The era of "blind" laser soldering is coming to an end. The new Intelligent Laser Soldering system has an infrared "eye" focused on the solder joint being heated by the laser beam. As soon as all the solid solder has melted, the laser shuts off. In this way every joint receives precisely the amount of heat necessary to reach full liquefaction of the solder alloy. No more overheated joints. No more "cold" joints. And no more need for subsequent inspection, because for each joint, theinfrared,detector's output is the "infrared signature", containing all information about the joint's quality characteristics.
"New Laser Soldering Has Vision", Proc. SPIE 0856, IECON '87: Industrial Applications of Robotics & Machine Vision, (19 October 1987); doi: 10.1117/12.943032; https://doi.org/10.1117/12.943032