Plastic are synthetic compounds that can be molded into different forms and shape. To manufacture plastics into different shape and size, we need some methods for doing it. Here are some of the common plastic manufacturing processes used in industry.
- Injection Moulding
- Extrusion Moulding
- Blow Moulding
- Rotational Moulding
Below we have briefed moulding processes with some YouTube videos for your reference.
Injection moulding is the most common processes and used widely for making plastic parts. Injection moulding serves in mass production of parts. In this process molten material is injected into the mould though nozzle into the die and allowed to cool.
Image Source: www.xcentricmold.com
Image Source: www.intechopen.com
As we can see in the above photo, there are four phases in injection moulding; namely Plastifcation, Injection, Packing & Ejection.
Plasticfication phase: Plastic granules are heated to form molten material into the hopper.
Injection phase: Molten plastic is injected through the screw feeder into the mould.
Packing/cooling phase: Molten material is held for certain time to help the plastic cool under pressure. This process maintains the pressure inside the mould and avoid defects in plastic part.
Ejection phase: The finished plastic part is ejected from the die, releasing the pressure.
YouTube Source: tronicarts - Multimedia-Agentur
Extrusion Moulding is a process similar to injection moulding. Unlike injection moulding, the product manufactured is continuous. Instead of filling the mould, the die is fixed onto the nozzle, and the product is passed through the cooling chamber through conveyor. General shapes in extrusion moulding are C, L, Square or rectangle.
image source: sciencing.com
Blow Moulding is used to manufacture hollow parts, best example is a bottle. In this process, molten plastic is allowed to flow into mould which is split into two halves. Upon reaching the desired length, the mould closes, sealing one end and air is blown into the die. The plastic material elongates and acquires shape of mould. After cooling, the finished part is ejected.
image source: custompartnet.com
YouTube Source: PolytekMX
Rotational Moulding is a process in which hollow parts are manufactured, but by rotating them inside the mould. Rotational Moulding is a time consuming process, but large size parts are mostly made with this process.
YouTube Source: Gordon Bain
YouTube Source: Sunil Raithatha