The testing processes for rigid flex circuit boards can be extremely challenging. This is because these circuits are designed as extremely thin, and with complicated geometries. So it is not surprising that certain hurdles can be faced during the testing processes. To thoroughly test the circuit board, many PCB manufacturers choose the Flying Probe test. What makes this test far better than others? Read on to know more.
Comparing the PCB Testing Procedures
There are three basic testing procedures utilized by PCB manufacturers. These are fixture, manual, and flying probe tests. We will look at the problems faced in each of the processes.
- Fixture Testing: This procedure is mainly used when performing high volume PCB production. It involves the use of wired and pinned fixtures. The advantage of this test is that the fixture holds the board in place accurately. It is also inexpensive, and requires minimal testing time. However, When it comes to rigid flex circuits, the problem lies in affixing (registering) the circuit board to the fixture. If the circuit has non-plated mounting holes, registration repeatability becomes difficult. Also, fixture registration is not possible if there are no mounting holes.
- Manual Testing: This procedure is known for its simplicity. A digital volt meter is used to test open and short circuits of PCB nets. However, many meters are designed to only test open circuits. The reason is the volt meter is designed to IPC and MIL-Spec specifications, and testing isolated shorts can be difficult. Also, it is a time consuming procedure, and hence, there are many possibilities for errors.
- Flying Probe: The Flying Probe is by far the best procedure created for PCB testing. It has a lot of advantages over the other two testing processes. First, it is not that expensive to use. Also, the need for fixtures is eliminated, as registration holes are not required for circuit alignment. Extremely small sized pads can be tested without any possibility of mis-registration. Single sided as well as double sided rigid-flex circuit boards can be tested. It can also test circuits with resistor cores. The only disadvantage with the Flying Probe PCB testing is that it is time consuming.
Looking at the advantages and disadvantages of all three tests, it is clear to see why Flying Probe is the choice for rigid-flex circuit board testing processes.