How to detect double metal domes with electric measuring fixture?
Do you know how to detect double metal dome? We often receive this question from customer, today I want to advise our testing method to you, please kindly check below for details, then you could understand, hope it’s helpful for you.
The principle is: the upper fixture is equipped with a probe with a higher force than the single DOME.The bottom board is PCB, connecting the lead to the computer. During the test, the upper fixture is pressed down and the probe is pressed into the dome center. If there is a single DOME, the probe will press the DOME down to the PCB and conduct it. The computer shows PASS.If double DOME, the pressure of the probe cannot press down DOME, then the PCB cannot conduct, the computer shows NG;The force of the probe is generally about 1.2~1.5 times, such as 160g of metal dome and 200~250g of probe.
This fixture should be used with the electric measuring machine, and the sole fixture cannot be used. If you has assembled the metal dome and tested it again, in case of NG, it should be removed again. Therefore, it is not recommended to test the finished product.