Thermocouple attachment methods for PCB profiling during Vapour Phase Soldering

Vapour Phase Soldering (VPS) is an alternative reflow soldering method, which had a comeback after the introduction of Galden fluid. The heat transfer in a VPS oven is totally different than in the case of conventional soldering methods, such as convectional and IR radiation soldering. Most of the energy (which is required to melt the solder alloy) is transferred to the board during the condensation of the Galden vapour. Printed Circuit Board (PCB) temperature profiling is usually done with thermocouples attached to the board itself with different attachment methods. An unprocessed laminate PCB was prepared for temperature profiling. Standard K-Type thermocouples were attached to it with the standard methods, such as thermocouple fixing with Polyimide tape, SMD adhesive and High-Temperature Solder (HTS) alloy. The paper highlights the importance of condensate film layer, which have an effect on attachments and the thermocouples themselves. The results of the measurements are investigated in the paper.