Issue link: https://iconnect007.uberflip.com/i/1467185
18 DESIGN007 MAGAZINE I MAY 2022 Kolar: Either that or everybody is too busy. Some smaller companies don't have an electri- cal engineer on staff. ey're relying on us for more of what should be an internal function. Sometimes they literally don't know what they don't know. Matties: What would you advise designers who are working in a vacuum? Kolar: I think one thing would be having a good, consistent deliverable package. If you don't have any contact with a final fab vendor or assembler, make sure that your package is clean, and your fab notes are correct and thor- ough. Make sure your data is correct, the draw- ing is consistent with the net list, and the data is self-contained so that someone seeing it for the first time can pick it up and build it. Matties: Great advice. How many DFM checks will you do on a design in-house? Grunwald: It will usually be at the output stage. e internal tools will guide us as we're doing our routing. But once we do output, we do a DFM check internally, and if there are any errors or modifications, we go back and do a check again. e goal is that what we're out- putting is clean, with zero errors. Matties: Good communication skills are criti- cal here. Grunwald: For sure. Part of what Jen mentioned about having your output package being good is organizational skills. Not only should your data be the same outputs for any project you're doing, but having it organized in the same way so it can be found quickly and easily is critical. If you're going to the same shop with multiple projects, they know exactly where they can find the data they need. Kolar: One of the other big vacuums where we rarely get feedback is about how the board worked or whether there were any issues in fab or assembly. When we go to the next build, we aren't getting that knowledge. We aren't learn- ing anything. Closing that loop is very rare unless we're doing project to project. You don't want to propagate the same mistakes over and over. It involves picking conservative best prac- tices. You hope they won't throw you a curve ball by going to a low-end shop. I've seen designers trying to design rigid-flex in a vac- uum, which is difficult. Grunwald: You could run into situations where you end up with a design that's not "fab-able." If you go with the assumptions that your board shop can do a 3-mil trace and space, and this ends up going to a shop that can't do 3 mils, you now have an unfab-able design. Matties: So, you know you're adding more cost, because you're having to compensate for a lack of information. Kolar: I could say that it could take more time because you're essentially having to make edu- cated guesses. at could add more time that you wouldn't have to add if you had clear infor- mation.