Plastic Injection Molding: A Basic History

Manufacturers who want to take raw plastic and use it to produce a viable product have various processes at their disposal. One of the most common means is plastic injection molding. It takes thermoplastic materials, melts them and then reshapes them into the desired form before cooling them off. Although people who are not in or are new to the industry tend to think of it as a modern invention, the process has a history that dates back to the 19th century.

Early History

Injection molding is a growing concern. Patents first emerged in the United States in 1872. The technique was employed using celluloid. The inventors of the first injection machine were two brothers John Wesley Hyatt (1837-1920) and Isaiah Smith Hyatt ( -1885) created the machine in 1868, perhaps in response to a request by Phelan and Collander, billiard ball manufactures. The company offered a $10,000 prize for someone who could come up with an ivory substitute. J Hyatt did just that.

Although primitive by today’s standards, the machine performed its function, properly and accurately, using a plunger to inject the celluloid into the molds. He and his brother’s patenting of the process and the material was the beginning. They also were to use the material for creating dentures and invent the blow method of plastic molding.

In Germany, during the 1920s, hand-operated machinery more quickly and easily processed thermoplastic materials. The devices were simple and consisted of a lever and clamp to hold a two-piece mold together. The molten plastic once injected into the mold took on the desired shape. The process, still quite slow, was improved somewhat in the 1930s by the addition of hydraulic systems. This took place at the same time the available plastic materials was expanding.

Overall, plastic injection molding remained rather basic until 1946. This was the year James Watson Hendry (-2014) revamped and improved Hyatt’s injection machine introducing auger design to replace the plunger. This same technique is still a basic component of today’s modern plastic injection machines. Hendry went on to improve various aspects of gas-injected molding devices. He helped to launch the reliance of manufactories on plastic molding machinery for the production of components for a variety of devices.

However, the invention of another important component in Germany (Hans Beck of BASF in 1943) and in the United States (William Willert in 1952, patented in 1956) thrust the plastic molding industry further ahead. This was the reciprocating screw. Yet, it did not become a common component of the machinery until over a decade later.

Plastic Injection Molding Today

Today, while essentially the process remains the same – consisting of a heated plastic, a mold and a cooling method, the machinery has developed and continues to develop. Technology is automating and improving quality controls. In this technical age, the once very basic plastic injection molding continues to grow in popularity among many manufacturers.

For more than 50 years, Molded Devices Inc (MDI) has providing superior Plastic Injection Molding and engineering. Their commitment to high quality solutions has given them an enviable reputation in the industry. From the employment of sophisticated and advanced technology to statistical process control to their ability to provide their clients of all sizes with what they want when they want it, MDI continues to flourish. For further information, contact their experienced engineers and sterling customer service online at

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Leah Austin

Meet Leah Austin, the Swiss Army knife of writing, whose love for crafting captivating content knows no bounds. Armed with a magnifying glass for detail and a treasure trove of research skills, Leah has mastered the art of delivering articles and blogs that don't just inform, they enchant. Her journey into the realm of writing started with a curiosity so profound it could rival a cat's obsession with cardboard boxes. From the depths of technology to the peaks of finance, Leah fearlessly navigates diverse subjects, infusing each piece with a fresh perspective and a commitment to accuracy that's tighter than a squirrel guarding its nuts. Fueled by a voracious appetite for knowledge and a burning desire to share it with the world, Leah possesses a superpower: the ability to turn brain-busting concepts into prose so clear even your grandma could understand. Her dedication to quality and knack for spinning a yarn have made her a digital oracle, sought after for wisdom in a sea of clickbait. When she's not hammering away at her keyboard, Leah can be found communing with nature, whipping up culinary concoctions, or disappearing into the folds of a good book. With a lifelong love affair with learning and an unwavering commitment to excellence, Leah Austin continues to dazzle and enlighten through her writing antics.