First Build - Yet Another Alu Profile Router - 900 x 800

[CaptainBarnacles]

Hi All,

Here's the first ramblings and outpourings of my mind as I embark on my first CNC router build.

Obviously I have already fallen into the trap of having purchased much of the gear before finalising the design. Here's what I have so far:

4 qty Hiwin 20mm Linear Rails and Carriages @1000mm (X & Y Axes)
2 qty Hiwin 20mm Linear Rails and Carriages @400mm (Z Axis)
2 qty 2010 Ball Screws @ 1000mm (Y Axis)
1 qty 2005 Ball Screw @ 1000mm (X Axis)
1 qty 2010 Ball Screw @ 400mm (Z Axis) - May look to replace this with a smaller, lighter screw??
2 qty 40 x 160 Alu Profile @ 1000mm
2 qty 80 x 80 Alu Profile @ 1000mm
4 qty 40 x 80 Alu Profile @ 1000mm
4 qty NEMA 23 motors
4 qty TB6560 Drivers
24V 250W PSU
4 qty Flex Couplers
6 qty Proximity Sensors
Misc Fasteners and fixings etc.

Engage sarcasm mode: I'm having so much fun learning Fusion 360 :Disengage sarcasm mode. Here's my part finished design:





As you can see from my partial design I have opted to use tall profiles for the Y axis sides of the frame in order to reduce the height of the gantry support plates as much as possible. My thinking is that it will keep the CoG of the router as close as possible to the same height as the Y axis linear guides. On the X axis I have opted for 2 qty 80 x 80 profiles in the hope that it provides way more rigidity than I need. X Axis guides are mounted top and bottom of the gantry to minimise the router's extension from the gantry.

My current design considerations:

Direct or belt driven X and Y axes? I am currently leaning towards belt driven.
Reduce the Z Axis ball screw size to reduce overall Z axis assembly weight and provide a finer pitch, perhaps a 1204 or 1604 screw?
Use universal connectors or use L brackets to join the 40x80 of the bed to the 40x160?
Are my stepper going to have enough grunt if I use a 1:1 belt drive? They are 270oz rated, perhaps a 2:1 ratio?
Whether to make my own aluminium plates or have them made for me? I think I am plenty capable of making them but I have no mill or CNC machine so it'll all be hand work (I have woodworking tools such as mitre saw, jigsaw, router table, drill press etc.) so I question whther I can make them to the tolerances required for a really strudy machine.

I have given very little thought to the Z axis at this point but I am treating it as a 'module' that I'll bolt on towards the end of the project.

I think that's it for now. As I have more thoughts and ideas I'll vent them here.

Cheers,
Paul.