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Plastic Injection Moulding Process

As the primary process for manufacturing plastic parts, injection moulding is a fast method to large scale production of identical parts from high precision engineering components to disposable consumer goods.


There are a many different manufacturing processes, all have their individual benefits and require specific skills and knowledge to execute. The injection moulding process is one of the most widely used and counts for a significant proportion of all plastic products.



The injection moulding process consists of six fundamental steps which include; clamping, injection, dwelling, cooling, moulding opening and ejection. In summary, granules of plastic material are placed into the moulding machine via a variety of conveying systems. Through the application of pressure, the melted plastic is injected through a runner system into the cavity. The moulding tool then provides the cavity which defines the shape of the moulded part. The material is then cooled and finally ejected from the mould as a finished part. The cycle is then repeated to produce an identical part.



There are a variety of advantages which attribute injection moulding to being the primary process for manufacturing plastic parts. It’s quick, producing large volumes per hour and its typical cycle can be as short as 15 seconds. There is great flexibility in terms of material choice and colour. The process offers low labour costs, as parts can be made ready with little or no assembly. When it comes to designing for plastic moulding, there are guidelines (see our Design Guidelines Section) but ultimately you can be very flexible with the design of your parts. Another advantage to using injection moulding is it produces little waste, as often plastic waste can be recycled. 

To read our blog about the advantages of injection moulding, follow the link. 



There are a few disadvantages that must be considered. The first is that the initial tool cost is high when looking to get plastics moulded. Finally, it is worth noting that there are design restrictions for plastic moulding, but by working with an experienced design team you should be able to overcome such issues. 


people product partnership 

CJ Tool & Mouldings offer a full range of injection moulding services, with a customer centred and personal approach. We pride ourselves on delivering quality products to meet customer needs, with a strong focus on quality service and value. CJ Tool & Mouldings are a dynamic and growing business through people product partnership.  



Get in touch today and talk to the specialists, click here.

Our team will be more than happy to help, advise and quote for your requirements.

Looking for more information? Check out our blog, News & Views for useful articles, tips and tricks on plastic injection moulding.