Need Help!- Have no spindle orientation

[plofkop]

Hello

I'm having a problem with a okuma lb-15, i want to stop the spindle on a same position, it has to be every time the same.
We don't have spindle orientation (m19 = Option)
Any body have a idea to stop the spindle

Thanks

[pilsburyagain]

I don't recognise the machine, so I'm guessing.

Can you program the C axis to a known position. If you can screw thread, then some type of orientation must be possible

Hope it helps

[Algirdas]

You check if Your lathe has brake hardware on spindle first.
It hasn't perhaps.
So, You can modify the spindle, but that's a lot of job and expenses. It would be easier, if spindle has no built-in motor.
Ther is modern possibility - smart tool. A position in turret will be occupied at this case.

[plofkop]

Originally Posted by plofkop Hello I'm having a problem with a okuma lb-15, i want to stop the spindle on a same position, it has to be every time the same. We don't have spindle orientation (m19 = Option) Any body have a idea to stop the spindle Thanks

I want to program the okuma LB-15 to stop at say c20, this is not a problem on the other okuma LU-45 M because this one is with spindle orientation, i treid programming with making thread because there is a kind of orientation but it wil not work.
Is there a way of changing parameter or so because it's a option and i know that sometimes it is in the machine only it is disabeld.

[DIFF OVER]

Spindle Orient ( electric type ) is an option. Sounds like you know you do not have it. Is this LB an M tool machine, if so, you can use C axis. If not a M tool machine, you can check into getting the option, based on OSP model, that retrofit might not be supported.

[Ghallow]

Hello

I think you'll have to do like this M30 (programstop back to beginning of program) & after that a T0 M06 (toolchange,tool back in toolpocket,empty the spindle)
I've worked in the past with Okuma machines & with a T0 M06 the spindle will automatically jump in the same position (spindle orientation) over and over again for a toolchange.
This is just basic cnc-programming it doesn't matter or you are working with fanuc or heidenhain.

[Algirdas]

after that a T0 M06
LB15 is lathe, not machning center.
easiest way is to see if there is brake on the main spindle. Otherwise orientation of spindle by command is impossible.

[OkumaWiz]

Diff Over is correct,

Unless you have a C-axis machine, there is no way to orient without the spindle orientation option. Electric type is available for most of the machines since the 5000L as an option from Okuma. It is a software only option, so the price shouldn't be real high...good luck!

[Algirdas]

Hi

I am undergoing through the same problem.

==> After M19, my spindle orients properly but it jerks suddenly

==> Also if i rotate the Clamped spindle by hand it moves 2 to 3 degrees & again tries to restore its original position.


I think i should increase the clamping force on spindle after M19 - BUT

1. Is it possible to change through Parameter Setting ?
2. What is the recommeded force ?
3. What is maximum force & need to know if any consequences are there if the force exceeds maximum limit ?

Thanks...Need Help Urgently.

Ash

Also attaching a parameter dictionary for easy refrence.

After M19, my spindle orients properly but it jerks suddenly
this is quite different problem.
Check if there are some modifications on spindle brake units, spindle control unit.
check the condition of spindle bearing.
it is abnormal if You can rotate clamped spindle by hand. It is normal if it returns to commanded position. Unclamped spindle is easy to rotate.
check, if spindle clamp/ unclamp functions are working correctly (it is M147).
M110 is C-axis engage and spindle brake works with fraction of clamping force.
On the "data check" screen check which value of c axis is unstable: RDIFF ODIFF or what.

Hi

Ya i can rotate my spindle (after M19 ) only upto 2 to 3 degrees but it retrives its original positions suddenly....(I cannot say how precisely it retrieves its original position)

But sometimes i find that the spindle jerks or swivels ( 2 to 4 degrees ) on either sides without any external force. I am shocked to see hw it can move without any force or any contact.
I think there is some parameter controlling or allowing that drift.


What is the mode of C-axis engage ?

What force is recomended to apply brakes to spindle ?

Sorry on machine C-axis is disabled.

Actually i got the name of the problem mentioned previously. The name is Overshoot of spindle which results into oscillation of spindle.

Any Comments WELCOMED.

Ash

C-axis is disabled
how is that? Do You have the message saying "axis disabled" when You command to use C axis?
i got the name of the problem
perfect. That makes further diagnostics much easier.
Overshoot of spindle which results into oscillation of spindle
If I understand correctly, this explains exactly nothing. Axis doesn't goes to commanded position, so what?
can rotate my spindle (after M19 ) only upto 2 to 3 degrees but it retrives its original positions suddenly
3 degrees is normal.
spindle jerks or swivels ( 2 to 4 degrees ) on either sides without any external force
I suspect, that there is an force. "C-axis engagement" means, that hydraulic brake is applied to spindle brake disk. Engagement only involves low braking. Full brake force is applied by axis clamp command.
it can move without any force or any contact
You can see ODIFF rising on check data screen, if my idea is right.
What is the mode of C-axis engage ?
hm ... I'll try to explain briefly what happens. The brake is applied partially to brake disk and spindle stops in accurate position - so it acts as axis does. It's also possible to clamp C axis, if the operation doesn't requires it's movement. So, C-axis engage is when spindle is used not for rotation at required revolution speed/ cutting speed, but for angular positioning.
What force is recommended to apply brakes to spindle ?
See the manual of Your lathe. The pressure differs from spindle to spindle and maybe different brake systems are used also.

C-axis is disabled
how is that? Do You have the message saying "axis disabled" when You command to use C axis?

No, i don't get any alarm / Message


i got the name of the problem
perfect. That makes further diagnostics much easier.




Overshoot of spindle which results into oscillation of spindle
If I understand correctly, this explains exactly nothing. Axis doesn't goes to commanded position, so what?

See, positioning is not a problem. The problem is that periodically spindle starts oscillating without any external force. The oscillation is so intense that u can sense a movement of upto 3 degrees without any external force.
It doesn't happens everytime. It happens periodically. I think there is some residual value of the complete process which results into oscialltion periodically



can rotate my spindle (after M19 ) only upto 2 to 3 degrees but it retrives its original positions suddenly
3 degrees is normal.

Thanks a lot. I was suspecting that i need to change a mechanical part...i.e belt, pulley.


spindle jerks or swivels ( 2 to 4 degrees ) on either sides without any external force
I suspect, that there is an force. "C-axis engagement" means, that hydraulic brake is applied to spindle brake disk. Engagement only involves low braking. Full brake force is applied by axis clamp command.
it can move without any force or any contact
You can see ODIFF rising on check data screen, if my idea is right.



I will check to it. But what is the solution for such movement.

I was suspecting that i need to change a mechanical part
most likely, the problem is mechanical
what is the solution for such movement
if You see ODIFF/ RDIFF rising, as I said, You must check:
1. geometry of brake disk
2. condition of brake blocks
3. solenoid valves involved in spindle brake system
most likely, You will see the reason after 1.
any alarm / Message
I don't understand what it means:
C-axis is disabled
then

Hi

I think i previously posted remedy of problem & not the problem.

I will try to describe my problem as under -

I have a application in which i orient spindle 2 times.
Firstly i orient it at 0 degrees. Secondly, i orient it at 30.3 degrees apart from 1st position.
I need to know/measure the actual rotation of spindle from first position because it overshoots / oscillates sometimes & i am finding errors. (as we discussed previously)

I am sure that some parameter at servo drive receiver end must be tracing the actual spindle orient rotation.

But how to dig it out & do you have any idea that which parameter traces that actual rotation.

COMMENTS WELCOMED.

Thanks
Ash

Your explanation makes more mess in the subject.
which parameter traces that actual rotation
You can see actual readings of axis location in details:
check data, select screen with C-axis and read: RDIFF, ODIFF and other actual axis data.
As I understand Your problem, the C-axis is not holding the position even when no force to workpiece is applied.
In that case the process of it could be as follows:
Spindle brake disk is flipped or curved or whatever. When brake blocks are applied to the disk, the small part of braking force is directed to rotate the axis a little. Then control makes efforts to put axis back.
The result is as You described.
I have no idea what could be except of that.

Hmmm.....

Getting you. The problem associated is truely mechanical wear & tear of Spindle brakes.

Can you do a favour & donate some time and just go through latest posts on - Spindle Orintation Problem

I hope you will get a clear idea of what i am trying to figure out

Thanks for your Response & Continual Support.
Ash