Problem- Z Offsets

[Perfect Circle]

I am having a problem with my Z offsets.
Every part that I run im having to change the wear offsets for the z axis on every tool. The control is a MSC-516 Fanuc. I contacted Fanuc and Mori and im still waiting on a response. The offsets where fine yesterday and today every part will not repeat in the Z axis. The X axis is working just fine. My offsets from yesterday to today are .006 diff. that would be .002 per part moving the offset away from the chuck. I think that it has something to do with maybe humidity, today its at 60% and yesterday it was at 20% but the X axis is not affected?? If anyone else has had a problem like this or has any ideas pleas let me know.
Thanks for any and all help in advance.

[sti2011]

Humidity should have nothing to do with it. And more info such as, bar feeding, chuckwork, material, tooling etc etc would be helpful. On it's face does not sound like a machine issue to me though. Workholding or tool issue are more likely. Try putting a dial indicator in the turret and run a repeatablilty test against the face of the chuck or spindle. Prog home to target spot.....

[Perfect Circle]

Found the problem.
It turns out that the spindle was growing, because of the heat in the shop.
The headstock cooler is not able to keep up with the heat that the spindle produces. At the time I was running small parts for this machine at 5" in dia.... High RPM's..over the weekend I ran some parts that where 15.5" in dia. that is the norm. for this machine with much slower r's and I did not have the problem with the spindle growing. It has been 100+ here in Texas for over
30+ days now...these small parts where the 1st that Ive ran since the heat..I have no probs when the shop is NOT at 104-108 everyday So keep cool out there and be safe! Thanks for your reply sti2011

[underthetire]

My brother lives in Dallas. He was at Tahoe with us last week. He's moving now ! You do know the Mori manuals state not to run the machine in areas over 100 degrees, right?

[Perfect Circle]

Originally Posted by underthetire You do know the Mori manuals state not to run the machine in areas over 100 degrees, right?

Yes, but we have no choice our shop has no climate control
I pulled the manual and it says 50-95 and humidity not to exceed 75%

[sti2011]

That is thermal growth an order of magnitude I have never seen. Eventually despite how hot it is it should stabilize out though. I and our machines are also spoiled with Climate Control being heat and AC. Don't know what your tolerances are that you normally work with but I would be f effed if the shop was 100 degrees...or 60...be lots of math involved to get good parts out the door! I have actually had inspectors check parts that just came off the UPS truck in 10 degrees and reject them...and after a phone call and 24hrs of normalization they pass with flying colors. Keep the chips flying.

[MILLMARK]

Wow. They can afford Mori Seikis, but not AC? I think I'd have to find a new job. I'm in Austin, so I can't imagine an un-air conditioned shop. I feel for ya