Stuffing boards with pulled QFP chips

allison ajp166 at verizon.net
Fri Mar 31 12:51:34 CDT 2017


On 03/31/2017 06:32 AM, David Griffith via cctalk wrote:
>>
>> I'm down to the last few P112 boards for sale and am pondering
>> another run of them because demand is steady.  One of the biggest
>> challenges for the last run was getting the QFP-packaged 100-pin
>> chips[1] in a state such that the pick-and-place robot wouldn't throw
>> a fit about slight differences in lead position.  The stuffing house
>> insisted that I send them new chips.  Pulls, though they looked
>> perfectly okay to me, were not acceptable.  Does anyone here know
>> anything about pick-and-place robots using pulled 100-pin QFPs,
>> particularly a stuffing house that can work with such chips and not
>> screw up?
>>
>> [1] The now-obsolete super-io chips
>>
>>
>
Is this something that an experienced hand can manually do?

Of all the CP/M platforms its one of the few I haven't done.  But
it keeps popping after I've long figured its long gone.

I'm not afraid of SMT as I proto using 0603 and 0402 parts
at uhf/microwave freehand.

Baving delt with layouts for BGA and large pinout devices usually getting
fiducial marks on the board so it can locate and position without
optical works.
One time the board designer messed up and we had to use existing fixed
points
for that.  PITA but it worked. After that I got into the board layout
bit and DFM.


Allison






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