Trends and recent developments in mass soldering techniques for electronics assembly

Outlines the latest developments and current trends in the PCB assembly industry. Since the advent of wave soldering, most of the major changes in the equipment have been brought about by SMT. This has required the development of complex waves to solder SMT components, i.e. dual waves, turbulent waves, etc. It has also required the development of a more controlled process, which has been achieved by making extensive use of PCs. Wave development still continues, but the main thrust is now towards controlled atmosphere soldering. The claims being made for the process are that, using nitrogen atmospheres (with oxygen contents below 10 p.p.m.), an order of magnitude improvement in defect rates is achieved. The process also allows the use of an extremely mild flux which does not require cleaning of the assembly. Also, reflow soldering is discussed