As specialists in the manufacture of rubber components, we have many years of experience in producing and supplying bespoke rubber mouldings for use in a vast range of different industries. With our in-house capability, we can choose from a number of different process in order to achieve the ideal results to suit customer requirements, including compression moulding, transfer moulding and rubber injection moulding.

All rubber moulding processes share some principles, for example, all moulded parts start as raw rubber compound, before being subjected to heat and formed into the required shape. Compared to compression moulding, injection moulding is a more complicated process.

The injection moulding process

Rather than simply placing rubber material into a heated mould as is the case in the compression moulding process, raw rubber pellets are instead fed through a heated barrel and pushed through an injection nozzle as a molten liquid until the moulding cavities are full. Similarly to other moulding processes, the rubber material is then subjected to considerable pressure to form the intended shape. The parts can then be cooled and removed from the mould.

The key advantages of injection moulding

Injection moulding is a commonly used process as it is ideally suited to producing small and large parts, as well as very intricate mouldings. Some of the biggest benefits of this process include:

• Parts can be produced with much quicker cycle times than through other moulding processes.
• There is little rubber waste as only the required amount of material is injected into the mould.
• The raw rubber is preheated and molten before it is fed into the cavities of the mould, so the viscosity of the material is decreased and it flows more effectively to fill the mould evenly.
• This process produces very consistent results, so it is very beneficial for creating reliable parts.
• There is rarely a need for finishing once the rubber mouldings are removed from the mould cavities – there’s no need to trim down edges or remove excess material.
• Injection moulding can be an automated process, so parts can be mass-produced very effectively.

Potential downsides of the process

As is the case with practically any manufacturing process, there are some situations for which injection moulding isn’t ideal. When compared with some other moulding processes, the up-front costs can be quite high as a result of tooling requirements. If moulding requirements are very high in volume, it’s essential to get the design right before starting full production. To achieve this, designing, prototyping and the refining of moulding tools is carried out before mass-production can commence.

If customer requirements are to keep costs as low as possible and to meet fast lead times, then injection moulding is not usually the best suited process, however, for complex designs and uniform quality, it is a technology well worth investing in.

For more information on rubber moulding processes, or for advice on the best materials and technologies for your bespoke rubber mouldings requirements, please contact our team on +44 (0)121 773 8494 or email [email protected].