SYSTEM FOR REAL-TIME MEASUREMENT OF THERMALLY-INDUCED PWB PWA WARPAGE/

An automated on-line warpage measurement system for printed wiring boa rd assemblies (PWBAs) has been developed. The system is capable of sim ulating an infrared reflow soldering process and performing real-time PWBA warpage measurements using the shadow moire technique. The system can be used to characterize the warpage behavior of virtually any PWB A during infrared soldering processes as well as during operational co nditions. Using this system, warpage of PWB test vehicles was measured during simulated infrared reflow soldering. The measurement results a nd the measurement system will be presented. The measured warpage vari ed significantly during reflow soldering from that obsessed both befor e and after reflow. These results help us to understand how the board deforms at every stage of the reflow process.