I worked for a large captive shop in the late 80's that used dry
film mask.  Our corporate quality spec required Meseran testing
on each lot.  The test takes about 5 minutes per trial run so we
spent many operator hours per year running the test.

The tester dribbles an aliquot of solvent containing an isotope
onto the mask and then measures the residual radioactivity over
time.  The assumption being that fully cured mask will not absorb
as much solvent as will soft mask and so there will be lower residual
radioactivity frum fully cured mask.

I did a gauge R&R study and found that the instrument variability
exceeded the specified acceptable range for product even when we
substituted a polished glass plate for the cured sample to take out
product variability.  We tossed out the process and the instrument.


-----Original Message-----
From: <Michael Hess> [mailto:[log in to unmask]]
Sent: Monday, December 06, 1999 10:28 AM
To: [log in to unmask]
Subject: [TN] Degree of Cure Testing - Solder Mask
I'm looking for information on testing degree of cure of photoimageable
solder masks.  In particular, the Meserand or Meseran test procedure.  I
would appreciate information on articles written or testing labs with this
capability.

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