Precautions for using FPC film key switch

1. The FPC film key switch will be coated on the surface to effectively prevent oxidation. Storage, the environment has certain requirements. The temperature is controlled below 25℃, and the humidity is controlled within 50%-70%.

2.FPC film key switch has strong folding resistance, but the exposed part of the wire is not suitable for bending, nor can it be bent directly on the through hole. In the assembly process, FPC ink protective layer is strictly prohibited to bend more than 90°C, more strictly prohibited to bend to 180°C, may lead to broken line and other problems.

3.3 stress concentration zone. FPC film key switch, such as covering film, gold finger end, corner, etc. , assembly is prone to circuit break, so special attention should be paid when using.

FPC film key switch performance test indicators:

The performance test content of FPC film key switch mainly includes: adhesion of copper foil, weldability of pad, roundness of pad, silkscreen clarity, surface smoothness, circuit connectivity, insulation performance and so on. FPC flexible circuit board appearance, material, performance should be verified.

Copper foil adhesion refers to the adhesion between the FPC wire and the substrate. The adhesion of copper foil is small, and the FPC wire is easy to peel from the pad substrate, which needs to be verified. Tape the FPC line to be tested with transparent adhesive, remove bubbles, and quickly tear it off in a 90° direction. If the wires are intact, confirm that the copper foil adhesion of the FPC flexible circuit board is qualified.

Pad weldability test is the wetting ability of solder to printed pad, which is one of the important indexes of FPC test. The circuit connectivity and insulation properties represent the electrical performance indicators of the FPC flexible circuit board. During the test, the high-current shrapnel microneedle module can be used for connection and conduction, which can not only effectively transmit large current, but also maintain a stable connection within the range of 1-50 years. In addition, it can cope with small spacing, and ensure that no pins or needles are stuck between 0.15mm-0.4mm, so that the FPC flexible circuit board test can be carried out stably.