Humble Beginnings - For Alu

[JAZZCNC]

Will there be more frame work to that base frame.? If not then then you'll need to be sure what ever it sits on is 100% flat and true other wise that frame will easily twist and put the rails on different planes.
Profiled linear rails don't tolerate twist (Or bend) very well and will bind to some degree. Doesn't take much to lock them up solid.!!

One other thing I see thru experience of mostly cutting Aluminium is that chips get fired every where and with this design the profiled rails are in direct firing line. They will act has stops and chips will collect building up in the profile of the rail. While the bearings will mostly push these out the way some of them will get thru and into the bearings, which over time will considerably reduce the bearings life. Over time It will also have an affect on finish quality because it will reduce the bearings smooth running causing notchyness that passes thru to the cutter.!

You could get away from this very easily with a slight design change to how gantry mounts to bearings.? Instead of using the short piece of Box section has riser then make that piece full length of the machine and mount directly onto the frame. Put the linear rails on this then mount the gantry to the bearings directly using a plate to replace the short box section.
The plate could be 20mm Ali or 10mm steel either would work ok. Personally I'd use Ali plate has welding thick to thin steel creates heat distortion and make the Triangle brackets out of Box section along with larger Triangle plates for strength. (see pic)

This one change will give several advantages other than moving the rails out of direct firing line.?
#1 Increase travel 100mm because rails can now go right to end of machine.
#2 Make aligning rails parallel and planner to each other easier by simply shimming or adjusting the Long piece of box section.
#3 Make gantry mounting and bolt access easier.
#4 Will be stronger and looks neater.
#5 Easy future height clearance upgrade if required by simply inserting another piece of box section or spacer between bed frame and linear rail box section.

Hope that helps.