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

This paper describes a technique for the monitoring and control of the refl ow soldering process. The technique combines state-of-the-art infra-red (IR ) sensor technology, coupled with application-specific process monitoring a nd control software, providing a unique capability both to monitor product temperatures during processing and to modify the process settings. The deve lopment 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 temperatur es recorded for each PCA provides full traceability to the reflow process s ettings for each individual PCA, The incorporation of IR sensing technology also provides a means to monitor the performance of the process.