Effect of the vapour concentration decrease on the solder joints temperature in a vacuum vapour phase soldering system

Abstract

Purpose The vacuum vapour phase soldering method was investigated by numerical simulations. The purpose of this study was to examine the temperature changes of the solder joints during the vapour suctioning process. A low pressure is used to enhance the outgassing of the trapped gas within the solder joints, which otherwise could form voids. However, the system loses heat near the suction pipe during the suctioning process, and it can result in preliminary solidification of the solder joints before the gas could escape. Design/methodology/approach A three-dimensional numerical flow model based on the Reynolds averaged Navier–Stokes equations with the standard k-e turbulence method was developed. The effect of the vapour suctioning on the convective heat transfer mechanism was described by the model. Temperature change of the solder joints was studied at the mostly used substrate and component combinations, as well as at different system settings. Findings In the function of the substrate thickness and the component size, the solder joints can lose large amount of heat during the void reduction process, which leads to preliminary solidification before the entrapped gas voids could be removed. Research limitations/implications The results provide setting information of vacuum vapour phase technology for appropriate and optimal applications. Originality/value The relationship between low pressure generation and convective heat transfer mechanism during vacuum vapour phase soldering has not been studied yet. The possible negative effects of the vapour suctioning process on the solder joint temperature are unknown.

Vapour phase soldering (VPS) technology: a review

“…According to the industrial experiments if the difference in onset of melting is over 0.2 -0.3s, then the probability of component displacement failure increases considerably. The effect of the low pressure generation on the solidification of the solder joint were also examined during the vacuum VPS process (Illés et al, 2018B). It was found that process zone can suffers considerable heat loss on the suction pipe which results in the drop of the solder joints temperature.…”

“…It was found that process zone can suffers considerable heat loss on the suction pipe which results in the drop of the solder joints temperature. In the case of thin FR4 PCB (<1.5mm) with small components (<0.5mm), the solder joints can solidify during the low pressure generation before the voids would be removed from the solder joints (Illés et al, 2018B).…”

Measurement and regulation of saturated vapour height level in VPS chamber

“…We use the knowledge that the transition temperature from the gaseous (saturated steam of boiling liquid) to the liquid state is precisely defined as the boiling point of liquid. The saturated vapour condenses and transfers its latent heat of vaporisation to the surface of assemblies (Illés et al, 2017;Illes et al, 2018). At the boiling point of liquid, the properties of the capacitor change from a single plate to a parallel plate capacitor, filled with two dielectric environments in a stacked configuration: condensed fluid and saturated vapour (air).…”

Machine learning-based prediction of component self-alignment in vapour phase and infrared soldering

“…Reflow soldering technology is the most widespread technique for creating the electrical and mechanical connection between the electronics components and the printed circuit board in electronics mass manufacturing today as described by Illés et al (2018). The continuous request for electronic devices that are faster, smarter and smaller is the driving force in electronics technology, which resulted in the shrinkage of component sizes.…”