Increasing Productivity in Vapour Phase Soldering Using Vertical Stacking of Boards

During vapour phase soldering, the lateral size of the specimen tray determines the number of assemblies that can be soldered at once. Increased productivity, thus less power consumption can be achieved by increasing the size of the tray, and the workspace of the oven; therefore, also the size of the machine. This means significant additional costs both in terms of machine design and the amount of heat transfer fluid used. The aim of our research was to find out how we can increase the productivity of an industrial grade oven and improve the technology for a more energy efficient production, without making any significant retrofitting modifications. By stacking multiple printed circuit boards (PCB), we could increase the number of PCBs that could be soldered at once up to three times. We designed a sample holder with reduced mass, which shortened the cycle time. We performed comparative tests in several vertical configurations, compared to the default setup. We examined the resulting thermal profiles, performed shear tests, examined the surface of the cracks with optical microscopy, and also performed a cross section analysis. The results show that the solder joint quality was degraded due to increased void formation; however, the overall product quality might fit the requirements of commercial electronics.