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Elementary, Mr. Watson: Managing Risk in PCB Design

I recently attended a risk analysis meeting that focused on the question, "What can go wrong in a system design?" They slowly worked their way around to me. As the senior PCB engineer, my first thought was, “This is a loaded question.” My answer, though, was short and sweet: "Anything and everything." 

That is so true, though; I have seen some crazy things during my 40-year career. One of the weirdest things I saw in a PCB design many years ago was that underneath the PCB solder mask there looked to be a mosquito—like a fossil of some prehistoric creature right there in the middle of my board. I couldn't believe it. I was expecting the board fabricator to come back and say, “You should have included a note on the fabrication drawing saying, ‘Please make sure no mosquitos are implanted under the solder mask.’” 

Not much was accomplished in that meeting because, you see, the starting point was all wrong. To begin a conversation based on the "what ifs" of what could go wrong is both an impossible question to answer and an exercise in futility. It is unquestionably the incorrect way to handle risk management, especially in the PCB design process. 

PCB Design is a High-Risk Process
PCB design is like bungee jumping. With the complexity of a PCB design, the intricate details, and various steps, it's rather easy to make mistakes. Those mistakes, many times, do not show up until it's too late and the board has gone off to fabrication and assembly. By the way, a good rule is to not use your assembly house as your quality control team for PCB designs.

Furthermore, you are not in control of the complete process since it involves third-party vendors outside your company. Managing the risk that is not under your control is even more difficult. Before taking a deep dive into the risk management area, we need to understand that the PCB design is a by-product of your process and design data. If either one of those is incorrect, your PCB will be built wrong.

Managing this risk is vital if you intend to keep your job as a PCB designer. So, what is the correct process to identify the risk and put in place the required solutions before they get into your design? As we have already seen, good risk management does not occur from the top-down based on the "what-ifs" but rather from the ground up, examining and controlling your process.

The management of any risk must start early and often, and look at the process that results in that design. If you only conduct risk management processes on the finished goods, you may find yourself a day late and a dollar short.

Also, no matter what measures you put in place, you cannot entirely remove all risks from your PCB design. But, with some simple steps, you can reduce the probability of problems.

To read this entire column, which appeared in the June 2021 issue of Design007 Magazine, click here.