When clients receive Flexible Printed Circuit boards, they sometimes ask whether it's necessary to take any precautions before assembly, especially if the FPCs have been in storage for some time. Our advice is straightforward: baking before assembly can make a significant difference in ensuring optimal performance and reliability. Below, we explore why this step is crucial and offer practical tips on storing FPCs properly.

The Ideal Assembly Time for FPCs

While proper storage helps protect the FPC, the timing of assembly after receiving the board is equally important. Different surface finishes on the FPC require different assembly timelines to ensure quality. Here's a breakdown:

• For FPCs with OSP (Organic Solderability Preservative) and Immersion Silver finishes, the best practice is to assemble the boards within one month of receiving them.

• For FPCs with Immersion Tin and Immersion Gold finishes, it's recommended to schedule the assembly within two months.

Assembly beyond these timeframes may result in reduced solderability or other performance issues, so timely assembly is key to preserving the board's quality.

When to Bake Your FPC Before Assembly

If the FPC has been stored for over two months, regardless of the surface finish, baking the board before assembly is a best practice. Over time, even in vacuum-sealed packaging, the board may absorb moisture. Moisture trapped in the FPC can lead to several problems, such as solder defects, delamination, and other performance issues during assembly.

Baking helps to eliminate this absorbed moisture, ensuring that the FPC is in prime condition for the assembly process. The recommended baking process will depend on the specific type of FPC and manufacturer guidelines, but generally, low-temperature baking over an extended period is preferred to avoid damaging the components.

To get the best performance from your FPCs, proper storage and timely assembly are crucial. Always keep FPCs in their vacuum packaging until they are ready for assembly, and follow the recommended timelines for different surface finishes. If your FPC has been in storage for over two months, baking it before assembly can help mitigate the risks of moisture absorption, ensuring smooth and successful assembly.

By following these practices, you can maximize the lifespan and performance of your FPC boards, ensuring they perform optimally in their intended applications.