Regreasing/clean linear actuator worm gear and rail

[ori333]

Hello everyone,

I'm resurrecting some old equipment that has not been used for >5 years.

A linear actuator with what looks like a worm gear system and guiding rails.

It 90% working, but has some trouble during a small portion of the travel...about where you see the grease buildup on the worm. Also an another section it does a little short skip.

Any recommendations how to re-grease/clean this thing. What grease to use? Should I remove the buildup?

Specs:
speed, up to 2 cm/s
travel: 40cm
weight capacity: ~500lb

Thanks in advance.

P.S. Happy to read any source material...like Machinist Handbooks etc.

 

[technocrat]

try some high quality light machine oil and use it to thin the grease. Rub it in with a q-tip or similar. That is the quick and dirty and if it works you are laughing.

 

[technocrat]

There could be some fretting on that top rail from a dry heavy load. If that is the case, you will probably need to replace it.

 

[ori333]

I recall the engineer before me told me to douse it with WD-40. Reading into it, WD-40 may not be good for this high load application. Does that mean I need to do a thorough cleaning?

 

[Scottl]

My go-to for softening old grease is Marvel air tool oil.

After it soaks in a while I wipe off as much as I can and then apply new grease. It may take multiple applications to remove the old crud. If this is a high load application I would suggest using an EP (extreme pressure) lube such as CMD (Chicago Manufacturing & Distributing).

 

[reboots]

I recommend removing as much of the existing grease as you can, and re-lubing. I would not under any circumstances use WD-40 as a bearing lubricant. WD-40 is primarily kerosene, and will dissolve and wash away the existing lube without replacing it. If you can identify a make and model of the components, you can look up the manufacturer's recommended lubricants. HiWin lists Mobilux EP 1 as one of cheaper and more available recommendations for their linear rail systems, which would probably be an improvement over the black grease that's there now.

 

[ori333]

Hello everyone. Thank you for all the advice. We also noticed that on the other side there are two nipples to add lubricant to.
Is it possible there is another nipple on the device for the worm gear? Do those exist?

Thanks again
Valentin

 

[reboots]

The worm gear actuator in the photos is technically a ballscrew, paired with a ballnut. They do need lubrication. Some ballnuts have a grease nipple or lubrication port. If you can't find anything like that, or if the ballnut isn't easily accessible (I don't see it in the photos), I think your best bet is to clean and lightly grease the visible portion of the screw. It appears that's how the machine was maintained in the past.

When you are cleaning the rails and screw, carefully inspect them by sight and touch for any perceptible roughness, wear or damage. As @technocrat says, any wear sufficient to cause binding probably means that one or more components are at the end of their life.

 

[ori333]

Hello everyone,

Cleaning the rails and re-greasing the sliders on the rails is going well because they have nipples. Any idea if there is a way to re grease the ballnut?

I'm afraid if I unscrew the ballnut anymore all the ball bearings will fall out.

 

[ori333]

Well...i did it anyway. As they say "Fear is the mind-killer."


Before


After


Any tips on how to regrease this?

 

[Bill D]

For heavy weight gear oils there can be an issue with yellow metals. The more modern ones have high pressure additives that attack yellow metals used as bushings. bearings and gears. Gl 4 is okay GL5 can be a problem.
Is this an issue with grease or not? I have no idea .
Bill D

 

[ori333]

The Rail Blocks are: NSK,LH-LA25

NSK Global—Bearings, Automotive Components, and Precision Machinery and Parts

Global leader in Motion & Control. NSK keeps the world moving with bearings, ball screws, linear guides, auto parts, and precision machinery solutions.

www.nsk.com

 

[ori333]

Update:
The local supplier for the rail blocks told us to use Lithium based grease , grade number 2 (thickness).
Now hope to find the manufacturer of the ballscrew, and ballnut. The motor the drives it is a Kollmorgen MODEL:AKM22E-ACB2R-00