The efficiency of assembly of electronic components into PCBs relies on a large number of materials and processes being carefully specified and controlled. Improved production routes for PCBs and new soldering techniques frequently appear and yet, 40 years after the first PCBs and nearly 30 years since the advent of wave soldering, the perennial problems have not been eliminated and the industry is still beset with trial and error adjustments of process parameters. Scientific research at NPL has progressed towards an understanding of the basic causes of the 2 main problems of PCB soldering: outgassing and lack of solderability. Applying the scientific method, in direct collaboration with production line technology, the mechanisms of outgassing are now understood and test procedures for materials specifications are being developed. The work is at a stage where the PCB industry is heavily involved with controlled monitoring of the various stages of through‐hole‐plating and inter‐company round‐robin tests are in progress in order to confirm the transferability of laboratory tests to the industrial production line.