A lifetime designing PCBs: Merging design and fabrication

-November 20, 2017

My role in the PCB industry continued to evolve. In the previous article, I wrote about my venture into the software side at Redac. However, in late 1984, I resigned from Redac because I needed to give all of my attention to Computer Circuits.

As I should have known, trying to be successful with major responsibilities at two companies was beyond my ability. I have no regrets about diving into the software side; however, the timing wasn't right. Computer Circuits had struggled in my absence.

Our design team was strong, with members including Johnnie Travi, Mike Chaney, Linda and Max Mazzitelli, Pat Heinz, and Jim Redel. I had no worries about their abilities – the company just needed my focus to manage the sales and operations. We also had new design challenges, mostly because circuit boards were getting bigger and denser. It was refreshing to be back on the design side. The business stabilized, and while it wasn't without the usual problems of a small company, I felt that it was on a good track.

In 1985, Automata, a local PCB fabricator that wanted to expand into design, acquired Computer Circuits. Because Automata was committed to leading-edge fabrication processes and equipment, I felt good about the relationship and the opportunities for the future of our design team. Mohammed El-Ezaby, the founder of Automata, and Bob Lowry, treated me like family, and I miss working with them, as well as learning about fabrication processes from them. Being at Automata helped all of us become better designers. Seeing how our work was used in manufacturing enabled us to understand why so many fabrication concerns were important during the design process. The layout of the fab process is shown in Figure 1. The design services were in “Engrg.” (blue) and my office was in “CP” (orange).

 

Figure 1  Automata layout

At Computer Circuits, we had a Cadnetix CDX-75000 Route Engine that was interfaced with the Redac Maxi systems. It was fairly effective for the designs of that time, yet, like all autorouters, it wasn't a panacea. The system ran on its own hardware, tuned specifically for high-performance routing. At Automata, the decision was made to purchase Cadnetix CDX-5000 design stations for layout as well. Cadnetix was a popular PCB design software company at the time, and there were plenty of potential customers in our area on that platform.

We did have several problems with the autorouter; e.g., it completely failed on all of the initial designs we tried. After numerous calls to Cadnetix support, it was finally discovered that the system was shipped without the extra memory required to route large boards. Once that was addressed, the system mostly did what we expected it to. No hardware or software is perfect, and experiences like this one helped me – later in my career – to have empathy for customers who get frustrated when software problems occur and make it difficult to get the job done.

When we got the CDX-5000 systems, Mike Chaney and the other designers found quite a few problems. He called in many of them. After a while, the support team must have tired of hearing from Mike, because they wrote me a letter stating that for them to continue to support us, at least one of the designers had to attend Cadnetix training. They felt the problem was our ignorance, not the software. Mike took the training, but everyone discovered rather quickly that he knew as much or more than the trainer, plus, he scored the highest mark ever on the test at the end of the session. So, it was no surprise that from then on, the support teams treated Mike and our design group with much greater respect.

The CDX-5000 system had on-line DRC that gave feedback when an error was made. If there were an award for the dumbest feature in PCB design software, this one would certainly be at the top of the shortlist. The error notification was a rather loud series of four beeps. What designer wants others in the office to be notified whenever an error was made? For those working nearby, the frequent beeping sound from multiple design stations became exceedingly irritating. Thus, after losing its role in the PCB layout process, the X-Acto knife had a final encore. We used it to cut the speaker wires.

With more circuits crossing into the high-speed realm, our customers became concerned about impedance control. Automata was the perfect environment to learn about design and fabrication techniques to manage impedance. I remember creating test coupons and doing measurements with a time-domain reflectometer. This data was used to understand what stackups, trace widths, and materials would be appropriate for our design and fabrication process in order to meet the impedance requirements.

Automata kept abreast of fabrication innovations, and always considered updates to its production line to optimize efficiency. As part of this commitment to new technology, they alpha-tested the first Laser Direct Imaging (LDI) system, Excellon’s DIS-2000. Instead of using photoplotted artwork to expose the etch mask (a largely manual process), the laser would directly expose the mask on each layer. It was an amazing advancement for the 1980s. While LDI was a big step in automating the process, it was much too slow, and had some registration problems. It wasn’t until the late 80s that the LDI process performed well enough to be adopted across the industry. One of the joys of being in our industry is watching the continual evolution of technology and process.

In late 1987, the software side called again, presenting me with another career-path quandary.

 

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Charles Pfeil is a Senior Product Manager at Altium, working on definition of their products with a primary focus on routing tools.

 

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