Hi Deanos,

Looks like a 'landscape' format machine with such a long Y axis gantry. 1500mm is quite a long span for a pair of 45mm profile sections. You could double the (torsional) stiffness if you go for 'portrait' format and have an 850mm gantry, although you do mention that you want to make it easy to load material.

If you want to continue with this style then here's Joe's cnc in case you haven't seen it, which is very popular:
http://www.joescnc.com/themachines-hybrid.php

Any thoughts on how you will attach the X axis drive system (pair of leadscrews I assume) to the gantry sides?