A: PCB cleanliness is critically vital before soldering for several reasons:

1.  Solderability: Clean PCB surfaces ensure proper wetting and adhesion of solder to the pads and components, resulting in robust and reliable solder joints.

2.  Electrical Performance: Contaminants like dust, oils, or residues can interfere with the electrical connections on the board, leading to poor signal integrity or even shorts.

3.  Heat Transfer: A clean PCB allows for efficient heat transfer during soldering, preventing overheating of components and reducing the risk of thermal damage.

4.  Reliability: Clean surfaces reduce the chances of defects like cold solder joints, voids, and cracks, which can cause intermittent connections or outright failures over time.

5.  Solder Mask Integrity: The solder mask, which protects the PCB traces and pads, must be free from contaminants to ensure accurate placement of the solder during assembly.

6.  Ease of Inspection: PCB cleanliness makes it easier to visually inspect solder joints, identify potential defects, and make necessary corrections before they become critical issues.

A clean PCB is essential to ensure good soldering quality, reliable electrical connections, and electronic devices’ overall long-term performance and durability.

Watch this PCB cleanliness video to learn more:

Importance of PCB Cleanliness (video)