Comment on me 3d printer/ cnc (body/frame)design ?

Hey I've designed a body/ frame for a 3d printer/ CNC I'm thinking about building.
I'm using this design because I already have the materials ( and most of the electronics like motors and drivers too).

Note: I've designed it so that the drawer slides (on X and Y axis, NOT Z axis) are pointing the opposite way, so that the axis is never just "hovering" when the drawer slide is at it's outer postion (look at the pictures, hope it makes sence)

please come with some comments / inputs thanks :)

btw. sorry for the amateur like design/ drawing I just needed a quick draft so I made it in Google SketchUp, I didn't want to use the time on designing it Autodesk Inventor

Comments

[frollard]

The cheaper the components you use for the bearing surfaces the worse slop there will be. Drawer slides in particular will result in garbage prints when .01mm tolerances on your print are required.

It's a decent gantry system but don't expect a lot from drawer slides.

[lordl9999]

I don't expect that much accuracy from the drawer slides and if it's too bad and I'm unsatisfied the drawer slides is easy accessable in this design, and therefore should be easy to change to another guide system (like rods and linear ball bearrings) if "needed" :)

[lordl9999]

...and the table will be "mounted"/ connected to the feedscrew with a nut mounted (somehow) on a bracket and on the table. Just like a regular ballscrew system, except that I'll be using more or less a regular nut.

[frollard]

which again, will work, and a leadscrew is way more accurate than a belt, but the slop will reduce your precision considerably.

[steveastrouk]

Yet on my big-ass CNC mill and lathe, the DC drives are coupled in via belts - and certainly on the lathe, the feedback appears to be on encoders on the motor. There is VERY little stretch in MTD belts.

[bwrussell]

How are you interfacing with the feed screws?

[lordl9999]

I will build some kind of bracket and use a flexible coupler to connect the stepper motors to the feedscrews... if that's what your asking?

[bwrussell]

I was talking about attaching the screws to the table and gantry but you answered that above/below.

Is the step down to where the table sits necessary? It will reduce the print area in that direction because the table will hit the frame before it reaches the end of the screw.