New build - fixed gantry mill using extruded profile

[toolchimp]

Hi all,

I have been lurking for a while following other people's builds and absorbing the excellent advice so freely given on this forum and I thought it about time I stuck my head above the parapet!

I am planning on building a machine that will be used initially for 3D machining of aluminium and PU tooling board with a cutting envelope of approximately 620 x 330 x 130mm. The frame is mostly 80 x 40 and 40 x 40 profiled extrusions and I hope to use it to make parts that replicate sand casting tolerances which are around +/-0.37mm (10mm feature size) up to +/-0.9mm (600mm feature size). I have schemed Nema 23 motors driving 1605 ballscrews through belt drives - these are currently at 1 : 2 but the design allows for 1 : 1 drive for more precision and higher torque if required. All axes use profiled rails - 15mm on the Z and 20mm on the X and Y. The spindle in the design is a DIY as well - it is an ER20 collet which I am looking to drive with a 2kW RC brushless motor (not shown), again belt driven to give some flexibility on operating speed / torque.

Given the size, I may also consider the 'going vertical' option and have the table upright as I can see good benefits for chip clearance (we have a 2 axis CNC at work which sounds more like a grinder when you don't clear the chips well enough)

The design is about as far as I can take it without more guidance. I am looking to start procuring the hardware shortly so I thought it a good time to get some feedback on what I have so far. All comments gratefully received.

Many thanks,

Paul.