Stuffing boards with pulled QFP chips

[Paul Koning]

> On Mar 31, 2017, at 1:51 PM, allison via cctech <cctech at classiccmp.org> wrote:
> 
> 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?

Yes, definitely.  100 lead PQFP is perfectly doable if the lead pitch is not insanely small.  It takes a good fine tip soldering iron (mine is a Weller with a PTS tip), fine solder (preferably real, i.e., 63/37 non-PC solder).  Liquid flux is a big help, as is a magnifier and bright light or modest magnification microscope.

If you have to do a couple of dozen boards this gets very tedious, but for 5-ish it isn't a big deal.

	paul