Jim,

Following printing, does the paste fill the entire hole ? Hole size,
squeegee angle, volume of paste will dictate the amount of paste hole fill.

What is the angle of your squeegee ?  I have found, a shallow angle
increases paste hole fill and a 45 degree squeegee will help this. If you
are using a DEK265 printer, the pro-flow option will fill the holes without
finepitch side effects.

What is the volume of paste at the squeegees ? the greater the size of the
paste bead (0.75") will increase paste hole fill but you must maintain this
volume.  The use of an automated paste dispenser does help.

Is there any evidence of paste dropping in your placement machine or reflow
oven ? (the square pins will push most of the paste from the hole and may
fall off in the reflow oven entrance bays. I have found a spade type pin
will promotes less paste drag through. Also the pin to hole clearance at
the diagonal points is very tight and promotes voiding in the centre of the
hole.

What is the pin and PWB finish ?

Review the underside of the connector to ensure the plastic moulding does
not disturb the off-pad paste. Optimize the stencil apertures with a oblong
shape and keep a 0.012" clearance between each aperture. Orientate the
oblong apertures to achieve the maximum paste deposit within the formula.

Finally, is there any evidence that a part was placed into the paste and
removed because of mis-insertions, then discarded and a fresh part used in
its place ?

regards,
Felix

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