CNC Spindle Killer 

Curious of what exactly the problem /damage of your spindle that caused its death.

Back in the 80's and 90's, some commercial CNC shops with a specialty of making high precision components would keep their machines running cutting paths during hours when the machines weren't making parts. This kept the ball screws, bearings, lubricant, etc. at normal operating temperatures, thereby minimizing the impact of thermal expansion. Your procedure will not only keep the spindle in good condition but will also improve the overall accuracy of the machine by improving repeatability of positioning. Warming up the entire machine is a good practice, even though it is a bit of a nuisance. I recommend writing a simple program to exercise the spindle and drive system. Start off with slow spindle RPM and feed rates, increasing over the course of several minutes as the system warms up.

What killed my spindle (1.5KW ER11 spindle) was running a long program with a lollipop cutter sticking out too much. The vibration that caused increased the runout to a degree it was unusable and it made a lot more noise, even with a 1/8" cutter. I never let it warm up though, other than the lollipop incident it has been working fine. I've tried to replace the bearings of the old spindle but I can't get the fan part off. If someone has a tip to get it off I'd appreciate it.

Can't you automate the warm-up process with some G-code?

Is this because your shop is cold? Mine is in a finished basement that’s heated year round.

This is very very cautious. Perhaps warranted, but, your problem could likely be solved by letting it run at low speed for a few minutes or so before starting. These things come up to temp very quickly, and they never really get "hot". What you're trying to avoid here is hitting the spindle with load while it's cold, because the cold lubricant in the bearings isn't in-spec until it warms up to operating temps. You may also consider a program where the machine makes a large, slow circle for a few laps so your steppers aren't stone cold when they start working, for the same reason. Also it gives you a chance to make sure the machine is running right before putting work in it. In terms of ramp up/down, again, as long as you're dialing it up/down slowly, you're fine. You want to avoid slamming a ton of power at a spindle all at once, because it'll take time to catch up, during which it is mostly producing heat in the windings. The same goes for ramp down, because it's on a VFD, the VFD slowing the spindle will cause it to electronically brake, which again, just produces heat. Not the end of the world, just easy to avoid with a few seconds of time. Depending on your VFD, you can likely program in a short warmup cycle, and a ramp up/down cycle, that'll simplify all of the above. A couple seconds is all you really need there, or about a casual dial turn. Also you mentioned that you have a Vevor spindle setup here, and, it would probably be best to not run it at maximum speed, you can probably realize some additional longevity at 80% or so. Yes that'll be slower overall, but, not a ton slower. The other thing to consider is making sure the whole machine stays clean. It makes sense to have a vacuum system with a cyclonic separator on these, and that's possible to retrofit as well. That keeps them and the shop much cleaner. You still have to clean everything, just, less. Keeping the moving parts clean will extend their life alot.

i dont really think you need to max speed while warming up the spindle, Im using a hiteco 11kw spindle which max out at 24k rpm, i go 1000rpm for 4-5mins then 5k for 2-3 mins then 10k for another 2-3mins and at last i set it to 15k rpm for another 5 at least. 15k is the rpm im mostly working on btw. Also never forget to lub the spindle axle every month or so with a metaflux paste spray (if you have access ofcourse). The previous spindlle didnt last for long since i was working almost always at max RPM which is 24k, and the lub the "technician" told me to use was WD-40... AAAND yeah this destroyed it.