Liam,
Sorry for the late reply, I have been out of commission at SMI then took
awhile to get my plate clean again when I returned. The cleaner we used at
Raytheon was an EMC Technologies mosel "Spirit 301PA", they can be reached at
ph:215-340-0650. It is a full-blown large size cleaner, with intense pulsed
spray. we ran an alcohol-water mix, for cleaning both stencils and boards,
worked very well, but we were cleaning RMA paste...should work with no-clean
also, but might have to play with the chemical type you will use.
Whichever cleaner system you use, keep from disturbing (DO NOT WIPE) the solder
paste print before clean, (catch the bad bd BEFORE placement) this injects the
solder balls in all of the crevices, much harder to clean. Keep board tilted
about a 10 degree minimum angle with paste facing down, so solder balls fall
gravity-wise away from board.
I am looking at two smaller systems that look promising, with heated and
ultrasonic tanks, and water/detergent chemistries for no-clean: PMR industries
(602-829-8170) and SmartSonic (805-499-7440). I would be happy to compare notes
if you like, call me directly. Good Luck.
United Technology Electronic Controls
Jeff L. Hempton, Sr. SMD Engineer
3650 West 200 North
Huntington, In
46750-9002
Phone: 219-359-3514
Fax: 219-358-0695
E-mail: [log in to unmask]
______________________________ Forward Header __________________________________
Subject: Re: [TN] Solder-ball
Author: "Liam Barry"<[log in to unmask]> at Internet
Date: 8/21/98 8:17 AM
Jeff, you mentioned in your mail to Fulton Feng that you use 'an alcohol
based wash/spray system' to clean boards, can you expand on this ? Can this
system be used on double sided SMT (no clean) boards ? Can you wash side 2
when side 1 is built ?
I am currently building a double sided GSM product. Some prints are
rejected from the DEK printer. I then need to remove 100% of the no clean
paste from the 4-up panel to avoid any subsequent solder balls forming on
the PCB edge, mounting holes etc.
I would be grateful for your help.
Thanks, Liam ..........
[log in to unmask] on 28/07/98 18:47:08
Please respond to [log in to unmask]; Please respond to
[log in to unmask]
To: [log in to unmask]
cc: (bcc: Liam Barry/DOV/DIIG)
Subject: [TN] Solder-ball
Fulton,
Just a quick note: if caught before part placement, we instruct our
operators NOT to wipe the boards before cleaning, and this all but
eliminated the solder balls. If there are parts on, there is not much
choice.
We use an alcohol based wash/spray system without ultrasonics (can
damage multilayers?) Good Luck.
Jeff Hempton
United Technologies Electronic Controls
______________________________ Forward Header
__________________________________
Subject: [TN] Solder-ball
Author: Fulton Feng <[log in to unmask]> at Internet
Date: 7/28/98 11:46 AM
Hi, TechNetter
I am wondering anybody out there ever experienced solder ball with
mis-print
PCB. The scenario is when we have mis-printed PCB in solder paste printing
process, we used to wipe off the paste with alcohol from the PCB surface
and
send them to aqueous cleaner. What happened is when we looked at the PCB
under microscope, we found all the masking edge and vias sticked with
solder-balls(Solder paste). The solder paste we used was no-clean
water-soluable paste. The questions are:
* Is there any difference in between clean and no-clean paste for
cleaning PCB?
* Has anybody used ultra-sonic cleaner for PCB cleaner?
* What kind of cleaning agent are your guy using?
* Any different approach to take care of this solder-ball issue?
Any input is appreciated!
Thanks in advance!
Fulton Feng
Nortel
MPK
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