Protect a Flexible PCB From Moisture
If you’re designing a flexible printed circuit board (PCB), you need to ensure it is as safe as possible from damage. Whether due to environmental factors or manufacturing processes, a PCB that is not adequately protected can become prone to failure. Moisture is a common problem that can be especially dangerous for flex circuits. Moisture can lead to delamination, conductive anodic filamentation and other serious problems with a PCB’s functionality. Moisture can also lead to electrical damage, especially if it comes into contact with components and traces. Moisture can cause oxidation and corrosion of the copper, which can result in a short circuit.
There are several ways to protect a flex circuit from moisture. One way is to use a protective coating. This coating is available in a variety of colors and textures, making it easy to apply and remove from the surface of a flex circuit. Another way to protect a flex circuit from moisture is to use an air-permeable solder mask. This material is designed to be durable, allowing it to hold up against exposure to moisture and other threats to the circuit board.
The baking process is another effective way to protect a flex circuit from oxidation and corrosion. This is a practical solution for PCBs that have been exposed to moisture in the assembly or shipping processes. This method involves drying a PCB in a controlled environment to remove the excess moisture from the material. However, it can be expensive and time-consuming, which can make it impractical for many manufacturing situations.
How to Protect a Flexible PCB From Moisture
Another way to protect a flex circuit pcb is by ensuring the stiffeners are of the appropriate thickness. The thickness of stiffeners can affect how much a flex circuit bends. The stiffener’s thickness should be based on the design of the flex circuit, including how much it will be flexed. The stiffeners should also be made of materials that can withstand high temperatures and be compatible with soldering temperatures.
Stiffeners are also useful in preventing traces from becoming damaged by heat. The insulating properties of the stiffeners can help to dissipate heat more effectively and prevent the traces from melting or cracking. This can reduce the likelihood of the traces being damaged by power surges, lightning strikes and other electromagnetic phenomena that can harm them.
Other potential sources of PCB damage include pests and physical force. PCBs stored in warehouses and other types of storage can be susceptible to mice or rats, which can chew on them. In addition, a PCB that is dropped can be crushed or dented, which can damage components like surface-mount devices. Finally, a PCB can be damaged by chemicals. Chemicals in cleaning supplies can corrode a PCB, especially if it is left with the cleaner for an extended period of time.
