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AIM Processing Small Plastic Parts Blog

The Benefits of Plastic Injection Molding Compared to Extrusion

[fa icon="calendar"] Jun 29, 2023 1:02:00 AM / by Jon Gelston

Plastic Extrusion Machine


Plastic injection molding is sometimes compared to extrusion when customers are searching for the most optimized manufacturing method for their products. While the injection molding and extrusion processes are very different, they are both capable of producing high-quality parts with complex designs.

Nevertheless, there are certain types of products – or production goals – which are much better suited for the injection molding process, and vice versa. Learn more about these two unique manufacturing services below, including the common advantages and product applications.

Comparing Custom Plastic Molding Processes

If you’re interested in learning more about how injection molding services work in general, check out our Custom Injection Molding Services page. Or, to see how injection molding compares to thermoforming and vacuum forming, check out our previous blog – Plastic Injection Molding vs. Vacuum Forming.

How does the plastic extrusion process work?

Once an extrusion material is chosen and prepared, the plastic pellets are loaded into a reservoir on the extrusion machine called a hopper. The hopper precisely feeds the plastic material into the extruder once the process is underway, where the material is barrel-churned against the extruder screw. The plastic pellets are thus melted within the extruder using both heat and mechanical energy from friction and compression. 

Once molten, the plastic is forced through a custom-made extrusion die, which shapes the material into the desired cross-sectional profile of the finished product. The molded product is then carefully cooled, colored (if required), cut to the desired length, then sent off for additional processing such as drilling or machining.

Some common benefits of extrusion services include:

  • Lower initial design cost due to the simplicity of the dies vs. the complexity of injection molds.
  • Capable of producing internal features without the draft required in injection molding.
  • Produces a smooth surface finish, often eliminating the need for post-production finishing.
  • Extrusion is often the best manufacturing method when numerous lengths of the same essential design/product are required, such as plastic piping and wire insulators.

The Advantages of Plastic Injection Molding Services

The above benefits aside, plastic injection molding offers numerous advantages over the extrusion process.

Why choose injection molding services over extrusion?

    • Enhanced Precision – Injection molding is capable of producing precision plastic parts, generally offering tighter tolerances than the extrusion process. While the initial mold design and manufacturing process can take longer, the time investment is worth it if your project requires highly accurate, high-precision plastic parts.
    • Material Versatility – Another advantage to injection molding services is the process’ compatibility with virtually all common plastics. This enables you to choose the ideal plastic for every unique product – optimized for quality, cost, and performance – instead of being limited to extrusion plastics.
    • Process Versatility – Injection molding is capable of molding multiple parts in the same cycle which can increase production output.
  • Part Complexity – Injection molding is capable of producing more complicated features and side features such as through-holes or molding around another object such as a metal insert.

More than 30 Years of Quality Plastic Injection Molding Solutions

A leading injection molding company in the Denver, Colorado region since 1993, AIM Processing offers experience-backed contract manufacturing services. From custom electronics and consumer goods to specialized industrial products and medical devices, we inject quality and innovation into every product we manufacture.

Topics: Plastic Injection Molding Defects, Plastic Types, Quality, Plastic vs. metal, Texture, Small Plastic Parts, Choosing the right plastic injection molder, vacuum forming

Jon Gelston

Written by Jon Gelston