Combining soldering with inspection

A procedure is described in which an infrared detector is used to control the quality of solder joints being formed on printed circuit boards and a laser is used to inspect the quality of each joint at the same time. This approach eliminates after-the-fact inspection while making available real-time data for process control of the soldering operation. Although the joints are formed one at a time, with somewhat longer manufacturing time compared to alternative processes, the extra time is partly compensated for by elimination of a separate inspection. Moreover, when joints of different sizes occur on the same circuit board, each one receives a tailored amount of reflow energy, thus avoiding underheating or overheating, which can occur when the entire board is soldered at once. Further potential savings arise as a result of the real-time availability of process control data, which make possible rapid correction of process anomalies.<>