Requesting Guidance on Designing a CNC Machine for Machining Wood and Polystyrene

Hello dear friends and engineers. For about two months, I have been working on designing a CNC machine that can machine wood and polystyrene without any issues in dimensions of 2500x1300x500mm. Additionally, this machine has a fourth axis and a rotary, which are separately placed on the machine's table.

Due to my lack of sufficient experience in CNC design, I request you to take a look at my machine and point out any flaws so that I can fix them.

Furthermore, some parts of the machine have been removed to clearly display its structure.
Also, this is a preliminary design!


Materiels : 1 - 80x80mm Aluminium Extrusion T-Slot Profile (8 slot), slot width 10mm
2 - Closed Loop Stepper Motor NEMA 34 - (85Kg XY , 120Kg Z)
3 - Linear Guideway Rail (HG20 XZ , HG25 Y)
4 - Ball Screw Diameter 20mm Pitch 5mm
5 - 2.2kw Spindle motor water cooled
......
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Nobody is going to agree with this but let's give it a try...

You have an enormous Z axis overhang for that day when you want to cut something 8 inches thick. This is going to make for problems on every other day when you want to cut a sheet. Why not make the whole Y/Z axis assembly moveable so you can bolt it to the frame at whatever height seems appropriate?

If the Y axis linear rails were bolted to the underside of the table then the linear bearings could all sit in a neat row below the tool path where they are needed. You could condense a large floppy framework into a chunky vertical frame, put the metal where it can do the most good.

Have a nice day

Robin

Riser blocks would work but you would need to align the axes each time to make them perpendicular. The other common approach is to swap the Z rails and carriages over so the carriages are fixed to the Y axis plate (at the bottom) and the rails on the Z axis plate slide up and down. That keeps the minimum offset for all Z positions. Optionally you can also then have a riser block on the bed to bring the work up to the spindle as required. Depends how big the work piece is and if you would want to skim the bed riser before use to ensure it is flat relative to the spindle.