Tips for Considering Machined Plastic Parts in Your Product or Design

Today’s OEM’s are always searching for ways to remove costs from their products. Designing in or substituting plastic parts and components for metal parts is a proven way to achieve cost reductions through lower material costs and lessened product weight.

The marketplace today offers a bewildering array of metal, non-metal and plastic materials to choose from. Product designers and developers should always take care to fully understand the properties and advantages of each material type they may consider for inclusion in their products.

Advantages of Machined Plastic Parts

Metal materials can offer strength and durability, but trade-off mass and weight. Plastic materials can be more vulnerable to change under certain operating condition, but offer lower mass and weight compared to metals. Today, there are an number of plastic materials available that offer high tensile strength and excellent resistance to heat and chemicals, meaning that a suitable plastic can usually be found for almost any application.

Machining of plastics with CNC equipment permits close-tolerance, burr-free finishing. By choosing the right material, machined plastic parts can be an effective substitute for metal parts in many product applications.

Questions to Ask When Considering Machined Plastic Parts

What tensile strength is required in the part?

Certain plastic materials (i.e., UHMW) have extremely high tensile strength and will outwear carbon steel in some settings. Other plastics have a lower tensile strength and are more flexible and forgiving. Knowing the stress or load that a plastic part may have to bear is important for selecting a material with an appropriate tensile strength.

What temperatures will the part be exposed to?

Some plastic materials are more suitable than others for making parts that will be exposed to temperature extremes. Knowing the serviceable temperature range that a part will have to support is key for selecting the right material.

What media will the part be exposed to? 

In some product applications, plastic parts may be exposed to aggressive chemicals and compounds. Understanding the media that may come into contact with machined plastic parts is important for choosing a plastic material with the appropriate level of resistance.

Does the part have to conduct electricity or heat, or be capable of shielding radio frequencies (RF)? 

Conductive plastics are available as well as those which have insulating and RF shielding properties and qualities.

What tolerances are required to ensure fit, form and function? 

With today’s CNC equipment, close-tolerance machining to within ±.005” is possible, if required.

CNC machining of plastics involves the production of finished parts using a computer controlled (CNC) router or milling machine. With this technology, plastic materials can be cut, shaped, drilled, contoured, and surfaced with the use of precision tooling under direct computer control.

CNC machined plastic parts offer three distinct advantages over parts which are molded. First, the need for expensive molds is eliminated when plastic parts are machined. Secondly, part designs can be altered quickly and easily. And, thirdly, complex part geometries, including those with threads and undercuts, can be easily produced.

Using CNC machining technology, CRG can process a wide variety of plastics materials ranging from .001” thick and greater to widths and lengths up to 126”. Our close-tolerance cutting to within ±.005” ensures your specs will be achieved with minimal waste of material. Produced in our ISO 9001-registered facility, CRG cut-to-size parts are always clean and dust-free, with smooth, chip-free edges.

If you are seeking machined plastic parts for your product or application, CRG will be pleased to review and discuss your needs.

To find out more about the machined plastic parts we can supply, please contact our sales department at