It sounds like you went from a 100% defect to 50% yeild, in my book that is
quite an improvement.  Not knowing what kind of flux your using or any of
the other process parameters makes it hard to know what the problem could
be.  There is however one thing I find quite often and usually in a
no-clean process.  The length of the connector leads are critical
parameters to overcoming bridging defects.  The leads should only protrude
below the board by .020-.025.  If your boards are .062 then get your
connectors with a .085 lead length.  Try a test and let us know if this
solves your bridging problems.

Ken Kirby
Product Specialist
Speedline Technologies










 (Embedded
 image moved   "Uday V. Putcha" <[log in to unmask]>
 to file:      08/12/99 05:25 PM
 pic05092.pcx)




To:   [log in to unmask]
cc:    (bcc: Shean Dalton/ElectrovertUS/Cookson)
Subject:  [TN] 50-mil pitch two row connectors




Hello All

We have 50-mil pitch two row TH connectors on some of our boards. The
direction of flow in wave is parallel to the row of pins. This part always
bridges on the last pins as there is lot of drag at the end. We also tried
to add a thieving pad at the end of the last pin in the direction of flow
to help, but the test results didn't help much. (only 50% yield).

Does anyone has experience with this case? Any help is appreciated

Thanks
Uday

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