In-process board warpage measurement in a lab scale wave soldering oven

An automated on-line warpage measurement system for printed wiring boards (PWBs) and printed wiring board assemblies (PWBAs) has been developed. The system is capable of simulating a variety of soldering processes, including the wave soldering process, and performing real-time PWB/PWBA warpage measurements using the shadow moire technique. The system can be used to characterize the warpage behavior of virtually any PWB/PWBA during the soldering process. Using this system, warpage of PWB test vehicles was measured during simulated wave soldering. The measured warpage varied significantly during wave soldering from that observed both before and after wave soldering. These results help us to understand how the board deforms at every stage of the soldering process.