[Saintgp]

Hi Guys

I have been a member of this forum for some time now and loving it. Long Live the CNC Brotherhood.
I’m based in South Africa and have been a Hobbyist CNC machinist for about 15 years now. I have 2 small 3 axis mills and a small 3 axis Plasma table (800mm x 800mm), all running Mach3 with LPT port break out boards. I now I need more, I need to feed this Beast(passion).

I’m planning to build a machine with a cutting area of 1500mm x 1200mm x 300mm to cut aluminum and some steels. The machine needs to be extremely rigid/stiff and have the commercial quality tolerances (fingers crossed). I have done some renderings in fusion and this is what I have come up with.

Specs are as follows (so far):
Y – 1200mm
X – 1500mm
Z – 300mm
Frame Epoxy/Granite/Concrete
Nema 34 1600oz (12nm) closed loop hybrid steppers with 60v psu
RM1605 ball screws
HGR20 Linear Rails
2.2kw Water cooled spindle with VFD, ER20 collet
100mm 4th axis with a 4 jaw chuck

I have purchased all the above items already. Accept the epoxy/granite.

The base and Y-axis uprights are 200mm thick (RED)and hoping to be cast as a sigle piece.
The X-axis gantry is 100mm thick (GREEN)

Advice/Opinions needed:
1> Concrete will be the cheapest and easiest to cast. Will it have the rigidity and with stand the stress loads?
2> What type of Epoxy can be used for the frame? Where in South Africa can I find it at a good price?
3> What speeds can I expect from the motor and ball screw combination?
4> Seeing as the motors are 12nm can it be geared up for more speed? Maybe 2:1
5> Have 3 bearing blocks on each rail. Will it have any rigidity and load bearing benefits?
6> Is having the 4th axis in the y-axis upright a good or bad idea?

All advice and opinions will be highly valued.