The Emergence of Injection Molding in Plastic Industry
3 min readTo those less familiar, plastic Injection molding may be defined as a manufacturing process for creating products from plastic materials. The plastic is fed into a heated barrel, mixed, and forced into a mold cavity where it loses the heat and solidifies to the configuration of the mold cavity.
Plastic injection molding industry has had a fascinating history. Plastic material was invented in Britain in 1861 by Alexander Parkes and he called the material as Parkesine. People found Parkesine to be extremely useful that it could be heated, molded, and made to retain its shape when cooled. In 1868, American inventor John Wesley Hyatt developed a plastic material he called Celluloid that was an improvement over Parkesine 'as it could be processed into finished form.
Together with his brother Isaiah, Hyatt patented the first machine in 1872. This machine was however far too simplistic compared to the machines widely used today. The present day machines consist of a material hopper, an injection ram or screw-type plunger, and a heating unit. Also, some advanced machines have built-in sampling and approval process for stringent quality control.
The plastic injection molding industry began to boom in the 1940s as the World War created a demand for inexpensive, mass-produced products. Six years hence, American inventor James Watson Hendry constructed the first screw injection machine, which provided greater control over the speed of injection and the quality of articles produced.
During the ensuing decades, the industry has evolved and started producing a wide range of plastic goods ranging from combs and buttons to an array of technological products for several industries including automotive, medical, aerospace, consumer products, toys etc. Though there are several different methods used in the manufacture of plastic goods, injection molding is the most popular.
Plastic is durable, lightweight and unlike metals, plastic is resistant to corrosion and wear and tear. Some striking advantages of this technique are high production capability, repeatable high tolerances, low labor costs, minimum scrap losses, and hardly any need to finish parts after molding. Of course, this technique has its own share of demerits – the process entails high investment in equipment, potentially high operational costs, and the need to design moldable parts.
However, the steadily increasing demand for plastic products has led to the rise of the plastic molding industry. Today, you would find the use of plastic from products of daily use to those used in critical industry sectors like aviation and building construction – amongst others.
Injection molding is the most common method of plastic part manufacturing. It is ideal for mass producing of the same product. The demands for plastic products are growing at a rapid pace and, today we need machines in almost all industrial sectors.
Earlier, the machines were manually and automatically operated but now the machines can be operated in a computerized way. While the earlier versions are known just as plastic injection machines, the latter is called as CNC plastic machine. CNC plastic machine has succeeded in solving some of the problems associated with conventional molding processes.
