Hello to all,
While going through this long soldermask thread I could not help noticing reference to Dry Film Soldermask.
So, please let me rise a little subject from aside the point:
I was under the impression that it has gone almost extinct and everyone iis working LPI.
Am I wrong - is Dry Film still widely used ? For what applications ?
Thank you .
Yehuda Weisz
Tel: (972)-3-6342045
Cel: (972)-53-556897
----- Original Message -----
From: "Franklin D Asbell" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, February 10, 2004 6:51 PM
Subject: Re: [TN] Solder Mask Flaking
> We still have a customer that desires UV mask over tin/lead reflow...he
> believes this is the magic cure to a problem he had many years ago with
> 'noise' on a few boards...we've stopped trying to convince him to go
> SMOBC...
>
> Yes, I remember your problems with the dry film mask...as for it not being
> as shiny, how long was her board exposed to air before the pictures were
> taken, as opposed to your boards?
>
> Poor surface prep is the most common (99.6%) cause of mask failure
> documented here at this facility...luckily it is a very rare occurence
> anymore...(by the way, did someone ask if we were the fabricators of Sue's
> boards...no...not us). This would also include things such as fingerprints
> after cleaning, contaminates on the panels after cleaning, etc.
>
> I agree with your comments about LPI durability, it coming off as massive as
> that pushes me more towards cure, mixing of the mask, or possibly a
> combination. I could not see clear enough for staining (moisture, chemical
> residue, other contaminates) but I still would not be convinced it's
> contaminate or cleanliness only because the widespread areas...that tells me
> look to the mask itself...
>
> still pondering the possibility, wonder if Sue would provide more feedback
>
> Franklin
>
>
>
>
> ----- Original Message -----
> From: "Steve Gregory" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Monday, February 09, 2004 6:31 PM
> Subject: Re: [TN] Solder Mask Flaking
>
>
> > In a message dated 2/9/2004 4:55:42 PM Central Standard Time,
> > [log in to unmask] writes:
> > Okay, and those times not 'most often' what are the causes in your
> > experience, of flaking mask?
> >
> > Hi Franklin!
> >
> > Not sure who you're directing your question to, but I'll tell you my
> > experience.
> >
> > I've just experienced three scenarios for mask failure.
> >
> > 1. The mask was applied over tin (very old design, and SMOBC wasn't called
> > out on the drawing), and it wasn't caught until the assembly was
> waved...this
> > was was quite a while ago.
> >
> > 2. Incompatibility with a certain dry film mask and cleaning chemistry. To
> be
> > specific; Dynachem Dynamask (now Shipley's line since they bought it from
> > Dynachem) and Kyzen Aquanox XJN don't like each other.
> >
> > 3. The last incident was bad surface prep that was acknowledged by the fab
> > vendor, and what I have pictures of on my page.
> >
> > Number one of my three occasions was like I said, a long time ago...nobody
> > should see that anymore. I'd like to think that everybody nowdays know
> that
> > solder mask needs to go on over bare copper.
> >
> > Number two could happen if you happen to use XJN and have a board with the
> > Dynachem dry film on the board.
> >
> > Number three could happen to anybody if your fab vendor doesn't have good
> > checks and balances on the production floor to make sure a step isn't
> skipped.
> >
> > The pictures that Sue sent me, looks like an LPI was used. I have never,
> ever
> > had any trouble with LPI mask coming off a fab unless it was applied over
> > something other than bare copper. This tells me that something wasn't
> quite right
> > when it was applied. I have a hard time trying to think of what could
> cause
> > the mask to come off the board the way that it did on Sue's boards during
> the
> > assembly process. I know you haven't seen the pictures yet, but there's
> great
> > big areas where the mask came off. The difference between what I saw
> between
> > her case and mine, was that the copper is not as shiny on her boards as
> was
> > mine, and to me it looks like a LPI was used...which kind of suprises me.
> LPI
> > usually is pretty bullet-proof, unless something wasn't right during
> application.
> >
> > My 2-cents...
> >
> > -Steve Gregory-
> >
> > ---------------------------------------------------
> > Technet Mail List provided as a service by IPC using LISTSERV 1.8e
> > To unsubscribe, send a message to [log in to unmask] with following text in
> > the BODY (NOT the subject field): SIGNOFF Technet
> > To temporarily halt or (re-start) delivery of Technet send e-mail to
> [log in to unmask]: SET Technet NOMAIL or (MAIL)
> > To receive ONE mailing per day of all the posts: send e-mail to
> [log in to unmask]: SET Technet Digest
> > Search the archives of previous posts at: http://listserv.ipc.org/archives
> > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
> for additional information, or contact Keach Sasamori at [log in to unmask] or
> 847-509-9700 ext.5315
> > -----------------------------------------------------
> >
> >
> >
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 1.8e
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
> Search the archives of previous posts at: http://listserv.ipc.org/archives
> Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------
> -----------------------------------------------------
|
