Transient Thermal Stress Analysis of a Plated Through Hole Subjected to Wave Soldering

During a typical wave soldering operation a plated through hole (PTH) is exposed to temperatures which are higher than any rated operating temperatures. Understanding the heat transfer and the potential PTH damage mechanisms, which arise during the wave soldering process, is critical to PTH quality control and reliability. In particular, cracks may be initiated during the wave soldering transient and become manifest only after operational cycling. This paper presents a transient nonlinear thermal stress analysis of a nonsolder filled PTH that is subjected to a typical wave soldering process. A full three-dimensional orthotropic analysis and an axisymmetric analysis with cylindrically anisotropic properties are used and the results compared. Temperature and stress/strain history curves are examined to determine the impact of the wave soldering operation on the PTH fatigue life. The effect of PWB innerplanes on the PTH maximum stress and strain is also investigated.