Hi Steve,

Relax Steve.......   Why don't you let your management do the hard work ?
It's them who are responsible for the "we've always done it this way"
atmosphere.
Face the facts : the specification cannot be changed ("we've always done it
this way") and your machine doesn't meet it.
The solution is simple :  your company has to invest in a better machine (if
any available that's good enough) or leave pcb-assembly business and start
baking cookies. The latter is of course only an option if your reflow oven
performs within specification ;-)
Putting it this way means it's hardly a technical problem anymore, but a
managerial issue.
Not everybody will like this attitude, but it definitely saves you some time
to work on the problems where your expertise really matters.

Daan Terstegge


----- Original Message -----
From: Stephen R. Gregory <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, October 06, 1999 8:05 PM
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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