Hi Everyone,
Thanks for the helpful input. I should have provided more details.
We are currently spec'ing this as a new machine to be built. The company is Acctek. I've researched quite a bit about them on here and was pleased with what I found. They have also been good to work with so far, very responsive.
What we are spec'ing (in more detail):
-1100x1800 table, t-slot top
-Full table structure with heavier steel (8mm)
-Taiwan Hiwin rails (25mm)
-Taiwan ball screws on XYZ (25mm on XY, 16mm on Z)
-Taiwan servo motors, 750w on each axis
-Rapids are only 4000mm/min
-3.5kw air cooled spindle
-dust collector
-coolant mist sprayer
-control is mach3 on a separate computer
It will looks something like this machine:
http://www.acctekcnc.com/uploadfile/...0095439723.jpg
After communicating with them more, they have clarified that the gantry on these is cast aluminum. Unfortunately I don't have any better pictures of the internal structure. They have though said that a steel frame gantry using 3mm material (about 1/8") can be done for a small up-charge.
I wonder which would be stronger? My guess would be the steel, but as you point out NIC, it depends on the details of the cast aluminum one.
I don't know what gear reduction there is on the servos. Also there is currently only one ball screw driving the long axis Z. Given the span across is over 1m, does having a ball screw down each side make more sense to reduce twisting forces when cutting near the edges?
Thanks,
-Gord
[Edit] Updated the ball screw size for Z, had originally written it was 25mm.