A Brief History of Plastic Injection Molding Since the 1880s

Plastic injection molding is the most standardised process to manufacture plastic products. Itis usedfor the mass production of plastic parts. It produces low scrap rates and helps a business maintain consistency in product design.

Injection moulding involves the following items:

  • Raw plastic; most commonly, thermoplastic.
  • Injection moulding
  • Mould.

The injection moulding machine melts hardplastic and injects it into amould. It then cools this plastic and solidifies it to make the final product.

History

The conception of injection moulding dates back to 1868. John Wesley Hyatt, an American inventor, devised a method to manufacture billiard balls, upon receiving a request from Phelan and Collander.

He found a method to manufacture these balls with celluloid, which at that timewere made from ivory. Hyatt acquired a patent from England’s Alexander Parkes, who invented Parkesine, the first human-made plastic.

Hyatt began experimenting with this material, and eventually became the first person in history to use plastic moulding.

He patented this machine in 1872 along with his brother Isaiah. It used aplunger that injected plastic into moulds with the help of a heated cylinder. Although undeveloped at that time, this machine conceived some of the most widely used plastic products like hair combs, buttons, collar stays, etc.

Abreakthrough

A significant development to these machines came in the 1920s in Germany. Numerous hand-operated moulding machines were invented to manufacture products with thermoplastic.

This plastic injection moldingmachine used a simple lever that secured a two-piece mould jointly. Then, molten plastic was injected into the same for manufacturing products.

Although this process was a breakthrough, it did not find much application owing to lack of sufficient pressure from hands. Later, these machines used pneumatic cylinders to hold the mould together, which did not help it at all.

Introduction of hydraulic machines

In the 1930s, these machines saw an improvement with the addition of hydraulic systems. This changed the scenario a bit and produced numerous plastic products.

Arevolution

It was in 1946 when James Watson Hendry, another American inventor revolutionised the injection moulding machine. He invented the screw-injection machine for addressing the growing demands of plastic products with the onset of World War II.A majority of these machines is based on this design now.

His machine enabled users to mix recycled or coloured material with the raw material before injection. It also gave more power to operators for adjusting the quality and speed of materialsbeing injected.

Today’s plastic injection molding machines are some of the most efficient ones that reduce operating costs and increase revenue.