Richard,

Other folks have asked pertinent questions which I am not repeating here.
You might want to look at the preheat temp.... What is the topside temp just
prior to the boards hitting the wave?
What kind of flux are you using and how is it being applied?
Is it the same 4 - 5 holes on each board?
The the hole-to-lead diameter ratio big enough to allow the solder to flow/wick
up the lead?
Is the solder just simply not flowing up the lead or is the solder being blown
out of the hole due to outgassing due to contamination or pin holes in the
plating in the holes?

These are a few things to check for.

Good luck,

Charlie B.








Richard Tilbrook <[log in to unmask]> on 10/25/99 09:33:39 AM

Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to
      Richard Tilbrook <[log in to unmask]>








 To:      [log in to unmask]

 cc:      (bcc: Charles Barker/US/I-O INC)



 Subject: [TN] HELP!!! - flow solder problems RT








Hi Technetters,

I have a not so little problem:

I am finding no flow through on TPH holes after the boards are being put
through the flow solder machine. It looks like there are 4 to 5 holes per
board that have not wetted. This gives us between 3000 and 4000 ppm
faults on this problem alone.

Those are the symptomes, but what are their implications? Is it one
problem? What can I do to solve it?

Best Regards,

Richard Tilbrook

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