Factors Affecting the Mechanical Strength of Reflowed Solder Joints for Surface Mount Technology (SMT) Products

At present, the PEM SMTSO product line is used for providing mechanical fastening to Printed Circuit Boards (PCB). The most important parameter in this fastening system is torque-out attainability, with the primary determiner of this value being the solder joint.

This paper explores how solder joint strength is affected by reflow curves, and what the impact is of lower reflow temperatures and the use of lead-free solders. The peak temperature (PT), time above liquidus (TAL), and cooling rate that drives PennEngineering’s current maximum performance is shifting as the direction the Printed Circuit Board Assembly (PCBA) industry shifts. That being said, PennEngineering will continue to attain the performance values of their SMTSO at lower peak reflow temperatures