Unconventional Geometry Design Techniques

Estimated reading time: 2 minutes

We survey our readers from time to time, and a number of respondents have mentioned that designing boards with odd geometries can be a real challenge. We asked design instructors Kris Moyer and Kelly Dack to discuss the challenges related to designing odd-shaped PCBs, as well as some solutions for designing today’s boards that are anything but rectangles. What’s the craziest-shaped board you’ve ever worked with?

Andy Shaughnessy: Kris and Kelly, thanks for joining us. Let’s start with Kris. You talk about the challenges of designing odd-shaped geometries in your design classes? Tell me about those challenges. 

Kris Moyer: One thing that comes to my mind regarding oddball geometries: To fit in all the parts, you have to learn how to place your parts at oddball rotations, not just 90 or 45 degrees. I don’t want to give away any classified stuff, but I was working on the design of a circular board that goes in one direction really, really fast and doesn't come back, ever. The parts were laid out, and all the circuits were laid out like pizza wedges, radially out from the center. This board had very large stacked ceramic caps, the SMPS type, which ended up being over an inch long, but they needed to be normal to the radius—but not on a standard 90- or 45-degree radius angle—with all these different angles. 

We had to start rotating the parts so they would follow the curve of the circular board around the diameter without hanging over. We had these parts placed at, say, 12.7 degrees and 33.9 degrees—all these weird angles and rotations. But the pads were no longer where you could route cleanly into them at the 90- or 45-degrees with standard interactive routing or autorouting because we were doing all these oddball route angles. 

To read this entire conversation, which appeared in the December 2024 issue of Design007 Magazine, click here.