Injection moulding and die cast moulding have both been with us for a long time and there are many arguments for and against each process. As a moulding method, injection moulding has many fans and has been refined to the point of perfection. However, it does have its own limitations that can be addressed by other methods. Below, we discuss both processes and their pros and cons.

Injection moulding is creates finished parts, mainly consisting of a resin-type material, by forcing molten plastic into a mould, which is then left to cool and harden. The parts produced can be virtually any size, although it is most commonly used for producing large quantities of mass produced items such as plastic bottles or parts for the automotive industry, amongst many others.

Injection moulding was born from the die cast method which used metal in a similar way to plastic to mass produce items at a low cost. The metals used were mostly zinc, aluminium, magnesium, and brass, with just about any part able to be cast from almost any metal. The most common and popular metals used for die casting, due to its lightness and malleability is aluminium. Dies used in the casting process are stronger than the moulds used in the permanent die process so as to withstand the force of the injections into them. This high-pressure process produces a durable, high strength product that is often used for mechanical engineering purposes such as automotive engines and other high stress and temperature functions.

Die casting, for its many benefits, does have many limitations and these include limited part size, high initial tooling costs and a fluctuating cost of raw materials that can add substantially to the cost of production. Injection moulding, on the other hand, produces parts that are light weight, impact and corrosion resistant at a very low cost, with very little change in the cost of the raw materials.

The benefits of injection moulding have gained in popularity over the years because of the advantages it offers over traditional die casting manufacturing methods. Namely, the immense amount and variety of low cost, affordable products that are made from plastics today are virtually limitless. There are also minimal finishing requirements. This being the case, it is going to be dependent on the engineer and customer to decide which type is more suitable for their particular requirements before they commence manufacture, notwithstanding the cost, quality and use of the final part.