Measurement and regulation of saturated vapour height level in VPS chamber

Abstract

Purpose The purpose of this paper is to investigate measurement and regulation of saturated vapour height level in vapour phase soldering (VPS) chamber based on parallel plate capacitor and retaining a stable saturated vapour level above the boiling fluid, regardless of the quantity and size of assembled components. Design/methodology/approach Development and realisation of capacitance sensor that sensitively senses the maximum height level of saturated vapour above the boiling fluid in the VPS chamber was achieved. Methodology of measurement is based on capacitor change from single air to a parallel plate, filled with two dielectric environments in a stacked configuration: condensed fluid and vapour (air). Findings An easy air plate capacitor immersed in the saturated vapour above the boiling fluid can serve as a parallel plate capacitor owing to the conversion of the air to the parallel plate capacitor. A thin film of fluid between the two capacitor plates corresponds to the height of the saturated vapour, which changes the capacity of the parallel plate capacitor. Originality/value Introducing the capacitive sensor directly into the VPS work space allows to achieve a constant height level of saturated vapour. Based on the capacity change, it is possible to control the heating power. There is a lack of information regarding measurement of stable height of vapour in the industry, and the present article shows how to easily improve the way to regulate the bandwidth of saturated vapour in the VPS process.

Refined Approach on Controlling Heat Transfer in a Vapour Phase Soldering Oven

“…The figure has an inverted temperature axis, representing the vapour space in the Z dimensions of the oven. In Figure 5 a reflow profile of 42Sn58Bi (Indium), low melting temperature solder alloy is presented, where the "Theoretical" programmed plot (practically masked by the measured real profiles) refers to the recommendation of the solder paste profile (based on adjusted datasheet parameters [13]). With 40x40 mm surface area, 1,55 mm thick FR4 test boards for soldering, the system can follow the profile with close relation to the theoretical plot.…”

“…Over the last years few new approaches were introduced on the control and inspection of the oven. Livovski and Pietrkova presented a new approach on the measurement and regulation [12,13] of the saturated vapour height level in a VPS oven, where a parallel plate capacitor was used for the regulation of the saturated vapour level height. Combine this with a PID controlled vertical lift setup and a thermocouple-ladder feedback, less than ±2 °C deviation can be achieved with continuous profile setting.…”

A gőzfázisú újraömlesztéses forrasztás megfigyelése újszerű alkalmazott szenzorikai módszerekkel

“…kétféle anyag a fegyverzetek között; b) a konstrukció [12] Amennyiben a szenzort a folyadékba is bemerítik, úgy a Galden hőtágulását is vizsgálni lehet, amivel a forró folyadék felső szintjének pontos megfigyelése válik lehetővé. [12]…”

Analytical Solution of Heat Distribution Inside a Printed Circuit Board During Vapour Phase Soldering

“…The optimal soldering profile and heating factor have considerable effect on the solder joint quality [8]. Besides simulation and modelling aspects, there are new measurement approaches which can be used for VPS process regulation [9,10]. For using and achieving an adequate soldering profile recommended by the paste manufacturers, simulation and modelling is a key investigation aspect, due to the low cost and possibility of generalisation.…”