Originally Posted by catmix  Y Axis
The Y axis is a rather deep channel section. Ive seen many different designs with RHS, rails, simple narrow beams etc. But i believe the channel is superior because the shear center is closer to the center of the load (spindle) which means the section will distort in a planar manner rather than torsional (which is good i think). |
Yes, but it only applies to vertical inertia and cutting forces. Your cutting forces in the X direction will put a torque into your Y-axis regardless of its cross section. In your case since your channel ends are left open, it won't resist that torque efficiently and the vertical wall of the channel will see bending stresses. At the minimum put a rigid cap on your channel ends. Channels don't do well in torsion, so IMO strictly from a rigidity standpoint, a full rectangular/box section would be better a Y axis.
Also, a possible pitfall with dual screws is synchronization. But I have no solution, just pointing it out.
I don't see a problem with your offsett Z drive. It’s a relatively short offset so racking should not be a problem.
Otherwise, concept looks good.
