I’m learning the hard way. I ordered 10 boards of the same design and I received 12. Populated the first board and it failed. I looked for solder bridges and found none so I began removing components I thought might be the problem but no luck. So I tested the other 11 boards and found two more that were bad. How often are boards defective and do they test the boards in any fashion? It took me a long time but I found I could fix this particular problem by scraping away the stuff on top of the traces including the silkscreen then running an exacto knife between the traces which were shorted. I could not see the short with a magnifying glass but cutting solved the problem.
I can now see that it would have been better to route this particular trace on the bottom of the board but I just let Eagle’s autorouter do the work. Is it a problem to allow the silkscreen to overlap traces?
I don’t bother with electrical testing for simple PCBs, but I pay the extra for more complex ones. It isn’t all that expensive and can save a lot of problems. I don’t think that the Batch PCB service includes testing and I am not surprised that you got three bad boards out of the 12 supplied. PCB manufacturers generally make more boards than are actually ordered to allow for failures.
Testing is performed with a “flying probe” system that checks the board for connectivity according to the supplied Gerber files.
I guess I’ve been lucky. While I’ve had a few manufacturing errors on PCBs, I’ve never had a short circuit or open circuit. This may have something to do with the fact that I try not to use track / spacing & hole diameters any smaller than they need to be. I normally stick with 10 thou track / spacing and go to 8 thou if I need to.
Hi RC, were your boards 4 layers pcbs with very narrow (6mil) traces?
So far I have only needed 2 layer layer pcbs and used 10mil traces. I figured the odds of making an error while producing such a board would be quite low and it would be easy to spot the bad connection.
I did not see anything in the FAQ about a policy for defective pcb. They only mention that you could get a refund if they find a problem with the gerber before it is sent to production.
MichaelN:
I guess I’ve been lucky. While I’ve had a few manufacturing errors on PCBs, I’ve never had a short circuit or open circuit. This may have something to do with the fact that I try not to use track / spacing & hole diameters any smaller than they need to be. I normally stick with 10 thou track / spacing and go to 8 thou if I need to.
I recently found my first short on a PCB. Two layer PCB, done Stateside, 6 mil trace/space. The short was between the ground plane and a via. The funny thing was that I poured that ground plane with 20 mil clearance. Very, very bizarre. The other 4 boards in that batch were just fine - just the one was bad.
I’ve gotten maybe 15 other boards built up by that company, most of them in quantities like 10-20, and not a single other board has been bad.
My board is two layer with 8mil traces/spacing following the suggestion in the Sparkfun Eagle tutorial. I can now see that manually routing one of the traces would have been a good idea. But, hey, the tutorial suggests 8mil traces/spacing so that’s what I used and it worked for 9 of 12 boards.
Now that I’ve “fixed” the problem with an exacto knife, should I seal the exposed copper traces with something to protect the repaired area?
Well, this really sucks. There may be more serious problems with the boards. I originally found continuity between two pads on 3 boards where there should not be continuity and using the exacto knife between two traces solved the continuity problem. But after populating these and the other boards I thought were good some still fail. I’ve now populated 9 boards and only four are working. If not for the continuity failures, I’d think the problem was my soldering or the components but that seems unlikely.
I’m really annoyed and discouraged. I’m not sure what to do now. Should I send my design to another board house and hope for the best? I have three unpopulated boards remaining. Is there a methodical way to test to try and find the problem? I guess I’ll just stare at my schematic and try as best I can to troubleshoot the boards.
I used BatchPCB and I posted here thinking maybe they monitored these forums. I just checked and BatchPCB’s Forum link leads right here so obviously they are affiliated.
I reviewed my schematic and with one of the remaining three boards I began populating only the minimum number of components and tested after each component. After adding a transistor the board failed. I removed the transistor and it worked again. The base of the transistor is fed by a voltage divider so I did the math and where the divider should have been yielding about 2V I had 12V. That uncovered another short on some of the boards. Again, I suspected my soldering but I tested the other two untouched boards and one had the short. Give me a break!
If the bot at BatchPCB verifies that your board complies with their design rules and I used 8mil traces/spacing with Eagle’s auto router who is at fault here? The BatchPCB bot, Eagle, or the board manufacturer?
I ordered 10 boards of a completely different design from BatchPCB and I received 13 boards. Now I’m agonizing over what I’ll encounter with those boards if the first batch is any example of the quality. Obviously, I will not use BatchPCB again. Can anyone recommend an alternative supplier for small quantities of up to 10 boards? Thanks for all your comments and suggestions.
The problem is probably down to the board manufacturer - Gold Phoenix makes the boards for BatchPCB. BatchPCB is a cheap and cheerful service intended for hobbyists, you should have used a supplier that tests their boards. Gold Phoenix probably does offer that for the boards they supply directly to customers.
I’ve used PCB Pool for prototype boards for years. Their boards are made in Germany and are very high quality so I don’t usually bother getting them tested. They can also supply production quantiities. I also use PCBTrain, but they are more oriented towards UK customers only.
On another note, if you’re getting that many bad boards, you may have some bad artwork… Try not using such small traces and spaces, dont do 90degree corners on traces, allow extra space around pads/vias, things like that. You may want to consider setting yourself up with a home etching system to see how your boards turn out before sending them off to a manufacturer. Granted, their entirely different processes, but if you can etch it at home without a mill, chances are the board manufacturer will be able to make it as well.
Why would you order 10 boards from batch pcb? They use Gold Phoenix and they’re made only for prototypes.
They must be super small like 1"x1". If they were 2"x2" that’s 40sq inches=$100+$10 processing + $5 USPS shipping=$115.
You could have got the same price at gold phoenix directly for $89 for 100sq inches, + $20 for electrical test = $119, shipping included and 8 days to your door instead of 30 with batch.
I always get electrical test for orders > 1.
You would think BatchPCB would pay for electrical test. $20 over 155 sq inches = $0.13 a square inch.
I’d pay $.13 an inch premium in a heartbeat ($2.63 instead of $2.50) and made sure all my boards worked. It would be a better customer relations with BatchPCB also instead of having people complain about their lack of quality.
Right now I do:
1 board < 10 sq inches = $65 BatchPCB
1 board < 10 sq inches and I need a free metal stencil = $75 PCB Pool
10 sq inches or I need it fast = Gold Phoenix $89 (100 sq inches)
10 sq inches or > 1 board or production = Gold Phoenix = $119 (155 sq inches + $20 electrical test)
RC:
I used BatchPCB and I posted here thinking maybe they monitored these forums. I just checked and BatchPCB’s Forum link leads right here so obviously they are affiliated.
I reviewed my schematic and with one of the remaining three boards I began populating only the minimum number of components and tested after each component. After adding a transistor the board failed. I removed the transistor and it worked again. The base of the transistor is fed by a voltage divider so I did the math and where the divider should have been yielding about 2V I had 12V. That uncovered another short on some of the boards. Again, I suspected my soldering but I tested the other two untouched boards and one had the short. Give me a break!
If the bot at BatchPCB verifies that your board complies with their design rules and I used 8mil traces/spacing with Eagle’s auto router who is at fault here? The BatchPCB bot, Eagle, or the board manufacturer?
I ordered 10 boards of a completely different design from BatchPCB and I received 13 boards. Now I’m agonizing over what I’ll encounter with those boards if the first batch is any example of the quality. Obviously, I will not use BatchPCB again. Can anyone recommend an alternative supplier for small quantities of up to 10 boards? Thanks for all your comments and suggestions.
Not to say that you did anything wrong, but I have never had that many problems with BatchPCB. Typically I have holes that are not plated through all the way.
I have never had a short, ever. We use a lot of BatchPCB boards, and Gold Phoenix boards. Our customers use a lot of Gold Phoenix boards.
This sounds more of a design flaw than a bad batch of boards.
You need to go back through the schematic, and the board layout, and check to make sure there were not traces routed to the wrong place. if you changed the schematic after routing the board, not always does the PCB side rip up the traces. Also compare the schematic to the pcb in the software.
I had an entire ground plane missing once. And I had to fight to get the PCB house to recognise that they should have noticed all the vias were going nowhere!