Analysis of strains in plated through holes during current induced thermal cycling of a printed wiring board

Current induced thermal cycling (CITC) of the printed wiring boards (PWBs) is proposed as an alternative stress test to traditional accelerated thermal cycling (ATC) to determine the fatigue life of the plated through holes (PTHs). In order to compare PTH strains, simultaneous thermal and stress analysis of CITC is carried out, then a comparison is made with ATC strains. Analysis results show that the rest of the PWB does not reach peak cycle temperature at the end of heating cycle and that the resulting PTH strains are smaller than in ATC. Furthermore, the analyses are continued to determine dwell time to be added to the heating cycle so that the entire PWCB reaches peak cycle temperature and that the PTH strains in CITC are the same as in ATC.