Tom Hausherr Discusses PCB Libraries’ BOM Builder Service

Estimated reading time: 13 minutes

Dack: Is there automation now in finding design-related component data sheet information?

Hausherr: We finally have the ability to bring all the data together for the PDF file datasheet link, the logical description, the manufacturer part number, the manufacturer name, the physical description, the IPC-7351 footprint name, the package dimensions and the component family type. What we have is a centralized database with millions of component dimensions tied to the logical information and we're adding tens of thousands of new parts every month. These new part numbers are primarily new part requests from our customers.

There are new component manufacturer startups or component manufacturers merging together all the time. As people submit their bill of materials to us, they're notifying us of the new manufacturers. When we're filling a BOM, we might get a 70% match on our database. So, 30% doesn't exist on the server yet. We quickly build and upload the missing 30% and give it back to the customer. It’s a free service that we offer 24/7. The parts that we build for every customer are added to our central database and made free to all other Library Expert Pro users.

Dack: Great way to leverage customer data, neutralize it and then share it for the good of all users.

Hausherr: My favorite tag line is “Build it once, build it right, never build it again and share it with the global electronics industry.” Elimination of duplication is our primary goal. Neutralizing the data into basic component dimensions is simple. Component manufacturers normally do not change the package dimensions once its released. The quality control of package dimensional values is straight forward and it’s difficult to make a mistake using an IPC calculator. However, if you’re manually creating PCB library parts in a CAD tool you can easily introduce mistakes. Human error is a reality, but software produces consistent results. I hear about the failures of poor quality library creation all the time however, I have never heard anyone using component dimensions to calculate a footprint pattern make a mistake. When PCB library parts with errors go to the assembly process and they can't solder the part on the board, the PCB build turns to scrap or the rework is costly. With the component dimensions we apply the toe, heel and the side goals provided by IPC-7351 and the IPC mathematical model for tolerancing and it’s impossible to make a mistake. Then you apply the cosmetic items like silkscreen legend and assembly outline, polarity marking, placement courtyard excess and the reference designator height and width. All of these rules in the user personal preferences.

Preferences is a comprehensive menu of items that users can select from. “I want this polarity marker style. I want this pad shape. I want this toe, heel, and side solder joint goal. I want this footprint rotation, I want this origin location.” Preferences is a simple menu of items that users select from and when you match the component dimensions with those preferences it outputs a customized PCB library footprint that meets your corporate standard and quality.

Dack: You mention component dimensions play a role in footprint calculations. Are the component dimensions between various component manufacturers the same to make it easy to source multiple vendors to fit in the same footprint?

Hausherr: Well, it used to be that way in the 1990’s but today it’s a very competitive world and it seems as if component manufacturers intentionally make their package dimensions different. We have gathered component dimensions for millions of packages from over 600 manufacturers and the growing trend from those manufacturers is “Let’s make our package dimensions unique to attempt to single source the customer into using our package.” The IC industry is off the charts with unique custom packages. Even discrete parts for chip, molded body, SOT23, etc. it’s hard to find 3 manufacturers that provide the same package dimensions. We will have to get used to the idea of single sourcing components in the future. But with an IPC calculator, user defined library preferences and free access to millions of part numbers and component dimensions it doesn’t make much difference. It’s fast, free and very accurate.

Dack: I have to ask: Does it address the more complicated 3D environment?

Hausherr: An IPC-7351 calculator requires all the component package body the terminal lead dimensions. It doesn’t make any difference how many different component dimensions there are, the Library Expert Pro software program auto-generates accurate high quality 3D STEP models per every unique component package dimension. The 3D environment is becoming very popular in the PCB design industry today. Before my PCB designer career started, I came from a 3D modeling background right out of high school back in the 1960’s using T-squares and triangle templates. I've been familiar with 3D modeling most my life. I quickly learned SolidWorks and generated all the master component package models. A chip is not just a chip; a chip resister has a different model than a chip capacitor, inductor, diode, thyristor, varistor, LED or fuse. They all have different package styles. There are about 144 “standard” component packages in the industry today. By creating the master models, our programming team was easily able to scale the packages up and down to be able to create millions of various 3D STEP package sizes. I’m really excited to combine my 3D modeling, PCB layout and PCB library skills together.

Dack: I find with more of the 3D PCB design layout tools that with engineers, if you give them an inch, they want a mile from the standpoint of detail. Now that they see they can get anything other than a 2D footprint that is almost similar for an 0402 or an 0603, when you go 3D and show that part, you're right, they want to see the size and height differences. Now they're asking for custom colors.

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