aw288 at osfn.org
Sat Jun 10 22:24:35 CDT 2006
> I've not noticed that. I use cost solely as the criteria for
> when to specify a socketed part on a board of mine. But, that
> is OVERALL cost (which is burdened by in-warranty repairs, etc.)
Please do not take this as a slam, but have you done real floorwalking
amongst the assembly lines with your boards? Most design engineers have
not - many have never even seen an assembly line*. Depending on the
company, or even the project team, communication between the "front
engineers" and the "back engineers" can range from excellent to poor. IBM
generally was very good, I understand, across the board. At USR (where I
spent time), it was mixed - some products were well coordinated but others
were bombs (FaxServer, NetServer leap to mind. They were so hard to make
properly that the line was killed prematurely).
Anyway, my point is that you may not be getting appropriate feedback about
the your designs when you send them out. They may get a board and say -
"Great, more goddamn sockets. I wish he would stop." - then go ahead and
make the boards. Or they may get back to you and say "Do you really need
Yeilds do go down when sockets are used. Insertions are not perfect, and
bad insertions can result in poor reliability and/or rework time. Sockets
fatigue the machines (or people) more, and slow the line down simply due
to that extra sliver of time spent on the sockets. All this adds up, tiny
is it may be, but manufacturing lives and dies by yeild numbers.
* Once again, please do not take this as a slam. I just suspect that many
design engineers on this list have never seen the other side, regardless
of their skills. Manufacturing engineering is an interesting mix of
hardcore engineering, economics, unskilled labor, tricks of the trade,
ancient Chinese secrets, and that ISO9001 garbage.
> And, anything that can add value by being socketed E.g., in
> some markets, it's easier to get a set of DIPs through
> customs than it is to try to get a whole *board* through.
Yes, there are places for sockets, but any manufacturing engineer will try
his hardest to convince you otherwise!
aw288 at osfn.org
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