Watch out for added surprises - Page 1
Forum section: electronics / general

author: rollatorwieltje
author_rank: Unknown
timestamp: March 17, 2014, 08:41:13 pm
content: A few days ago I received some boards made by Seeed. Now Seeed advertises that they add some markings to the board to indicate their production run. I sort of expected it to be silkscreen markings, although they did specify the letters were tiny. I don't care about those markings, as long as the boards are good.Turns out they actually placed them on the bottom copper layer. Good thing I kept my stuff far from the edge, as they placed it on the edge near some traces that carry 230V mains to a PCB mounted transformer.In my case it's not an issue, the distances are still good. But be careful when your board is densely packed, who knows where they will place it. Maybe in your carefully designed creepage distance between primary and secondary, because it was a nice empty spaceOther than that the boards look absolutely fine, although my quickly designed board wasn't exactly a challenge. Drill registration and silk screen are spot on. Also no nasty mousebites, the 10x5cm boards were all nicely routed out.

author: c4757p
author_rank: Super Contributor
timestamp: March 17, 2014, 08:43:27 pm
content: That's just horrible. What dumbass thought it'd be good to put that in thecopper? All the ones I get from itead and Elecrow have silkscreen numbering...

author: 8086
author_rank: Super Contributor
timestamp: March 17, 2014, 08:55:49 pm
content: Maybe because you didn't already have any silkscreen, so they saved themselves a process.

author: LukeW
author_rank: Frequent Contributor
timestamp: April 10, 2014, 06:32:50 am
content: Having numbers or text added that you don't want - whether silkscreen or copper - is my number one pet peeve with PCB fab houses.The preliminary basic expectation I have is that, for the quoted price and subject to pre-defined set of design rules, they will fabricate exactly what is on the files they're given. And if they can't meet that I get grumpy.

author: toohec
author_rank: Contributor
timestamp: April 11, 2014, 04:13:08 am
content: I always specify on my fab drawings that the fab house place their logo and lot identification number in silkscreen only and in a specified open region on one side of the board. If I do have a board without silkscreen, I'll specify that etching is allowed, but again, only in a particular area that I have specified. Since the fab house is unfamiliar with your design, you can't expect them to know the most logical place to put their info... so it's best to spell it out (especially in the etched case).

author: kony
author_rank: Regular Contributor
timestamp: April 11, 2014, 10:37:53 pm
content: Cheap China PCB pool servises ain't capable to do that. Been there, tried that. Even if you specify it, add note in textfile in production files, then again add this specification to order email, they still manage to f*ck it up.But I believe it's mainly due to high level of automation in preproduction processing. Even if not - what are You expecting at this price point ? It's still superb for prototypes and small one-off runs.And yep, for Seed studio / Elecrow / Itead - if you ommit silkscreen layers, they will place their marking either in copper or soldermask layer depending on design density - so beware of that !(That means leave out gerber for silksreen only if you really need that one side of PCB clean, otherwise include all layers, even if there are no appetures.)And it is not due to saving manufacturing steps - all designs are pooled on big panels, cca 450x600mm and then individual boards are routed-out.Also - as I see on first post, sharp board edges. Take advantage of fully routed PCB outline ! Make nice rounded corners - it's nicer and practical. It's not once that I have seen cable bundles cut by sharp edge of PCB in some devices.

author: rollatorwieltje
author_rank: Unknown
timestamp: June 15, 2014, 03:10:52 pm
content: Ordered another board, this time they did silkscreen it on the bottom. I didn't put anything on the bottom silkscreen myself, not sure if I actually sent them the layer or not.