Plastic Injection Moulding Manufacturer UK

Your products in Plastic…

Pentagon Plastics is a pro-active plastic injection moulding business based in Horsham, West Sussex, United Kingdom.  As a family run business that has enjoyed well over 40 years of trading, we provide a wealth of knowledge and skill to our diverse customer base.  Services offered here at Pentagon Plastics include design assistance, development, toolmaking and injection moulding.

As a UK plastic manufacturer of bespoke thermoplastic products, our experience is hugely diverse. We provide both mould tooling solutions and repeat production of injection moulded components across a wide range of industries; from medical and aerospace to construction and security.

To find out how Pentagon Plastics can help your business, no matter how big or small, call us today on 01403 264397.

Our Services

design assistance icon

Design Assistance

We are pleased to be able to offer design assistance to both new and existing customers, assisting with material selection for your product through to guidance on tooling and keeping a handle on those all-important costs. Being involved from the early stages of a product allows us to gain a greater product knowledge which helps us support you and your production requirements in the future.



The development stage of a product is crucial in its overall success and ease of manufacture. We are able to provide assistance in many elements of the development phase allowing you to draw on our knowledge and expertise. Prototyping can be provided both in-house and as a managed service with a view to taking the project on to the injection moulding stage. Meanwhile, our modular insert tooling option is a step further to allow you to trial various materials and check key features of your product.

Tool Making

Tool Making

Our offering of a full on-site Toolroom to support the moulding process allows ease of manufacture as services are carried out here on site. Our toolmakers have a wealth of experience, giving you confidence that the tooling we manufacture will be of excellent quality and fit for purpose. By keeping a strict tool maintenance programme in place between production runs, we ensure your tool will always be ready for the next run.

Injection Moulding

Plastic Injection Moulding

Our mould shop is home to nine moulding machines ranging in size from 22-280 tonne and is run by our highly skilled setters. With a rich history in producing bespoke technical mouldings to various industries, we are able to process a wide range of thermoplastic materials, including high engineering grades. The machines are supported with a monitoring system and dedicated patrol checks throughout the run.

Post Moulding

Post Moulding

We also provide a service beyond the injection moulding stage to produce a finished component which meets your requirements. This may include the fitting of inserts, drilling, milling, trimming or light assembly. We are also able to provide a small range of out-sourced post moulding operations as a managed service when required.

What is Plastic Injection Moulding?

Injection Moulding is the process of injecting hot liquid plastic in to a mould tool to produce a quantity of plastic components to a customer’s specific design. We are able to cater for very low batch volume production runs sometimes into single figures through to the 100,000 range, utilising a range of in-house tooling solutions. Find out more about the process.

How we can help…

From design assistance at an early stage through to repeat production of your component including development options and complete manufacture of your mould tool, you will benefit from a full in house service. Call us today on 01403 264397 or email for more information.