What must occur prior to the application of conformal coating on assemblies?

Prior to the application of conformal coating on assemblies, moisture removal treatment is essential. This step is critical because any residual moisture on the circuit board can lead to various issues, such as the formation of bubbles or defects in the coating, reduced adhesion, or even corrosion over time. Moisture can critically impact the performance and reliability of the assembly, as conformal coatings are designed to protect against environmental factors. Ensuring that the assembly is completely dry helps to ensure that the coating adheres properly and provides the necessary protection.

Other steps, while important in the assembly process, do not focus specifically on ensuring the integrity and performance of the conformal coating. Visual inspections contribute to overall quality control but do not specifically address the moisture concerns that can arise prior to coating application. Documenting validations and applying additional flux are important in their own contexts, but moisture management directly impacts the efficacy of the conformal coating process.