Hello,

I just got a new Haas SL-10 lathe. We can't get it to hold tolerance. From the begining to the end of the day the parts will grow .0025". I have verifyed this by using a dial indicator and the tool presetter to eliminate tool wear, programs, or matieral veriations. Even if the lathe does nothing just sits it moves .0025" a day.

Has anyone else seen this. I have a mini mill that I did the same test on and it only moved .0001" the entire day. The Haas service guys have been out several times and no luck.

HELP!

Doug

I'm thinking you have a mechanical problem .. not a thermal problem. Put a one-tenth indicator on the turret ... put it against some turned stock or something rigid .... in .0001 jog mode click it ten times one way ... then the other way .... see if it returns on the indicator to zero.... Also the nut housing might be the problem .. check parameter 138 on your machine and let me know what it is ... the nut housing might not be perpendicular ... this would cause friction and heat on the X-axis ballscrew ... The machine will hold tolerance ... we just need to pinpoint the problem .. sometimes everyone is looking at the most technical thing .. when it is something really simple. This seems like the case. I will help as much as I can ... just give me a little feedback.

I will check those and get back to you. But if you want to call me, please do. 530-533-4444.

Doug

I am not at he shop where the lathe is now, but in the morning I will get back to you with all the details. I think we can rule out a machnical problem though. The way I tested this today was using the tool presetter built into the lathe. I would re-zero the tool every 1/2 hour or so. THen just back the tool off .010" and let it sit. Then re-zero the tool and logg teh changes in teh X 0ff set for that tool. I never put the tool presetter up or moved the turret more then .030". The offset would gradually get farther and farther off as the day when on. From 10:30Am to about 3:PM it had moved .0025".

There is a lot more to the story. If you would like to talk about give me a call. 530-533-4444. Thats my shop number, I will be in all day tomarrow.

THanks,
Doug

If the lathe shows growth just sitting, but with the power on, I'd suspect some sort of unsymmetric thermal growth. It would be interesting to take a digital temperature probe or infrared gun, and measure temperatures in several locations around the machine's castings, anywhere where motors or fans are powered on.

You said you move .03 .. that's all you need if there is slop .. You have had the Tech out there messing around witht the machine .. hopefully he put everything back together correctly ... an indicator test against a rigid piece .. zero out the indicator and move it ten clicks one way ... ten clicks the other way and the indicator should be zero +- .0001 .. parameters 138, 13, and 229 .. what are they?

Okay here are the parameters you asked for.

138 = 125
13 = 12
229 = 100000

I setup the dial indicator and didn't see a lot of backlash, But I only have a indicator down to .0005". I just ordered a Mitutoyo that goes down to .0001" grads. I will have it monday. THen I will redo the test.

I have not had the tech here for this lathe yet, its a long long story. If you want to call and talk about it feel free. I put my number in the previous post.

DOug

If you have the thermal probe on, the value in 229 is ok ... BUT if your thermal probe is turned off the parameter for 229 should be zero ... parameter 138 doesn't seem that high .. but I'm still curious if the ballscrew has some unnecessary fricition .. causing it to heat up fast ... The probe test your doing .. move the probe a little each way and make sure there is no debris around the base before doing your test ... the probe should repeat within +- .0002 at the most when it is not moved .. there is no way it should be moving .0025