Quote Originally Posted by Yaser View Post
[/B]By the way, the Y-Axis and Z-Axis will act as a single unit.
Think you better explain this one because you got me head scratching.?

Z axis design wants to be strong and uncomplicated. Short as possible with good bearing spacing. Widest foot print as possible on the rear plate where it meets the connecting axis which in your case I've no clue what your meaning. . Lol
Don't use thin flimsy plates.

For ease of building and setup then you don't need a bottom bearing on the ballscrew if screw not too long.(upto 350mm) Optional if you connect motor to screw with a timing belt but doing so is better for resonance reasons and gives option of a ratio if required.

Usually stronger if rails are placed on the front plate, thou dependant on travel amount not always the case.

Draw it up and let us take a look. Pics of what you have so far will help also.