Keeping static discharge out of membrane switches

Aug. 4, 2005
Electric membrane switches often have pressure-sensitive adhesives securing an overlay on top of the switch.

But to get the most out of the adhesive, engineers usually call for a rough surface, giving the adhesive plenty of sites to form mechanical bonds. Unfortunately, these rough surfaces create networks of microscopic fissures, an open road for electric static discharge (ESD) to find its way to the switch and compromise its integrity. The usual fix is to add an ESD shield above the switch. It acts as an antenna, "grabbing" static charges and routing them to ground. But such shields add costs and production time.

At The Bergquist Co., Chanhassen, Minn. (www.bergquistcompany.com), engineers have developed a lower-cost alternative that relies on a polyester resin to seal the switch against ESD as well as thermal stress, solvents, and changes in pressure. Dubbed HeatSeal technology, the extra layers of resin leave no air gaps, microscopic fissures, or any other path into the circuitry. The HeatSeal resin withstands 135 kV of ESD without breaking down. Conventional PSA switches, in comparison, only withstand 15 kV.

Sponsored Recommendations

NEW Low Profile, Ultra Compact Power Supplies

March 13, 2024
Learn more HERE about Altech's Power supplies!

Altech's Liquid Tight Strain Relifs Catalog

March 13, 2024
With experienced Product Engineers and Customer Service personnel, Altech provides solutions to your most pressing application challenges. All with one thought in mind - to ensure...

Industrial Straight-Through Cable Gland

March 13, 2024
Learn more about Altech's cable glands and all they have to offer for your needs!

All-In-One DC-UPS Power Solutions

March 13, 2024
Introducing the All-In-One DC-UPS, a versatile solution combining multiple functionalities in a single device. Serving as a power supply, battery charger, battery care module,...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!