Dust on rails causing chatter?

[Hyrum R]

Hi,
It's been a while since I've been around these parts.

I just upgraded my Solsylva belt-drive table to where it hardly follows any of the plans (see attached pictures) I put on a new Z-carriage that I paid lots of good money for from K2CNC (and it works like a charm), upgraded the gantry to an 8020 aluminum extrusion, and upgraded the bearings to using the bearing blocks from CNCRouterparts.com

Everything is much more stiff and solid that before, however, I still get a fair amount of chatter, and it seems to happen when very much dust gets on the steel rails. Does anyone have any good ideas of what to do about this? I've wondered if I were using rack & pinion, would I have as much trouble? It seems like the dust that gets caked on to the bearings exerts more force than the belts can handle, and they stretch, causing chatter marks in my cuts. It hasn't been a real bad problem, but I would like to know if there is any solution to keeping the dust cleaned off the rails, so that everything rides smoothly.

Any good suggestions? On my next machine, I'm definitely going to be using something like the Hiwin linear rails, but I do want this one to work as well as possible without putting a lot more money into it. This machine has a cutting area of about 40" x 60", and I can jog it around all day long at 850+ IPM (could be faster if I was using a better computer.) Gotta love that Gecko G540.

Oh, and yes, that is a touch screen that my brother gave to me.

[revwarguy]

Originally Posted by Hyrum R Hi, Any good suggestions? On my next machine, I'm definitely going to be using something like the Hiwin linear rails, but I do want this one to work as well as possible without putting a lot more money into it. Gotta love that Gecko G540.

Nice upgrades! As for rail build up, what are you doing about dust collection? I believe its a lot better to collect the dust at the point of generation than clean it up all over the shop later (not to mention your lungs!) No dust collection is perfect, but I didn't see anything in your pictures, so IMHO, I would think that's the place to start. It should be effective enough that you should only have to clean the rails every 20 or 30 hours of operation, instead of needing to clean them in the middle of a job!

Wanna show us some things you've made with it?


PS Yep the 540 is great.

[Hyrum R]

I have a bunch of dust collection hose, and a dust collector a little ways away, but I just haven't got it hooked up yet. I agree that would probably take care of a lot of the problem right there.

I just got it back together after all the upgrades, and haven't cut very much stuff with it since. I'll have to get the camera out again and take some more pictures. I made a big pile of wooden gears just for fun, several little signs, etc. Just for kicks, I even cut one octave of piano keytops out of Formica! (My nephew has an old piano he's trying to restore, so we were trying this as an experiment. I can share the .dxf files if anyone's interested, same with the gears.)

[EBC]

check your settings in mach

i will take any dxf file u wish to share

thx

Gene Crain
www.plantasymaderas.com
www.cnczacatitos.com

[Hyrum R]

EBC,
What do you mean? It's not like chatter around corners or a radius; the chatter occurs just as much on straight areas as anywhere else (and seems very dependent on the amound of dust that's on the rails/bearings.) I'm wondering about building some sort of enclosure or even mounting some sort of brush to the bearing blocks to keep the rails clean. Just wondering if someone has already done something like this.

I think I'll put a few of my dxfs in another thread. Everyone needs a waffle iron pattern, don't they?

[quadtech]

Apparently old toothbrushes make excellent rail cleaners.

[Jesse B]

I'd go with a combination of dust collection and some form of "rail-cleaner". Collecting the dust will eliminate the majority of it, and some brushes will ensure that the remaining dust does not build up on the rails and cake onto the bearings. Judging by the picture of that dust caked on that bearing, I'd say it's probably safe to say that's the culprit.

[ger21]

I've seen two ways that bigger commercial machines with similar rail systems use.

One, is to mount thin strip brass scrapers that scrape the dust off the rails before the bearings roll over it. The brass is softer than the steel, so there's no wear.

The second way is to mount oiled felt wipers , which wipe the dust and leave an oil film for lubricant.

[Hyrum R]

Thanks for the suggestions everyone. Once I get the dust collection hooked up, I'll try attaching some sort of brush to the bearing blocks.

[lunchtrayrider]

dust collection solved my problems with the rails. still had to wipe the rails off occasionally but only every few hours of cutting not every few minutes.

[freecncplans]

Your bearings may be a bit too tight. We don't have anything to wipe off the rails and have issues when the bearings were too tight. I spray them down every couple of hours with WD-40 and wipe the dust off. On my new machine I will be setting it up to have a wiper system installed on it because I can.
Sean

[CarbonKevin]

I wonder if you would get some benefit from switching to a dry lube.

WD-40 leaves a film, even when wiped off, that dust sticks to like a sonofagun. Maybe switching to a dry graphite, silicon, or lithium lube would be better? Or maybe even graphite impregnated bushing blocks that would self lubricate?

Just a thought...