Real-time profiling of reflow process in VPS chamber

Abstract

Purpose This paper aims to present a new method of real-time monitoring of thermal profiles applied in vapour phase soldering (VPS) reflow processes. The thermal profile setting is a significant variable that affects the quality of joints. The method allows rapid achievement of a required thermal profile based on software control that brings new efficiency to the reflow process and enhanced joint quality, especially for power electronics. Design/methodology/approach A real-time monitoring system based on computerized heat control was realized in a newly developed laboratory VPS chamber using a proportional integral derivation controller within the soldering process. The principle lies in the strictly accurate monitoring of the real defined reflow profile as a reference. Findings Very accurate maintenance of the required reflow profile temperature was achieved with high accuracy (± 2°C). The new method of monitoring and control of the reflow real-time profiling was verified at various maximal reflow temperatures (230°C, 240°C and 260°C). The method is feasible for reflowing three-dimensional (3D) power modules that use various types of solders. The real-time monitoring system based on computerised heat control helped to achieve various heights of vapour zone. Originality/value The paper describes construction of a newly developed laboratory-scale VPS chamber, including novel real-time profiling of the reflow process based on intelligent continuously measured temperatures at various horizontal positions. Real-time profiling in the laboratory VPS chamber allowed reflow soldering on 3D power modules (of greater dimensions) by applying various flux-less solder materials.

Modelling thermal properties of large LED modules

“…The PCB comprised an aluminum-core base layer, a thin thermally conductive dielectric layer and a copper-circuit layer of thicknesses 1.5 mm, 0.100 and 0.035 mm respectively. The modules were soldered using two different techniques: convection reflow and vapor phase reflow in vacuum [6,7,[24][25][26][27]. Alpha Metals OM340 solder paste of InnLotTM type was used for the LEDs assembly [28].…”

Alternative Inspection Methods of Vapour Phase Soldering Work Zone

“…[10][11]. Setting of this profile [12] or optimizations with statistical methods [13] were also investigated. Power electronics manufacturers utilize VPS due to the efficient soldering of large components [14][15][16][17].…”

Component level modelling of heat transfer during vapour phase soldering with finite difference ADI approach

“…Real time temperature profiling [9] or optimizations with statistical methods [10] were also investigated by Livovsky and Tsai, respectively. Power electronics manufacturers utilize VPS due to the efficient soldering of large components [11][12][13][14][15][16].…”