When thermoplastic and thermosetting plastic materials are produced, this process is referred to as the plastic injection molding process. In order to create these products, material must be heated, mixed, and placed inside of a mold. When the mold cools, the material is extruded resulting in specific objects.

While plastic may seem like a relatively new invention, the first plastic object was actually created in 1851. A British inventor by the name of Alexander Parkes created a material that was then called Parkesine. Even though Parkesine proved to be both durable and innovative, it was also highly flammable. Thus, Parkes' invention did not enjoy a long lifespan. In 1868, an American inventor by the name of John Wesley Hyatt developed a similar product that he dubbed celluloid. After joining forces with his brother, Hyatt created the first injection molding machine in 1872.

This injection machine revolutionized the way that objects were made. Items such as buttons, hair combs, and collar stays were a result of the Hyatt brothers' injection molding machine. When the 1940s rolled around, the plastic injection molding process became an essential part of the manufacturing business.

Consumers were demanding inexpensive products. In turn, these products also had to be inexpensive to produce, causing plastic items to drastically grow in popularity. The plastic injection molding process changed as a whole when the first screw injection machine was created in 1946. James Watson Hendry's screw injection machine allowed manufacturers to have more control over plastic injections. The screw injection machine proved to be such an advancement that many of the machines used today still function in the same manner. Once it was observed that the plastic blow molding process could be entirely precise, plastic replaced other materials such as steel and ceramic.

Today, nearly every plastic item -- milk caps, car dashboards, combs, phones -- is created through the plastic injection molding process. In many different ways, plastic has replaced most other materials. Due to its flexibility, versatility, and reliability, plastic objects are popular around the globe.

The plastic injection molding process makes it possible for manufacturers to create thousands of products at once. In addition, labor costs are relatively low within the plastic industry, and parts can be refined following the injection process. The main drawback to injection molding equipment is that this equipment is often expensive to maintain and purchase. Still, plastic proves to be one of the most widely produced materials in the world.

The first man-made plastic was invented in Britain in 1851 by Alexander Parkes. He publicly demonstrated it at the 1862 International Exhibition in London, calling the material he produced "Parkesine." Derived from cellulose, Parkesine could be heated, molded, and retain its shape when cooled. It was, however, expensive to produce, prone to cracking, and highly flammable.

In 1868, American inventor John Wesley Hyatt developed a plastic material he named Celluloid, improving on Parkes' invention so that it could be processed into finished form. Together with his brother Isaiah, Hyatt patented the first plastic injection molding machine in 1872. This machine was relatively simple compared to machines in use today. It worked like a large hypodermic needle, using a plunger to inject plastic through a heated cylinder into a mold. The industry progressed slowly over the years, producing products such as collar stays, buttons, and hair combs.

The industry expanded rapidly in the 1940s because World War II created a huge demand for inexpensive, mass-produced products. In 1946, American inventor James Watson Hendry built the first screw injection molding machine, which allowed much more precise control over the speed of injection and the quality of articles produced. This machine also allowed material to be mixed before injection, so that colored or recycled plastic could be added to virgin material and mixed thoroughly before being injected. Today screw injection machines account for the vast majority of all injection machines. In the 1970s, Hendry went on to develop the first gas-assisted injection molding process, which permitted the production of complex, hollow articles that cooled quickly. This greatly improved design flexibility as well as the strength and finish of manufactured parts while reducing production time, cost, weight and waste.

The plastic injection molding industry has evolved over the years from producing combs and buttons to producing a vast array of products for many industries including automotive, medical, aerospace, consumer products, toys, plumbing, packaging, and construction.