Aluminium profile CNC

[Nr1madman]

Also on the Z axis it's stronger to build the rails on the moving plate and the bearings on the stationery side :)

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[routercnc]

One thing to watch with that design is that the gantry will need to be shimmed on one side between the gantry and side plates because you have trapped the long X axis rails between the sides of the bed. That is why most people put the rails on top of the profile as the tolerance can then be taken up by slightly over sized holes in the side mounting plate.
In other words the gantry length will have to be cut very accurately so the side plates are a snug fit into the rail carriages

[BriceO]

Nr1madman, you're right there is a space between the linear bearing and the plate. I was thinking to add a 20mm spacer.


Thanks for your advices, I will do the changes. In my actual design I have a another profile in the middle of the left and right profiles, but I will add more.
routercnc, nice idea I was thinking that I can order the profile already cutted.

Thanks everyone ;)

And what do you think about the linear bearings?

[routercnc]

Your question about linear bearings - do you mean size? If so 20mm on all axes.
What is the plan on the Y ball screw? It goes straight through the Y and Z axis? With that type of layout some people space the YZ away from the gantry and run the ball screw behind. But this weakens it because of the overhang.
A more popular design is the L shaped gantry with the ballscrew running behind allowing the YZ to be close into the gantry.

[BriceO]

Your question about linear bearings - do you mean size? If so 20mm on all axes.

I mean which lead should I take, 20 or 10mm lead? I calculated a max speed of 500 IPM, does it seems to be correct? And do I need to have a ballscrew preload ?

What is the plan on the Y ball screw? It goes straight through the Y and Z axis? With that type of layout some people space the YZ away from the gantry and run the ball screw behind. But this weakens it because of the overhang.
A more popular design is the L shaped gantry with the ballscrew running behind allowing the YZ to be close into the gantry.

I planned to run the ball screw behind the gantry for this axis, but you're right I'll change it for the L shaped gantry.

For the longest axis, which one is the "best" design?
Add a spacer to the ballscrew. The ballscrew runs behind the plate and this plate will be near the bearing blocks. Something like this:

[Nr1madman]

I mean which lead should I take, 20 or 10mm lead? I calculated a max speed of 500 IPM, does it seems to be correct? And do I need to have a ballscrew preload ?



I planned to run the ball screw behind the gantry for this axis, but you're right I'll change it for the L shaped gantry.

For the longest axis, which one is the "best" design?
Add a spacer to the ballscrew. The ballscrew runs behind the plate and this plate will be near the bearing blocks. Something like this:

Hmm don't really understand but is "lead" the same as "pitch"?
Have read a lot about lead on the zone but that seems to talk about trapezoidal screws and not ballscrews?
Anyway what do you want to cut and in what resolution?

If you plan on having the ballscrew on the outside of the plate as in the picture then please don't forget that the screw must be longer then the calculated travel as the plate will travel inside the bearings :)

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[BriceO]

Hmm don't really understand but is "lead" the same as "pitch"?

Yes, exactly I mean pitch. I would like to cut mainly wood and a few tests with aluminium.

My goal is to have a resolution of 0.01 and an accuracy of 0.1mm. I tried to calculate the speed with a hiwin 2020 ballscrew, KL23H2100-35-4B NEMA23 and found a max speed of 500 IPM. Is it possible?

Here is the specs of the motors (4X):