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Help with x axis noise on older lathe

BWS JAZE

Plastic
Joined
Jun 11, 2019
So I have isolated the noise, which is a low volume thump but it is consistent with the revolution of the servo while jogging. This servo and x axis assembly has obviously been messed with in the past, it looks thrown back together.

It is hard to hear over the hydraulic and tough to catch on camera but the that coupler is jerking at a certain point in rotation. Almost like it is slipping and catching. The strange part for me is there is no backlash on a drop indicator, which means less than .001. This is also just started happening, I've had this lathe for a month or so.

Is it a bad idea to unbolt the servo to investigate further? I wanted to check with some vets before jumping too far down the rabbit hole. This is a Hyundai HiT 8s with a SIEMENS 840c control from 97.


 

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WOW!
Gunna be tough chasing tenths with a LoveJoy coupling in there! :eek:


I would first look at thrust bearings.
Those are a wear item.
Grease packed for the life of the bearing.
(however long that may be)


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Think Snow Eh!
Ox
 
WOW!
Gunna be tough chasing tenths with a LoveJoy coupling in there! :eek:


I would first look at thrust bearings.
Those are a wear item.
Grease packed for the life of the bearing.
(however long that may be)


-----------------------

Think Snow Eh!
Ox
Yep, I just read up on those couplers and it appears to be a low cost option. Regardless of that, it seems to be more accurate and faster than my ST15Y from Haas.

To check an/or replace the thrust bearing (which I assume is angular contact bearing) I would have to unbolt the servo right? I just didn't know if that has a procedure or if it is a bolt and unbolt type for situation. It doesn't have absolute encoders as I have to home the machine on start up if that is a factor.
 
Well, if you have to HOME the machine then no worries mate!

But - to keep it the same, scribe or somehow mark your coupling fingers so that they go back the same, and you should be fine.


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Think Snow Eh!
Ox
 
The encoder is an odd one, it is a tachometer inside the servo. I can attest that the machine is more accurate than my 2020 ST15Y from haas and faster...even with this issue.

I have a medium sized run, after I get it done...I will fix this. Possibly look in to a retorfit to get rid of this SIEMENS 840c which sucks to use IMO. Thanks fellas.
 








 
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