Linear bearing alternatives

[robotopdx]

Hello Everyone I’m New to the forum, I have a small machine shop and would like to get back into CNC after a 7 year break from having access to equipment.
I am working on a CNC router table using 6” aluminum I beams for the structure. Cost is a real Barrier for me so I was hoping I could construct carriages that could ride on top of the I beam out of Teflon / delron rather then paying for Linear Ball Bearing slides. I would like to use the cash that I save to buy ballscrews rather then using a rack drive.
My question is… Will the resolution / repeatability that I gain from ballscrews be lost by using a sliding carriage. Or should I put my $ into Linear Bearings and use a rack instead. I am trying to make the machine capable of cutting aluminum with light passes.
Thanks in advance.

[RICHARD ZASTROW]

There is a supplier that converts worn/surplus ball slides-linear ways by filling them with something like Moglice. I understand they are inexpensive. I do not know much about them but if the application fits.......