Improving efficiency of vapour phase soldering ovens with pressure and temperature-based process monitoring

Abstract

During vapour phase reflow soldering used in electronics manufacturing, the process control of ovens is usually based on temperature measurements, which can be insufficient due to the saturation differences in the temperature and the vapour concentration. Therefore, the ovens use extended cycle times for process identification to ensure the proper formation of solder joints. This study offers a solution to eliminate the idle time by investigating the hydrostatic pressure conditions in the process zone. A pressure measurement system was developed for vapour phase soldering ovens which can monitor the vapour pressure changes by a gauge-type pressure sensor with fused temperature measurement. It works as an IoT-enabled node for data logging and subsequent control. The fusion of the hydrostatic pressure values with the temperature values allowed us to identify and reduce the idle time by approximately 60 s, which is 15–20% of the total soldering cycle time. This increases the oven's yield by 15–20%, reduces the system's power consumption by 15–20%, and reduces time above liquidus of the solder by ∼35%. The presented method could enhance the more sustainable electronics production according to the Sustainability Development and could improve the quality and reliability of the lead-free solder joints.