Re: Linear rail & ball screw size suggestions

Hello,

A good question. Yes, it is an issue with these as well.

One major difference however is that the seals on the linear round
rails are pretty effective since there is no "open" area for
dust/dirt to enter. And the fully supported open types have effective
wipers for the areas where the recirculating balls are rolling.

The same cannot be said for a ballnut/screw assembly. Due to the
rolling screw nature of the screw/nut interface, dust,dirt and swarf
will be "enticed" to enter the precision confines and wreak havoc...
And the shape of the opening makes it difficult to use a wiper as
above. "Brush" style wipers are often used, and will get the bigger
stuff (Sealeze is one mfr.); but the only truly effective way to keep
the bad stuff out is complete enclosure, combined with positive
pressure ventilation.

Now let's get a bit back to reality<G> There are more than a few
ballscrew/nut assemblies working quite well for many seasons which
ignore many if not all of these suggestions/rules... Just know that
the farther you get from the suggestions, the greater your chances of
early failure, or poor results.

In the meantime keep in mind that the people who make this stuff are
trying to be sure that the choices made by a customer do not shine
badly on their product, and are often dealing with designers/
engineers who for ecomomic reasons are forced to push the envelope...

Hope this helps,

Ballendo

--- In CAD_CAM_EDM_DRO@y..., "J.Critchfield" <js3mc@a...> wrote:
> If dust is an issue with ballscrews what about ball bearing linear
> components?