Structural Foam

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Methods of Producing Structural Foam The Low Pressure Process To achieve consistent quality mouldings, it is recommended to use dedicated special purpose injection moulding machines. The machines introduce a gas into the melted plastic which when injected into the closed mould tool subsequently foams the plastic material of the component being produced. Conventional Moulding Machines Another widely used method is the use of standard injection moulding machines with added "blowing agents" incorporated into the material. Using dry chemical blowing agents mixed in with the granules of plastic, the plastic is melted in the barrel of the machine. A measured charge is injected into the mould tool. The heat of the melted plastic causes the blowing agent to react, which forms a gas, which in turn foams the plastic.

Structural Foam Products

Typical Mouldings Produced
The use of the more controlled Low Pressure Process enables larger mouldings to be produced. Almost all thermoplastic materials can be foamed and wall sections at 5 -- 15 mm, are thicker than compact (normal) injection mouldings. Limited only by the size of moulding machines, mouldings of up to 40 kgs and in excess of one meter have been produced.

The nature of the process leaves a rough streaky surface finish on the surface of mouldings. If this is not acceptable, then a subsequent filling and painting operation is applied. Often this painted surface is of a textured type thus minimizing any irregularities in the moulded surface.

Mould Tools
With the low cavity fill pressures the mould tools can be made in lighter grade materials, Cast Aluminium and Cast Steel. As such the costs are cheaper than with normal injection moulding.

When Structural Foam mouldings are made using Conventional Moulding Machines, invariably the mouldings are for engineering applications. In both processes, the foaming action within the material demands that the material is fed into the mould tools quickly and as such large feed gates are utilized and high injection speeds are necessary.

Whilst the process has lower cavity fill pressures than conventional injection moulding, if the mouldings are being made in conventional machines, then the tools are often constructed in a more robust manner to take into account the possibility of the higher machine clamp pressures being used. 

About Hallam Plastics

As the UK’s first and foremost Structural Foam Moulder, Hallam can demonstrate an enviable track record for over 40 years, providing creative thermoplastic solutions to some of the biggest players in a wide range of industrial sectors.

Uniquely, Hallam can offer 4 separate processes under one roof, ensuring impartial advice as to the best solution for your requirements, as well as facilitating supplier base reduction for those clients currently sourcing products from a number of providers.

Attention to detail, clear understanding and good communication form the basis of our Project Management to ensure that projects are delivered on time, in budget, and using the most suitable and cost effective process. As part of the project management package, the most suitable toolmaker, material supplier and, if necessary, external designer, will be selected from our preferred supplier list, to ensure early supplier involvement in every project thus reducing the risk

Hallam Plastics offer the following services: Structural Foam Moulding Injection Moulding Finishing Vacuum Forming   Underpinning all they do is BSI accreditation, Hallam has been involved since 1988, currently working to ISO9001:2008 Quality, Ethical and Environmental considerations drive the business to ensure they will be supplying the right products for the next 40+ years. Email: enquiries@hallamplastics.co.uk    |   Web: www.hallamplastics.co.uk

We are grateful to Balmoral for their assistance in the preparation of this processes page. For more information click here. Alternatively enquiries@hallamplastics.co.uk directly.