DIY CNC Milling Machine From Scratch

[Jonathan]

Good start - almost getting jealous!

A few general observations...

Have you seen the BT30 ATC spindles on Aliexpress? If you're happy with 6000rpm then they're not excessively expensive:
http://www.aliexpress.com/wholesale?...initiative_id=

PSU - why no decision? A toroidal transformer of around 500VA would be ideal.

What is the mass of the Z-axis (head, spindle etc) and what are the dimensions of the Z-axis ballscrew? I've made a script to calculate it more accurately, so if you post that information we can make sure the motor you've chosen is the best option. I suspect you may be OK with one of the 3-4Nm Nema 24 motors. The gas strut makes surprisingly little difference if you try to get a reasonable acceleration...

Correct me if I'm wrong, but it looks like you're leaving the back of the Z column open, so it's a C-shape section not a box? If so then you should defiantly put another plate on the back, as the torsional stiffness of a C-section is very low compared to a box. That's one of the big advantages of putting the ballscrew on the front of the column, not inside - you can have a closed section.

[Lee Roberts]

Good start - almost getting jealous!

Correct me if I'm wrong, but it looks like you're leaving the back of the Z column open, so it's a C-shape section not a box? If so then you should defiantly put another plate on the back, as the torsional stiffness of a C-section is very low compared to a box. That's one of the big advantages of putting the ballscrew on the front of the column, not inside - you can have a closed section.

Dito!, Jonathan if he was to close the back up and opt for a box, would it be of worth while benefit to also add some ribs inside the box, I was thinking towards cantilever, an X in a square, the through sections on each plate would also allow then for the filling of the column?

I have a nice solid slab of aluminium as shown in the drawing, about 500mm x700mm by 76mm thick so i hope this will be solid enough.

I was going to fit some of the electronics into the colomn but i am now going to make a stand to house the spindle cooler, electronics, pc and coolant pump, so will probably think about filling the column with something after the z stepper and y stepper is mounted so i know where to fill.

Trouble is the cost keeps mounting up :( best not to take note and hide the reciepts from the missus hahah

Sounds like it would be.

I think its fair to say that making it a box and filling it would be of more benefit to the machine.

Hehe, what's new .

.Me