The modelling option ... lead-free soldered circuitry faces a reliability onceover

Connect, no.135, March/April 2005, p.3

The reliability of printed circuit boards which use lead-free solder can now be modelled using calcePWA software at TWI.

The software simulates the effect of temperature profiles and mechanical loading over the design life of a PCB, to predict times to failure. This approach indicates where joints will fail as a function of thermal and mechanicalloadings.

Costly field failures can be avoided by modifying PCBs at the design stage. TWI can simulate boards made with leaded or unleaded solders, for a range of industry sectors including military, automotive, avionics/space and consumerelectronics.

To learn more about this invaluable software contact Chris Otter at TWI. E-mail: chris.otter@twi.co.uk

Fig.1. Control electronics for jet engines are mounted directly to the engine assembly and experience significant fluctuations in thermal and mechanical stresses

Fig.2. Modelling the PCB can predict the time to failure and mode of failure. An example shows a failure in a SnPb solder connection on a ceramic surface mount component