Right,

Been quite a while since I was posting about this but it is still going ahead, albeit "general life" has got in the way as it does with so many projects but I now have a Friend on board so we are splitting the costings 50/50 so we have a realistic budget to work with and hopefully the specs are adding up now. Still got a few questions really.

Here is the current spec:

1200x900 footprint area with approx 1000 x 800 cutting area
80x40x4mm steel box section frame with adjustable bed
Aluminium gantry made from a combination of 20mm/15mm plate either standard 6082 or ecocast for the bearing and guide plates
20mm Profile rail on x,y,z
20/05 on x axis (running 2:1)
16/10 on y axis
16/05 on z axis
250mm cutting depth on z
2.2kw chinese spindle

electronics (just ideas at the moment)

1 x nema 34 7.7nm running 2 x axis ball screws via a timing belt (as suggested by JAZZ) running 20/05 screw on a 2:1 ratio
1 x nema 23 3.1nm running y axis on 16/10 screw
1 x nema 23 3.1nm running y axis on 16/05 screw for better resolution

80v Chinese Drives

80v PSU

Mach 3

Price wise everything has been accounted for in our budget which is great managed to get some really good prices on steel and aluminium. I have a couple of questions which as I know may not be possible to answer without imagery but I thought I would pose them anyway!

The length of the x axis thread is 1200mm would this run with 16/10? or is it better to just stick with the 20/05 to prevent the chance of whipping as I was under the impression thats getting to the limit or even past what it should before it whips?

Running the X off a nema 34 and the y and z off nema 23s, would this pose any sort of problems with setting the machine up? is it better to have 34 all round as I am quite happy to do this as all of the screws are belt driven in some form so adjusting the gear ratio to compensate for slower rpm is not a problem. The machine is still being designed to cut aluminium primarily and then hardwoods

The current weight of the gantry based on calculations of size and weight including aluminium, bolts to assemble, spindle, rails and carraiges, Stepper motors and any other parts that were per the design is in the 65-68kg range.

We are hoping to get started on this in early feb and to have a moving machine by the end of march, thats not a completely finished machine but one that can move, even if we have to push it!