Fanuc Live Tool Rigid Tap Issue

18T

Live tool RPM works fine, but when I go to Rigid Tap with it, the RPM starts out slow and then builds and builds to run-away speeds while feeding ultra slow at the same time.

I was thinking encoder, as I have replaced those before, but I think it was on the other turret, but not the same issue either....

I talked to Hardinge and their guess was encoder as supposedly this reader has a tach side and a servo side. But they didn't sell those.
I ordered one from Fanuc. I don't recall if I talked to tech support there or not?

So I got it on just now and - no change.

So what now - some daughter board in the control or in the amp or ???? maybe needs changed?
Anyone seen this problem before?

I cross tapped the last 500 pc job by hand (cordless drill)
I have another 500 pc order to run, but the parts are shorter and don't offer as much room to hold/leverage for quick work.
Would like to git it fixed.


It is this type encoder (reader)




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Think Snow Eh!
Ox

O'scope check the encoder signals at the control or drive? I'm wondering about a broken wire or bad connection somewhere. Depending on what type drive it has, will determine where to check. Analog drive feeds the encoder back to the control. Serial spindle drive feeds the encoder back to the drive.

That sounds like a problem that might take a bit of work to track down.

In the meantime, could you get by with a axially compensating collet to get the next job out the door?

Hadn't thought about it, but I could prolly just run that tap off the lower turret for now.
The hole is on center...


Could scope it out, but I will need to find out where to check.



edit:

Hmmmmm, better check if the lower turret tapping works!




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Think Snow Eh!
Ox

OK - a quick check shows that the routine works just fine on the lower turret.

Not 100% sure what that means?

I need confirmation as to where this part of the encoder feeds back to and run that check I guess, but at least I can run these parts first.




EDIT:

I'm guessing that it is the JY4 port cable that we should check with the scope?



EDIT II:

If that's the case, and I think it may be, I will next swap out the amps between the two turrets and see if the issue migrates.




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Think Snow Eh!
Ox

Swapped amps and the problem followed the amp.
That's a great thing!

Now I have tapping on the upper and I'm in the game aggin!


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Think Snow Eh!
Ox

Cool! I am a bit surprised that it's the amp rather than a cable or connection.

Not sure why I didn't think to start there?
But once I started thinking about the two sepparate enc feeds, I went'n looked at a live tool amp on another machine that doesn't have Rigid Live Tapping, and there was no JY4 cable on that machine, while both of these did have one.

I googled JY4 and it sounded exactly like what I was looking for.


That's one of the great things with the twin turret machine b/c it has 2 of everything, and if there is an issue, you can just start playing musical amps for diagnosis.


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Think Snow Eh!
Ox

Many times there's a minimum RPM specified in the parameter tables for M29 rigid tap mode. You may want to check that. We had an issue in the showroom when I worked at Doosan of rigid tap failures, turned out that the RPMs were too low.