Pressure measurements in a batch type Vapour Phase Soldering Station

As Vapour Phase Soldering (VPS) has again become a significant alternative method for reflow soldering [1], several investigations are in progress to determine the possibilities of the re-introduced technology. During Vapour Phase Soldering Galden fluid is heated, forming a layer of vapour inside the sealed processing zone of a VPS station. The controlling of transferred heat is done through condensation, and the amount of condensation depends on the temperature of the board and the amount of available vapour. The basic method of VPS implies soldering should be carried out under steady state conditions with saturated vapour. Therefore, identification of the level of the saturated vapour layer is essential. Yet, this is commonly accomplished only by temperature measurements inside the processing zone [2]. This paper presents how pressure parameters of the processing zone of an experimental VPS system were measured with novel methods. The results indicate that from the aspect of soldering, the saturated vapour indication is more precise and immediate than temperature measurements with thermocouples.