Many industries use injection molding to produce their parts and products. The process enables them to create components of various shapes and sizes in high quantities (i.e., thousands or millions of pieces) quickly, consistently, and cost-effectively. While it can be used with a variety of other materials (e.g., glass, metal, and rubber), it is most commonly utilized for plastic. For example, clear plastic is often injection molded to form personal protective equipment (PPE), such as face shields and goggles, for industry professionals.

plastic extrusion

The following article provides an overview of plastic injection molding. It highlights what the process entails, key advantages of using it over other manufacturing methods, and challenges faced when conducting injection molding operations.

What Is the Plastic Injection Molding Process?

The plastic injection molding process involves heating plastic (in pellet or grain form) until it has melted. The molten material is then injected into a closed two-part mold under high pressure, where it cools and solidifies. Once the material has fully hardened, it maintains the shape of the mold cavity. At this point, the mold can be opened so the piece can be removed and sent for further processing as needed.

Benefits of Injection Molding

There are many benefits to using injection molding over other manufacturing methods to produce plastic components. For example:

  • It readily accommodates mass production. The injection molding process can be used to create a large number of components with a high degree of accuracy and precision. Additionally, after the initial costs associated with starting an injection molding project have been paid, the price per unit is very low, with the price dropping as more components are made.
  • It produces little scrap. Unlike other manufacturing processes (e.g., CNC machining), injection molding requires little to no cutting away of excess material to form the component. As a result, it produces much less scrap.
  • It maintains high repeatability. Injection-molded components are practically identical from part to part and batch to batch, which is essential to achieving and maintaining brand consistency and part reliability when making mass-produced products.
  • It offers broad material flexibility. The injection molding process can handle a variety of materials, which allows companies to choose one that suits their exact needs; they can select a material based on highly specific functional and/or aesthetic characteristics (e.g., color).

Challenges of Injection Molding

While injection molding offers a number of advantages over other manufacturing methods, it also comes with some challenges, such as:

  • High upfront costs. The cost of producing an injection mold is high. Simple, single-cavity molds start at $2,000–$3000, while complex, multi-cavity molds can be $100,000 or more. However, once the mold has been made, the manufacturing cost per additional unit is relatively low.
  • Long lead times. Since injection molding projects typically require the manufacture of a custom mold, which can be a time-consuming process, the project lead time is generally longer than is normal for other plastic manufacturing methods. However, once the mold is manufactured, it can be used to produce millions of pieces over its lifetime.
  • Large part limits. The size limitations of injection molding machines and molds often require large components to be produced as separate pieces that need to be assembled later.

Quality Injection-Molded PPE Products From Paulson Manufacturing

The injection molding process can be used to produce parts and products for various industries. At Paulson Manufacturing, we leverage the technology to make high-quality, dependable safety equipment for industrial workers and fire responders. By carefully designing and building our own molds, we ensure we create solutions that surpass even the most rigorous safety standards. To learn more about injection molding in general or our capabilities, contact us today.

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