The Past, Present and Future of Injection Molding

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Plastic injection molding is a fundamental manufacturing process capable of producing a variety of components and pieces – from intricate parts to large sections or panels.

While plastic injection molding has evolved over time – due in large part to technological advancements – the process remains fundamentally the same. This post will provide a brief history of plastic injection molding, as well as projections for what the future likely holds for the process. Here we will also discuss how changes in injection molding have provided manufacturers with more flexibility and reliability.

What is Plastic Injection Molding?

First things first – in order to explore plastic injection molding (PIM), it is important to understand what the process entails and what elements have remained constant throughout the evolution of PIM.

Plastic injection molding can be defined simply as a process through which plastic pieces are melted and injected into molds. The molds are then chilled, allowing the plastic to harden. After the plastic has set and hardened, it is removed from the mold and is ready for one of a variety of applications and uses.

The History of the Process: A Plastic Injection Molding Primer

The practice of plastic injection molding dates back to the late 19th century. Plastic forms were invented in the 1850’s. however, early plastics from this time period were very difficult to manipulate. The 1870’s gave birth to the practice of plastic injection molding, and soon more malleable forms were also developed. These advancements allowed manufacturers to form more quickly and efficiently. Better plastics and a better process also offered manufacturers a new level of customization and accuracy, allowing them to produce parts and pieces to exact specifications for a wide array of applications.

PIM Today

The plastic injection molding process of today offers a versatile and efficient means of manufacturing various parts and products. Numerous plastics – representing various melting points and compositions – offer unique advantages and benefits for specific applications. Many have specialized uses. Modern plastics can also be combined with other materials to provide additional uses, features, textures, and coloring.

The most common and most versatile plastics currently in use, include: polyethylene, ABS, PVC, polyurethane, nylon, polypropylene, and HIPS.

The Molds and the Machines

Traditionally, molds used in PIM were comprised of two plates – one containing the cavity and one containing the core. Computer-assisted manufacturing (CAM) is now used to create modern molds, which can be significantly more intricate than their two-plate predecessors; containing multiple parts and sections. While the previously mentioned mold cavity and core remain the main components of the mold, today’s molds are detailed and designed to exact specifications allowing a higher complexity in the molded product.

Manufacturing was forever changed in 1946 when James Watson Hendry, an American inventor, built the first screw injection machine. The screw injection molding machine provided much greater control over the speed of the plastics injection – significantly improving the quality of finished pieces. Hendry’s machine also allowed materials to be mixed prior to being injected – blending colored, recycled and virgin plastics.

Hendry went on to refine his concept by introducing a gas-assist to the screw injection machine. Gas-assisted screw injection machines proved ideal for the creation of complex, hollow pieces, which required significantly less cooling time than more standard components. Gas-assisted screw injection machines appealed to manufacturers seeking an efficient and cost-effective solution for complex pieces that also offered unmatched strength and finish.

The overwhelming majority of injection equipment used today are screw injection molding machines.

The Road Ahead for Plastic Injection Molding

The future of plastic injection molding is bright thanks to advances in technology and the continual development of better materials. Important shifts within the plastics industry are already occurring and shaping the future of manufacturing.

  • Improved, light-weight materials and automated systems are reducing costs and streamlining processes.
  • Customization features are allowing manufacturers to use precision technology to create quality pieces to exact specifications.
  • Increased awareness of climate change and other environmental factors will continue to drive demand for more eco-friendly materials, such as recycled, reclaimed and renewable plastics.

The Team and Tools to Respond to Whatever Lies Ahead

At New Berlin Plastics, we know plastic injection molding. Our experienced team understands that the history of injection molding will inform its future. As the processes and systems manufacturers utilize today continue to evolve, it is essential to ensure your company is executing the best approach to production and using materials conducive to each piece’s unique application.

New Berlin Plastics can help you do just that. We offer custom solutions to help you improve your firm’s processes while protecting your bottom line.

Contact our experienced team at 262-784-3120, or visit us online at to learn how you can reduce costs and improve the quality of your finished product through a custom solution for your company.

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