A lifetime designing PCBs: early design adventures
Article By : Charles Pfeil
PCB design was all about creating proper interconnects between components so when the power was applied it would behave and perform as the engineer imagined.
My first exposure to PCB design was in 1966 working for Northrup Corporation in the quality assurance (QA) department. My father got me a job there during the summer of my junior year in high school; I was so proud to be working for $1.75 per hour. With gas at 32 cents per gallon, my wages would more than cover my 45-mile round trip.
Working for QA sounds pretty good for a first job, but back then it really was not so glamorous. My primary responsibility was to inspect a Rubylith artwork that PCB designers created. I used an eyeglass to find X-Acto knife cuts and scratches made in the red plastic. Once the offending nicks were found, I would use a red pen to fill them in. Frankly, it got boring after just a few days, but, little did I know, this teenage experience would launch my career in the PCB industry, for which I am forever grateful!
It didn’t take long to understand that PCB design was all about creating proper interconnects between components so when the power was applied it would behave and perform as the engineer imagined. Now 51 years later, I can honestly say that nothing has changed in that regard. Sure, materials, components, and signal performance have evolved to enable astounding capabilities; yet, it’s still all about hooking up components. With that perspective, PCB design seems like a rather simple task. I often ponder why it hasn’t been completely automated after all these decades, but that is a topic for another article.
In 1969, I was fortunate to get a job designing keyboards for Datatronics. This was a summer job while I was studying for an architecture degree. In my calculus class, we wrote little programs with punched cards for the mainframe computer. This piqued my interest in computer technology and made the idea of PCB design even more appealing.
Before working at Datatronics, I interviewed for a draftsman job at an architectural firm. Much to my surprise and embarrassment, I did not get the job because my printing was not fancy enough. Soon, I realized that in architecture, either you were Frank Lloyd Wright or you were a draftsman, nothing in between. Since I failed as a draftsman, my dream was ruined by reality. My work at Datatronics made me understand that as a PCB designer, I could fulfill my primal desire for my career, which was to be creative and get paid for it.
At Datatronics, the PCB assembly for the keyboard consisted of two layers with membrane overlays made of plated Mylar that would complete a circuit when pressed together by each key. Designing a layout was done with red and blue pencils on matte surface Mylar, and the scale of the layout was 2x. Using black tape for the routes and round dots for the pads, we could create the artwork on clear Mylar. Each sheet of Mylar had two punched holes that fit onto registration pins. The layout and the tape-up were aligned and when placed on a light table, it was easy to see if all the interconnects were taped up properly.
My first design at Datatronics was fabricated and worked without any problems. Designers, like every creative person, want to be involved in projects that can provide a sense of accomplishment. This first design meant a lot to me and validated my decision to abandon architecture for electronics. Figure 1 illustrates two Mylar layers of an early keyboard design.
During the ‘70s, I worked as a contract designer. The electronics age was emerging and PCB designers were in demand. Employment contract companies, called “job shops,” which normally supplied engineers to this industry were now being asked to provide PCB designers. But where were these designers found? There weren’t any school courses for PCB design, and most electronic engineers wanted to focus on circuit design. This is when the opportunity arose for all those who are now considered the old artistic designers. The typical designer was creative and artistic, while also very detail oriented. Count me in!
As a job shopper, I didn’t have much security. Often, my role lasted as long as a single project and then I would jump to the next company. The good news was it enabled me to gain a wide variety of experience and to meet a lot of wonderful people.