[Fourzin]

Hey you all !
So I am planning to build myself a CNC router for woodworking. At first I was going to use the default gantry moving design, but I had some minor issues about it. As you might know, support shafts and linear bearings are strongest when subjected to load normal to their plane. Basically they do not like any torsional loading, moment or twisting. The second issue was the relatively long gantry (in the z direction). To me the center mass seems a bit elevated and therefore "tipping/deflecting" seems easier (due to cutting forces and accelerations). So, I tried to make some modifications on the default design.

I do not know if the default design is actually optimal and that might be the reason why its everywhere. But I hope you can give me some feedback on my conceptual design. I already have some pros and cons to it.

Pros:
1) Linear bearings are loaded with minimal torsion (longer life and better accuracy).
2) Gantry's center of mass is closer to x-axis (more robust).
3) Gantry's overall weight is lighter and therefore faster velocities can be achieved.

Cons:
1) Overall needed material is increased (Thinking to use Aluminum 6061 plates)
2) Gantry may deflect more due to z-axis assembly (I added a normal plate on the gantry as can be seen in the last image, which may "solve" this problem).

Have a nice day,

[stiffethomas]

Hey that is the nice concept,

Keep going

[awerby]

The beam that you're hanging your Z axis assembly on needs to be a lot thicker in the vertical direction, or it will sag like a wet noodle.

[LeeWay]

Yes, the gantry is too thin. Consider also removing the cross braces and add gussets to the outside on the side walls. That will still provide the support needed and make loading and unloading much easier. The trade off is a little larger footprint.