Is it possible to salvage this PCB? or how to prevent this next time - Page 1
Forum section: electronics / projects

author: progrock
author_rank: Contributor
timestamp: November 21, 2017, 05:16:10 am
content: So I recently made a PCB order from pcbway.com of the 3 different boards for the UniSolder 5.2 (http://dangerousprototypes.com/forum/viewtopic.php?f=56&t=7218)I was originally going to order the full panel design, but then found out by ordering them as individual boards, it would literally cost 1/3 the price, and I had no specific need for the panels. I must say, the price and speed was both surprising, got 10 of each of the 3 boards, shipped to the US, for $35 total, and it took just about 1 week to get here (give or take a day). Sadly, after a quick inspection, I think either 9, or probably all 10 of the main front panel board appears to have a fatal flaw (at least fatal as far as I know). Basically, one of the rows of connectors for one of the smaller/denser microchips has at least 2 of the connectors merged together completely (sorry if I am using incorrect terminology, please correct me, will do my best to get it right in the future then). So far this was the only obvious flaw I found on that specific board. Sadly, the OLED board also had a similar issue... though I think not as severe, and only a few of the boards had it (at least it appears like I have a few that should work fine)... and considering I def don't need 10, that's not the end of the world (As long as I am correct, and these ones are functional). The 1 piece of good news, the 3rd board, the back, does not have any obvious flaws (to my untrained eyes).Sadly, I don't have a good microscope to get a real good look at them, or take any highly zoomed in photos.... but I am currently seriously considering getting an Amscope, something along the lines of an SM-4TP (with no frills initially, tho might get a different stand than the standard). After having this problem, I am much more motivated to forking up the cash for the Amscope.I'll attach a photo or 2 to show my issues/concerns, just in case I am not describing them correctly.... also in case I am wrong, and that there is a way to salvage these boards.While it would be great news if I can salvage them, whether I can or I can't, I'm wondering if there are easy ways to prevent this kind of problem on future orders. This order I used all the default settings on pcbway (aside from changing the PCB to black, though I am assuming PCB color is irrelevant). As far as I was told, the default settings should have been good enough for the UniSolder board design, and there were no issues brought up during pcbway's audit of the design. Also, this is obviously a heavily tested design, not some prototype of my own that no one has successfully built yet. So I am thinking it's safe to assume that the problem was either my fault in the way I ordered, or just pcbway's fault in the way the built the boards.Are there any adjustments on the PCB order form that would likely prevent this problem?.... ie. different surface finish... or min tracking/spacing, etc.Thanks in advance for the help, was definitely disappointed, if I had 2 of each board without problems I'd be happy enough for now... but with none of the main board, at the best, I'm set back a week on this project, likely even longer.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 21, 2017, 05:23:26 am
content: Anything different? Sure, pay more for:- accurate manufacture- inspection- 100% electrical testAssuming that wasn't in the design files to begin with, of course. (In that case, a very good mfg may review your files and note clearance errors or shorted nets, but you're not going to get that level of service on budget protos.)At least it looks like excess material, which can be cut off. Get out the utility knife and stack hacking!Tim

author: rs20
author_rank: Super Contributor
timestamp: November 21, 2017, 05:30:48 am
content: Can you post your original gerber files? Might be interesting to see to what extent these errors are in your provided files.Also, I know it can be impossible without the right equipment, but posting higher-quality images would be helpful wherever possible.

author: Monkeh
author_rank: Super Contributor
timestamp: November 21, 2017, 05:40:38 am
content: The OLED connector is definitely bad - one of those pins is meant to be floating. I can't help but wonder if that's just the solder leveling gone wrong, try and wick it off.U10 on the front board, however, is just a mask issue - those pads are all connected directly together. In fact there aren't any pads, it's just a massive copper pour.

author: progrock
author_rank: Contributor
timestamp: November 21, 2017, 05:49:11 am
content: The gerber files are the ones available on the first psot of the UniSolder thread, version 5.2 .... FRONT, BACK, and OLED. Here is a direct link:http://dangerousprototypes.com/forum/download/file.php?id=11719&sid=5972fc677e069bd34892eb5c1cd5dafaIf this is just excess material I can scratch away, that would be great news... while I am capable of understanding schematics, and handling the lower level calculations in circuits, up to some basic DiffEQ (as much as I have mostly forgotten everything from my school years, I did get a CoE degree, which was only 2 classes different from an EE degree at my school)... I have pretty much zero experience with manufacturing/order PCBs, etc. But I can only assume the design isn't inherently flawed based on all the people who have built it.And yes, I'm sorry about the photo's... it's pretty close to the best I can do with what I have right now. As I mentioned, I'll likely have an Amscope SM-4TP (or comparable) soon... though I likely won't have a camera specifically designed for it for some time longer. I think they at least show my main concern clearly enough to have a general idea of the problem.And as for the other recommendations. Needless to say, this isn't my product, and is not something I will be making a penny on... just something I want to build, and maybe give some boards to friends so they can build (or, I suppose more likely building them myself to give to them as a gift). Obviously that's gonna reduce the number of options I have... if I even get close to the cost of a JBC unit... it would be utterly pointless.With that said, I'm still open to suggestions on how to prevent this in the future. Primarily viable solutions that would make sense for this project... though I'm also happy to learn about better solutions in the case that I ever do make something of my own that I'd be willing to spend a considerable amount more. But as far as these boards go... as I said in my original post... is there specific options when ordering the PCB that could improve the quality (again, things like surface finish, etc). Also, if there are better places to order boards from, I'm glad to hear recommendations. But again, viable ones that make sense for this situation is my primary concern... so recommending I do things that would cost a lot just doesn't fit the situation... but upgrades from the default ordering settings on pcbway... or recommendations of other suppliers that are practical for this would also be helpful.Thanks again, any useful help is very much appreciated.

author: progrock
author_rank: Contributor
timestamp: November 21, 2017, 05:52:52 am
content: Monkeh, are you saying those pins happen to be connected anyway?... where it really doesn't matter? Or am I misinterpreting you?If that's the case, that would be amazingly good news (and pretty surprising).As far as the OLED board... luckily I'm pretty sure at least half of the boards do not have the issue... and the few that do is not of the highest concern... just means less friends will be getting free boards from me.

author: Monkeh
author_rank: Super Contributor
timestamp: November 21, 2017, 05:55:18 am
content: Yes, those are meant to be connected. The mask just didn't stick.

author: progrock
author_rank: Contributor
timestamp: November 21, 2017, 06:06:18 am
content: OH, wow... that's amazing. Also, that looks incredibly clearer than what the gerber files look like when I load them (given I am on linux... and just installed gerbview a couple of days ago). May I ask what software you're using for that?Either way, thank you so much... that is great news. Though now I need to do a more thorough inspection to see if I find anything else troubling. Definitely seeing why a good microscope is so highly recommended... I'm just using a $100 LED light +Magnifying glass combo... better than nothing, but still is what it is, and is by no eans a microscope.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 21, 2017, 07:13:32 am
content: Solder mask sliver rules are more important with HASL, especially on the top of copper areas. Too narrow solder mask bridges between pads easily lift off in the HASL process. Make the openings smaller and/or use separate pads with thermals to the fill.Does this matter? I see no issue here whatsoever.gerbv can easily produce an image just like above. Just set the colors that way and use high-quality rendering mode.

author: Mjolinor
author_rank: Frequent Contributor
timestamp: November 21, 2017, 07:30:51 am
content: Quote from: progrock on November 21, 2017, 06:06:18 amIt is an online viewer:https://gerber-viewer.easyeda.com/

author: progrock
author_rank: Contributor
timestamp: November 21, 2017, 08:38:02 am
content: Thanks for all the help guys. Pcbnew is gonna make me a half dozen new OLED boards to replace the ones that are a little off. They also responded pointing out the same thing Monkeh did, with a pretty quick response. After being somewhat disappointed at first, actually very happy and impressed with the service, and speed. I actually ordered just after 5 pm on the 16th, received my order in California around noon on the 20th. Got 30 boards, 10 of each of the core 3 UniSolder 5.2 boards, for $35 shipped... and they are replacing the few OLED boards that came out a little bit funky. They've also been very great with communication, their Live Chat has been available every time I went to use it, and they responded very quickly to my emails, and dealt with my problems seamlessly. The boards also look pretty good all in all, the silk screening is aligned pretty close to dead on, all the holes/vias are centered, etc.I still can't get over the fact that 3 different 2 layer pcb designs, 10 boards of each, shipped via DHL, costs so little. And to go from ordering them to having them in my hands in under 96 hours is pretty damn impressive. It's pretty amazing how much the price for small quantities of custom PCBs has gone down in the last 10 years. With this kind of turnaround, the ability for anyone to design and prototype a new piece of electronics is incredible. I've been wanting to create my own bank of super capacitors to use with a DIY spot welder for some time now, and hopefully end up with something that can weld copper to batteries consistently... this definitely motivates me to get working on this. And I honestly don't think I'll be bread boarding this at first, like I expected to, can skip straight to PCBs, even if it takes a few revisions, won't take much time, nor much money.. I'm excited.