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Date: | 27 Sep 96 12:56:42 -0500 |
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bare copper panels are never subjected to HASL or HASL fluxes, which
leave residues that do not show up on an omega meter. This means that
bare copper panels coated with an Organic Protective Coat arrive with
higher SIR.
HASL panels are also more variable in metal amount, finish and
solderability.
I never do SIR testing on solder plated panels. The incoming SIR can
sometimes be lower at the start than the end of my process due to
supplier inconsistancies. I.E. the supplier may give me a panel that
starts with more contamination than I put on during my process.
______________________________ Reply Separator _________________________________
Subject: Flux complinace to J-Std-001A
Author: [log in to unmask] at internet
Date: 9/27/96 10:44 AM
We are in the process of trying to comply with the provisions of J-Std-001A,
Appendix D-4.1, which basically states that level 2 testing (SIR test, Ionic
Contamination, and visual inspection) needs to be done to qualify your
process for the use of water soluble fluxes. I have the IPC-B-36 Circuit
boards and the 68 Pin LLC's needed to run the test. I was quite surprised to
see that my IPC-B-36 boards have copper lands and traces on the boards.
There is a document called IPC-TP-1044 which outlines an oven bake process
followed by a microetch process using Enplate PC-499, cascading water
rinses, and other materials (18 steps in all !). This microetch process is
followed by Omegameter 600SMD process and then followed by board drying in a
nitrogen autoclave. The boards were then placed in Kapak bags which were
"tested" to be non-contaminating.
I have the following questions:
- Why do the boards have copper traces ? Why aren't they tin-lead ready for
soldering ?
- Is there a simpler way to get these boards clean in preparation for
soldering ?
Thanks,
Bill Kasprzak, Moog Inc., 716-652-2000 ext 2507
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