Good afternoon,



We have had a problem today with a reel of 0402 resistors where the
placement machine would not pick some of the parts out of the tape (paper).
A part I examined would not fall out of the pocket when the feeder was
turned upside down.  I examine the part sitting in the pocket and it
appeared to be jammed into one corner.  After some tapping on the feeder the
part dislodged.  When I examined the part under a microscope, I noticed a
filament attached to the bottom of the part starting at the corner of the
electrode.  The following part in the tape would, likewise, not fall out
until persuaded.  This part fell into my hand and when I examined it under
the scope I could see a filament lying beside it in my palm.



These parts are a 2002 date code.  Tin whisker?  Anyone seen this before?



I took the reel on components to our environmental test lab, bolted it to
the sinusoidal vibration table and shook for about a minute.  We then
reinstalled the reel on the placement machine and the picking problem went
away.  Interesting stuff for a Friday afternoon.



Gary Camac

Senior Mfg. Eng.

Dickey-john Corp.






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