Cars drive over cobblestone pavement, and commercial vehicles make their way around bumpy construction sites. In the summer, they are exposed to heat, and in the winter, to freezing temperatures. All of this places strict requirements on the individual components of products such as printed circuit boards (PCBs). They are the crucial element of electronic modules. Vibration and thermal deformation can cause small cracks between the board and the component, which can lead to failure. Because of this designers measure the effect of mechanical loading very precisely during the development of a prototype. In this way, they can ensure that the PCBs will function properly up to the loading limit and also not undergo any damage in the production process.
Cars and commercial vehicles are just one field of application where measuring mechanical loading is useful. Trains and laptops are also continuously exposed to vibration. “Basically, there is a risk of breaks and cracks at every connection between the PCB and a component placed on it,” explains Christof Salcher, Product Manager at HBM. That can be expensive, for example, when the electronics in an automobile no longer work due to a small crack. Manufacturers are increasingly requiring their suppliers to prove the mechanical stability of PCBs. "Strain values are the only parameters that are reliably predictive in terms of the stress loading of PCBs. They can be measured using strain gauges, which are placed directly on the PCB to do this,” continues Salcher.