Why does a PCB board develop a tin appearance after wave soldering? How can this issue be mitigated? Is a flawless PCB design the end of concerns? Not quite. Throughout the PCB processing and production journey, various challenges often arise, including the occurrence of tin soldering post-wave soldering. While not every issue can be attributed to PCB design flaws, it remains crucial for designers to ensure the correctness of their initial designs.

Wave soldering involves the direct contact of the plug-in plate’s welding surface with high-temperature liquid tin to accomplish soldering. This liquid tin, maintained at a specific angle, creates a wave-like phenomenon through specialized equipment, hence the term “wave soldering.” The primary material involved is the solder bar.

Tin joint, a defect categorized as such by IPC-A-610D, occurs when two or more solder joints merge due to solder material, leading to both aesthetic and functional impairments.

What causes the appearance of tin on a PCB board after wave soldering? Firstly, it’s essential to clarify that tin connection issues on PCB boards may not solely stem from poor PCB design. Factors such as inadequate flux activity, insufficient wettability, uneven application, and uncontrolled solder temperature during wave soldering can also contribute to this problem.

However, if the issue does relate to PCB design, several considerations can be made:

How can tin formation in PCB design be circumvented?