bases.

In any product design process there are a huge number of structural, operational and functional variables to consider. The Amber enquiry form is designed to prompt you to ensure nothing is inadvertently missed.

Tip SevenYou can download detailed guidance on design parameters for rotational moulding and on the performance characteristics of different thermoplastics from the Amber Plastics website – www.amberplastics.co.uk/design_guide.

Tip EightTwin walled moulding; foamed thermoplastics for insulation; high gloss finishes; post-mould CNC machining to create additional product features. You can take advantage of all these benefits and more by talking to Amber Plastics’ design engineers on 01246 453544.

Tip FourThere is a vast range of thermoplastics for you to choose from.

Polyethylene, polypropylene, cross-linked polymers and Nylon-12 are just some of the thermoplastics which can be used in rotational moulding. They offer a wide variety of performance characteristics such as resistance to chemicals, UV stability and performance under load. In many applications the material chosen must also be able to withstand high temperatures, have good impact strength, and provide a container which remains leakproof under internal pressure.

Amber Plastics’ engineers have a detailed knowledge of polymer physics. We will work with you to undertake a technical review of your product’s specific requirements to ensure the correct material is selected.

Copies can easily be downloaded from the Amber website - www.amberplastics.co.uk. Alternatively call 01246 456525 and we will send copies to you in the post.

Cut-away of foamed materialCNC machined cover


Effective and flexible project management is central to successful rotational moulding.

Here, our project management skills are illustrated by the design and manufacture of fuel tanks. A critical component, the creation of successful fuel tanks demands expertise in every phase of the rotational moulding process; from choice of material, through prototyping and testing, to the delivery of a fully-tested product ready for immediate use. There is no room for error with fuel tanks.The same principles apply to all our projects.

Enquiry – Process CheckUpon receiving your enquiry, our first step is to ensure that rotational moulding is your most effective manufacturing option.

Our project engineers will talk to you about your enquiry and how we can facilitate your requirements. A project brief will be established which both Amber and the customer can work towards.

Review – Engineering, Design, ManufacturingTaking your idea or concept, our engineering team analyses it from design, engineering and manufacturing perspectives. Using DFM principles, our engineers will suggest ways in which your product can be manufactured more effectively without reducing quality or effecting functionality.

A project engineer is allocated to your enquiry from concept to completion.

In the case of fuel tanks the review could also include elements such as metal inserts, mounting points, and the possibility of

Amber Plastics supplying the tank as a complete sub-assembly including caps, filters and electrical connections.

Our knowledge and understanding of thermoplastics and moulding techniques means we can help you source ancillary products as well as providing your rotational moulding requirements.

Our outsource team has a wealth of experience sourcing parts from around the world.

Project Management

Project Management

‘The planning, monitoring and control of all aspects of a project and the motivation of all those involved in it to achieve the project objectives on time and to the specified cost, quality and performance.’

BS6079:1996


DFM – Design for manufacture is a development practice emphasising manufacturing issues throughout the product development process. Successful DFM results in lower production costs without sacrificing product quality.

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Visuals and Customer ReviewVisuals are developed using CAD which allow you to review the finished look of your product. This provides feedback which allows our engineers to hone your design and develop concepts for your evaluation.

Solid ModellingThe CAD process is taken a stage further and a 3-D solid model is created. The model allows the calculation of tooling and product costings.

Finalise DesignWorking with our customers and the project team the design is finalised and key decisions such as the choice of thermoplastic material are agreed.

PrototypeUtilising verified data (2D or 3D information) Amber Plastics selects from a wide variety of prototyping techniques depending on the need for accuracy and speed. Conventional modelling materials include wood and GRP. Rapid prototyping (RPT) methods include SLA and SLS. The objective is to create a ‘fit and function’ model which provides the reassurance needed to proceed to production tooling.

Once the prototype has been approved, CAD is used to design the mould tool. For complex shapes detailed flow analysis and finite element analysis can be applied to the tool design to ensure the finished product meets the agreed performance criteria.

SLA – Stereo Lithography - SLA is the most common RPT technique, and produces acrylic and epoxy parts. SLA offers almost unlimited geometric possibilities, fine detailing and high accuracy.

SLS – Selective Laser Sintering. SLS offers the advantage of making functional prototype parts in standard thermoplastic materials. SLS is more complex than stereolithography.


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Fabricated model

Wooden model

Ureal model

ToolingGood quality tooling is critical to project success. Amber Plastics works alongside industry leaders such as Persico and Maus to develop high-quality mould tools. For larger and less complex products, sheet

steel is frequently the preferred tooling material. With smaller, more detailed items, machined or cast aluminium is more appropriate. From this stage,

Amber Plastics team will issue you with a project plan every week to ensure you are

fully informed on your project’s progress.

SampleFor each new product, Amber Plastics’ engineers generate an Initial Sample Inspection Report. The ISIR is a detailed review of every aspect of the first sample.

Full Production and Quality Control.

JIT production techniques put the DFM principles in to practice. Kanban systems are used to ‘pull’ your product through the manufacturing process.

Many products, particularly fuel tanks, require testing over and above a visual inspection. Product integrity can be tested using water and air pressure, ultrasound is employed to verify wall thickness, and impact and dimensional checks can also be undertaken.

JIT – ‘Just-in-time’ manufacturing. Works in tandem with DFM to achieve manufactured products with minimum waste of raw materials, time and other resources.

Kanban – An integral part of JIT manufacturing, Kanban uses cards or plastic markers to signal the need for an item, thereby ‘pulling’ production.


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Tool photos provided by Persico S.p.A


Finishing and AssemblyCNC machining is used on many products to add additional features.

Amber Plastics is a market leader in supplying fully assembled products. In the case of fuel tanks this can include fitting caps, filters, gauges and other ancillary elements.

LogisticsWherever possible, Amber Plastics works with you to develop environmentally friendly packing specifications such as the use of returnable stillages. We are a true supply chain partner. Deliveries direct to your production line are often carried out to fit in with your schedule.

Continuous ImprovementOur dedicated project engineering teams continuously seek to refine designs using techniques such as value engineering to help you keep costs under control, and offer on-going advice and ideas on the latest trends in materials and manufacturing techniques.

Annual product reviews keep the customer up to date with product and process developments or changes.


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Wordsworth Holdings plc owns some of the world’s leading and most innovative engineering brands in the construction, commercial vehicle and agricultural sectors including Barford, Fruehauf, and Stanhay.

“Barford prides itself on a long tradition of designing and manufacturing robustly engineered, reliable dumpers.”

www.barforddumpers.com

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Case Study Wordsworth

“Amber Plastics has supplied Barford with hydraulic and diesel tanks for many years.

We call off tanks from Amber on a weekly basis and they are delivered as complete sub-assemblies ready for immediate installation into our range of site dumpers. All the tanks are fully pressure-tested by Amber before despatch.

Barford sets demanding quality and performance standards for all its suppliers. Amber Plastics’ performance has been exemplary, not only in the quality of the finished product but also in their technical support and ‘design and development’ activities.

Over time we have worked together to drive down costs by introducing standard components wherever possible and by value engineering the tank designs to minimise waste.”

John Pritchard Group Purchasing Director Wordsworth Holdings plc


ComplexityA tank is just a funny shaped box, isn’t it?In many cases, designers look to Amber Plastics to maximise the capacity of fuel tanks to ensure the greatest possible range for their vehicles: this can often lead to complex shapes with demanding geometry.

StrengthDurability is a key characteristic demanded of many tanks. By incorporating ribs and cores in a tank design, Amber Plastics is able to create strong tanks which are highly resistant to mechanical damage.

VarietyThe performance characteristics of plastics when in contact with oils, diesel and modern ‘green’ derivatives can vary significantly. Amber Plastics manufactures tanks in a wide variety of materials

including polyethylene, polypropylene and nylon-12. Recent innovations have included the development

of twin walled mouldings incorporating a layer of foamed thermoplastics which greatly enhances a tank’s insulation.

TurnkeyAmber Plastics can satisfy your tank requirements from outline concept to a fully-assembled and tested product delivered direct to your assembly line – just-in-time.

A product category in which Amber Plastics excels is rotationally moulded tanks. Used by many of today’s leading manufacturers of construction plant, caravans and road vehicles, Amber Plastics has almost thirty years experience in the creation of tanks for fuels, hydraulic oils, water and waste.

For a detailed explanation of how tanks are designed and manufactured see our pages on Project Management.

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Case Study: Tanks


How to find us:

We’d like the opportunity to add your product to our

gallery.

Call Amber on 01246 456525

We’re always ready to think

outside this box.

Amber Plastics Ltd Broombank Road, Chesterfield Industrial Estate, Sheepbridge, Chesterfield, Derbyshire S41 9QJGeneral: +44 (0)1246 453544 Sales: +44 (0)1246 456525 Fax: +44 (0)1246 450339Website: www.amberplastics.co.uk Email: [email protected]

Brochure created by Bluejohn Marketing Ltd and Oakleaf Graphics Ltd: 01246-566560.

rotational moulding - bluejohn, marketing · the advantages of rotational moulding ... the mould is...

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