Process Control in Soldering SMDs — Analysing and Improving the Process

Although wave soldering is a long established technique, the touch‐up percentage is still unacceptably high. This leads to high touch‐up costs and too low product quality. One cause lies in the fact that the complexity of the boards is increasing all the time (greater component density, greater diversity, more leads and smaller pitches). The main reason, however, lies in the lack of a fundamental process technology background. This becomes even more serious now that soldering processes are becoming more critical. The touch‐up percentage can and must be lowered through accurate process adjustment and control. A further improvement in process adjustment and control will give a considerable improvement in soldering quality in the short term. In this way, the actions are successful, although benefits can be achieved only if the improvements are consolidated. Further improvements can be achieved through systematic application of design rules.