> >Mask should be 3 mil away from copper, and slivers should be at least > >6 mil wide. That means, if there's less than 12 mil between pads you > >go with a gang-opening. > > Where did you get these numbers? Did a manufacturer give this as > their capability limit?
Yes. I've found this to be the "usual" rules for prototype services. I suspect you can pay more for better accuracy :-) > >Silk should not overlap the *mask opening* and should be 3 mil away at > >least. 5 mil min silk lines. > > Same here, who's rules are these? Many fabs automatically delete silk that overlaps mask holes. The 3 mil rule comes from the mask rules. Fabs I've talked to say the mask placement is +- 3 mil. > >Origin and license should be stored in element attributes, not file > >comments, so they're copied into schematics. > > IPC has developed a set of rules for designing footprints to match > parts of all sorts and has even provided a library of data for > this. They provide three standard sets, Most, Nominal, Least which > differ in the amount of land protrusion. Armin's footprint is likely > a "Most" catagory footprint from his description. IPC-7351 seems to > be very widely adopted and would be a great starting point for any > footprint library. We have IPC footprints in the ~geda library. Not all, but some. > I don't bother with putting the refdes in any particular location for > a library part. The times a default location would work out is so > seldom, that it just isn't worth the effort. I put the refdes in the > middle of the library part and move it to suit the design. Agreed. I think middle of the part, despite being bad for the *final* board, is the best starting point. *Size* of the refdes should be considered when making a footprint though. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user