In a message dated 12/21/99 5:47:09 PM Central Standard Time,
[log in to unmask] writes:

> Look like I am going to hand pick and place a fine pitch device for
>  prototype.  Does anyone can recommend me a "manual vacuum hand pick pen"?
>  The requirements are:
>  (1) handle large components, such as 45 to 60 mm square with body weight of
>  300 to 500g (top of the body would be either moulding epoxy or metal
>  lid-hybrid).
>  (2) vacuum pick and hold for 5 min. solid (no dropping).
>  (3) predictable release time (control release speed if it is possible).
>  (4) not too heavy (can handle with one hand - I need the other hand to
focus
>  the microscope).
>  I found Pac-Vac pen...It looks good with pager size motor...Any experienced
>  comment?
>  Current vacuum pen we have can only pick up the CPGA for 20 sec.  With my
>  aging eye sight, it is almost impossible for me to focus and coordinate all
>  my limbs into smooth action within 20 sec.
>  Many thanks in advance.
>                                          jk

Hi Joyce!

Am I reading you right? 500 grams?!! Holy Toledo!! If I do my math right (and
ya'll know how I am with math) 500 grams divided by 28 grams (= 1 ounce)
divided by 16 (= # of ounces in a pound) = 17.85714285714 ounces!! You're
talking over a pound of part!! Hoo-doggies!! That be one BIG part!!

I found a couple of other vendors of vacuum pens that have separate vacuum
pumps that will supply the vacuum...I think you'll need more vacuum than what
the standard pens supply. Kinda pricey though...the first link wants around
$220 for their unit, the second link has pens to handle 8" wafers and are
clean room spec'd $1,000 + for those!

http://www.emulation.com/whatsnew/press/vacpens.html
http://www.tedpella.com/grids_html/520.htm

Might try a trick I used one time for some big heavy QFP's that had a
aluminum tower heat sink bonded to the top of them. Fuji IP couldn't place
them because they were too heavy, and ran into the same problem as you with
the standard pens not having enough "oomph" to hold the parts when we tried
to hand place them...

Took some kapton tape and put on top of the heat sink and folded it so there
was a little flap that I could grab with a pair of forceps (you know the kind
that have the locking dealies in between the handles, just ask any pothead
about them, used as "roach-clips" quite often...not that I have ANY direct
experience of course!), and then grabbed the kapton flap and locked the
handles together, and you could walk around slinging the thing all over the
place and not worry about dropping it.

Just takes a little care to release the forceps without moving the part after
it's been placed...but with a "pound-o-part" that shouldn't be a big
deal...hehehe.

-Steve Gregory-

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