Drastic temp change

[Jeffrey Lovely]

My Thermostat quit working correctly
it gets to 62 degrees then I turn off the ac
let warm up to about 73 to 75
then open the doors
if it dont cool down
turn the ac back on
go home come in to 62 degrees

I have complained for about 2 weeks
told some one its not good!!!!
to shrink and expand the rails
waiting for warpage

bs excell mach

any real life stories or feed back I can present
before some one forks out 30.00 $ ?

[Bill **********]

Simply look up the installation requirements for the machine. It will read something like 68 degrees +/- 2. Anything else is unacceptable and will typically void and accuracy specification on the machine.

Bill

[John Kingston]

Run some tests on a "standard" part. Chart the results at various temps. There are a number of threads here discussing this issue. One was started by kbotta last week. You could use that data. That much fluctuation is sure to blow out your volumetric compensation.

[ag1979]

It's like a hotel shower, too hot, too cold, never just right

Our temperature changes are terrible. Our CMM's are in the middle of the office. This office used to be the engineering department and management offices. This area was never design for a stable temperature. We have sky lights so the sun always helps. We have to heating and cooling units which are constantly fighting each. Temperatures usually fluctuate about 8 degrees celsius throughout the day. Despite ASME standards which call for all measurements to be taken at room temperature (20 degrees celsius) unless otherwise specified or compensated for (we do not have any equipement for temperature compensation), and our constant arguing about the need for a stable temperature, we alays have temperature issues. On one bumper fixture I was inspecting I saw a 0.005" difference on one net from the temperature in the morning compared to the temperature near the end of the day.

[Jan d.]

Want another one? ISO stadard number 1 (yes the very very very first one in a long long long list) defines that all GD&T shall be measured at 20 degrees C (or wording to that extend). That just says it all! If you do not measure at 20C you do NOT measure to the print.

So pull the standard and show it to whoever does not coorperate!

On top of that, this is easily proven by measuring a longer steel step gauge or even ball bar. You'll be all over the map.

Management, that does not take the temperature issues seriously, is not interested in how well their process is controlled. Instead, they'll be measuring constantly how well their piece of aluminum/steel/granite/caramic expands and contracts.

I agree though, there are cases in which open tolerances do not required great temp control. Also, so called shop floor machines can improve the temp range. But there is nothing that reduces your uncertainty more than a well controlled environment (I'm an old guy with hardly any hair, mostly due to this issue).

I feel bad for you. I have been in your shoes and was also told to be just happy to have a job. Fortunetaly, in my case, a customer came in one day and just blasted away at management for not taking temp control serious. That got things solved in a hurry. But this is a long long time ago.



Jan.