"If we fail to plan then we are planning to fail."
Given a professionally diverse readership composed of many people with differing company structures and situations, my intention isn’t to give a ‘sole’ method or plan that will magically fit everyone’s situation. Rather, I want to give a detailed explanation of how it “could” be done. I aim to give the bird’s eye view of this whole thing with the hope that I can point you in the right direction. As one of my school teachers used to tell me…. “your mileage may vary”.
The unspoken rule of the universe is that when things are left to their own devices, they gravitate toward chaos. We should take to heart Benjamin Franklin’s warning: if we fail to plan then we are planning to fail. Although it’s never anyone’s intention to start anything with the hope of failing, failure does happen, and usually, the root cause can be directly traced to lack of preparation.
Several vital principles are NOT optional but instead required for a successful PCB library management system. To not have them in place substantially increases the possibility of failure, additional costs, lost design time, and other very nasty things. These principles can be described as the SMART rule of PCB Library Management; to help us remember them, I shall use the acronym S.M.A.R.T.
You must understand that these five pillars are not particularly tangible physical items, but ideologies. Like a pillar in a building provides support and structure, these pillars support and structure our entire PCB design process system.
S. Singularity M. Managed A. Architecture R. Reliability T. Traceability
The first pillar stands before us; a singularity of Data and Processes.
Before we fall too deep into the rabbit hole, just a word regarding PCB design integrity. Our objective is to get through the design process and come out the other side with something of quality. That means controlling each step along the way.
Regardless of the size of your design team, it won’t take a psychic to determine the results of their work if they start using different data. We wouldn’t expect a group of people to arrive at the same point if they’re each given completely different maps, conflicting directions, and mismatching destinations. The PCB library should be the sole source of all truth.
Time and time again I’ve seen the problems caused directly by what I call “Rogue Libraries.” These are libraries of components which aren’t managed, verified or controlled. Consider the massive amounts of work necessary to prepare a PCB design. The engineering, layout, fabrication process, and then as you get into Assembly, the notorious unwanted phone calls begin, letting you know that the assembly house was hitting “snags”. These problems could be anything ranging from parts not going onto the PCB because of wrong footprints, to component tombstoning or falling off entirely when you start to investigate the problem, only to find that someone used their own personal “Rogue Library”. It usually ends in a fatal error for the PCB design and the scrapping of the entire fabrication. At this point, you begin that long walk to the management office to explain the situation. That is never a good feeling. That PCB library resulted in a lost profit for the company.
Several years back, I joined a company, which, although it had existed for many years and was considered “successful”, had a PCB design area with no structure or organization. They had a tremendous fallout of boards in both fabrication and assembly. It would be an understatement to say it was in total disarray. The problem became very evident when, I remember, I went over to one of the designers and he opened a desk drawer filled with Bare PCB boards. They were piled up. He let me know that those were the designs that did NOT “make it” through Assembly due to some problem. When I looked back and put together the numbers, I estimated the cost these PCB design area failures to be around $750K. It was like I got kicked in the gut by a mule. That was $750K that would not come back. It was wasted and gone.
However, bear in mind that because a design “made it through” does not mean that it was correct or that it was a board of high quality. All it means is that we were getting lucky. With the PCB designs that did make it through, I concluded that the PCB designers were the luckiest people in the world. That, as they say, was only the tip of the iceberg.
When I investigated further, I determined there was a total of 1,123 PCB libraries with endless component information, symbols, and footprints. Moreover, probably none of them were correct. Each designer had a personal PCB library. No wonder there were significant problems. The rule of cause and effect was alive and well.
My expectation can be summed up very simply for every PCB design: first, conduct a single spin and produce the highest quality PCB design possible. What is a design with integrity meant to be? One definition of integrity is ”the state of being whole and undivided.” That’s a great mental picture of a well managed PCB Library. To be unbroken and undivided. I like that. When we tried to work from a thousand libraries, we were not even close to starting from information that we could trust or that would result in a design of integrity.
There is an old saying, “To get something you have never had you need to do something you have never done”. I knew the solution to the problem, although it was a radical step. It was simple and staring me straight in the face. On a Friday evening, after everyone had gone home, I went into the server and DELETED ALL THE LIBRARIES WITH THEIR BACKUPS. I must say that was an exciting Monday morning. I said it was radical but necessary. In a short period after that, we began to see significant improvements in the PCB design integrity. It first started with getting control of the source of information and making it singular. The moral of the story is to have PCB design integrity; we must first have integrity in our information, processes, and the libraries.
A significant tool to assist in the setting up of our first pillar is a feature called Item Manager. The Item Manager is a phenomenal tool which accomplishes several things.
Determines the source for all components and dividing them up between what is called managed and unmanaged parts — looking first at the data source for each component. Meaning what library did they come from?
How does the component on the design match up with the source information in the library? If changes have been made to a component in the PCB library then it will indicate them as being Out of Date. You will have the option to update the part to the latest from the library.
As we will see in the next chapter, it is essential to revise the components used. This will separate the parts that are NEW from the components that you still need to review and place into a “Released” State. For an even further layer of protection, it is essential to assure that we check and double check each separate part of the design.
Through the Item Manager, we have a piece of concise information to provide a snapshot of the status of the Design. These sorts of checks should be done continually throughout the design process.
A chain is only as strong as it is the weakest link. Through the Item Manager, it clearly shows those weak links and allows for them to be corrected.
I do not merely wish this to become a manuscript of ideologies and never touch the practical side of things—the goal is to provide the full picture necessary to understand both the principles of a good PCB library but also to set one up and use it. The best way to accomplish this is to reinforce each pillar with practical steps and procedures. I will be solely focused on specific features of the ECAD software of Altium, however, these rules will work well with any ECAD software package you might be using. You can read about the rest of the S.M.A.R.T library management system on my blog.
Would you like to find out more about how Altium can help you with your next PCB design? Talk to an expert at Altium. You can also learn about PCB data Management and how it interrelates to the PCB Design process and roles of everyone involved.