As i said before , and it may sound weird ,
one of the factors i stuck with foaming stones on gold was
i never got the tops soldered with spray.
So that is one thing , ponder over it over ribs & Bud.
the second puzzle of physics of heating interrupted HIGH = LONG barrels is
simple .
Almost regardless how slow you drive it (agree with Phil),
the designer actually f...ed up :
You DO need full contact (not a relief) to heat the >long< barrel and keep
it hot
with significant inside dissipations, learned that one on PS's.
The high speed standard assembly and thick specials have non transferable
sets of physics,
ie horses for courses, = tractor is faster than ferrari in places.
One of the reasons why i hate standards = makes folks to asses with carrots
to follow
Enjoy yourself mate, no way out paul
-----Original Message-----
From: Stephen R. Gregory [mailto:[log in to unmask]]
Sent: Friday, 11 August 2000 4:00
To: [log in to unmask]
Subject: [TN] Topside solder fillets after wave...
Hi all!
Been trying to dial a profile in on the wave today with a board that's
fairly
thick, probably around .090", polyimide, all PTH with a fair amount of the
IC's being ceramic. We use a spray fluxer and a RMA flux.
The first boards have been coming off without the preferred topside fillets
at a number of locations. I've been playing with the pre-heat, belt speed,
and even did something that I don't like to do, which was to flux the
topside
of the board.
All to no avail...I still had quite a few places that didn't have topside
fillets, and that is something that doesn't go over well here at all.
I started noticing that the places that didn't have topside fillets were at
the same locations. So I came back to my 'pooter and looked at the gerber
for
the board. What's really weird was that everyplace there's a thermal for a
pin is where I have no topside fillet??? I thought that thermals were
supposed to help prevent that from happening? But it's true, every single
place there is a thermal= no top solder. Has anybody ever seen that before?
-Steve Gregory-
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