Reading time ( words)
I’ve been designing PCBs and flexible circuits for decades now. I’ve heard a lot of advice over the years, but what really sticks in my mind are the wise words of a mechanical engineer I worked with back in the ’80s. He was an older guy named Clarence. One day, Clarence and I were doing a design review, and he gave me some sage advice: “Kelly, never design something that can’t be built.”
I got a chuckle out of his statement. Well, duh! Of course, it must be manufacturable. Every designer knows that, right?
But as the years went by, I engaged with more designers, design teams and manufacturing stakeholders. (In my view, the stakeholders are anyone with “skin in the game.” We don’t want to let down any of our fellow stakeholders.) I soon realized that Clarence’s words were a prophetic warning for my future career path as a PCB designer. While I was thinking “duh,” I had only begun to start reaching out to suppliers and manufacturers in the PCB industry.
As I spoke with these manufacturing stakeholders about what they need from a designer to make successful circuit boards, I heard woeful tales of PCB designs that were unmanufacturable. Some designs had lines that would etch away, or via pads that would be obliterated if over-drilled to allow for plating. Multilayer PCB stack-ups would often need to be a quarter-inch thick to achieve the specified impedance requirements. It was as if these PCB designers had never set foot inside a fabrication facility before. And that turns out to be the case more often than you might think; many designers have never visited a board shop.
After many years, I’m still designing rigid PCBs and “flexitos,” and I’m still reaching out to PCB manufacturing suppliers and making queries to find out what designers can do to help our manufacturing counterparts be successful. And you know what? I’m am hearing Clarence’s words echoing from an entire industry of fabricators: “Never design something that can’t be built.”
If you are a PCB designer, are you surprised? Maybe you are responding “Duh,” as I did 30 years ago. In the spirit of Clarence, I’m here to warn you that “duh” is an inadequate response. Unmanufacturable designs are still prevalent in the PCB industry, on a worldwide scale.
To help alleviate this issue, I’m trying to convince designers that they need to visit a board shop every now and then. I recently had the opportunity to take a group of designers on a tour of Streamline Circuits, a rigid and flex fabricator in Santa, Clara, California.
As a design instructor for EPTAC, I was teaching an IPC Certified Interconnect Designer (CID) class in Santa Clara. This four-day class drew a group of five PCB designers, all hoping to achieve their CID certification by the end of the week. During the segment of the course materials that covers the importance of reaching out to other PCB process stakeholders, I always ask the class if anyone has visited a PCB fabrication supplier to see the process up close. I am constantly amazed that a very small percentage of designers have ever done so.
During this class, I had learned that the training facility that EPTAC uses in Santa Clara is a block away from Streamline Circuits. Streamline does a lot of military and aerospace work, as well as communications and industrial electronics. The company manufactures quite a bit of multilayer flex and rigid-flex circuits, in addition to rigid boards. This would make a great field trip for my CID class!
To read this entire article, which appeared in the April 2018 issue of Flex007 Magazine, click here.