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Tips for Using Plastic in Custom Electronic Enclosures

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Protocase Inc.

The incorporation of plastic into custom electronic enclosures is becoming more and more popular for engineers and designer. To keep you on track with completing projects, we stock acrylic, acetal and Ultra-High Molecular Weight Polyethylene (UHMW) here at Protocase. These materials can be machined in 2-3 days, so that you can employ them either as standalone parts, or as part of an enclosure or assembly.

Tips for Using Plastics in Enclosures

Acrylic, acetal and UHMW are generally milled, either on CNC router or mill (work envelope up to 4ft x 8ft). This means that countersinks, counterbores, pockets, or any other milled feature may be added.

Cutouts on acrylic and acetal are milled and are subject to a minimum corner radius (0.022″ for material up to 0.250 thick, .032″ to 0.375, 0.062″ to 0.750, and 0.094″ to 1.000) and get larger as thickness increases. This must be considered when mounting square or rectangular components in cutouts in plastic. If these constraints are a problem, our Engineering and Design Services would be happy to help you find creative approaches to achieve your goal.

When attaching plastic via threaded fasteners, it is advisable to use through holes in the plastic with bolts, nuts washers, etc, rather than threading into the plastic. If desired, we can tap plastic, but you must be very careful not to strip the threads when installing fasteners.

Acrylic or acetal panels are very useful if your design incorporates RF sensor technology or antennas inside the enclosure (Wi-Fi), because sheet metal can sometimes attenuate signals.

Plastic materials can be mounted flush to enclosure surfaces. This is done by milling the edges of the plastic to create a boss that matches the cutout in the enclosure face. Fastening can be via threaded fasteners or structural tape.

Acrylic can be etched during milling, and silkscreened graphics can be applied. Both techniques give very attractive results.

Using Acrylic in Your Enclosure:

Most designers use acrylic for its transparency, although sometimes it is also used for other reasons such as electrical insulation or RF transparency. It is often used to create viewing windows in enclosures, and also to achieve certain aesthetics.

Using Acetal in Your Enclosure:

Acetal has great dimensional stability and low friction, which makes it great for close-tolerance machined parts and enclosure components that slide on each other. Customers typically use acetal for such things as clamps for cables or bus bars, fiber optic trays, panels, rack stands and clamping brackets.

Using UHMW in Your Enclosure:

UHMW is a versatile thermoplastic that offers low friction surface, good electrical properties and high impact strength. We can machine UHMW to create a variety of parts and components, including mounting blocks, bearings, guide rails, sprockets, starwheels and more.


In the end, our sole mission is to help you complete projects and meet your deadlines, by building custom electronic enclosures, panels and parts in 2-3 days, with no minimum order. Whatever you’re envisioning, we’re there to help you achieve it. Contact us at info@protocase.com or by calling 1-866-849-3911 to get started.