I recently ordered and received quantity 10 of a board design through BatchPCB. While the boards looked perfect to the naked eye, after several frustrating days of debugging, on the first board I found two serious board fab errors.
The first was a ground plane fill that ran between two 24mil traces. Right underneath a silk screen line (which made it hard to see with the eye) there was a 10mil wide trace that shorted the ground fill to both traces. (It was not in my gerbers this way, and all of the other boards did not have this flaw.) This caused problems because the 24mil traces were power outputs to a stepper motor and this caused the driver chip to go into shutdown mode until I found and fixed the problem. There was 10mil spaces on either side of the ground fill to the 24mil traces.
The second was a via that did not plate through. It was connecting one ground pour from the back of the board through to the front of the board. I’m not able to take the time to ohm out every single one of the vias on every single board, but at this point I’m afraid that there may be other open vias.
I understand the boards are not electrically tested, I understand this is why we get such a great price, and I’m totally cool with all of that. This message is simply to let other people know that your 2-layer boards may have fab failures on them (and the chance of this happening is not close to zero, although it does appear to be small).
And I want to pose the question - has anyone else ever had either of these types of problems with their BatchPCB boards? Any other type of electrical failures in the board fabrication?
We’re generally pretty good on QC - but we had one panel that we think had some QC issues [esp regarding vias]. We’re in the process of harassing the fab about that.
The only error I’ve seen on a board that I’ve run is a gapped trace - had a small cut across it.
also, please give us a shout at support@batchpcb.com with your order # and we can remake the order.
No need to remake the order. Yet anyway. We’ll see how well the other boards work (I only have 1 stuffed right now.)
We ordered 10 and were billed for 10, but were shipped 20 boards. Is this common? This also gives us lots of spares in case any of the first 10 can’t be made to work.
Let us know how your harassment goes.
BTW, the order number was 3758 (Elias Crespin ordered them)
Fabs commonly make extras incase the first don’t pass QC [apparently they passed too many in this case]. Most fabs only give you what you ordered, however we pass along any extra the fab had… consider it a free bonus :P.
It doesn’t happen on every order… and it looks like you got exceptionally lucky [usually its only 1-3 extra, not 10!]
busonerd:
Fabs commonly make extras incase the first don’t pass QC [apparently they passed too many in this case]. Most fabs only give you what you ordered, however we pass along any extra the fab had… consider it a free bonus
Greetings David, *Brian,
In my experience the fab often makes extras for in-house use.
These are often called “solder samples” (and passed to the
customer for QA).
In this case it might be that the first boards were a problem,
but not removed from the work flow. The bonus boards might
be free of defects, and the bonus and first lot groups were
somehow exchanged before shipment.
It would be worth testing the bonus boards for the specific faults
(bad vias, shorted tracks, etc). If these are better than the first
few you have solved your QA problem.
I’ve received a few bonus boards (from BatchPCB) that were
cosmetically poor (bad silk-screens, uneven routing of the
outline, registration errors on the silk-screen, off centre
drills, etc.). For my needs they are quite useable!
I had one board made a while ago (last year) that had a drill hole shorted to the surrounding copper pour similar to your first problem. It was only like that on one board.
I haven’t had any problems on my boards since then, other than my own mistakes
I had a board made that didn’t have a few via’s totally plated through…it did cause some time to find the problem…but I had made other mistakes on the board and felt it was a minor oversight. I just used some small diameter wire and conected the vias…and the board worked perfectly.
I now check my boards with a pad to pad list.
It is very easy to have through holes not plated through, because this is very hard to verify without ohm checking.
But the price truely offests this minor consideration. I don’t mind doing the continuity check myself.
I still think Batch PCB is the best service for my use.
I have had a problem with a via not being plated thru. This caused me to re-check my design work and software until I found the via (about a weeks work). I also noticed a track that was not connected but no problems with the design gerber. The service is cheap and for some designs is useful. But I think for designs that use extensive components and small tracks you need the board electrical checked.
We’ll see how well the other boards work (I only have 1 stuffed right now.)