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 ----------------------------------------------------- > -----------------------------------------------------