Servo draws too much current near edges of machine.

[Ox]

Sounds logical Ox.
But on my Siemens lathes they definately used a lot more oil after me changing it.
Looking in the back the slides were always nice and wet and the machines stayed as accurate as the day i bought them.

Maybe your machine had orifices rather than metering valves?


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

Think Snow Eh!
Ox

 

[machina]

UPDATE: I put a 0.002" shim between the underside pressure plate before reattaching. The servo current draw remains @ 30% when jogging X through most of its travel and worst case gets to about 70% at one end. I'm not sure if this is going to affect surface finish or chatter in my cuts if the table is a little looser but I'll find out soon.

In the meantime I can replace all the metering valves (24x) for $10 each from Dropsa USA in texas. If there is a lubrication issue that seem the most likely clogged point so I'll see if things improve after installing those.

Any other suggestions? Has anyone heard of the possibility of Turcite swelling a bit from absorption of oil or water? A tech I called mentioned that but it seems far fetched to me.

Aaron

 

[machina]

I attached a couple pictures. I pulled out the Gibb bar to inspect and I can see a little bit of damage to the turcite at one end. Its kind of smushed for about a 1/2" in length but I don't think it is a big problem ??? More interesting is all the red rusty sludge that came out with it. The rust seems to have embedded itself in the turcite, changing the color from blue to a muddy grey. This photo is after I cleaned it off several times, pulling more red stain on to the paper towel each time.

The turcite from the bottom pressure bars was similarly stained and reddish. I wonder if this is causing the extra friction I'
m seeing? What can be done?

Aaron

 

[machina]

 

[Ox]

Any chance that corner has gotten dinged somehow?
[from here] it just looks like that corner is pushing harder than the rest.


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

Think Snow Eh!
Ox

 

[machina]

I looks like it was running fairly dry of oil?

There seemed to be plenty of oil on all the turcite (gibb + 2x pressure bars from underneath)that I inspected. The photo's are after I cleaned it well, but it remained stained reddish.

The damage to the corner does look like it got caught on a chip or smashed by something at some point. I think there was some bulging around that damage that may add to the pinching. I shaved it down very selectively and have reinstalled it. I'll see if it helps tomorrow.

Aaron

 

[guythatbrews]

Looks like fretting occurring which might indicate low lube.

Decrease lube interval and use a bigger metering device at the problem area. Sounds like this will be harder than it sounds.

Flaking the turcite will help. There might be plenty of oil in the gallery but if it can't spread out onto the sliding area almost might as well be none.

 

[guythatbrews]

Try posting your question about turcite swelling on machine rebuilding forum. Lots of knowledge there.