Stuffing boards with pulled QFP chips

[David Griffith]

On Fri, 31 Mar 2017, Paul Koning via cctech wrote:

>> 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.

That's why I put this in the context of PNP robots rather than 
hand-soldering.  My last run of P112 boards was 150 and I'm thinking of 
doing another 150 or maybe 200.


-- 
David Griffith
dave at 661.org

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