When is Injection Moulding Used?
Injection moulding is used to make a range of widely used products, including common plastic items like bottle tops as well as remote control casings, syringes and more. It is also commonly used for manufacturing larger items such as car body panels.
Injection moulding is mainly used where there is a need to manufacture many thousands or millions of identical parts from a mould.
Types
There are many different injection moulding process variations, including:
l Cube moulding
l Die casting
l Gas-assisted injection moulding
l Liquid silicone rubber injection moulding
l Metal injection moulding
l Micro injection moulding
l Reaction injection moulding
l Thin-wall injection moulding
Materials Used
Injection moulding can be performed with a variety of different materials including metals, glass, elastomers, confections and, most commonly, thermoplastic and thermosetting polymers.
Materials can be combined to deliver different properties and effects for the finished parts.
Advantages
The main advantage of injection moulding is being able to scale up production to produce a large number of parts. Once the initial costs of the design and the moulds have been covered, the price of manufacturing is very low. The cost of production drops as more parts are produced.
Injection moulding also produces minimal wastage when compared to traditional manufacturing processes like CNC machining, which cuts away excess materials. Despite this, injection moulding does produce some waste, mainly from the sprue, the runners, the gate locations, and any overflow material that leaks out of the part cavity (also called ‘flash’).
The final advantage of injection moulding is that it allows for the production of many identical parts, which allows for part reliability and consistency in high volume production.
Disadvantages
While injection moulding has its advantages, there are also a number of disadvantages with the process.
Up-front costs can be high for injection moulding, particularly with regard to tooling. Before you can produce any parts, a prototype part needs to be created. Once this has been completed, a prototype mould tool needs to be created and tested. This all takes time and money to complete and can be a costly process.
Injection moulding is also not ideal for producing large parts as a single piece. This is because of the size limitations of injection mould machines and the mould tools. Items that are too large for an injection moulding machine’s capability need to be created as multiple parts and joined together later.
The final disadvantage is that large undercuts require experienced design to avoid and can add even more expense to your project.