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12 PCB007 MAGAZINE I AUGUST 2021 Happy Holden: e reason that I dislike the term DFM is that what Valor sells is design rule checking, not DFM. Korf: Exactly. Holden: I managed the so- ware engineers for Mentor. ey were in Poland, and these are brilliant guys who write the EDA soware, but they had never been to a printed circuit shop. So I ar- ranged one day to take them all over to Krakow to visit a fabricator. You've never seen such upset, disturbed en- gineers in your life. Maybe they thought this was going to be an ultra-modern clean place with bunny suits. Instead, they find vats of ac- ids and other things going on there. Korf: I developed a course for IPC on DFM. One of the key elements I put in there is, what is DFM? When a fabricator opens that file, what is in their mind? And what are you try- ing to do? One of the most important require- ments is that the board must work when it gets shipped to the customer. One key element is you're trying to get the lowest cost maybe, or maybe not. And then, what does that mean? Well, you're trying to use the cheapest materi- als that won't negatively affect the design per- formance. e process steps are pretty much well-de- fined, you can't really add or delete process steps that oen. And then you must make sure the data will yield whatever the intended yield is for that product, to Mark's point on technol- ogy. You open a file, and you look at the im- pedance. I'm going to modify the line widths and release it very quickly, but the modifica- tions may not work within the SI noise budget. And none of the soware that you have— even the soware tools you're mentioning— really have an automated check that checks So, if they include 274D, 274X and ODB, and as you said, there's a flaw in one of those three, we need to catch it; therein lies the rub. e CAM operators don't like having to look at three sets of data. ey'd much rather have one set of data like the '70s again. Send us Gerber data, ODB, or whatever you're going to send, but just send one of those. Nolan said earlier, "Share your capabilities with the world." Now as an FAE, I was constantly getting questions, such as, "Can you provide us with your Valor ERF settings?" Well, we had a prob- lem doing that. We'd much rather they look at the capabilities published on the website as op- posed to providing them with a spreadsheet of numbers that have no rhyme or reason. I had a conversation with a guy from an aerospace company about a month ago. He said, "Mark, it would be a whole heck of a lot easier as a de- signer if all fabricators provided us with their ERF settings for Valor." I said, "Yes, it would, but that doesn't allow the fabricator to no-bid based on intangibles." So, if you had a situation where you send them their ERF settings and it meets all your ERF settings, but the quantity is too large, or there are six or seven different caveats and it exceeds the amount of heartbreak, if you will, the fabricator would like to no-bid. But if you send him those ERF settings, then they're go- ing to come back and they're going to say, "Well, it meets all your ERF settings." at is one problem. e other side of that is, what if you don't provide them those ERF settings, and you just rely on them to look at your capabilities page on your website? ey're not very straightfor- ward, and a lot of them are convoluted. Hon- estly, look at them. What is "advanced" and what is "standard" exactly? Define them. at ends up being a bit of a problem as well. Dana Korf

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