Injection Molding vs. Extrusion: A Comparison of Two Plastic Manufacturing Processes

As specialists in injection molding prototyping, we recognize that producing plastic parts for medical, commercial, or industrial applications isn’t a one-size-fits-all process. It involves various techniques depending on the part’s intended use and shape.

Our customers frequently inquire about how injection molding prototyping differs from extrusion and how they can choose the most suitable manufacturing technique for their plastic parts. In this guide, we compare these two processes to help you make an informed decision that will save time, effort, and money.

The basics

Extrusion produces continuous, two-dimensional, linear shapes, while injection molding yields three-dimensional forms through molten die-casting technology.

In injection molding prototyping, a custom mold is created for the heated resin to fill. After cooling and setting, the material is ejected as a solid, three-dimensional product. This method is perfect for producing a variety of items, such as plastic cups and plates, chess pieces, crates, and baskets.

In contrast, plastic extrusion heats the material and forces it through a custom metal plate, creating a continuous shape that stretches and cools. This results in linear products that can be cut to length, making it ideal for medical device tubing, industrial piping, plastic rails, drinking straws, and synthetic filaments.

Differences and advantages for your end product

Injection molding prototyping may require a complex custom mold, yet its cyclical production process typically eliminates the need for secondary processing or assembly.

Extrusion, on the other hand, can produce complex cross-sections like multi-lumen tubing, which is beneficial in industries such as food processing and medical devices. It also allows for various product lengths without the need for post-processing, thanks to the smooth surfaces of extruded materials.

These are just the basics of extrusion and injection molding prototyping. For more detailed information, please contact our experts at HLH Proto. We’re here to assist you in making informed manufacturing decisions and adding value to your project.


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