Injection Moulding Process… What is it?
You’ve heard about fabricating plastics. You’ve seen plastics of all kinds. You’ve experienced the toughness and softness of almost all types of plastics.
You’ve known about the benefits of having plastics and the negative impacts of plastic materials due to negligence.
So how do they do it?
Plastics are either malleable or rigid enough to be someone’s chair.
The process of moulding these plastic materials is actually called Plastic Injection Moulding Process
Injection Moulding Process Explained
Plastic Injection Moulding is the common method of producing parts out of plastic material.
Examples include toys, chairs, consumer electronic cases, disposable cutleries, and also, Lego parts.
With this process, we can mass-produce any high quality plastic material with accuracy in just a short period of time.
The First Injection Moulding Machine
Injection moulding was actually invented to solve a problem for billiards.
Billiard balls were composed of ivory that is being harvested from the tusks of African Elephants in the 19th century.
And this devastated the Elephant population, so billiards manufacturer offered a $10,000 prize for a replacement for ivory.
John W. Hyatt was the one who developed one of the first plastics celluloid to create billiard balls.
Hyatt patented an apparatus for moulding products from celluloid. And his apparatus was the birth of plastic injection moulding.
Injection Moulding Process is Not that Simple
In principle, injection moulding is simple:
Melt plastic, inject it into a mould, let it cool, and then out pops the plastic product.
But in reality, injection moulding is an intricate and complex process.
Injection Moulding machine is composed of three parts:
The injection unit, the mould, and the clamp.
STEP 1: Injection Moulding Process–Plastic Granules
All injection mould objects start with plastic granules or pellets, which are a few millimeters in diameter. They can be mixed with small amount of pigment called colourant, or with up to 15% recycled material, and fed into the injection moulding machine.
These plastic pellets in the hopper feed into the barrel of the injection unit.
STEP 2: Injection Moulding Process–Reciprocating screw and Heater Bands
Inside the barrel, a screw transports the granules forward. The reciprocating screw is the most important contribution that revolutionised the plastics industry in the 20th century.
Heater bands wrapped around the barrel warm up the plastic pellets. As the pellets were moved forward by the screw, they gradually melt, and they’re entirely molten by the time they reach the front of the barrel.
STEP 3: Injection Moulding Process–Inject into a Mould
Once enough molten plastic is in front of the screw, it rams forward like the plunger of a syringe.
In a matter of seconds, the screw injects the molten plastic into the empty part of the mould called the cavity image. The plastic solidifies in under a minute.
STEP 4: Injection Moulding Process–Eject Finished Plastic Product
The mould opens and the plastic part is ejected. The mould then closes, and the process repeats.
So that’s how plastic injection moulding process works.
Do you have something in mind that could use some help from plastic injection moulding machines?