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

[Robin Hewitt]

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

[routercnc]

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.