Issue link: https://iconnect007.uberflip.com/i/1276973
18 DESIGN007 MAGAZINE I AUGUST 2020 Matties: Is there any sort of standard for creat- ing fab notes, or is this really up to the designer to decide what you need to know? Korf: A lot of board shops will give suggested standard notes to customers, but there are no standards in the industry that I'm aware of. Holden: There will be with IPC-2581. Korf: It will give you a way to transmit the data, not the actual note contents themselves. Holden: Yes, but you have more descriptive descriptions. You also have a section of 2581 that includes notes. Korf: Correct. You can embed it in the file. Matties: But it's still discretionary as to what the exact notes are. Holden: That's the whole thing about electron- ics and printed circuits: If you come up with a neat idea that nobody has ever thought of, and it involves PCB assembly, if you want the right product back, you'll have to describe it in the notes because it's not coming by any standard. Matties: The designers realize that there are problems, and they're looking for answers. If you're looking for an answer, what is it, Dana? Korf: I'm a simplistic person. My goal is to build whatever you send me without having to ask a question, and you get what you wanted. It sounds like a simple mission statement. The biggest issue is conflicts. Matties: That puts the onus on the designer. Korf: Yes. It puts it on the designer or whoever prepares the document package. Now that we have an EMS step in there, sometimes, it gets confused in there. They mix and match revi- sions together. I see that a lot, such as Rev B fab print with Rev C data. Someone will revise a layer, so you'll have one layer of Rev D and everything else at Rev C, and it doesn't match all of a sudden. There are lots of reasons. As I tell the CAD system people, "None of your tools work." Talk to anyone in the world and say, "What percent of your data packages is coming clean that you don't have to clean up or have issues with?" Most people will say very few. It's a very small percentage. Matties: If a designer is looking at the data set that they need, is the best course of action to first talk to the manufacturer? Korf: From a design and capabilities standpoint, absolutely. The data required is the same for everybody. I doubt if there's any vendor-to- vendor or region-to-region difference there. It just needs to match. The problem is, a lot of times the vendor isn't selected until the design is done. The designer hands it off to an EMS company, which then visits 12 people. They select two, and it's too late. Matties: Are fab notes generated during the design process or post-design? Korf: Probably both. Dack: From the standpoint of the designer, the designers don't know what they don't know. They need to know what they don't know. The only people that are going to enlighten them are the stakeholders that they're working with. In this case, if it's a bare board, they need to engage the fabrication stakeholder or supplier to discuss topics of capability because with- out marking that line in the sand, they are not implementing DFM. Korf: As a fabricator doing pre-design DFMs, I was always happy to do that if they would do what we asked, or we compromised on what would work for the design. Unfortunately, there's a lot, especially large companies, that have in their process, "I have to have two DFMs before I can release to manufacturing." They get the first prototype and test it. Then, you get the second revision of the board, and