There’s nothing more frustrating than going through the complete membrane switch design process, manufacturing the part, running the parts through testing and inspection, and then shipping them to the end customer only to find they are failing! Typically the number one cause of keypad failures is improper handling. Here are a few quick prevention tips to help you avoid damaging your membrane switches.
- Only press the keys or switches when the membrane keypad is on a flat solid surface. If the operator presses the domes or keys in the air, unsupported, there is a serious risk of bending the legs of the metal dome.
- Never bend a membrane switch. Bending the switch puts the placed components (domes, LEDs, etc.) at great risk of being damaged.. If a metal dome leg is bent the dome could pop out of place and not properly snap back or the bond with the LEDs could become damaged causing them to fail.
- Prevent any creasing of the tail. This really pertains to silver flexible circuits as copper flex circuits can certainly be creased. Severe creasing of the silver flexible circuit will cause the silver ink to crack which creates an open circuit or keypad failure.
- When applying the membrane switch to your assembly, use a tacky cloth with isopropyl alcohol to clean the entire assembly surface. This will ensure any dirt or debris are properly removed. Dirt or debris on your assembly’s surface will not only prevent the keypad from being completely adhered to your part, but it will also cause a deformity (irregular bump in the surface) after the membrane switch is assembled. Once the strong pressure sensitive adhesive is applied, it is almost impossible to rework the parts without causing damage to the membrane switch.