Abstract： Three groups of drop impact tests of solder joints have been conducted with different drop height. Proportional hazards model (PHM) is used to evaluate the effect of drop height on the solder joints’ life span. The mean-time-to failure (MTTF) and the failure probability density function (PDF) estimated from the PHM agree well with the experimental data, and this validates the effectiveness of the PHM. By the curve of the MTTF (with respect to different drop heights), it can be observed that the MTTF<10 when the drop height is greater than 0.6m, and this demonstrates that the lead-free solder joints are very sensitive to drop impact. Finally, the estimated lifetime of MTTF is integrated with the Miner’s law for cumulative damage model of lead-free solder joints.
2011, Vol. 30 
