EEVBlog #155 Itead Board Fail - Page 1
Forum section: electronics / general

author: dimlow
author_rank: Frequent Contributor
timestamp: March 11, 2011, 12:20:43 pm
content: Your not the first Dave, i sent an unfinished Gerber to ITead for them to check, as i had not used them before and i use Proteus ARES for my boards and was not sure they could take the format..Anyway, i only asked them to check if my Gerber would be ok for them. I got no reply from them. Later i decided to send the final Gerber to them for production, only to find that they had already produced my unfinished PCB board board. Lucky its not to bad, but i will have to add a couple of jumpers and a resistor to the board for it to work. Wont look nice but it will function.THEY NEED TO PAY ATTENTION TO DETAIL!

author: the_raptor
author_rank: Regular Contributor
timestamp: March 11, 2011, 12:47:32 pm
content: Was this a case of them over stating what their equipment could actually do?That is the only reason I can see for them mucking around with it (which they might not have done at all, this just might be what their equipment did with the supplied gerbers).Classic lowest bidder stuff really.

author: EEVblog
author_rank: Unknown
timestamp: March 11, 2011, 01:00:40 pm
content: Quote from: the_raptor on March 11, 2011, 12:47:32 pmNo, their system can easily do 6/6, as evidenced by the 6/6 tracks that are not near ground planes were all just fine and untouched.Dave.

author: apex
author_rank: Regular Contributor
timestamp: March 11, 2011, 04:46:40 pm
content: Did you really need to go down to this level?I mean, they shouldn't have touched your gerbers, but I would have just made a trace for the ground.Since I normally just do hobby stuff, I question myself if the flood-connection way is the normal way in the industry?apex

author: FreeThinker
author_rank: Frequent Contributor
timestamp: March 11, 2011, 05:27:31 pm
content: Just a thought but IIRC they 'Patch' your boards into the spare space on their production boards (Hence the board size restriction). Perhaps they needed to adjust something on that and Daves boards got caught up in the change? Quality seems quite good otherwise.

author: Zad
author_rank: Super Contributor
timestamp: March 11, 2011, 05:46:52 pm
content: I have a theory about this problem. They are over-etching. It might be that the etchant is too strong, or that they are simply etched too long and it is undermining. It could also be that they are having problems with the sharpness of the mask, possibly due to the distance of the mask from the copper clad. This might explain why small feature like the thermal relief is comparatively thin.

author: steaky1212
author_rank: Regular Contributor
timestamp: March 11, 2011, 07:36:49 pm
content: Zad: If they had ver-etched then the 6thou track from pin3 of the bottom connector would have been over etched also.It looks like they've just changed the flood fill clearance for whatever reason. I was always taught to route all tracks (including ground) and not to rely on floodfill, that way you can direct the return current and help with EMC issues etc. Obviously they state they do 6/6, but do they have any info on via clearances etc?

author: hans
author_rank: Super Contributor
timestamp: March 12, 2011, 12:01:02 pm
content: Quote from: apex on March 11, 2011, 04:46:40 pmI think this is not in question. If a design manufacturer specifies they can make 6mil trace width and clearance board, why would they go through the gerbers and change this? If a manufacturer can't reliably supply 6mil boards, then they shouldn't specify it.If they can't do these boards properly, I guess you should take note that they are only good to boards with 10mil traces or something, and put them aside if you design a PCB with anything smaller.However, if I do have to add to Dave's PCB I find it hard to imagine you're making your board so reliant on a single trace. Personally I would try to give ground connections the best connection as possible, even if the board doesn't consume much power at all (as you said it's USB powered).I also learned this week at internship it's wise to route ground traces manually in addition to flood fill. Flood fill is useful to connect all grounds together in 1 go, but manually routing the grounds also puts attention where to place via's for your ground connections. It may avoid that ground currents have to flow around other sections or chips to get to the 'mainstream' path back to the power connector.

author: TheDirty
author_rank: Frequent Contributor
timestamp: March 12, 2011, 04:55:55 pm
content: I think understanding this limitation and the chance for your ground pour to be modified still makes this a good deal.Dave keeps saying there's "no need to make your own boards now", but even if this worked out 100% there's still a number of people that benefit from making boards. Personally I like to "play" with electronics, so I buy sensors, uC's, and other chips just because I want to test them out. I get my digikey/mouser order, make sure my little breakout design looks good and it takes me an hour or so to toner transfer and etch it up. If I screwed something up, I just try again. If I had to wait two weeks to get a board and then find I did something wrong, I'd quickly give this up. I do get boards made, after I've verified the designs, and once you get experience you don't even really need to "play" anymore so the need to make up test boards isn't as high.

author: monpjc
author_rank: Contributor
timestamp: March 12, 2011, 08:22:24 pm
content: Quote from: apex on March 11, 2011, 04:46:40 pmThis is a very good point. I generate PCB layouts as part of my job and was once caught out by not checking the flood. My board did not have a fault like Dave's but I have power issues as the track route was long and width restricted.Sine then I always - always run a ground trace as part of the layout, defining were it will run. After all its pretty important connection! This was it dose not matter where the flood goes.I'm not saying what Dave did was wrong because he had already assessed the route, the fab screwed up and should replace at their cost.

author: EEVblog
author_rank: Unknown
timestamp: March 13, 2011, 05:10:10 am
content: Quote from: apex on March 11, 2011, 04:46:40 pmYes, I needed to go that small.Yes, flood fill is standard industry practice.Dave.

author: frank26080115
author_rank: Regular Contributor
timestamp: March 13, 2011, 05:28:57 am
content: Quote from: dimlow on March 11, 2011, 12:20:43 pmYou need to understand that these people simply work hard, fast, and cheap, but lack communication. If you can leverage this fact, you can still be a happy customer who saves a ton of money, you just have to be careful not to make any mistakes.

author: dimlow
author_rank: Frequent Contributor
timestamp: March 13, 2011, 05:37:45 am
content: Yes agreed, I have another board to send in a week or two. It ill use 6 x 6 rules, and will also be using some ground fills, will be interesting to see how that turns out. I wont be sending any gerber for them to check!Dave, i assume you got in touch with them over this issue, have they got back to you ?

author: FreeThinker
author_rank: Frequent Contributor
timestamp: March 13, 2011, 12:12:56 pm
content: Just an aside but looking at the screen print does that say 'aduino'?

author: firewalker
author_rank: Super Contributor
timestamp: March 14, 2011, 10:40:03 am
content: Itead replied on the blog.MatrixDuino!

author: dimlow
author_rank: Frequent Contributor
timestamp: March 14, 2011, 11:19:55 am
content: Finally, I found the reply, for others here it ishttp://iteadstudio.com/iforum/viewtopic.php?f=20&t=417

author: Unknown
author_rank: Unknown
timestamp: March 14, 2011, 04:54:54 pm
content: It appears itead studio are having quality issues by 'over the wall effects'.I would suggest to itead to work closer with their manufacturing plant, laying down and agreeing on a detailed set of specifications. If non-compliance issues arise in the future they can be traced to the source and corrected.Even though itead is blamed by the untrained eye, this is not damaging their reputation at all, quite the contrary actually.Congratulations to itead for offering an affordable pcb prototyping service.This post:http://iteadstudio.com/iforum/viewtopic.php?f=20&t=417#p1996is also interesting.

author: dimlow
author_rank: Frequent Contributor
timestamp: March 14, 2011, 06:12:16 pm
content: Quote from: Alex on March 14, 2011, 04:54:54 pmDuh! Didn't i just post that!your research must be full of detail!

author: Unknown
author_rank: Unknown
timestamp: March 14, 2011, 06:25:07 pm
content: That link specifically points to the post by itead with the distance measurements on the gerber files, not the entire thread. So no, you did not just post that. Have a more detailed look.

author: zilym
author_rank: Newbie
timestamp: March 14, 2011, 09:41:39 pm
content: Itead's 5cm x 5cm for $12 sounds good, but I'm not clear on the size restriction. Is it 5cm max in X/Y direction period, or is it 5cm squared total area limit? For example, say I have a design that is 6cm x 4cm (to fit my enclosure), will it qualify for the $12 pricing? I can not change the dimensions to be 5cm x 5cm, as it would not fit the enclosure anymore.

author: 8086
author_rank: Super Contributor
timestamp: March 14, 2011, 09:43:06 pm
content: 5cm x 5cm seems pretty clear to me...

author: Unknown
author_rank: Unknown
timestamp: March 14, 2011, 10:29:10 pm
content: Looking at itead's posted gerber images on their forum, they seem to be measuring the distance between the top copper layer (GTL) and the top solder mask stop layer (GTS) which apears to be 4.1 mil. Just looking at the scale of 4 mil, the track-pad distance does indeed look like 6 mil.On the current iTead page for their pcb service 6mil is the specified minimum spacing but it is not stated if this applies to copper-soldermask or just to copper-via copper-copper etc.Could this be why itead's manufacturing decided to widen the clearance? In this case the safe thing to do would be to alter the soldermask layer, not the copper layer. The soldermask is a separate process to the copper layers so, apart from a clearance from the pad itself, I dont see how such a limitation is valid.Itead needs to clarify what they mean by:Minimum Line : 6mil (recommend >8mil)Minimum Space : 6mil (recommend >8mil)

author: tinhead
author_rank: Super Contributor
timestamp: March 15, 2011, 02:32:29 am
content: Quote from: Alex on March 14, 2011, 10:29:10 pmit is always, if not extra specified, copper-copper distance, it have only something to do with PCB fab technology.The 6mil (or 150µm - which is btw. what Dave selected , that's 5.906mil) are common for most PCB fabs,the iteadstudio answer is just bullshit.

author: FreeThinker
author_rank: Frequent Contributor
timestamp: March 15, 2011, 07:38:06 pm
content: So there we have it, simple human error. It's all bloody Bens fault. Bet it takes a LONG time for him to live this one down.Nice to see Itead put their hands up and make a public apology, shows a great understanding of their customers and the market, Impressed.

author: Unknown
author_rank: Unknown
timestamp: March 15, 2011, 09:00:26 pm
content: Spot on Alex.

author: frank26080115
author_rank: Regular Contributor
timestamp: March 18, 2011, 02:52:47 pm
content: question, when a design is finished, is it a good idea to disable the flood-fill and then run an auto-route and then re-enable the flood-fill? is there a better technique for this?

author: FreeThinker
author_rank: Frequent Contributor
timestamp: March 21, 2011, 11:34:48 am
content: This is the official reason for the failhttp://iteadstudio.com/service/prototyping-pcb-minimum-spacing-limitation/

author: steaky1212
author_rank: Regular Contributor
timestamp: March 21, 2011, 06:01:23 pm
content: what I dont understand is how they managed to fit the a trace between two vias (TWICE!), but cant do the same with a flood fill.Still, I am glad it didnt happen to me

author: dimlow
author_rank: Frequent Contributor
timestamp: March 21, 2011, 08:38:31 pm
content: So Dave, What is a uRGB MatrixDuino anything to do with a RGB LED Matrix ? seems Itead Published your board design and the name of your project on the link above. I dont think that was very good. I guess its like their Colorduino v1.3

author: RayJones
author_rank: Frequent Contributor
timestamp: March 22, 2011, 08:00:09 pm
content: With hindsight, I can see two ways of avoiding the problem in future.1/ do your polygon pour at 8 thou clearance and check the DRC. If OK, re-pour at 6thou and submit.2/ add a deliberate track under the polygon pour to ensure connectivity.It is amusing (in a way) to get this sort of result from the ultra precise Altium package.I have been known to have similar issues with polygon pours when panelising many identical boards onto one large panel for another PCB service.My problem was the copies were pasted without netlist connectivity (avoids the ratsnet appearing between boards).The problem was allowing a polygon re-pour after the no netlist paste.Result - instant isolation of all ground pins from the polygon pour.Arrgggghhhh - wasn't funny at the time, but once the pain wore offBTW despite the issues, the boards look great, must give them a go myself.Reasonable turnaround?

author: Unknown
author_rank: Unknown
timestamp: April 03, 2011, 12:00:43 pm
content: It seems this is not so uncommon after all and it is something to look out for when evaluating EMC performance.Have a look at the highlighted text in the attached pdf.

author: aXit
author_rank: Contributor
timestamp: April 22, 2011, 05:57:35 am
content: Just got an order from Itead. Seems good enough, few holes slightly out of allignment with the pads, but nothing too serious. No issues like dave's, but this design was easily made with 10/10.A very strange thing though... is that I got 11 boards, and only 4 were e-tested. I'm not sure what this really means. Maybe one failed the e-test, and they threw in 2 extra? Seem strange that they're making extra boards just in case they fail e-test.

author: FreeThinker
author_rank: Frequent Contributor
timestamp: April 22, 2011, 01:03:43 pm
content: Quote from: aXit on April 22, 2011, 05:57:35 amPerhaps not. As I understand it they 'tag' the boards on to there production boards spare space, just as easy to make enough to fill the spare space as waste it and helps guarantee yield.