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Wicking-solder found under mask


DL

#7177

Wicking-solder found under mask | 5 July, 2001

I've never seen this and was wondering how bad is this?

We've tried to re-create this defect, but could not.

Comments????????

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#7178

Wicking-solder found under mask | 5 July, 2001

Most of our boards are fabricated with solder mask over bare copper [SMOBC], but we have couple where the solder isn't removed before masking. And ever so offin they's a liddy bit mo' solder than we'd like, which when reflowed, ends-up connecting some traces together. Our crafty iron operators remove those bridges and no one is ever be the wiser. [Well, at least til now, where ol' Mr. BIG Mouth got to yammerin' on the computer with who knows who, that is.]

Rather than say that you probably shouldn't leave the solder under the mask, but then again may be you could; why don't you spell your situation to us and maybe we'd be able to picture it better and give sound reasoned advice.

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DL

#7179

Wicking-solder found under mask | 6 July, 2001

Thanks Dave, and yes we can leave the solder there in this instance. These panels, 12up, are NCMR from the customer. The customer is saying that after the panels have been reflowed 5 times! solder starts to accumulate under the mask. Get this, My senior staff have PHOTOS of this from the customer. You'd think I would've seen them by now, no matter, I took 10 panels from the lot, scren printed, inspected, reflowed(five times each) with inspection between flows. I saw nothing special. I did look in the IPC manuals for guidence, can't say I saw much to really put to use. My best guess is that the customer is doing something funky with the panels, whatcha think? Or we had one bad panel out of 1,000's. Maybe I can see these PHOTOS, and let ya'all know more.

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#7187

Wicking-solder found under mask | 6 July, 2001

The senior staff have the pictures!!! Oh, that�s just GREAT!!! What the blank are these gerbils doing with �em? Nothin�!!! They�re probably sitting in a folder on whatzisname�s desk, until he has "a change to study them more". [Like he�s going to bust the genetic code of solder wicking wide open!!!] Maroon!!! [Bring him here!!! I wanna pimp slap em!!!]

Gimme the pix and I�ll post �em [er, better yet, why don�t you post �em?]

Just printing; based on the flimsy description, no pix, absence of certified test reports, and everything else that you�ve provided; I agree, we gotta blame someone else. Two prime suspects are: customers and suppliers. [Let�s keep the buyer in reserve, just in case we need �em.]

CUSTOMERS: It�s always the same, isn�t it? What�s with these people? What are they doing to get paste into the keep-out [between the pad and the mask] during these 5 reflows? Now, if they had said something about wave soldering cycles �

SUPPLIERS: It�s always the same, isn�t it? What�s with these people? What are they doing [not doing] to the solder mask that allows molten solder to get under it?

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Hussman

#7231

Wicking-solder found under mask | 12 July, 2001

Since your customer is complaining, you'd better be pro-active. Doesn't mean they're right, but without customers, life sux alittle. Anyway, ask them for a profile of the 5 reflow processes. If they don't have that and you have a profiler, ask if you can profile the processes for em'! I bet they get you some numbers pretty quick then.

Hard to say what you've got there. Especially with all the evidence against you being held without you seeing it.

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#7240

Wicking-solder found under mask | 12 July, 2001

Hussman: Please help us understand how knowing the profile will point us in the direction of how solder got under solder mask.

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DL

#7247

Wicking-solder found under mask | 13 July, 2001

Quick update on my issue of " wicking ". I had some talk with the company QA guy. Told him I saw no wicking on the test panels at 30X. The next day he came up to me and said, he kinda saw a little something at 60X then verified that at 100X, So, he decided to ship them. Still no pictures. I email him today as a reminder. I hate to sound like I don't know squat!!, but when you work for a company that treats you like a mushroom...............................

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Hussman

#7261

Wicking-solder found under mask | 16 July, 2001

Easy, DL says the customer is telling him after 5 reflow processes they get solder under the mask. He tried it and didn't see anything. DL needs more information to understand why and where this is occurring. So, if he can't duplicate the problem the customer is seeing, then investigate what the customer is doing. Perhaps there customers reflow process is significantly different that DL's. If so, maybe the customer is exceeding the limits of the board material or something of this nature.

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#7274

Wicking-solder found under mask | 16 July, 2001

Speaking of people we'd like to pimp slap, why did the not-so-quality guy decide to ship defective units, anywho?

This sorta says we can't blame the customer any longer. So, it's either blame the fabricator or umm er, sorry to say this ... YOU DL, buddy. So, fess-up!!! Watjadoto those poor defenseless boards? Didja really reflow 'em five times? Jesh, what a monster!!!

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