[JerryBurks]

I am in the design phase for a new CNC, using supported rails with linear ball bearings and Kuroda ground ballscrews. Purpose is mainly milling of wood, plastic and the occasional small aluminum part.

I am a bit concerned about dust in the linear motion parts but I do not want to go with bellows due to cost, design compromises and loss of travel.

I would rather use a guided "curtain" (maybe 0.5mm clear PVC film) that goes all around the gantry box and moves together with the sled where the z-axis is mounted on. It would be quite easy to do with my design but is that a common method and where are the pitfalls, maybe some examples?

Another question is if that will do the job alone or if I should have positive airflow. I could for instance install a small computer fan with HEPA filter to create a flow of clean air from the inside of the box out. That should prevent fine dust from creeping in over time or is that crazy overkill? If I can keep it really clean I hope I might be able to use long-term grease lubrication for the ballnuts instead of frequent oil application.

Sorry if these are dumb questions but I am new in the hobby CNC stuff.

Thanks, JB

[adprinter]

I mounted nylon bristle "brooms" on each end of the trucks on my machine, which differs from your round supported rails (mine are square tube rails). This does not keep all of the dust from getting onto the rails, but it does keep the dust swept off of the rails so that it doesn't end up caked onto the bearings or the rails. I purchased the brush material from McMaster Carr. They sell the material in different bristle lengths, and rigid or flexible styles. You might try the flexible style, and mount it in a wrap-around fashion at each end of your trucks. I am sure it won't keep 100% of the dust off the rails, but it should (like mine does) at least SWEEP the bulk of the dust off the rails. Hope this helps!

[ger21]

A good dust shoe around the tool coupled with a good dust collector should minimize the dust on your ballscrews and rails.

[JerryBurks]

Thanks for the opinion. Maybe my idea is indeed a bit overkill. I just have an image in my mind how the fine dust and the oil will over time create an ugly goo in the precision passages and block the ball circulation.

But I did see some kind of sliding curtain style dust protection (don't know if there is a better name for it) that covered all moving parts on commercial machines and wondered if somebody did that on a DIY machine, too.

JB