Numerical Simulation of Condensate Layer Formation During Vapour Phase Soldering

This paper presents a modeling approach of the condensate layer formation on the surface of printed circuit boards during Vapour Phase Soldering (VPS) process. The condensate layer formation model is an extension to a previously developed board level condensation model, which calculates the mass of the condensed material on the surface of the soldered printed circuit board. The condensate layer formation model applies combined transport mechanisms including convective mass transport due to the hydrostatic pressure difference in the layer and the gravity force; conductive and convective energy transport. The model can describe the dynamic formation and change of the condensate layer after the immersion of the soldered assembly into the saturated vapour space and can calculate the mass and energy transport in the formed condensate layer. This way the effect of the condensate layer changes on the heating of the soldered assembly can be investigated. It was shown that the numerical modeling of the VPS process becomes more accurate with application of dynamic condensate layer instead of a static description

Modeling Method of Heat Transfer During Vapour Phase Soldering Based on Filmwise Condensation Theory

The paper presents a practical method for calculating the heat transfer during Vapour Phase Soldering (VPS) process. VPS is a reflow soldering method based on condensation heating and used in the electronics manufacturing. The presented explicit model describes solutions for filmwise condensation heat transfer based on the Nusselt theory. Different approaches on describing the filmwise condensation were investigated, compared and modified in order to determine a proper heat transfer coefficient for the VPS process - where the heated assembly can be considered as a horizontal plate. For the verification, measurements were done in an experimental soldering oven. The results of the calculations show a proper approximation with the measured temperature data. Finally the results were compared with a solution obtained from complex multi-physics simulation. The results point out, that the application of filmwise condensation model for VPS can be more practical than a complex multi-physics model, from the aspect of calculation error and computation time

Characterization of Vapour Phase Soldering Process Zone with Pressure Measurements

Purpose: With the spreading of Vapour Phase Soldering (VPS) technology it is important to understand and optimize the process itself. The paper presents a novel approach on the process zone characterization for direct feedback on the state of vapour, for better monitoring, control and understanding of the process. Design/methodology/approach: The simple model of condensation heating shows the importance of vapour concentration during condensation soldering. Different pressure sensors were applied in an experimental VPS station, where the hardware setup is focused for the current experiments. Static and dynamic pressure values are analyzed and correlated with additional thermal measurements. Findings: The results reveal the dynamics of the vapour blanket generation. The correlated measurements show different stages of the process initialization, highlighting better accuracy than sole temperature measurements of saturated vapour identification. It is possible to trace the height of the available saturated vapour blanket with static pressure measurements. Originality/value: The methods provide a completely novel approach from the aspect of process zone state variables and parameter characterization, focusing on pressure measurements. Practical implications: The VPS process may benefit from the more precise saturation detection, giving better control on the heat transfer, enabling more efficient production with the reduction of idle time, and resulting in better soldering quality. Social implications: Reducing the idle time of the VPS stations may result in better efficiency and smaller power consumption, reducing the environmental impact of the method

A Review on Current eCall Systems for Autonomous Car Accident Detection

The aim of the paper is to give an overview on the existing eCall solutions for autonomous car accident detection. The requirements and expectations for such systems, considering both technological possibilities, legal regulatory criteria and market demands are discussed. Sensors utilized in e-call systems (crash sensing, systems for positional and velocity data, and communication solutions) are overviewed in the paper. Furthermore, the existing solutions for eCall devices are compared based on their level of autonomy, technical implementation and provided services

Vapour phase soldering (VPS) technology: a review

Zaharia Eugenia. Morminte sarmatice descoperite la Cioinagi în 1949 (r. Tg. Bereşti, reg. Galaţi) / Découvertes de tombes sarmates à Cioinagi, en 1949. In: Materiale şi cercetări arheologice, N°6 1959. pp. 897-902