Re: [CAD_CAM_EDM_DRO] Ball screw / ball bearing lubrication?

Jeff,

The short answer is yes.

Most any ball bearing device has more that point contact
between the bearing and race due to the material's elasticity.
There is some scuffing so a lubrication film is needed.

Specific lube recomendations can be had by looking at
manufacturer's data. A quick search will prob yield some
information right on the net.

I can give some general guidelines though.

Ballscrews are relatively low speed devices and are usually
grease lubed. A straight petroleum based grease is usually
fine. EP can be used but is not required. Lithium grease has
good water resistance; sodium has somewhat better rust
prevention (it can absorb water).

If the ballscrew is is used hard and has high preload oil
lube may be used. The oil has an important secondary function
of acting as a coolant.

Oil is sometimes better in a dirty environment as it can be delivered in a
way that the screw is cleaned.

But.... oil delivery systems cost money!

For angular contact....
At low speeds a 30% grease pack is often used. Too much
grease will cause churning and overheating.
Automotive wheel bearing grease is fine.

At high speeds oil is used, but it depends on the bearing
and application. Usually much above 10,000 rpm is in the
outer limits for grease. Some examples of grease in high
speed bearings can be seen such as wood router bearings
at up to 25,000 rpm. Their life is much much shorter as a
result. Other longer lived high speed angular contact bearings
are oil mist lubricated and can last a very long time.

Leslie Watts
L M Watts Furniture
Tiger, Georgia USA
http://www.rabun.net/~leswatts/wattsfurniturewp.html

----- Original Message -----
From: "jeffswayze" <jswayze@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, January 29, 2002 8:53 AM
Subject: [CAD_CAM_EDM_DRO] Ball screw / ball bearing lubrication?


> Here's a simple question for those more experienced than myself:
>
> Are ballscrews/ballnuts supposed to be lubricated in some way?
>
> What about ball bearings (angular contact bearings in particular)?
>
> -Jeff