Details of Flex & Rigid Membrane Switches The circuit of membrane switches can be flex and rigid. It depends on the customer end application and also related to the cost budget and other considerations. For example,Website: , life, resistance, connection type on main board etc.For the flex circuit membrane switches, there are two types. They are silver printed PET circuit and copper etched FPC circuit. Their difference and advantages&disadvantages listed bellow:ItemsSilver Printed CircuitCopper Etched FPC CircuitMaterialPET (Polyester)CopperConductorPrinted silverCopperContact FingersSilver and CarbonGold platedContact Buttons PadsSilverGold platedLife & ReliabilitynormalgoodStabilitynormalgoodResistancelowVery lowCostlowhighLead Time2-3 days7-10 daysPitch0.5mm (not suggested), 1.0mm,1.27mm,2.54mm0.5mm, 1.0mm,1.27mm,2.54mmUsually if the membrane switches need assembled many LEDs, then we suggest to use FPC circuit, it can get more stable LED soldering quality. For the normal application the PET circuit is enough, which is more economical. In addition if the conductor pitch is 0.5mm, although we also can print it, but we still suggest to use FPC circuit. Because of that 0.5mm pitch is too small and it is easy to occur the short circuit problem.For the Rigid circuit membrane switches, the circuit is rigid printed circuit board. The material of rigid PCB isusually FR4 and Copper. By this type of membrane switch, the connector usually is the SMD connector(sometimes also can be straight through connector). For some application which need very stiff capability, then use PCB circuit membrane switch.