Machining vs. Molding Plastics

CNC machining and injection molding are two highly effective and efficient ways of producing custom plastic parts for industrial assemblies, but deciding which process is best for your run can be a challenge. While evaluating machining vs. molding plastic components, consider:

  • What is your available budget?
  • What size is your planned production run?
  • Does your part need to meet specific tolerances?
  • Do you require design flexibility during production?
  • What plastic material do you plan to use for your components?

The answers to these questions, along with other considerations unique to your project, can help you decide which process is your best solution.

Molding Plastics

Injection molding is one of the most well-known manufacturing methods for custom plastic part production. Plastic material is heated and then injected into a custom hardened steel mold. Once the part has cooled, it is ejected from the mold.

Injection molding is used for many applications, including construction hand tools, food and beverage containers, medical devices, and more.

Benefits of Injection Molding

Injection molding offers extreme repeatability and produces durable and long-lasting parts. Once the mold is established, injection molding significantly lowers the per-unit cost of your plastic production, particularly in high-volume runs. As injection molding is an additive process, it produces less material waste than CNC machining.

Limitations to Molding Processes

Despite its lower cost during production, injection molding features a significant upfront investment as a custom mold must be built to your specifications, making it unideal for low- or medium-volume runs. This mold is expensive to replace or change to meet new design demands. Injection molding can often produce parts with lower tolerances and surface flaws. Material selection is also limited, as many high-performance precision plastics required by engineering applications cannot be molded.

Machining Plastics

CNC machining is ideal for creating custom parts with exacting tolerances or complex geometries. High-speed cutting tools remove material from a larger workpiece until your desired shape is achieved. Various kinds of CNC machining—including milling, turning, and multi-axis machining—are available to match the exact needs of your project.

CNC machining is used to create parts across virtually every industry, including aerospace, defense, medical, and semiconductor projects.

Benefits of Machining Plastics

Choosing CNC machining for your precision plastic production is a smart choice for runs requiring design flexibility, as it is an easy process to adapt or change. It is well-suited to low or medium-volume production runs and can minimize turnaround times for operations needing quick results. Machining plastics produces components with extremely precise tolerances, ensuring that all final products perform at a high level. CNC machining is also applicable to a wider range of materials than injection molding, giving you enhanced control over your final part’s quality.

Limitations of CNC Machining

As CNC machining is a subtractive process that removes plastic, the material waste rate is significantly higher than injection molding productions. Its per-unit price is generally higher than injection molding, particularly for high-volume production runs.

The most significant limitation of CNC machining is that successful production requires technical knowledge and experience. Not understanding plastic material requirements, attempting to incorporate sharp internal corners, and other common CNC manufacturing mistakes can waste time, resources, and significantly lower your production quality. However, this limitation can be quickly addressed by partnering with an experienced CNC machining shop, such as Upland Fab.

Upland Fab Delivers Outstanding CNC Machining for High-Precision Industries

Upland Fab is your full-service partner for precision CNC machining services. We work with you at every stage of production to identify and address design issues and ensure your complete satisfaction. When comparing machining vs. molding plastics, our reliable CNC machining team and processes will streamline your order and deliver parts with exacting tolerances. We are experienced in machining most plastics, and we have the hands-on knowledge to successfully create parts from:

Contact us today to learn more about how precision CNC machining can enhance and improve your custom plastic production. Request a quote to begin your order.
Precision Plastic and Composite CNC Machining

Precision Plastic and Composite
CNC Machining since 1970.

Precision Plastic and Composite CNC Machining
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