Solder Joint Fatigue

Solder joint fatigue (due to thermal cycling) of electronics devices is one of the main failure modes of electronics systems. It has resulted in serious failure and very costly recalls of electronics devices. This has lead to most large organization to have dedicated teams of engineers running simulations to prevent solder joint fatigue.

As PCB assemblies become more complex, the need for solder joint fatigue simulation grows. With large number of parts and multi-layered PCBs; the geometric complexity makes these simulation very challenging.

Singularity engineering offers a couple of approaches to tackle this issue.

  • Fast empirical equation based solder fatigue check

  • Details finite element based solder joint reliability simulations.

 
 

Fast check for SJR

If you have lots of caps, qfn, dfn and other basic components on a board and you want to quickly understand the risk of solder joint fatigue due to thermal cycling, this is the best option.

This method uses the Engelmaier model to quickly scan hundreds or thousands of components on a PCBA and estimate time to failure.

 

Detailed BGA solder joint fatigue

The components most in danger of solder joint fatigue are high powered devices like BGA’s. With the addition of heavy duty cooling, heatsink and bracket supports, the solder joint problem can become very complex. In these cases the industry standard is to use the Darveaux method with ANSYS to understand the details of solder joint failure.

This method allows you to predict failure down to a single solder ball and has high accuracy. It is also a fully non-linear viscoplastic simulation.

 

Best of both worlds

The biggest challenge for solder joint reliability simulation is the geometric complexity of today’s PCB assemblies. The solutions has been available for decades, but working with a fully load PCB with thousands of components remains challenging.

By combining DFR Sherlock and ANSYS Mechanical, we have a workflow that allows much faster set up of complex assemblies. This brings the power for rapid PCB centered setup to general purpose tools like ANSYS.