Thank you two for the replies! I have been implementing some of the things you were talking about in my spare time, but much more needs to be done yet.

Click image for larger version.  Name: Design v1-c.PNG  Views: 2926  Size: 669.3 KB  ID: 25743

What I changed:

  • I added angles and connector plates. My plan is to mount the spoilboard on the angles.
  • I added the Z-Axis. Currently, due to the different heights of the Rails and the Screw-sleds, the plate holding the spindle has a weird U-Shape. I could cut into the Z-Carriage and sink the screw into the gantry a bit to make this flat, but thus sacrifice gantry rigidity. Any thoughts on this?
  • I also added Angles to help support the Z-Carriage, like Washout recommended.


What I am yet to do:

  • I understand the thought about keeping the mounting plates adjustable, thus I will design out those green plates to make actual mounts. The same for the back bearings.
  • I want to add motors to both the Gantry for the Y-Axis and the Z-Axis. For the Y Axis I thought about mounting them in the sidepanel holding up the gantry. For the Z-Axis I thought about lengthening the top plate and hanging the motor there. Would this be a problem in terms of placing extra torque on the Gantry?


I also have a couple more questions:

  • Should I put in two more profiles to brace the bed in the Y direction? Crossbracing will be hard using only Aluminium profile
  • How thick should the different Alu plate parts, like the bearing plates, sidepanels and Z-Carriage be? Currently, I have all those set at 20mm thickness.
  • What about endstops? I have access to a 3D printer, can I use that to print mounts for the endstop sensors, or would those be too flimsy? I do not see them having to take much force, but maybe I am missing something here.


Quote Originally Posted by AndyUK View Post
On your long axis, you can either go with a pair, or you can use a single motor with a timing belt connecting the screws. If a belt across the CNC isn't a massive inconvenience to you, my vote is for the belt - otherwise dual drive. There is a motor calculations spreadsheet on the forum which will help direct you to which motors to use.
What would be the advantage using a single motor? I am guessing the, more or less, guaranteed synchronization of the ballscrews?

Quote Originally Posted by AndyUK View Post
I like your ballscrew placement idea on the gantry, but it doesn't leave a lot of room for height errors - the location of the top plate will be defined by the carriages, which may or may not co-inside with the height of your ballnut support. You may want to design with say, a 5mm shim under the BK/BF12, so that you can adjust the shims to get the right height. This is why the ballscrew on mine is on the back of the L shape, it allows me to adjust for height relative to the carriages - but leads to a slightly more flimsy 3-sides of a box shape.
Regarding this, would it also work if I were to flip-down the part of the Z-Carriage in the back that currently is mounted to the Screw Sled? That way I could freely adjust the height. I would only probably have to do it behind the current place where the screw is mounted, since I would hardly be able to actually screw anything in the other way around. Also, regarding the washers, would I just simply place washers between the sled and what I want to mount? The question arises, since that would massively decrease the area of contact between the two.

Again, thank you for the Replies!
-Chrono