Have you tried oblong apertures? As far as I know, studies made showed
overprint of something like 125 mils didn't cause solder balls.


-----Original Message-----
From: Tempea, Ioan [mailto:[log in to unmask]]
Sent: Friday, April 11, 2003 5:22 AM
To: [log in to unmask]
Subject: [TN] Apertures for intrusive reflow


Hi Technos,

I am investigating intrusive reflow and big part of the topic is OK for me.
I learned how to calculate the volume of the paste, I even tried the process
on several assemblies, all OK.

Now I'm running into a board with less real estate, so not so much space to
do the overprinting. According to my calculations the apertures for this
particular TH connector would overlap. It's a 78.7 mils pitch.

The question is: could I overlap the apertures and print paste all over,
bridging between the pins? Since we deal with large pitch and we're talking
liquid paste flowing towards the holes, would this not create solder bridges
after reflow?

Thanks for your insights,
Ioan

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