Damn it , and I thought Seho would cut off at 238 (???) .
Well , beats me this time , and I thought we've had the coolest pot around
(on gold) ;
do you trim the icicles Justin ?
Kidding , good to see somebody flying this low .
PS
Believe me , one day I retire under Mt. Aspiring ; love that place ; pity to
see Alpine and the board shop down .
With the price of gas here ; Steve would have to buy a tuk-tuk for a decent
job search ; this OPEC manipulators are getting on my nerve .
PK
-----Original Message-----
From: Justin Braime [mailto:[log in to unmask]]
Sent: Thursday, 7 October 1999 5:45
To: [log in to unmask]
Subject: Re: [TN] Wave solder pot temperatures...
Hi Steve,
Our Seho wave solder is set to 240 degC (464 degF), and the pot controller
is set and calibrated to keep the pot between 235 degC (455 degF) and 245
degC (473 degF). In reality the controller achieves better than this; +/- 3
degC, but thats definitely more than +/- 5 degF !!!
Even allowing for cooling of the solder at the board surface, at a 485 degF
pot temp. you are well above the solder liquidous temp. (365 degF ??) so I'd
say the +/- 5 degF is a little over zealous...
ps. I'm sure an engineer of your calibre (and humour) would be most welcome
in New Zealand
- don't believe anything Aussilek says about the place though!!!
----- Original Message -----
From: Stephen R. <mailto:[log in to unmask]> Gregory
To: [log in to unmask] <mailto:[log in to unmask]>
Sent: Thursday, October 07, 1999 7:05 AM
Subject: [TN] Wave solder pot temperatures...
Hi all!
It's been a frustrating day...
I was at our old wave solder machine this morning (a Hollis SMT Future-1,
about 12-years old) and one of our QA inspectors came in to check the
calibration on it. The procedure here is to verify that the speed of the
belt
is what's indicated on the readout of the machine, and to check that the
solder temperature in the pot is within +/- 5 degrees F (which seems
unnecessarily tight to me). from what is indicated. I run my pots a
485-degrees F. We were in the middle of a run, so she said that she'll do
the
belt speed check after we were through, but would go ahead and check the
solder temperature. We had the laminar pump running and she put the
thermocouple in the wave. The readout on the machine was 484 F., and she
indicated 490 F. on the hand held unit she was measuring with. She said;
"The
machine is out of calibration, your temperature is 6-degrees too high, it
needs to be re-cal'ed.." I told her it wasn't, that she should wait until we
finish the boards we were waving so I could shut the pumps off, let the pot
stabilize, and then she could take a reading. Her reply was (which I'm
getting so sick of); "That's not the way we do it around here..." ARRRRG! No
matter how much I tried to explain about the solder being pumped up to the
top to the wave formers and cooling down flowing back into the pot, then the
thermocouple in the pot sensing this, turning the heaters on to maintain the
set temperature and that's why the reading was a little high, I couldn't get
through to her...so I gave up.
But what's a realistic slop factor as far as the indicated temperature and
actual temperature of the solder. I think +/- 5-degrees F is way to tight, I
was thinking more like +/- 15-degrees....any opinions?
Thanks!
-Steve Gregory-
P.S. anybody need a good engineer?
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