Good Morning Steve,
Several things that I've seen which "requires" dry film are:
1) Legacy drawings for circuit cards designed in the 80's that we still
produce, and
2) New drawings when the draftsperson or layout designer has cut and pasted
notes from old legacy drawings noted in 1 above.

I attempt to review every drawing before it is released and getting "B2"
changed to "B1" before the fabricator gets it.  The other wicket is our
suppliers request relief from the dryfilm and provide LPI, which requires a
modification to the PO.  We own the majority of our data packages, therefore
customer consent is typically not required.

IMHO with the advancements in material technology and photoimaging
equipment, the person who selects dryfilm doesn't understand the big
picture.  A side by side comparison with pros and cons should shed an
immaculate light.  Let's face it, solder mask was designed as a process aid
to minimize solder bridging during mass soldering (i.e. wave, drag & vapor
phase) processes and was never intended to be relied upon as a dielectric
nor insulator.  A lot of the "old school" information is continually being
lost and that is directly proportional to the amount of "how to" being
removed from specifications and standards.  As you can tell I'm not a fan,
nor ever will be of the DOD Standardization Reform but I do know that a
solder connection doesn't have to bright and shiny to be reliable!!
Good Luck!

Steve Sauer
Sr. Mfg Engineer
Northrop Grumman, Electronic Systems
Xetron

-----Original Message-----
From: Steve Gregory [mailto:[log in to unmask]]
Sent: Wednesday, January 21, 2004 8:17 PM
To: [log in to unmask]
Subject: [TN] Why Dry film Solder Masks?


Can anybody tell me why dry film solder masks are still specified?

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