Mr. Joyce

Thanks for your reply,

1.      We are using medium/high solids RMA flux.
2.      Time delay between soldering and cleaning is less than 30 minutes.
3.      Cleaning process is batch cleaning with four tanks system and the
forth one is hot air dryer.
4.      PH for tank 1 (Prozone) is 5.45, tank 2 (Prozone/Tap water) is 4.15,
and tank 3 (DI water) is 5.85

Please note that we were used to clean assemblies even before wave soldering
and we had not faced any problem. But now we have the problem when we do
cleaning before and/or after wave soldering.

Is there a need to monitor and control the pH value for the cleaning
solutions?

Regards,

Yousef

        -----Original Message-----
        From:   joyce [SMTP:[log in to unmask]]
        Sent:   Mon, May 01, 2000 12:10 AM
        To:     TechNet E-Mail Forum.; MOTLAQY
        Subject:        Re: [TN] Rust on lead cutting edge

        question:
        (1) what kind of flux?
        (2) what is the time delay between soldering and cleaning?
        (3) Is your cleaning process continuous tank or batch? (sound like 3
tank
        system, but I could be wrong).
        (4) can you check the pH of the cleaning solution of the 1st tank?
                                             jk
        At 03:13 PM 4/30/00 +0300, you wrote:
        >Dears,
        >
        >Below is a short description of a problem we have faced recently at
our
        >plant with the Through/Hole assemblies.
        >
        >Problem: Unacceptable formation of rust (brown to red color) on the
CCA just
        >after cleaning (before and after wave solder)
        >Location: Exactly at the cutting edge of the T/H components leads
(most of
        >the T/H components)
        >Process used: Semi-Aqueous cleaning (Prozone wash 45?C, Prozone/tap
water
        >rinse 45 degC, DI water rinse 50degC, then hot air forced drying
110degC)
        >
        >What could be the reasons for this problem and what do you
recommend to
        >solve it and to prevent re-occurrence.
        >
        >Your expected useful response is highly appreciated in advance.
        >
        >Best regards,
        >
        >Yousef Almotlaq
        >Manufacturing Engineer
        >
        >Advanced Electronics Company - Saudi Arabia
        >
        >Email [log in to unmask] <mailto:[log in to unmask]>
        >Tel  + 966 1 220 1350 X 3215
        >Fax + 966 1 220 1355
        >
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