kb8tq@n1k.org said:

Could you give a few examples of the more obscure rules?

Do the low cost board shops give you enough info to check them?

Thanks.

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Hi

Well, a full list of all the rules we ran against would run about 10 pages. I think
that’s getting pretty far off topic for TimeNuts. I also, quite frankly never bothered
to memorize them all.

A few examples of what one might do:

1. “Allow” a violation. Things like courtyard overlaps often are non-issues. A fancy
   program would let you “allow” ( = suppress ) the error once you checked it out.

2. Zone based rules. The region under a BGA may be very tight in terms or clearances.
   The rest of the board likely will not be. Having rule zones helps deal with this.

3. Silk screen / mask rules. Getting the silk screen so it either shows right or is suppressed
   is a pretty basic process. Doing it manually is a major pain. Indeed a number of “pro”
   packages have the same issues.

4. Extras. Duplicate holes should not get into the drill file. Dangling trace bits should be
   spotted and flagged……..

Yes, this could go on and on.

No, the cheap board houses don’t check for this stuff. They just build and send it
back. If there’s a gotcha, you get it on the board.

Bob

On 5/14/20 5:07 PM, Bob kb8tq wrote:

I was pleasantly surprised last week when Seeed Fusion contacted me to
point out a problem where two vias were too close together (by a couple
of thousandths).  They asked if they could reduce the hole diameters
slightly to correct.  I agreed, they made the change, and the boards are
with DHL right now.  So they do have a process to kick at least some
issues to human beings for resolution, rather than just rejecting the job.

BTW, two things I've learned from my current project:

1. Seeed claims that they can do down to 4mil trace width and spacing,
   and down to 0.2mm holes, but those add extra charges.  For their $4.95
   for ten boards deal, the minimums are 6mils and 0.5mm holes (why can't
   they pick one dimension system for the specs???)  Go smaller and the
   price goes up 10x or more.

2. Where I had the clearance problem was on a USB C connector.
   Whatever advantages they have, they are a pain to route and solder.  The
   one I used (which seems fairly common) has both through hole and SMT
   pads, and the space to get all the signals lines connected and routed is
   very, very tight.  The smaller trace and hole sizes would have made the
   job easier, but I wasn't willing to jack up the cost for that.

John

Am 15.05.20 um 01:25 schrieb John Ackermann N8UR:

I had the same good experience with PCBway.

I used these 0.9 * 0.9 mm GaN FETs, and that does not mean 0.9mm gate
length:
https://www.digikey.de/product-detail/de/epc/EPC2038/917-1138-1-ND/5774048

and used the proposed Altium footprints from EPC. These pull the
solder mask onto the pad which is unusual but maybe essential for
a smooth soldering experience. I'm sure that EPC have experimented with
that.

PCBway emailed me directly and we cleared that up that it was intentional.
They still produced the board on the same day, and soldering was easy.
Very satisfied customer.

Nevertheless I'll try JLCpcb next week. They now have a proxy man somewhere
here in .de who gets one box from China a day and forwards the contents
to the different customers after the customs work is done, via normal
local registered mail.
The import VAT is then already done and billed by JLCpcb.
DHL Express is a royal pain to deal with.

Cheers, Gerhard