In situ non contact temperature measurements on PCB during soldering process

Abstract

The paper deals with investigation of non-contact electronic components' temperature measurements during soldering of surface mounted devices (SMD) to printed circuit boards (PCB). Approach and equipment for non contact temperature measurements with infrared (IR) thermometer is proposed. Measurements of electronic components' temperature on the PCB are difficult and practically impossible for a lot of electronic components during soldering process. In this paper the results concerning possibility for IR temperature measurements' application for in situ control of soldering processes are presented. Soldering equipment is based on low inert heaters for the middle IR spectral region without conveyor belt and allows realizing precise measurement and control (in situ) of the temperature on the PCB during the soldering processes, possibility of individual temperature profile for every printed board in dependence of its size, electronic components density and others. Contact temperature measurements (by thermocouples) in a few point on PCB allows controlling the soldering process, but the temperature is measured mostly in one or two points. Application of proposed method and equipment allows to optimize temperature regimes' control during soldering cycles and to avoid thermal damages of electronic components.