[JDenyer232]

We have had our SL10 up and running for about a month now, loving every minute of it as this is our first cnc lathe. Many thanks to Geof for posting some info awhile back about tooling selection for this lathe. Quick question though, when I start a production run I notice that I have to keep adjusting my G54 offset to compensate all my tools for thermal effects as the machine warmsup. After I run 10 or 20 parts it evens out and I don't have to make any more adjustments. I run a spindle warmup every morning, but I'm thinking I need to turn the thermal comp on, I know how to turn it on, but how does one go about setting it up? Many thanks in advance.

[Geof]

As I understand it you will only have thermal compensation if you bought it as an option with the machine but this may not be correct and you may be able to turn it on. I have no idea how to set it up.

We find this warming up effect on our machines but much of our stuff has enough tolerance to absorb it; try to aim for one end of the tolerance cold and see if it stays within the other end when warm.

[JDenyer232]

As I understand it you will only have thermal compensation if you bought it as an option with the machine but this may not be correct and you may be able to turn it on. I have no idea how to set it up.

We find this warming up effect on our machines but much of our stuff has enough tolerance to absorb it; try to aim for one end of the tolerance cold and see if it stays within the other end when warm.

Well I have +- .005" but I really run into the problem when I'm OD threading, most of the threads we cut are in the 0-80 to 4-40 range. As the lathe warms up my parts come out .0025" oversize, which is fine for the non threaded features, there's just not a lot of room to play with even with a class 2 fit. Not a big deal if I can't figure it out, I can just manually compensate until she warms up. On a side note, this is one sweet little lathe
Once she warms up it will hold great for the rest of the day.

[Geof]

Yes once they stabilise they are okay. How long is your warm up and do you move the axes also. I have never done it but you should be able to bring it close to stable by running both spindle and feeds for 10 or 15 minutes.

[JDenyer232]

Yes once they stabilise they are okay. How long is your warm up and do you move the axes also. I have never done it but you should be able to bring it close to stable by running both spindle and feeds for 10 or 15 minutes.

I have a 20 minute spindle warmup program that I run, never even thought of writing one up for the axes. Will do that tommorow and give it a try. Thanks for the insight.

[MikeOD]

On a lathe, I usually just turn the spindle on at half it's peak RPM and then program the 2 axes to make rapid moves as far as they can without crashing the turret into something...then I hit the 25% rapid button and let it do that for 20 minutes...then I set my tools and my work Z offset (I leave work X at 0) and run with it...I've been doing that for a while now and have been holding excellent tolerances every time I use that as a general practice.

I don't expect any machine (maybe a machine with glass scales...maybe) from any company to hold it's advertised tolerances until the whole machine has warmed up for 20 minutes or so (assuming the room it's in has been at a constant temperature for a few days too...if that hasn't been constant, that is a new wrench thrown in the works). Just warming up the spindle is good for it's bearings, but it's not warming up the rest of the machine.

[JDenyer232]

On a lathe, I usually just turn the spindle on at half it's peak RPM and then program the 2 axes to make rapid moves as far as they can without crashing the turret into something...then I hit the 25% rapid button and let it do that for 20 minutes...then I set my tools and my work Z offset (I leave work X at 0) and run with it...I've been doing that for a while now and have been holding excellent tolerances every time I use that as a general practice.

I don't expect any machine (maybe a machine with glass scales...maybe) from any company to hold it's advertised tolerances until the whole machine has warmed up for 20 minutes or so (assuming the room it's in has been at a constant temperature for a few days too...if that hasn't been constant, that is a new wrench thrown in the works). Just warming up the spindle is good for it's bearings, but it's not warming up the rest of the machine.

Do you have an example of the program you are using, it would seem like a lot of code to write to make the machine rapid around for 20 minutes, unless I'm not thinking about this clearly, it is NewYears Eve after all

[Geof]

....it would seem like a lot of code to write to make the machine rapid around for 20 minutes, unless I'm not thinking about this clearly, it is NewYears Eve after all

Put it in nested subroutines. The warmup starts at 500 rpm and normally waits on a G04, instead of the G04 go to the axis movement. This should do it:

M03 S500
M97 P1000
M03 S1500
M97 P1000
M03 S2000
M97 P1000
M03 S2500
M97 P1000
M03 S3000
M97 P1000
M03 S3500
M97 P1000
M03 S4000
M97 P1000
M03 S4500
M97 P1000
M03 S5000
M97 P1000
M30
N1000 G98 G01 X-10. Z-10. F100. M97 P2000 L20
M99
N2000 G01 X0. Z0.
M99

I made it feed per minute so the feed stays constant even though the spindle goes faster. You would change the L count and or the feed to make it stay longer at each of the speeds; in the program above it would take two minutes to work through the subroutine, 18 minutes total (I think).

[JDenyer232]

Put it in nested subroutines. The warmup starts at 500 rpm and normally waits on a G04, instead of the G04 go to the axis movement. This should do it:

M03 S500
M97 P1000
M03 S1500
M97 P1000
M03 S2000
M97 P1000
M03 S2500
M97 P1000
M03 S3000
M97 P1000
M03 S3500
M97 P1000
M03 S4000
M97 P1000
M03 S4500
M97 P1000
M03 S5000
M97 P1000
M30
N1000 G98 G01 X-10. Z-10. F100. M97 P2000 L20
M99
N2000 G01 X0. Z0.
M99

I made it feed per minute so the feed stays constant even though the spindle goes faster. You would change the L count and or the feed to make it stay longer at each of the speeds; in the program above it would take two minutes to work through the subroutine, 18 minutes total (I think).

Geof, thank you for the example, subroutines, I knew I was overlooking something. Will give this a try next week. As always your vast knowledge and willingness to help others is what makes you a great assett here on the zone. Again thank you and have a Happy New Year.

[Edster]

I'm pretty sure thermal compensation is standard on the SL-10. The brouchure explains their temp tracking under motion control it doesn't say anything about being an option. I also didn't see it listed under options or control options. I do know of a few people that complained about the machine not holding tolerances and they tracked it down to the thermal compensation. There is a parameter to adjust it, but most just turned it off. You could ask PBMW about it. He was one of the guys that turned it off.

[Edster]

Here is a link to a post about the thermal comp

http://www.cnczone.com/forums/showthread.php?t=57148

[Mic6]

I always liked to run my program with a small piece of stock to avoid the puller. Just let it go thru the program and warm up with the motions it's gonna do all day. This is of course if the geometry and tooling allow.

[MikeOD]

Do you have an example of the program you are using, it would seem like a lot of code to write to make the machine rapid around for 20 minutes, unless I'm not thinking about this clearly, it is NewYears Eve after all

The reply after yours overcomplicated what I have it to...I simly say
S3000 M03;
G00 G53 X0.;
G00 G53 Z0.;
G00 G53 X-10.; (change this value to whatever number you want that won't crash)
G00 G53 Z-10.; (same here, change it to make sure it won't crash)
M99;


Thats it, that will rapid x and z and send them back home again, I press 25% rapid, watch it make 1 full cycle to be sure it's not going to crash, then I walk away from the machine for 20 minutes or so.

To establish the X and Z positions to move to, I simply jog the turret somewhere and look at the machine coordinates on the position screen.

I prefer not to bother nesting it into any form of subroutine or any other program as depending on what jaws I have on the chuck, and what tools I have on the turret...the positions I have it move to change from day to day...like I said, for the S number, I just pick half of the machines peak RPM, in the case of an SL10 it's 3000 (half of 6000), in the case of an SL-30, I go with 1700 (half of 3400) and so on.

[Geof]

The reply after yours overcomplicated what I have it to...I simly say..

It didn't overcomplicate if you want to ramp the spindle speed in 500rpm increments. I just like starting cold bearings slowly at first.