Optmizing Build

Hi Guys, I am interested in getting my mpcnc to be a dual printer and cnc cutter. Because of this Im leaning towards the empty center table.

I plan to build a 4x4 feet table with 4.5inch legs. I am looking at values for my Z, is having 12 inch Z rails a bad idea? I am planning to cnc at 4.5 depth, and 3d printing at 300mm (whole print rod) depth. Will I lose stiffness/rigidity with is? Or should I consider shortening it.

Have you seen this page?

At more than 4’ you should be looking at a LowRider CNC, and a stand alone printer.

Hi Ryan,

I understand longer than 4 feet for X and Y is not ideal. I can also go 3.5’. I am talking about have short legs and a longer Z(300M). Would having a longer gauntry be a problem if I compensate the short legs with a open table? This way I can get CNC and tall 3d printing capability.

No, the legs are not really the issue.

Hanging anything off the end of a 12" z axis is going to sway. When you are using it with the bed up real close then you have a steppers swinging around 12" over the gantry, it is a lose lose situation.

Make it for your primary purpose, then try to do a side job or two and just by another machine.

The point of that page was to point out that all functions mix, except 3D printing. All other functions benefit from a short axis. Printers are so cheap now you will easily make up for the price difference in the time you saved by being able to print faster.

Ah, I see what u mean, Since the Z is so long, it will “wobble”. I am guess. Okay, I am fine sticking to 3.5’ x 3.5’ by 4’. Any tall prints, I can do with my normal 3d printer.

It’s totally possible, check my build thread, mine has similar dimensions and it works fine.
Don’t expect to mill anything with a long Z axis though, you will need two different Z axis, one for printing and one for milling, the milling one needs to be as short as possible, the printing one needs to be as light as possible at the bottom, so use a bowden type extruder, with the motor close to the gantry.
And you need a table that you can adjust in height.

Basically that’s what what I’ve done, works pretty good. You can check that here: https://www.v1engineering.com/forum/topic/my-mpcnc-made-in-china/