The electronic test (E-Test) for circuit boards is performed after manufacture. Your circuit boards are checked with a flying probe,dedicated, universal grid or many other methods for E-Test.
Circuit boards that are identified as defective are eliminated; defective circuit boards in panels are specially marked.This is extremely important, because only the E-Test can recognize incorrect and missing connections, meaning that without the E-Test, the usability of your circuit board is just a random chance!
The most popular E-Test methods are: flying probe, universal grid and dedicated.To get a better understanding to the features of this 3 types of E-test, let Shenzhen KEYOU PCB Co.,Ltd make the comparison below:
1). Flying probe tests depends on the XYZ servo-system movement of 2 probes to test vias, component pads and circuit interconnects on both side of PCB at end point of electrical net. The testing speed is about 1000points/minute only because of the limitation by the end point net. That’s why the flying probe is suitable for the small volume/ prototype and the high density PCB.
2). The universal grid tester is designed according to the circuit distribution of PCB. The grid distance is defined by the density of circuits and represented by the spacing. Only does the testing probe penetrates the solder mask to contact the holes, the fixture is easy to build and the probes can be recycled. There are many standard grid probe plates with all kinds of types for testing pads. It is convenient to build the active grid probe plate for different part numbers. During the mass production, different part number can be tested according to change the active grid probe plate. The universal grid tester is satisfied with the QFP PCB type.
3). The dedicated tester is specialized for a part number only; it can’t be applied to the others and recycled. And the testing points are around 10240 for single side PCB, 8129 for double side. The density is limited by the size of the probe size, it is applied the fine pitch PCB generally.