Need Help!- Haas SL-10 not holding size.

[Mr.Xtreme]

First I would like to say hello to the Community!
I have been lurking for a little and Registered to this informative site.
Now for my problem........................

I have a SL-10 lathe which is 1year old.
It has never been stuffed so far, but is exibiting this problem drifting in "x" axis. We warm up the machine and it will cut a specific size and then after a couple parts it will jump as much as .003 all at once to a smaller in size. If I move the offset to compensate for that .003 all is good. As more run time goes by with more running of parts it starts to show big by .0005-.0008. I make the change in the offset again following it as it needs to be reduced every couple pcs, then it ends up at original startup offset dimension and is right there, and stays there. Once it "jumps" and gets it out of its system, and it settles in after it will hold tenths all day long! I am totally baffled as to what is going on here and have run another Hass Sl-10 in the past and it didn't show this type of problem. We also spoke to the Haas Tech(A really Sharp Guy) and he could not find anything or think of anything other than Screw thermal comp settings, but they are blank. This is also not a material related issue, because it has been going on for a while with all types of material.
Other than this particular problem this Haas lathe is a decent machine.
Any help chasing this Demon out would be very much appreciated.

Paul

[Donkey Hotey]

Originally Posted by Mr.Xtreme ...he could not find anything or think of anything other than Screw thermal comp settings, but they are blank.

I don't have an SL10 but I don't think those values are supposed to be blank. Do you have the original parameters list that came with your machine (in the back of the factory-supplied manual)? The values should be in there. Or you can call the factory. They should have the records of exactly what was (and is supposed to be) loaded on there.

I wonder if there are some inter-related parameters that affect the thermal comp settings as well. Since it's holding value after a good warmup, I'd say some tweaking must be in order.

There--that should hold you until somebody more knowledgeable about the SL10 comes along.

[bbrown01]

Hi Paul,

There is a thread on the Practical Machinist website that sounds similar to the problem you are having.

http://www.cnczone.com/vb...d.php?t=150372

[philserveng]

if it has thermal compensation, try turning it off. the machine should then gradually "grow" from cold, but in a logical way. when the machine achieves optimal temperature the workpiece sizes will stabilize. if this happens after turning off the comp, then it points to a comp sensor or regulator card error. try running the machine in a warm up program to see if you can stabilize things sooner.

[Mr.Xtreme]

if it has thermal compensation, try turning it off.

How do you turn this off?

The thing that is puzzling me is that it might be fine 1st pc and then 2nd, 3rd pc than all at once it will move smaller by .003 all at once!
Geez, I wouldn't be so upset about it, but I'd rather it went to the big side error.
Warmup is always better to stabilize machine tool, but even after doing that for a 30 min warmup of the slide and spindle with the "z" offset brought back and running same part program for making pc it moved during the first pc.
There was 3 different sized journals on this part and the first two were right on the size and then the last one cut with same tool during the same cycle it cut small by .002

Paul

[gizmo_454]

It must be something with the SL-10. Although we love ours, it has a similar problem. We do not warm up the machine in the morning, though. I notice that it will run the first part or two right on size. Then it shrinks for roughly 30 to 45 minutes, sometimes as you stated up to 0.003". Then it will start to warm up and grow. Generally speaking, depending on the part we are running, it will take between 3 and 4 hours for it to completely stabilize. At which time, it will hold +/-0.0001 the rest of the day, provided the insert doesn't wear out.

As for the thermal comp, ours came set from the factory with no numbers entered. If I want it set, I will have to figure it out. For now, I think it is easier to just monitor it since we normally check parts regularly anyway.

Good luck!

Gizmo

[philserveng]

There is no mystery if the thermal compensation hardware is defective, it will cause the axis to jump around. Usually, the comp moves the axis in a plus direction because the machine is "growing" and will cut deeper as a result. For example for every 1 degree temp increase there may be 0.0001" in compensation.

There is usually 2 sensors (sometimes 3) on a machine and the the electronics monitors them both for temperature changes. The software then does the math for compensating axis or spindle growth. It could be just one of the sensors is at fault or the control card for them, or maybe even a loose connection. But you will need to investigate further, that is why I said before to turn it off if you can to progress the diagnosis.

[Mr.Xtreme]

How do you turn off the thermal compensation circuit?
Don't want to sound like a dummy, but the table have no user data there and I can not find anywhere else related to the turn-off.

[Mr.Xtreme]

Thermal comp sensor is set to "False" now.
We shall see what happens over the next couple of days.
So far a .0016 total comp was changed on the offsets afterwards instead of the usuall .003 or so. It also didn't seem to jump "All at once" as it did when the circuit was on.
At this point, I would leave it off and just follow it as it warms up, having no surprises. This is manageable
Thanks Guy's! All the posts here got the wheels turning to get this problem taken care of.
I will post back in a week or so and confirm or not if this truely was the problem.

Paul

[cam1]

Hi:
I had alot of problems with the X axis on a CNC lathe (Not a Haas).The machine would not repeat on X, or drifted as the day progressed. Turns out it had nothing to do with the thermal expansion.It was a stiffness/levelling issue.
Someone will probably argue that the castings are stiff, etc. as I did when we tried to solve the problem.
If you are a skeptic, mount a dial indicator on the crossslide, and indicate on a piece of stock. Have someone turn one of the jack scews near the headstock (+/- 1/2 turn), if you see a change in the indicator, consider fixing the machine to the floor (provided it's concrete).

Here's what we did:
1. Levelled the machine (spirit levels on both axis).Took a long time!
2. Bolted it to the floor.
3. Re-checked the levelling.

Since then (3years ago) it's been able to hold dimensions without a problem.


regards

[Mr.Xtreme]

Cam1

Yeah, I hear you. Ours is on an 8" thick one pc., not sharing another section of flooring. Although it is very level, still, it is not bolted. I believe that truely is the best thing you could do.
When the riggers brought the SL-10 in they used a hand pallet jack. The VF-2 Super was another story coming thru an 8' door!!!!!
We had set a pc of stock in spindle of SL-10 after the turn off of thermal sensor, and a tenth indicator and checked repeatability and it is right there.
I am a happy Camper

[cam1]

Hey: Just one more comment:
With no cutting forces presesnt, I'd expect the indicator to repeat, with cutting forces present you could have deflection & distortion, resulting in an inaccurate cut. It's a bit of the chicken and the egg thing. The company we purchased the machine from tried to say that we didn't know how to machine....so I invited them to see the problem. If I was the one who was the cause of the problem, I'd pay the bill. 2 days later the rep left frustrated and confused. After that the machine was bolted down and levelled at their expense.

PS:
They installed glass scales at no charge in order to try to solve the problem, befor bolting doen the machine. FREEBEE

regards