2 Apr
2017
2 Apr
'17
5:26 a.m.
On Fri, 31 Mar 2017, Paul Koning via cctech wrote:
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
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
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:
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.
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