Everything You Ever Wanted to Know About Injection Moulding

Who can remember The Graduate movie starring Dustin Hoffman? It's one of our favourite films here at Austraplas because the main character is told "there's a great future in plastics". Nearly fifty years since its release, that prediction is now a reality. Plastic is being used to make products lighter and stronger in ever increasing complex shapes. From aeronautics to the automotive industry, plastic can be found everywhere. There are even plastic bridges in Germany, the USA and Scotland. If it's metal, then it can usually be made into plastic.

What Is Injection Moulding?

Injection moulding is a manufacturing process which can produce lots of parts in large volumes. It's ideal if you want to mass produce thousands or even millions of plastic items which are strong and highly durable. Joints, brackets, and plastic casings for power tools are usually formed through injection moulding.

Just like the name suggests, the process involves injecting molten plastic granules into a metal mould.

There are five stages of injection moulding:

  • Clamping - this is required to keep the mould closed during the injection process, which is the primary purpose of the clamp unit. The moving and fixed platens of the machine hold the mould tool together.
  • Injection - this is the stage when molten plastic is injected under pressure into the mould.
  • Dwelling - this is the term used to ensure the plastic is injected into the mould pressure, so that all areas are filled.
  • Cooling - this is when the plastic parts cool, before being released.
  • Opening - this is when the moving platens pull away from the fixed platen to separate the mould tool.
  • Ejection - this is the process employed to eject the moulding from the injection mould tool.

What Are the Benefits?

The moulds are subjected to extremely high pressure so detailed and intricate parts can be created. Once the moulds have been designed to the client's specification and the presses pre-programmed, the process is relatively quick. Turnaround time usually depends on the amount of plastic within the mould. Injection moulding is an automated process and cost effective. Parts released are the finished product. The process is environmentally friendly and any scrap plastic can be reground and reused.

How Does It Differ from Blow Moulding?

Blow moulding is a manufacturing process used to create hollow plastic parts. The raw material of small pellets or granules are melted and formed into a hollow tube called a parison. There are various ways of forming the parison which make up the different types of blow moulding (extrusion, injection, and injection stretch). The parison is clamped between two mould halves and inflated by pressurised air which pushes the plastic out to match the mould. When the plastic has cooled, and hardened the mould is opened and the item taken out. Blow moulding is ideal for detergent containers and plastic bottles.

Austraplas has been established just over twenty years. We have a state of the art, custom designed manufacturing plant in Cockburn and provide high quality service at competitive prices. If you'd like to find out more, call one of our team today.

Contact Us

AUSTRAPLAS
6 Maclaglan Street
Cockburn Central
WA 6164
P: (08) 9417 4545
F: (08) 9417 2140
E: sales@austraplas.com.au
www.austraplas.com.au

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