Investagation of SMT laser soldering quality monitoring method

In this paper, a method, which has been used in real-time monitoring of laser soldering quality, based on the relation between the thermoelectrical potential and temperature of joint face of the jointed materials and the relation between the efficient heating volume (the integral of the part of the interface temperature above the temperature threshold) and the joint area, is presented. The experimental results show that the relation of the thermoelectrical potential of the jointed materials and interface temperature is well linear, the measured efficient heating volume fully shows the condition of the heating and melting of the interface and solder and can be used in monitoring and controlling laser soldering system.