[JerryBurks]

I bought one of the infamous Chinese spindles some 2 years ago and used it happily since (knock on wood) although the bearings made more noise from the very beginning when spinning by hand than I like. It has now probably some 200-300 hours of use, normally 12,000 to 15,000 rpm, sometimes 18,000, rarely higher. Mostly small bit wood duty but occasionally I machined brass and mild steel.

By chance I read somewhere that spindles are supposed to be heated up for 5-10 minutes with increasing rpm before use and, googling I found it seems to be quite a common recommendation. I never did that and the highly qualified Chinese seller did not tell me.

Now, should I change habits? What happens if I dont pre-run the spindle before use? Is it only about accuracy for precision mills and I can not care less for my router or is it a bearing wear risk? Thanks for any enlightenment.

JB

[ger21]

Depends on who you ask.
Over the last 17 years, I've been using two different $150,000 machines from different manufacturers. Neither manufacturer mentioned anything about warming up the spindles, and we never have. It's really not even an option for us, as a lot of the time, we'd spend more time warming up the spindles than actually cutting. Since they are electric fan cooled, with the fan constantly running, they'd be cold after they were stopped for more than a few minutes.

It probably wouldn't hurt to run them from 6000-1000 rpm for a few minutes, but I don't know how much it helps. Probably helps more in a cold climate than a warm one

[dmalicky]

AFAIK, the main purpose is to lower the viscosity of the grease, so it can lubricate better at high rpm. Also the bearing clearance will normally be reduced or change to preload. Both of these help the bearings live longer. The second reduces runout a bit. But personally, I don't do it. And given the cost of bearings in a Chinese spindle, I wonder if the extra electricity $ would be more than the incremental change in bearing life.

In a high precision machine, as you know, another purpose is to reach a thermal equilibrium before starting a job, as thermal expansion will grow the spindle by some tenths.

Of course, the critical purpose first thing in the morning is to let the operator go get some coffee.

[wizard]

I bought one of the infamous Chinese spindles some 2 years ago and used it happily since (knock on wood) although the bearings made more noise from the very beginning when spinning by hand than I like. It has now probably some 200-300 hours of use, normally 12,000 to 15,000 rpm, sometimes 18,000, rarely higher. Mostly small bit wood duty but occasionally I machined brass and mild steel.

If you are happy with it I wouldn't worry. Nothing lasts forever. The exception for these spindles would be start up in an extremely cold environment where it might pay to get the lube started so to speak.

By chance I read somewhere that spindles are supposed to be heated up for 5-10 minutes with increasing rpm before use and, googling I found it seems to be quite a common recommendation. I never did that and the highly qualified Chinese seller did not tell me.

Actually this is the first I've heard of such for this sort of equipment. In the past, when I worked extensively on diamond turning equipment warming up the entire machine was mandatory. In that case though the air bearing spindles had no grease so it was more about thermal equilibrium. Even a couple of microns growth would ruin the parts so a stable machine was very important.

I could see some value in doing this on a precision mill but a Chinese spindle is not in the same ball park as a precision mill.

Now, should I change habits? What happens if I dont pre-run the spindle before use?

Most likely very little. If I understand these spindles correctly the bearings are either sealed or prelubed with little expectation of lubrication prior to rebuild. As such the bearings are always lubricated.

Is it only about accuracy for precision mills and I can not care less for my router or is it a bearing wear risk? Thanks for any enlightenment.

JB

It probably isn't ideal to hit a spindle with 30,000 RPM from a cold start or even 12,000 but the specifics are probably very spindle manufacture related and depends upon the bearings and lubrication used. On the Chinese spindles I'm of the opinion that it doesn't matter all that much. However the smart thing to do here is to get clarification from the spindle manufacture or distributor. The reality is I could be flat out wrong.

[Fluxion]

At work we have an Onsrud CNC router. It's a big one, 28 feet long and I don't know what is cost but it was a lot. We have to run a spindle warmup daily. I am looking to build my 3rd router now and plan on using one of the Chinese 2.2kw spindles and I will probably use a warmup program, I figure what can it hurt?

[JerryBurks]

Thanks All for the feedback. So it looks like I should not worry too much about my Chinese spindle. While the warm-up would be theoretically beneficial, I will not always be patient enough to wait. And if it should fail sometimes it is probably because of the crappy materials used not the warm-up.

[wizard]

Thanks All for the feedback. So it looks like I should not worry too much about my Chinese spindle. While the warm-up would be theoretically beneficial, I will not always be patient enough to wait. And if it should fail sometimes it is probably because of the crappy materials used not the warm-up.

The CNC machine is a robot, let it warm up by itself. Seriously write a little NC program to do the warmup for you while you get the rest of the project ready. You can exercise the whole machine with simple code, keep the warm up program stored in a local hard drive and it will take seconds to get the machine into warm up mode.