The method of plastic injection moulding begins with using a raw material polymer, such as Polystyrene, Polypropylene, ABS or Nylon. There are many more polymers but these are the most common. The polymer can be coloured by adding Master Batch to match any colour desired.
The machinery varies in size from very small machines with clamp forces from 1 tonne, this would be for very small injection mouldings weighing a few grams, up to machines with a clamp force of 3000 tonnes plus, for boats and other large injection mouldings.
This is a 600 tonne machine producing a chair shell. The mould inside the machine comprises of two halves, one half male and the other female. When the machine closes this enables molten plastic to inject into the mould and the cycle time also allows the moulding to cool. Inside the tool are water circuits to reduce the material temperature from about 200 degrees C to about 60 degrees C. When the mould opens the product is then ejected and a robot will then lift the moulding onto a conveyor belt.
Settings, temperatures and timings are very important factors in the process. BSA has an excellent quality control system, where production is checked every two hours.
The product can then be packed and despatched to the customer