The application of IR thermography to process monitoring and control of reflow soldering

Abstract

This paper describes a technique for the monitoring and control of the reflow soldering process. The technique combines state‐of‐the‐art infra‐red (IR) sensor technology, coupled with application‐specific process monitoring and control software, providing a unique capability both to monitor product temperatures during processing and to modify the process settings. The development of techniques to allow variation of the heat transfer from the oven to the in‐process printed circuit assemblies (PCAs) provides the means to adjust the soldering oven’s process settings for each individual PCA. This automatic profiling ensures consistent thermal histories and optimises oven energy consumption. Archiving of the reflow profiles along with temperatures recorded for each PCA provides full traceability to the reflow process settings for each individual PCA. The incorporation of IR sensing technology also provides a means to monitor the performance of the process.

An autonomous low-Cost infrared system for the on-line monitoring of manufacturing processes using novelty detection

“…Thermocouples have been suggested for monitoring soldering processes [31], however, a thermocouple is capable only of measuring temperature of a single point and they also need to be physically attached to the components. High-resolution infrared thermography has been used [32] to model electronic soldering. In this paper, a low-cost infrared imager is used to study the heat generated from a soldering process in order to evaluate the imager capability for automated monitoring of soldering electronic components.…”

<title>Thermal signature for printed circuit board stress-failure diagnosis</title>

“…Other related work includes Conway from Loughborough University in England, who developed an infrared imaging system for re-flow soldering process monitoring and control 10 . Heat-up radiation rate, heat density and distribution of IR radiation were used as screening variables in evaluating how a component is functioning 11 .…”