Fanuc 18T Wanting to slow Spindle Indexing Speed

I recently picked up an older lathe off Ebay that was advertised as a 2003, but turns out to be more like a '96 or even '95 possibly.
This is a live toy / sub-spindle machine - just like one that I already have ... except that it's not ...

By 2003, C axis would have been std on a live toy machine, but in the mid 90's as some of you will recall, "Indexing" was the standard control of "S" in those days, and C was an expensive option.

So - I have a part that we are running pretty much full time that I would like to move to this machine ... but it needs a C axis....
OR - something that works like a C axis at least...

We doo run actual X/C contoured parts at times, but those typically end up on a Y machine.
This job does not require any X/C interp'ing. All I really need to doo is to be able to feed in C (S? B?) at a reasonable rate that my tiny endmill doesn't git flogged.

I need to be able to move in Z, then C, then Z, then C....

I have gone all through the params for FEEDRATES as well as ACC/DECC, and I have edited any that had "C" in the column, but to no changes.
These params appear to be the same as my actual "C" axis sister machine, so - even tho the machine doesn't have the option, they apparently still load those params as if it did.

The indexing is coded as "B", and it will rapid from one B to the next.

I would like to figger out how to adjust the feedrate of that indexing movement.
I'm just not sure where to look.


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Think Snow Eh!
Ox

I have a Hardinge Conquest T42 that has that indexing you speak of.

I don't know what parameter might control this, but can you accomplish the same thing by just programming a very slow spindle speed and then setting a timer? Or do you need to have it stop exactly at a certain degree?

I need to stop at a certain point.
A "B" command will get me to the correct spot, I just need to drag my feet getting there is all.

You must have C axis capability.
This machine does not have it as a programmable axis.


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Think Snow Eh!
Ox

Maybe a parameter for spindle orient speed? I'm thinking that spindle orient and spindle indexing might use the same parameters?

An indexing spindle commanded by "B" is a pretty prime candidate to be handled through the ladder rather than the CNC.

Ox, I think you can confirm that your spindle index is not controlled by a servo by looking at parameters 300 and 301 while doing an index. If nothing there moves, then it's not servo. For example, my T42 has X, Z, C, Y, and A showing for those parameters. X and Z are self explanatory. "A" moves with the turret index. None of them move when I index the spindle. I can't figure out what C and Y are- probably not used.

Take a look at parameter 3732. My book describes this as "The spindle speed during spindle orientation or the spindle motor speed during spindle gear shift". Mine is set to 100.

All of the params per C axis are still laoded and the same as on my sister machine that DOES have C axis, so just b/c it is entered doesn't mean that it is used on this machine.

Y axis is "Sub-spindle linear" for ball-screw driven sub-spindles.


I had edited params 8257 and 8258 with no change earlier.

I just tried 3732 and edited it to 5, and no change, but thanks!
The description on the CRT doesn't give me any reason to think what it might be, so I didn't touch that one.


I just shot Bill an e-mail.
Hopefully he has an idea.



edit:

As for "servo control" - well, it is controlled by the main spindle motor, which runs C axis as well.
Not sure what you are thinking "servo" vs what?




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Think Snow Eh!
Ox

I'm thinking servo that can very accurately control position vs dumb spindle motor that can control speed, direction, and (kind of) position, but not very accurately.

So, I'm giving this one more shot, and then I'm out of ideas.

parameter 4076: Motor velocity limit value during orientation
Mine is set at 33. See if yours has a value and try decreasing it.

There's also parameter 4038: "Orientation speed", but mine is set to 0, so I doubt that's it.

I think the control sends these parameters to the spindle drive at power up, so you should probably cycle power after changing them. And make sure you did that when you changed 3732 as well.

Hope you get this figured out. It seems to me that you should be able to slow the orientation speed.

I did NOT cycle the power.

I have adjusted the speed and ramps on a turret index before, and I don't think that I had to cycle the power, but maybe I did? And maybe this one is different too?
I will give that a shot tho!


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Think Snow Eh!
Ox

OK, I changed the last cpl that you mentioned, as well as some of the ones from earlier, and then cycled the power, and I doo have slower indexing now!

I need to slow it down more, and to figger out which one it was as well, so with the reboot and all - that will take some time prolly, but ...

Where are you getting the info for these params?
An actual Fanuc manual?
I don't see any info on any of these params that you have given me - like many are labeled and give idea what they are, but none that you have given me are labeled at all.


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Think Snow Eh!
Ox

This is all out of a Fanuc 18T parameter manual.

Glad it worked!

On my machine, the index is every 2.5 degrees. The spindle gets it close and then a pneumatic cylinder drives a pin into the teeth of a gear-looking thing mounted on the spindle. Is that about how yours works? Be careful when milling with that. The spindle might overshoot the desired end point and then rely on the pin to bring it in to the correct position. Just a warning. Might not matter for your application.

OK, it is found to be the 4076 S1 param, and it is editable w/o rebooting, which may be beneficial down the road.

However - I started @ 10 and at 1 it is still too fast.

I am going to see if I can doo some lying in the gear ratio / max speed params and see if I can get it down yet.
I'd like to cut it in 1/3 yet at least.

Still moving in the right direction!
Thanks!


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Think Snow Eh!
Ox

I don't think that I have a "big book" for params, but I doo have a pocket cheat sheet booklet (That is in terrible shape!) that does give me more info than just the CRT.
P 4076 reads as "%"

But % of what?
I have it at "1" and it's still too fast.
I adjusted "max motor rpm" as well as "max spindle rpm" and saw no notable change to the index speed.

I have totally redesigned the turret indexing mechanism and I know that somewhere in there I had to adjust the "gear ratio" for the drive/driven gears somewhere.
I read through the par list for everything "spindle" and I just don't see anything in there mentioning that, although it may be in ref to both the max motor and max spindle values as when I adjusted just one of those and not the other, I got run-away spindle rpm.

Maybe "gear ratio" edits won't help me....

???



Again - P4076 is a % "of what"?


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Think Snow Eh!
Ox

I'll check the manual and get back to you tomorrow. I don't think there was much description, but I'll check.

My parameter manual just has a list of parameter numbers with basic descriptions for all the parameters from 4000 to 4351. There are no other details about whether it's a straight rpm or percentage of something. I'm guessing that there is another book for the spindle drive that gives those details. A quick call to Fanuc would probably answer your question about P4076.

If you PM me your email address, I can share the list of parameters I have. There might be something in there that will help you. There are a few regarding gear ratio and max speed, but you're better off having the entire list to find the right ones to change.

wmpy said:

My parameter manual just has a list of parameter numbers with basic descriptions for all the parameters from 4000 to 4351. There are no other details about whether it's a straight rpm or percentage of something. I'm guessing that there is another book for the spindle drive that gives those details. A quick call to Fanuc would probably answer your question about P4076.

If you PM me your email address, I can share the list of parameters I have. There might be something in there that will help you. There are a few regarding gear ratio and max speed, but you're better off having the entire list to find the right ones to change.

Click to expand...

Thanks.

Oh, it started off so innocently ... but around O'Dark:30 last night - as I was sanding tits, thinking about my little "pocket guide" v/s your manual, I had an epiphany. I had edited many params when I did my turret mod, so it would seem that I had a decent list somewhere. I looked through my book pile, but nothing stating "Params", and the OP manual didn't list any either. But then - I might be able to find sumpthing online. Well! I bet that I already have a PDF of that manual already on my 'putor!

Well, there was a few files under "Fanuc" in my 'putor, but none stating anything about params.
However - Google took care of that right quick for me!

And I am likely looking at just what you are now, and the bigger book doesn't mention anything about "%" like the pocket cheat book does.


I am now looking at the "B" axis params @ 8240+.
There is mention of G0 / G1 in there, so I may play with that a bit next.


I may need to make that call....


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Think Snow Eh!
Ox

You know where to find me if you want me to look something up in my book.

Let me know if you ever get this sorted. I'm curious how you make out. I'm also curious about what you did to your turret, but that sounds like a story for another time...

https://www.practicalmachinist.com/...oxs-shop-08-a-167493/index14.html#post2074066


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Think Snow Eh!
Ox

Wow, Ox. That was a lot of work that you put into that turret. I'm impressed.

Poor Man's C Axis

OK, so I "made that call" to Fanuc.
My local guy in Cleveland (other side of the state) is Greg.
I recall talking to him before for whatever porpoise.

I told him what I want to doo.
I told him that I had backed 4076 off to 1 and could see the finish line from there, but was still coming up short..
"What is 4076 "looking at" as to be a ratio of?"
He said that he wasn't sure, and that I needed to call Hardinge and try ti get hep from them.
If they couldn't help me - then call him back and he would dig deeper at that time.

So I talked to John at Hardinge Chi-Town.
Good guy. I had actually talked to him earlier in the week on a different subject...
He really dug into it for me but to no avail.
He said that he didn't have any manuals that were any better than what I had, and that he had no clue what 4076 was looking at.

So then - I called Greg back and said that I had exhausted any posibilities there - although he sure tried!
He wanted amp and motor info, and I got his e-mail and took pics of them and wrote a detailed letter of what I wanted to doo, and where I'd been, and where I'm at.

A few hours later he mailed me back a screenshot of what I can only ass_u_me to be an integrator's programming manual. (???)

"6.6.3 Quickest Orientation Action"
The orientation speed is calculated as:
(the smaller value of either parameters 4100 and 4320) x P4076
And I'm told that I don't really want to be changing 4100. (although I might be able to for such a short time?)

AH! There we have it!
So I go and see what I have there....
Well, 4320 is all zero's. Not a good sign...

4100 was 870 I think.
So I changed that to 100 and gave that a whirl.
No change.
UGH!

Well, I don't know that I can enter a value lower than 0 in 4320, but ... mayyyybe "zero" doesn't count?
So - let's try 100...

THAT DID IT!
Now I have my speed in a useable range!

OK, so - with it that slow, it now will alarm out on the first B move as it needs to HOME, and not only doo I not want to waste a bunch of time if I don't have to - wqaiting for the B to go around a cpl times looking for a pulse, but the machine is timing out. But - if needed, I'm guessing that there is a timer setting somewhere to address that too eh?

OK, now - on to OPP2, and that is to hopefully be able to edit this "in program".
I know that some params are editable. Is this one? And how doo I go about that?
I was leary the whole time - hoping that the params that I was dealing with did NOT require rebooting after change, and up to now - all changes were taken with-out reboot, so I ass_u_med that this was going to be dooable...

I googled this site for that info, but didn't find it.

So then I had to go back to my guy @ Fanuc and ask how to code a param change "in program".
"Well, IDK if you can change these in program or not, but this is the coding...."

It took a few tries to git it right - but Houston - we have lift off!


I couldn't git the range of speed that I wanted with just one edit, so I am editing two params to git where I'm goin'.

O1 POOR MANS C AXIS;
G10 L50;
N4076 P1 R100;
N4320 P1 R400;
G11;
B0;
G10 L50;
N4076 P1 R5;
N4320 P1 R100;
G11;
B180;
G10 L50;
N4076 P1 R100;
N4320 P1 R400;
G11;
M2;


I can see that the decel ramp on the slow movement could be let out considerably for smoother action, but IDK that I'm going to pursue that or not?
But I'm a happy camper.
Fanuc and Hardinge essentially said that it prolly couldn't be done, as they had tried to doo this before, but had to go to C axis for similar results.
But here it is - bigger'n Dallas!


Thanks for your help wmpy!
You got me pointed in a direction. (4076)


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Think Snow Eh!
Ox