Spindle warmup programs

[SigurdACVW]

We bought two new Haas Mini Mills; a 6,000 RPM here in the toolroom and a 10,000 RPM in the CNC department. They came with a spindle warmup program that had the instruction to "set spindle override to 50% for 5,000 RPM machines, 100% for 7,500 and 10,000 RPM machines and 150% for 15,000 RPM machines." I've always set our 6K machine to 50% and the previous CNC guy went ahead and wrote his own program for the 10K machine, ramping it up all the way. In addition, he warmed up our 10K Fadal and 20K YCM mills at max RPM, again ramping up. Now, I've gotten moved to the CNC department and I'm trying to make sense of things. What is the reasoning behind some machines getting warmed up at half-speed and some getting warmed up at full speed? Does it matter?

 

[Mtndew]

What is the reasoning behind some machines getting warmed up at half-speed and some getting warmed up at full speed?

In my opinion, if the shop is cold in the morning, you don't want to go balls out right away.
What we do on our Okuma mills (15k spindles) and have for years, is:
S4000M04 for 10 minutes
S9000M04 for 10 minutes
M04 probably isn't necessary, but since all we do is M03, I like the M04....just in case lol

 

[PegroProX440]

They told you half speed because they were too lazy to rewrite a program for the different spindle speeds.

If I was you I would re write a program that does the spindle and traverse all axes to warm everything up. Since a good chunk of my work is done overnight its not uncommon to see my machine doing a warm up cycle for most of the day.

 

[boosted]

There is no one-size-fits-all solution for warming up spindles. Each manufacturer (and spindle) is different.

Look it up in the machine manual, they will have a factory recommended warmup procedure.

If you’re going through the trouble, might as well do it correctly.

 

[SteveEx30]

Years ago I had a small Taiwan made cnc with 15k spindle. I warmed it up each day by running programs at 10k when I walked in. Never had a problem in the 12 years we had it...

Wouldn't do that on my big expensive machines though! But I don't see the need to warm a spindle up to 25k if your only cutting at 8k all day...

 

[SigurdACVW]

I wrote a program for our Fadal the other day. I wrote P150000 for 150 seconds of dwell time at each RPM, and it put the machine into some sort of infinite dwell. Checked the manual, and turns out that P66000 will do that. I can't remember if the previous guy warmed it up or not.

 

[5 axis Fidia guy]

I have a 25k Hermle spindle on our machine. The warmup cycle goes from 200rpm's for like 5 minutes, straight up to 21k for another few minutes. This is contrary to my usual thinking and I asked the guys about it. They said the warmup cycle is not so much to "warmup" the spindle, but to properly lubricate it. They turn it slow to get it all oiled up properly, then spin it real quick, not to warm the bearings, but to fling and suck the remaining oil out. I will assume the Germans building the spindles know more than I.

 

[Billy_C]

I have a 25k Hermle spindle on our machine. The warmup cycle goes from 200rpm's for like 5 minutes, straight up to 21k for another few minutes. This is contrary to my usual thinking and I asked the guys about it. They said the warmup cycle is not so much to "warmup" the spindle, but to properly lubricate it. They turn it slow to get it all oiled up properly, then spin it real quick, not to warm the bearings, but to fling and suck the remaining oil out. I will assume the Germans building the spindles know more than I.

Yes, typically the case on most. Air-oil lubed spindles need a little bit of time running before the lube gets flowing again. A few minutes is all it takes. It certainly isn't a "warm-up" since the spindle shouldn't change temperature too much in the 10 minutes or so of free spinning.

 

[sinha]

I think the term "warm up" is used in the figurative sense. It is mainly for lubrication purpose. The oil tends to accumulate at lower points due to gravity. It needs to be evenly spread out before loading the spindle. The same is true for slides also.
Warming up implies gearing up for production.

 

[anchorman]

I think the term "warm up" is used in the figurative sense. It is mainly for lubrication purpose. The oil tends to accumulate at lower points due to gravity. It needs to be evenly spread out before loading the spindle. The same is true for slides also.
Warming up implies gearing up for production.

Yes. It needs to spin under no load condition in order to distribute oil properly in the bearing when it’s been sitting idle for a prolonged period of time. Somewhere I read about how long it takes sitting idle before the bearings typically become starved for oil. They like to be exercised regularly, and some recommend running it once a week, even if you’re not going to cut anything, just to keep everything moving properly. Letting a high speed spindle motor sit for many months without use is not supposed to be great for the bearings.

 

[DouglasJRizzo]

I wrote my own warm up programs.
I start at around 250 rpm and work up to about 3k or so. None of my spindles go past 4k currently so it's not really worth it for me to spool them all the way.
I was told that if the machine sits more than a week, to run the spindle, even at a fixed rpm, for a while as the grease pack lube drifts off of the bearings.

 

[michiganbuck]

I think it is a trade-off between enough warm-up, and the amount of time used based on economics...to not sell a machine because of more Warm up time suggested than for another machine brand.
Extra warm-up and a slower start will be best for any high-speed spindle. I think two jog starts to 300 and 1500 RPM, and then the prescribe would extend the life of a spindle.. But at 100 bucks an hour would cost a few extra bucks in warm-up over the 20 thousand or what hours expected machine life?

For a slow spindle cold start like a 3500 rpm grinder, I give a hand spin (or two) and then two jog starts to about 1/4 rpm and 1/2 rpm, it only takes one time that a ball drags rather than rolls to damage a spindle.

For a machine that sat for a long time what I call dead cats occurs inside a spindle...A little fuzz that is likely from dead air. A number/few hand spins can get the balls rolling, and the fuzz is not much of a problem..but with not the hand spins a ball is likely to skid/drag and make some damage.
A machine spindle that growls with a hand spin is likely damaged.