When we think of the great inventions of modern times — like automobiles, airplanes, rockets, and computers – we tend to focus on the final product. However, the manufacturing processes devised to make those revolutionary products are key to their success.
Plastic injection molding is responsible for the lightweight, durable components that make many of the things we enjoy today affordable. It is not a stretch to say that this versatile process paved the way for many modern inventions and designs. This article offers a brief history of plastic injection molding. And spoiler alert – it’s been around longer than you think.
Who invented plastic injection molding?
The credit for creating plastic injection molding goes to John and Isaiah Hyatt, two American brothers. In 1863, John was intrigued by the $10,000 prize offered by a New York billiards company to whoever could create a substitute for the ivory used in billiard balls.
The Hyatt brothers began experimenting with different compositions, eventually settling on a plastic material made by mixing nitrocellulose (a flammable nitrate of wood or cotton cellulose), camphor (the waxy resin from Asian camphor trees), and alcohol and pressing the heated mixture into a mold.
By 1872, the Hyatt brothers patented the first injection molding machine. It contained a basic plunger that injected the plastic mixture through a heated cylinder into the mold.
Their machine device led to the manufacture of buttons, collar stays, combs, and other everyday items made from celluloid.
German scientists later made the process less flammable by developing a soluble form of cellulose acetate. In years before World War II, some of the thermoplastics we commonly use today, such as polystyrene and polyvinyl chloride (PVC), were developed.
In 1946, another American, James Watson Hendry, invented the first screw injection molding machine with an auger that replaced the Hyatt plunger.
The auger inside the cylinder mixes the injection material before injecting it into the mold.
Most of today’s injection molding machines utilize a version of this same technique.
Watson also included gas in the manufacturing process, which enabled him to create plastic products that were long, hollow, and complex in design.
The industrial boom that followed World War II prompted a demand for affordable materials for the mass production of parts. This demand was also due to the shortages of rubber, metal, and other resources used to manufacture tanks, weapons, and aircraft during the war.
Plastic injection molding emerged as a reliable and cost-effective way to manufacture large volumes of parts for many growing industries.
By the 1970s, plastic production overtook steel production, and in the 1990s, lightweight aluminum molds offered a cost-effective yet durable substitute for steel tooling for some manufacturers.
How is plastic injection molding evolving?
Although plastic injection molding has been around for about 150 years, the process constantly responds to the changes new technology brings.
The plastic injection molding process of today offers a range of plastics that represent different melting points and compositions and provide unique benefits for specific applications. Modern plastics can be combined with other materials to provide additional strength, textures, and coloring.
Additionally, computer-assisted manufacturing (CAM) enables the creation of more intricate molds than were previously possible. Other breakthroughs in automated systems, like programmable setups and sensors, are reducing costs and streamlining the manufacturing process.
Here are some trends we are closely following in the industry:
- Concerns about climate change and its effect on the environment are driving the demand for more eco-friendly molding materials, including reclaimed, recycled, and renewable plastics.
- Micro-injection molding, a process that uses the technique of injection molding on a microscopic level, is emerging as an area of interest in medical device manufacturing. This technology could lead to life-saving medical procedures that use less-invasive tools and methods.
- Some manufacturers are testing plant-based materials, such as corn- and flax-based plastics, as an alternative to thermoplastics.
At ASPM, we have a proud history of quality tooling and plastic injection molding. We offer complete support from product design to mold maintenance and repair. Our trained and experienced staff is ready to answer questions about how plastic injection molding can serve your business.
When we think of the great inventions of modern times — like automobiles, airplanes, rockets, and computers – we tend to focus on the final product. However, the manufacturing processes devised to make those revolutionary products are key to their success.
Plastic injection molding is responsible for the lightweight, durable components that make many of the things we enjoy today affordable. It is not a stretch to say that this versatile process paved the way for many modern inventions and designs. This article offers a brief history of plastic injection molding. And spoiler alert – it’s been around longer than you think.
