Does warming up the spindle actually do anything to prolong bearing life as many believe? Or is it just to impart heat to stabilize the size of the castings prior to running parts? I note, that search of owner’s manual does not find the words warm or warmup.
Warm up cycles are run in production shops simply to stabilize the cutting size of the machine. If you are only running single parts or you have wide open tolerances than it is not necessary.
Had a mill with a 15000 spindle and a warm up was part of the startup. Did not mater if 1 part or 1000. I believe a warmup can help, I have the 1100mx. 10.000 RPM is a bit much for a standard lubed bearing. It would have been great if it were an air-oil spindle. Had a 12000 rpm that lasted for years. Did not have to worry about grease running out or going bad. I run mine 12-14 hours a day and warm it up ALL the time.
If the environment is cold i.e. lower than 70F (22C) then yes it is important and the colder it is the longer the warmup cycle to get the spindle column normalized.
The issue is when cold the fit of various components is looser so if you were to start machining with high forces you can prematurely wear the bearing components of the spindle.
The components may not be ‘loose’ in the sense of rigidity but at colder temps the rapid heating of components can cause stress over time to bearing surfaces, so going from a cold machine sitting at 40-50F straight to production may reduce the lifespan of bearings in the system due to rapid thermal expansion.
Most manufacturers recommend a warmup of the machine.
First it is not necessary to warm up until you intend on running the machine try to do this process within an hour of running any program.
My process is to come into the shop and before doing anything else I turn on the machine, let it run a 15 minute warm up cycle while I get my coffee and do some cleaning.
Alternate for colder climates
If you live in a cold climate or have a shop that is colder than 70F (22C) then you will want to monitor the temp the first time to get your process down and then make that your warmup routine.
I’m curious about the “various components” which may be loose due to being at ambient temperature. My understanding of sealed grease spindle construction is that the spindle bearings are pre-loaded which should not permit “looseness” so I am at a loss what other components would be at risk.
I’m just trying to wrap my head around what could be damaged in the specific instance of Tormach spindles. If the spindle was air/oil or had splash lubricated gear box, I can understand running the spindle at lower speeds with no cutting load would permit the lubrication to be circulated.
Optimally Tormach should be very aware of what is good or not for their spindle and would be great if they weighed in.
You are correct about the spindle bearings being pre-loaded this isn’t just Tormach I’ve built machines and managed large facilities with a wide variety of machine types. Having your spindle at an ambient temperature of 70F (22C) is an industry standard and is not specific to Tormach. Many guys keep these machines in garages and in that scenario you really don’t want to run a machine when it has low ambient temperatures because the rapid temperature increase is what causes the damage not the fact you are running it without warmup. The warm up cycle is intended to help the machine normalize before running a program.
Now that that is out of the way I have my machines in an environmentally controlled location the only time I concern myself with a warmup is if it is winter time because most the time here in TX it isn’t below 70F
But I do speak from experience because I used to have one of my machines in my garage in CT which would frequently get temps below 70F and in those cases I would give it a warm up depending on the ambient temperature.
Finally this isn’t a quality thing or a ‘looseness’ issue it is just a machine best practice for CNC equipment that isn’t in environmentally controlled spaces or spaces with cold temperatures.
I’m brand new and have a 440 in my garage. I can’t seem to find a “warm up cycle” in path pilot. Is there a “generic routine” you would recommend? EX: run spindle at 25% max RPM for 2 minutes, then 50% for 2 minutes, ect… then move X, Y, and Z(safely) through their full range of motion 5 time… or…??
There is no standard warm up cycle. If you want to make one in fusion NYC CNC has a video how to. I feel basically you are thinking correctly. Use g53 for your xy moves so it goes off the machine limits. I would not run x full width when the table is near the column just in case you have a vise or part sticking off, could tear the bellows. I don’t know that z would be very easy to program. Every day will be different if you have a setup or 4th axis on the table that could be a collision. You are just trying to spread oil and Z has gravity to help.
This is what I wrote for my 1100mx:
m0 (make sure short tool in spindle)
o101 repeat 
g53G0 X0.5 Y-0.5
g53g1 x17.5 y-9. f60
g53g1 x0.5 y-0.5
g53g1 x0.5 y-9.
g53g1 x17.5 y-0.5
g53g1 x0.5 y-0.5
M30 (end program)
Lots of great points Jon, I would only add one thing is warm up should be a tool holder without tool so it is minimal length. I usually put in a holder without collet/nut to let it warm up, because spinning the spindle without a tool is generally not recommended.
Agreed. I even have an m0 with comment in the program to make sure I put one in. with the bt30 system, havoc ensues if no tool.