Hans and Steve,
I had run into the similar problems many times... I was so @#$% and was
ready to go any length to fight for the "pride of the
righteousness"...Normally, I loss the fight (if someone is not going to
listen, there is very little you can do...Particularly, someone said that "I
was in this business before you were born"...). Until one day, one of the
"Sr. manager (one of the manager i really look up to)" told me that "seeing
is believing"... People have different backgrounds and different
capabilities. It is much easy to convince someone with a experimental
facts. Start from that day, I would do "demo" (even the result was
predictable) just to "show" my point, and bet a cup of coffee with who ever
was not believe me..(chicken wings too, if it was close to
payday)...Eventually, I would remind someone their losses if they want to
bet with me again. Most of them would check my words againest some of
"books or papers, even IPC Specs" before they bet with me again! (I do have
some losses).--- MY TRICK WORKED! The highest bet I have won is $200.00 (I
didn't see a penny of it, that's beside the point..It was about wire bonding)!
My recommendation is, fight with documentation may not neccessary improve
the work environment. If you indicate the machine parameter does not
require any adjustment after the calibration, make sure you documented and
using a calibrated "calibrating tester"...You will proof your point. It is
time and energy saving method from my point of view..
It took me 3 years to get from "I told you so" many times a day to one or
two times every 3 or 4 month...By the way, I was criticised not to take the
job seriously...(it is true that I wasn't pay that much attention to the
person who criticise me..)
jk
At 08:38 PM 10/6/99 +0100, you wrote:
>Hey Steve,
>
>Ideally, the temperature should be measured in the same location as the
>Hollis' thermocouple. That's how you verify the machines' temperature
>reading. Doesn't sound like she understands thermodynamics. I've got
>Kittel (Stat. Thermo) and a really great book by Fermi (Notes on Thermo) if
>you'd like to borrow it. :-) Who ever came up with that procedure needs a
>refresher.
>
>1). Ask for a copy of their written calibration procedure and get the
>bloody thing changed! Then it will be the way they do things.
>
>2). Is the handheld unit calibrated?
>
>3). Is there training & certification for this inspection?
>
>4). How long was the probe in the solder? Did the probe reach equilibrium?
>(That's what killed the Challenger Shuttle, in part.)
>
>I feel for ya bud. Remember, if engineering were easy everybody would do
>it. ;-)
>
>Hans
>
>PS. This crisis calls for Starbucks! (Okay, I'm Jonesing for a Venti
>Hazelnut Mocha.)
>
>~~~~~~~~
>Hans M. Hinners WR-ALC/LYPME Bldg. 640
>Materials Engineer 380 Second Street,
>Suite 104
>Manufacturing Eng. Sec. Robins AFB GA 31098-1638
>912-926-1970 (Voice) 468 - 1970 (DSN) 912-926-7974 (Fax)
>mailto:[log in to unmask]
>
>
>
>> 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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