Problem- How to set Backlash on OSP-5000MG

[parametric.ms]

Something strange with my machine CNC Lathe OKUMA & HOWA ACT-2SP-2 OSP-5000MG.
If I move the X axis in manual mode, looks like nothing problem with movement.
But it happen if I try to run in auto mode, after read G0 on program, the X axis move very fast and the alarm show 100-3 DIF OVER xxxxx.

I check on the NC AXIS DATA Page, and I check the value of R-CON and R-APA lagging.

I assume there must be a backlash value should I set. but I can't find where is the page to change that value.

FYI : It happens after I open the Servo motor X, is it related with absolute encoder that lost its position?

I really wait your attention.

Thanks,
Andre

[Superman]

Don't adjust the backlash, that's not the problem

Okumas have a closed loop positioning system
Linear scales for positioning similar to a digital vernier
but also an encoder

there is a difference between the two and it is on the X-axis

So, start with the cheapest
-check all connections, no dirt, no oil, no breaks, to and from this axis
-no interferrence on slideways ? ( all chips clear )
-lubs working
-start thinking of a rep visit ( service call )

[parametric.ms]

thanks for your reply, but I can't find the linear scale on my machine, even on part list book.

The point is, how should I do to make R-CON and R-APA has same value and R-DIFF back to 0 immediately after I move the x axis.

regards,
Andre

[OkumaWiz]

R-CON and R-APA are the commanded position and the actual position as fed back from the encoder. The Okuma is a zero DIFF control which means it is always trying to match the numbers. If there is a difference in them, you most likely have something binding which prevents the numbers from matching. Check your load meter when you move the axis manually. The X on your machine should almost always be at 0% when in manual. If it is not, try to move with the pulse wheel and watch the load. you should see it go to zero as the R-CON and R-APA match and climb as you move away with the R-CON value.

Check for binding in your covers and for damaged linear guides as well as what Superman suggested.

[Algirdas]

I would suggest to set axis backlash to 0,001 or even 0. Try to move axis mode and MDI then. Try variate speed override setting.
Make it with tool offsets =0 just for the case. It will be clear then, if it is control problem or mechanical sticking.

[Superman]

I repeat......Don't adjust the backlash, the machine was functioning OK before dismantling the X axis servo,

So the problen is there , .....and there only

If you adjust the backlash, you will only give yourself a bigger headache trying to get it back to what you originally had.

[parametric.ms]

Thanks for all your response,

I already found what is a major problem on my machine, according to all your suggest.
I try to run auto program without servo motor attached to ballscrew, and working OK.
I checked the lubrication line, some of line was leaked.

My linear rail and guide was so rusty, now I workin' to remove the ballscrew, it looks like little jammed.

Now, anyone can give a tutorial how to disassemble X axis feed unit?

Once again, thanks for all your support

Regards,
Andre

[Algirdas]

did You ordered new one for replacement?
how to disassemble X axis feed unit?
not so easy to describe without illustrations. You need to take away the bearing at motor side. First You release draw nut. You can move the table by hand then. Draw nut (6pcs) bolts are at opposite side of motor.

[parametric.ms]

Originally Posted by Algirdas did You ordered new one for replacement? how to disassemble X axis feed unit? not so easy to describe without illustrations. You need to take away the bearing at motor side. First You release draw nut. You can move the table by hand then. Draw nut (6pcs) bolts are at opposite side of motor.

No, I haven't order yet. I will search on local market.

Does anyone know what type of linear guide and ballscrew before I dettach from saddle? Include detail specification would be appreciate (brand,length,drawing part).
I only have assy parts book that have no single part detail for linear & ballscrew

Thanks,

[Algirdas]

what type of linear guide and ballscrew
Okuma should tell generally. You need machine serial number for sure, because specification could be slightly different

[Jarwalcot]

Try this procedure first...