Guide to CNC Machining Plastics

A CNC milling machine cutting some plastic parts

Computer numerical controlled (CNC) machining is a high-precision machining method that relies on computer instructions to machine workpieces more time and cost-efficiently. Plastics are a common material for machining components due to their versatile properties and machinability.

We will discuss the plastic materials suitable for machining and how CNC machined plastics are ideal for various applications.

Plastic Materials for Machining

The machinability of plastic materials makes them a preferred choice for many applications. They are typically flexible, lightweight, and cost-effective. Certain plastics can have a strength-to-weight ratio equal to or greater than steel. They also have corrosion resistance and insulating properties.

The following plastic materials are common and suitable for machining:

  • Acrylic
  • Delrin
  • Nylon
  • Peek
  • Phenolic
  • Polycarbonate
  • PVC
  • Torlon
  • UHMW
  • Ultem
  • Vespel

How Machine Shops CNC Machine Plastics

CNC machining is more precise than traditional machining. It eliminates human error and is highly replicable. The machining method will depend on the type of plastic, considering thermal properties, strength, and desired results. 

Plastic machining shops rely on the following CNC machining methods:

  1. Turning: A subtractive machining method that rotates the workpiece to provide a fine finish.
  2. Milling: A high-speed spindle makes precise cuts into the plastic workpiece.
  3. Drilling: Removes material from the plastic workpiece to create a hole or slot.
  4. Threading: A thread chaser creates a threaded slot to accommodate screws or bolts.


Plastics are typically not as rigid as metals, limiting the range of suitable machine tools. Plastics can deform under excess heat and friction. It is critical to work with a machine shop with plastic machining expertise.

Industries and Applications

CNC machining plastic is suitable for prototyping individual components to high volume mass-production of tight tolerance parts. It replicates parts with high precision, efficiency, and consistency in quality. 

The following are a selection of industries that depend on CNC machined plastics:

  • Aerospace
  • Medical and Pharmaceutical
  • Energy
  • Semiconductor
  • Laboratory Equipment
  • Chemical Handling
  • Microelectronics
  • Food Handling

Plastic CNC Machining From Ricaurte Precision, Inc.

At Ricaurte Precision, Inc., we have over 30 years of experience fabricating plastics for various industries. RPI is an ISO 9001:2015 and AS9100D certified machine shop, delivering the highest quality plastic machining services at competitive prices. Contact us to book a free consultation with our CNC machining experts.

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