The Invention of Injection Molding

harkness invention of injection molding

Injection molding is a staple in today’s plastics industry but how did it come to be?

The history of this revolutionary technology dates back to the 1800’s! The idea sprouted in 1861 when Alexander Parkes went public with the discovery of a new material called “Parkesine”. This new material, derived from cellulose, could be heated and molded and it had the ability to retain its shape when cooled. The material did have some down falls such as flammability and cracking, not to mention it was extremely expensive to produce, but it was an amazing discovery that eventually led to the invention of injection molding.

Parkes’ discovery lead to the Hyatt brothers creating the injection molding technique. Billiard ball makers Phelan and Collander made a request to John Wesley Hyatt and he responded by discovering a new material that held its form, called Celluloid. By injecting Celluloid into a mold, John had discovered a new way to make billiard balls. By 1872, John and his brother Isaiah Hyatt patented the injection molding machine.

Although, the first screw injection molding machine wasn’t built until 1946, by James Watson Hendry.  The screw injection machine improved the speed and quality of the plastics injection and introduced more control over what was being produced. This machine was also the first to allow material to be mixed prior to injection which introduced the opportunity to add color and recycled plastics to the mix. The 1940’s were a huge game changer. The industry flourished as production sky rocketed due to World War 2 and its’ demand for inexpensive mass produced products.

The first ever injection molding machine was very different than what we are used to today. The first injection molding machine worked like a large hypodermic needle. A plunger injected melted plastic through a heated cylinder and into a two-part mold.

Injection molding has grown from producing combs and buttons to major consumer, industrial, medical, and aerospace products. It’s safe to say that injection molding has had a huge impact on the world and has been involved in our lives and our great grandparents lives more than you might have imagined.

The wonderful world of plastics just keeps on giving, we’re always excited to watch our industry grow and evolve. We can’t wait to see what the future brings us.


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