CAMBRIDGE, MA – Draper has developed a predictive design tool that has been tested and validated to show it can predict material failure rates and help determine design requirements for printed circuit boards and similar products.
In tests, engineers found the tool accurately predicted methods to reduce and eliminate laminate crack initiation and propagation on a PCB.
The study, prepared for IPC Apex Expo 2022, was conducted by designing printed circuit boards, using different configurations and materials, and subjecting the boards to environmental stresses and other tests. Using principles of predictive design, engineers developed data sets to guide them. One data set included tests of the PCB materials for such attributes as fracture toughness and thermal conductivity. Another set included detailed design characteristics of the PCB itself.
With the data, the engineers developed a virtual test bed – a finite element analysis computer-aided model – and used it to run scenarios of various PCBs. The FEA model successfully predicted a 50% decrease in internal stress that would reduce or eliminate PCB laminate cracks.
By tweaking the kind of materials and design layouts of a PCB, the team was able to reduce the number, kinds and severity of defects in the board when minor design changes were made.
Wade Goldman of Draper led the team.
“The FEA model allows us to move attributes around to reduce the number and likelihood of cracks in the PCB,” Goldman said. “If each design works as expected, PCB designers and manufacturers are no longer limited to manufacturing by trial and error. Instead, they can spend their time evaluating design changes that might be useful in order to reduce defects and not change their processes.”
The model arrives at an opportune time for the technology industry, Goldman added. “These days it’s all about designing higher density PCBs. As a result, interconnects are becoming smaller, which introduces fragility, and the industry is making more material choices to make higher density interconnects work. You need a predictive design tool to support that effort.”
The predictive design tool is expected to provide PCB designers with a model for determining design rules for future products.
“With this new capability, we have taken a big step in being able to manufacture higher quality printed circuit boards.”