How Do You Protect Printed Circuit Board Manufacturers From Moisture?

Protect Printed Circuit Board Manufacturers From Moisture

Printed circuit boards require moisture protection throughout the production process to avoid malfunction, damage and short circuits. Moisture is a bad conductor of electricity, and it can cause serious failures in a PCB by traveling between layers or through the components mounted on them. In order to protect PCBs from moisture, a manufacturer must take multiple steps, including ensuring the proper storage and handling conditions for their products.

During manufacturing, moisture can be introduced through improper storage or packaging, through the wet processes used to prepare the base materials for lamination, or by accidental contact with the bare board during assembly. Moisture can also travel in and out of the board during assembly and operation, causing functional failures such as conductive anodic filamentation (CAF) or delamination.

To combat the hygroscopic nature of pcb board manufacturer material, manufacturers typically use a combination of drying agents to ensure that all excess moisture is removed from the prepreg before it is used for lamination. Once the laminate is ready for assembly, it may be baked to reset its moisture sensitivity level (MSL). The MSL value of a component determines how long the component can remain exposed to a humid environment before it is susceptible to corrosion. Once a component’s MSL is reset, it can be placed on the PCB for soldering and final assembly.

How Do You Protect Printed Circuit Board Manufacturers From Moisture?

Baking is one of the most common techniques employed to control the amount of moisture in a PCB, but it can lead to unpredictable results. Although baking raises the temperature of the PCB to levels that force moisture out, it also causes internalized moisture molecules to swell momentarily. This moisture expansion can cause irreversible damage to the board and leave it vulnerable to future failures like delamination or CAF.

It is important for a pcb board manufacturer to follow guidelines set forth in IPC standards for the storage and handling of electronic devices, which will help reduce the chances that moisture will make its way into a finished product. For instance, it is recommended that PCBs be stored in moisture barrier bags to provide the maximum vapor protection possible. Moisture barrier bags are more expensive than standard packaging, but they offer the highest level of moisture protection and are an effective means for preventing moisture-related failures in a finished product.

To further prevent the ingress of moisture, manufacturers can coat a PCB with a waterproof coating. While these coatings are costly and slow to cure, they can provide valuable moisture resistance that can extend the lifespan of a finished product. There are several different types of waterproof coatings, such as acrylic, silicone, and polyurethane. Each offers different advantages, such as flexibility, chemical resistance, and temperature tolerance. Regardless of the type of waterproof coating used, it is important to test the assembly for moisture ingress using a pressurized chamber. This testing will help to identify any small openings in the coating from traces or connectors, which may be an opportunity for moisture to enter the assembly.

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