[russmatt]

We have been having trouble holding tollerances when we shut down for lunch and during start-up at the begining of the week. We were told we could try using a coolant chiller to keep the coolant at a steady temp. Just wondering if anyone was doing or has tried this and how good it works. Also suggestions on name brands or types appreciated.

[underthetire]

I would ask several questions before recommending a coolant chiller.

What model mori, and what tolerance are you trying to hold.
Is the shop climate controlled?
Were the ballscrews checked for the proper stretch amount
Is the machine near a window, door, skylight, or vent.

I have used coolant chillers, but in all honesty they are pretty much useless if your shop swings 30 degrees during the day. There are test that can be done on the machine to determine if it is a machine growth problem or coolant temp problem. There are also a lot of calculations that need to be made to get the correct size chiller.

[rpm3000]

We had the same issue at a shop I worked at making aircraft instruments. We where using top of the line newer Mori lathes and trying to hold +/-.0001 in most cases.

When we'd leave for lunch or get there in the morning the first few parts would be off by about 1/2 a thou.

We solved the problem with a sub program spindle warm up routine. During lunch or a break the spindle was just turned on. When you returned to the machine everything was still dead nuts.

[russmatt]

we have a warm-up program that moves the X and Z axis and rotates the turret with the coolant on. It doesn't help. The machine is out in the plant and close to shipping doors. It is a NL2500 and we are holding +-.0125mm tolerances.

[underthetire]

So, that pretty much means +/- .0005 sorry, cant think in metric. Thats not too tough of a tolerance, however temp will not only change the machine, but the material as well.

I will tell you whats going to happen with a coolant chiller. They try to hold ambient temp, not actually a good 68-70deg. So, with doors right next to the machine, the ambient temp is going to swing wildly, and the cooler is going to try and follow. You really need to see if your coolant is actually getting hot from cutting. Put a thermometer (or TC) in the tank and monitor it for a couple days. If the coolant gets warm, it may help. My guess though for best relults, move the machine to a more stable environment. I have been told that the first gen NL's with live tooling would grow more than a non live tool machine.

[russmatt]

Thanks

[rpm3000]

we have a warm-up program that moves the X and Z axis and rotates the turret with the coolant on. It doesn't help. The machine is out in the plant and close to shipping doors. It is a NL2500 and we are holding +-.0125mm tolerances.

Does it also turn the spindle?

[russmatt]

Yes both spindles.