Injection Mould Tool

Rutland Plastics has been in the plastics injection moulding business for over 60 years and the injection mould tool is the key component in the injection moulding process. We have learnt a thing or two about injection mould tools over the years and we endeavour to share this knowledge to help optimise the injection moulding process.

In simple terms, the mould tool provides a passageway for molten plastic to travel from the injection cylinder (barrel) to the mould cavity. It allows the air, which would be trapped inside when the mould closes, to escape. If the air is not vented then the moulded component would contain voids (air bubbles) and have a poor surface finish. The mould tool also cools the moulding until it sets. The temperature of the mould is controlled because it is important that the moulding cools at the correct rate to avoid distortion and stress. In most systems water circulates through channels drilled through the mould, similar to a car engine cooling system. The finished moulding is pushed from the mould by means of ejectors pins.

There are many companies that make industrial tools for plastic manufacture and the GTMA is a UK-based trade association representing leading companies in precision engineering, rapid product development, toolmaking, tooling technologies, metrology and other critical manufacturing related products and services. The GTMA’s mission is to promote the individual expertise of its members and the collective engineering resource represented by the association and is a valuable resource for buyers forming and reinforcing manufacturing supply chains. Rutland Plastics are proud members of The GTMA.

At Rutland Plastics, we are able to specify and manufacture the most appropriate mould tools for your requirements, whether it is low volume or pre-production tooling or even high speed, multi-cavity stack tools. We have our own in-house toolroom that results in quicker modifications, if these are required, and less downtime in the event of a mould requiring repair. A reputable injection moulder should be prepared to offer some guarantees for the moulds they manufacture. Of course, nothing lasts forever and a mould tool has a finite life but an experienced injection moulder can indicate an anticipated life for a particular mould.

To find out more about mould tools and plastic injection moulding in general we have created our Knowledge Bank on our website which aims to help and guide designers and engineers through the plastic injection moulding process.

Free design guide

Rutland Plastics has produced a free Design Guide to help you with all aspects of designing for plastic injection moulding.
Download free guide


We can provide advice and quotes on anything from a simple sketch to a 3D computer model. Most drawing formats can be handled although we find STEP, Parasolid and DXF translate most successfully.