A brand new analytical mannequin that accounts for the form of solder joints, with a particular emphasis on the willpower of the mechanical properties of PCBs.
Hooke Electronics in France has developed a brand new analytical mannequin to guage the thermomechanical reliability of SAC305 lead-free solder joints. The method is designed for electronics uncovered to vital thermal biking in sectors similar to aerospace, defence, medical, and industrial purposes.
It’s supposed to exchange older simplified analytical fashions, which regularly lacked precision, whereas providing a sooner and extra accessible various to Finite Aspect Evaluation (FEA).
The SAC305 alloy, manufactured from 96.5% tin, 3% silver, and 0.5% copper, is the business normal alternative for tin–lead solder after restrictions on lead use beneath RoHS and REACh rules. Guaranteeing its reliability is essential, as thermal fatigue can result in failures in printed circuit board (PCB) assemblies over time.
This new analytical mannequin estimates solder joint life and calculates PCB thermal properties, similar to density, conductivity, and particular warmth, with out the necessity for resource-intensive simulations.
It incorporates solder joint geometry and the mechanical traits of each the PCB and its elements right into a simplified elastic–plastic and viscoplastic framework to simulate deformation and creep beneath temperature biking.
Improvement concerned calibrating the mannequin utilizing 83 datasets from sturdiness exams throughout totally different packages, PCB stack-ups, and thermal biking situations, adopted by validation with 23 extra datasets. It has been examined on widespread surface-mount elements, together with ball grid arrays (BGAs), chip elements, and Ceramic Leadless Chip Carriers (CLCCs).
