Re: [CAD_CAM_EDM_DRO] Request for ideas for lathe Z axis ballscrew covers

Kim Lux wrote:

>Hi people.
>
>We've got a lathe retrofitted with ballscrews, servos, etc. It works
>great (outstanding actually) except that the ballscrew is getting
>contaminated with metal filings, etc. This metal is jamming the
>ballnuts.
>
>The Z axis ballscrew is located where the feedrods and lead screw are
>mounted on a conventional lathe. We've got a roof over the screw, but
>debris is still getting on it. When cutting, we've got debris flying
>everywhere.
>
>I'd appreciate any and all ideas for covering the ballscrew. Don't
>forget that a ballnut runs up and down the screw... The best idea we've
>had thus far is an accordion type tube, kind of like the fork covers on
>a motorcycle.
>
>

There are a number of designs, but many of them would be REAL hard to
do without mold tooling. One thing that I have seen is a wide strip of
spring steel. It is wound into a coil, and diagonal corners of the original
strip are anchored by a rivet to round bushings at each end. The thing
works by pulling the coil into a helix as it is stretched out. I think
one end
bushing has to be free to rotate around the screw. I'm not sure this
design can handle the extremes of motion of a lathe.

I had some Gortite bellows that came with some ballscrews off an old
machine, but they have disintegrated. The guys at our shop got a quote
on some Gortite bellows, and they are VERY expensive in small
quantity. They really work nicely, though. There may be some other,
similar bellows material, like the motorcycle fork covers, that comes in a
roll, and you cut to length. Certainly worth some searching. I seem to
recall some cars with rack and pinion steering had some pretty long
bellows, too.

Jon