Rod diameter on x gantry ?

Hello there,
I'm building my first 3d printer with aluminum square tubes for the frame
Steel rods with linear bearing for the mechanics
I want it also to be able to mill foam and maybe mdf wood
For the x gantry , should I use 12 mm steel rods with 12mm bearing blocks (is it enough for milling or do I need a larger diameter)
or will this be heavy(with spindle weight is 1kg) on the z axis motor (will be using dual nema 23 4.7 v , 1.5 amp with ramps 1.4 board)

Edited 1 time(s). Last edit at 12/08/2017 02:36PM by Drstation.

N.B My machine working area will be x 300 mm
Y 250mm
Z 250mm
The x gantry rods will be 50 cm 12mm (should I decrease it to ensure successful milling of wood or increse its diameter to maybe 16mm)
Y is 60 cm 10 mm rods
Z is 42 cm 100 mm rods
Do I need any change in diameter of length of y and z axes also?

My first 3D printer build had 1/2" diameter guide rails and I didn't think they were rigid enough for 3D printing. I would never try to mill anything like MDF with them.

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

So changing x rods to 16 mm
Y rods to 12mm
Z to 12mm will be a better option?

Edited 1 time(s). Last edit at 12/08/2017 09:19PM by Drstation.

Fully supported linear guides are the best option, but if that's not possible, big, fat round guide rails. The mass is going to make printing slow. That's why there aren't many mill/printer machines around. In order to make a good mill, you have to make a slow 3D printer.

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

If you want rigidity try using aluminium extrusions with v wheels. Linear rails aren't particularly stiff themselves, they get their stiffness from whatever you bolt them onto, which is usually aluminium extrusions. You could also use your square tubing but the tolerances on that for straightness can be quite low.

For milling and routing, even 8mm rods that are standard can be used, you just need to adjust your expectations regarding what feeds and speeds you'll be using.

Doesnt one of the best selling printers use 8mm rods I'm yet to try milling with 12mm rods, but only on the Z or router plunger, will most probably find out your right but it's worth trying as I have nothing thicker but my head.

Edited 1 time(s). Last edit at 12/17/2017 11:48AM by MechaBits.