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Tom Woznicki has made a career out of his love for designing flex circuits. Woznicki, also known as “Flexdude,” has focused primarily on flex circuit design since he founded Flex Circuit Design Company in the 1990s, and he designed flex circuits for the Mars rover. But recently, Tom found himself designing rigid PCBs, this time for the TESS satellite. I tracked Tom down via email recently and asked him to discuss his work with TESS, and what it’s like switching between flexible and rigid PCBs.
Andy Shaughnessy: Tom, give us a quick thumbnail sketch of your background and your company.
Tom Woznicki: I almost exclusively design flex circuits and rigid-flex circuits. I have been in the flex industry since 1988 and started my company, Flex Circuit Design Company, in 1992, coming up on 25 years ago! I am a mechanical engineer by education, which I believe really helps me understand the intricacies of flex circuits; they are as much mechanical as electrical. In fact, most flex circuits are electrically simple, but mechanically complex.
Shaughnessy: Now, you’re more identified with flex design, but I understand you designed rigid boards for the upcoming TESS satellite. Tell us about that project.
Woznicki: Yes, for the past two years I have been part of the team working on the TESS satellite. The principal goal of the TESS mission is to detect small planets with bright host stars in the solar neighborhood. I actually designed the early prototype and development PCBs and worked in a support role in the designing the flight boards that are now assembled and in testing.
How did it happen? Once in a blue moon, my flex circuit customers need me for rigid board design help; they need something fast and their PCB designers are busy, or they don’t know any PCB designers and would prefer to work with someone they know. Most times it’s small test boards or interposers, but sometimes it's bigger. As long as we're working with Cadence Allegro or Altium I'm good. (One of the sales reps for Cirexx kids me whenever she sees one of my rigid board designs. "So, you're slumming again, designing PCBs?")
TESS began in a similar way. One of my flex design customer supplies the camera detectors for the project, and they asked if I could help. A TESS scientist had designed the first prototype PCBs on a Mac using a program called Osmond, and they needed someone to bring the design into a mainstream CAD tool and make some changes to that initial design. As I dug into the design changes, it turned out they needed a complete redesign, and of course they needed it in a hurry. I completed that design—it worked fine. Then they asked me to design a microprocessor evaluation board, and after that a spin of the two prototype revisions of the satellite PCBs.
To read this entire article, which appeared in the September 2016 issue of The PCB Design Magazine, click here.