Plastic injection molding is the most common manufacturing method used to produce the plastic items you use on a daily basis. Although new technologies like 3D printing and advanced recycling techniques have changed the industry in recent years, the injection molding process remains largely unchanged in many key ways. This process gives us everything from pharmaceutical bottles to food packaging containers and children’s action figures.
But few people realize that plastic injection molding was actually invented as a way to save the African elephant population from poaching.
Billiards, Elephants, and the Invention of Plastic Injection Molding Products
According to Bill Hammack with the University of Illinois, injection molding was invented in the 19th century because people needed billiards balls. At the time, people used pool balls made from ivory, which led to the decimation of the African elephant population. A gentleman’s sport indeed.
A billiards manufacturer offered a $10,000 prize — about $3 million in 2015 — for a viable alternative to ivory billiards balls. Eventually, a pair of men from Albany, New York submitted a design for a machine that could create billiards balls from celluloid, an early form of plastic.
Their machine was the basis of the plastic injection molding manufacturers we depend on today.
How Does It Work?
Although production processes vary, injection molding machines generally have three main sections:
- Injection Unit
Small plastic pellets are inserted into the injection unit. A large metal screw moves the pellets forward, while a heating source turns these pellets into molten plastic. When enough molten plastic is ready, the liquid is injected into a hollow mold. A clamp presses the plastic into the mold, and the finished product is ejected.
It’s not nearly as simple as it sounds. By using complex, custom molds, plastic suppliers can create a huge variety of plastic products. According to one 2012 market study, plastics manufacturers ship an estimated $373 billion in goods annually. Continue reading here.