MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
Rails bolted to the frame along their length will sag less. So, for the present Y axis they would be a slight improvement. For the X axis you need to do the calcs to figure out what will be stiff enough. A piece of 4mm x ??? x ??? aluminum which the rail bolts to and is then suspended from the Y axis rails? At issue is not having sag.