Lathe RPM

[Roger]

I was curious how fast you turn your lathe work.  Using a collet chuck, I've ramped up RPM to 4000 rpm on real small parts, but never faster.  I think the lathe will do 6000 rpm.

 

I believe there to be a point at which the cycle times take longer when stopping and starting the spindle at the higher rpm's.  What is your opinion on this?

[guitar]

You are correct. When I was a lathe guy, I would often slow the RPM to get a faster cycle. Switching to g97 instead of G96 between tool changes may help, and some of my posts do it automatically. Keeping your retract to a minimum can help. Another problem with high RPM is machine vibrations. Not all machine installs for lathes are on large, thick slabs of concrete. 

[The Cathedral]

The factors are numerous. What kind of lathe are you talking about? The biggest concern we have with spindle speed is bar whip. Slightly bent bars at 6000 rpm = no bueno.

[Guest MTB Technical Services]

I was curious how fast you turn your lathe work.  Using a collet chuck, I've ramped up RPM to 4000 rpm on real small parts, but never faster.  I think the lathe will do 6000 rpm.

 

I believe there to be a point at which the cycle times take longer when stopping and starting the spindle at the higher rpm's.  What is your opinion on this?

 

 

That' why you don't stop and start the spindle for small parts.

Heck, there is no need to stop it for any parts and less there is a gear change.

 

Modern lathes are quite capable of indexing turret while the spindle is turning.

 

If the machine isn't properly installed then nothing will help you.

All machines should be properly anchored to a proper floor.

 

If you are worried about vibrations, get a compact bar feeder and keep your bar length to a minimum.

You'll have a bit more waste via remnants but you'll be running a lot more efficietly.

[ScottBro4]

I would personally let it go max. If the machine is rated for that it should be fine provided your chuck is rated for that RPM. As far as the spindle stop and start, try putting a G97 at the end of your toolpaths with an RPM of whatever your next tool starts at so the spindle basically never stops. I've done this many time and it does save so time.

[Roger]

I failed to mention that I'm NOT starting and stopping the spindle, except for the bar puller.  I'm running 1/2" aluminum cut to 48" long and a spindle liner (ST20 Haas lathe).  This was just a question about how fast other people run their parts.

[crazy^millman]

6000 rpms all the way to the bank. That machine should never run any slower that that, expect for the part off and even then I would see what happens at 6k.

 

Took a part at one customer running at 2k max becuase of 6' bars and cut them in half. Part was 7 minuts ea. Runnign the machine at 6k the run time was less than 3 minutes per part. I like when I double prodution just showing people who crazy I really am. :laughing:

[Roger]

Sounds good Ron.  I personally have never had the cojones to do that!  Maybe, because years ago when I started programming, I had a 1/2"-48" long bar of steel get ripped out of the lathe chuck and thrown 25 feet across the room, when I forgot to change the max rpm (G50)!

 

The lathe started shaking, so I pressed feed hold, (that as you well know doesn't stop the spindle).  It wasn't tell after the bar went flying that I pressed THE BIG RED BUTTON!

 

Thanks for the replies!

[K2csq7]

6000 rpms all the way to the bank. That machine should never run any slower that that,  :laughing:

 

I miss this place! 

[Newbeeee™]

We have 2" spout lathes with a 5k spindle but I won't run above 4...and mostly 3 really.

I hate lathes - all they want to do is throw things out the chuck at you...

 

Ron - 6k part off. Really???

Surely the part will be beat to fook and still bouncing around inside the machine while you've bar fed and roughing the next component??? 

 

What G# is spin-dry cycle?

[ScottBro4]

6K part off sounds fun. I'd try it. try to leave a .005-.010 wall. Then it just taps off with a rubber hammer. I've done it many times. And no need to be scared guys. If you're going to crash into the chuck its only going to be on the first part. No different than running an endmill .010 over a vise. Run it slow on the first part and let it rip after that.