Hi again Sue!

Would you like me to post the pictures on my page so others can see them?
Just give me the word.

But looking at your pictures, your problems seems somewhat different than
mine. For one thing the exposed copper on your boards doesn't have the same shine
that the copper on my boards did.

Another thing I noticed, was that there was adhesion problems with the solder
mask from the beginning before hitting the wave, as evidenced by the solder
wetting out at places where solder mask should have been. This was a liquid
photo imagable solder mask wasn't it? There definately was some sort of adhesion
problem here, but I can't really say for sure what caused it. One thing I can
say with pretty good confidence, I find it hard to say that it's something
you've done in your process that has caused the mask to fail like this.

I must say, this is the first time I've ever heard of fab vendor telling a
customer to lower their solder pot temperature so the mask doesn't fall off, or
saying that if you don't flux your boards enough the mask might come off
too...but maybe I'm missing something.

-Steve Gregory-


> Thanks Steve, Looks like I may have the same problem, I have attached
> pictures of my problem here. I am also forwarding this response to our
> supplier to see if he will cooperate more and answer me to this point.
> Sue
>
>
>
> -----Original Message-----
> From: Steve Gregory [mailto:[log in to unmask]]
> Sent: Monday, February 09, 2004 1:55 PM
> To: [log in to unmask]
> Subject: Re: [TN] Solder Mask Flaking
>
>
> Hi Sue!
>
> I had problems with solder mask a few weeks ago that I posted about. In
> my case, I was seeing it after cleaning. Also in my case it wasn't
> merely flaking, it was like a snake sheding its skin...mask was coming
> off in huge slabs. I still have some pictures of it on my web page at:
> http://www.stevezeva.homestead.com/
>
> Look at the "Mask Peel" pictures there...it was ugly! What it turned out
> to be was that the pumice scrub before mask application hadn't been done
> on one panel even though the production paperwork at the fab vendor had been
> signed off that had been done. This was a dry film solder mask over bare
> copper by the way...
>
> The problem only affected 2 boards because it was built in a 2-up panel.
> For some reason, only one panel out of the lot that got built didn't get
> scrubbed as it should have been. The boards passed our tape test at
> incoming inspection too. It wasn't until the boards got thermally
> shocked at wave solder, and then washed, did the poor adhesion because
> of the bad surface prep show itself.
>
> -Steve Gregory-
>
>
>
> > I know this was up for a discussion a few weeks ago. Can anyone tell
> > me what the root cause was determined to be?
> >
> > I am experiencing solder mask flaking on a group of boards
> > manufactured by one certain supplier. It is a random occurrence for
> > example 10 out of the 100 boards we had this occurr. Then a different
> > board we ran 8 out of 40 were flaking same supplier as previous one.
> >
> > Supplier runs samples at his facility and he see's no flaking. We
> > changed our solder temperature from 500 degrees to 450 degrees at the
> > suppliers suggestion and flaking still occurs. He then states maybe
> > were not using enough flux but review shows plenty of flux if anything
>
> > maybe were using to much flux from the way the boards look coming out
> > of the wave and washer.
> >
> > Thanks
> > Sue Foulkes
> > QA Manager
> > AESCO Mfg.
>


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