There are three points for good wave solder quality conditions: 1. Sufficient and good wetting; 2. Appropriate solder joint size; 3. Good contour. Adequate and good wetting is an important indicator to let us know the status of'solderability'.

An unwetted solder joint is difficult to have enough IMC to form, which indirectly tells us that the soldering quality is poor. Here is a reminder that although signs of wetting indicate the existence of solderability, it does not fully indicate the qualification of IMC. The degree or condition of IMC formation is the key to determining the reliability of solder joints. This is an important limitation of visual inspection capabilities.

Wave soldering circuit board

Wave soldering quality solutions: 1. Clean all soldered surfaces before soldering. Ensure solderability. 2. Adjust the welding temperature. 3. Enhance the flux activity. 4. Reasonably choose the welding time. 5. Improve storage conditions and shorten the storage time of PCB and components.