Ivan,

The only real way your going to fix this problem is to keep the LEDs from
sealing the PTH as you have already concluded.  Reducing the amount of flux
may help and insure the carrier is completely evaporated.  If you are
fortunate enough to have a Hot Air Debridging Knife then turn it on, it
will heal the blowhole.

Ken Kirby





 (Embedded
 image moved   Ivan Barrios <[log in to unmask]>
 to file:      10/12/99 02:14 PM
 pic17347.pcx)




To:   [log in to unmask]
cc:    (bcc: Kenneth Kirby/ElectrovertUS/Cookson)
Subject:  [TN] Blow holes on assemblies




I am currently having an issue with blowholes on TH components. What I have
concluded is that the components are too tight and sit flush against the
top of
the board. When they go through wave solder, the outgassing has no way to
go but
down towards the wave solder. We have tried loosening up components but
then we
incurr having the LED's uneven after wave solder (and the LED's do not
match up
to the corresponding window in the enclosure) and are currently looking for
an
alternate LED that has standoffs so that the plated barrel is not sealed at
the
top. My question is: Is there anything that can be done process wise to
reduce
this defect? Thanks to all for your input

Ivan Barrios

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