Hi I'm considering a CBeam CNC similar to CBeam Platemaker, but slightly more XYZ dimensions. The main difference is that I want to use ball-screws and not Acme. I looked at 8mm, but too light duty, then 12mm, but ball-screw nuts to big to fit underneath build plate inside the c channel. @10mm, I had to consider the nuts. I wanted to go 1005, but the nuts available out there is too big. Eventually with a 1003 (10mm with 3mm pitch) I could fit the ball-screw nut underneath the build plate. The nut is a R1003T3-RSK (http://www.zappautomation.co.uk/mechanical-products/ballscrews/ballnuts-144/rsw-ballnuts/r1003r3-rsw-ballnut.html) The fixed end support is a FK08 (http://www.zappautomation.co.uk/mec...rts/fk-type/fk08-c7708-ballscrew-support.html) So far, the only custom made parts is the CBeam End Motor Mount bracket (thicker than stock and with holes for the FK08. the bracket for nut to the build plate for attaching the R1003T3-RSK See next post for my questions.
If you look at the picture below, when you pre-load the wheel by adjusting 2, the plate is not centre anymore, correct? (or does it balace out?) What is "giving in" during the load? What is the effect of this on the screw at n0 3? Anyone used ball-screws with wheels running in v-profile before and where the pre-load force between 1 and 2 have an influence on 3?
The holes in the build plate, where the bracket for nut to the build plate connects to, is 5mm diameter. If I make the holes slightly bigger, then my nut mounting bracket can adjust sideways to line up before tightening the bolts. But, I still need to know the effects the wheel pre-load, will have on the ball and nut?
If this is a major concern, it would be fairly easy to drill out the holes at 1 to 7.14mm and add eccentric nuts there so you could then tighten equally from both sides.
1 and 2 should end up close to symetric about 3 after the preload. I believe the adjustability of 2 is a plus and minus about the distance between 1 and 3. You'll still want to run the ballscrew nut up and down the beam while snuging the end mounts to make sure the assembly is comfortable. Joe
Thanks guys. Yes, with eccentrics on both sides, will make me more comfortable. Except for the much better efficiency of the C7 / C5 ballscrews you think the extra $$ is wroth it? (this machine build XYZ, 1000x500x250) will be used to make parts for a bigger CNC mill using Aluminium C channels (200 x 62) and linear profile rails and blocks, all inside mineral cast.
Hi, We are considering doing something very similar, do you mind if I ask where you sourced your Aluminium C channels (200 x 62)?
