Experimental Investigation and Numerical Simulation of the SMT Laser Microsoldering Thermal Process

In this paper, a numerical simulation of the thermal process in SMT laser microsofdered joints has been developed, in which the influences on the thermal process of factors such as the thermal conductivity variation of solder with temperature, light reflection coefficient of the lead wire surface, and heat transfer on the surface of SMT materials have all been considered. In order to put this numerical calculation into practice and prove its results, the reflective characteristic of light waves in relation to SMT materials has been determined, and the dynamic temperature process of laser soldered microjoints has been measured by a new experimental method invented by the authors. The numerical simulation results have been borne out by the tests, and the influence of heating parameters on the thermal process has been analysed in this paper. The conclusions will benefit the further study of microjoint quality control in SMT laser microsoldering.