Quote Originally Posted by NewMatter View Post
4. What is the printer displacement? - Possibly as a ratio, to the build volume, because the printing area seems super tiny, compares to the printer?

The print area is 150 x 100mm. With this design, by necessity, the footprint of the printer must be at least 2x the X and Y print dimensions. For a large print area, this becomes problematic, but for a smaller print area printer, this is manageable. For instance, the MOD-t is has only a 16% bigger footprint than the Makerbot Mini, but it has a 50% bigger build area.

5. It seems like the axises are controlled via servos, rather than steppers, which kind of position feedback is used? - hall sensors? - Also why did you go with servos?

The reason for using servos is that you never skip steps. Even if your motion profile exceeds the capabilities of the motors, you may get larger positioning errors, but you will never lose track of where you are altogether like with steppers. And the servos use high resolution optical encoders for position feedback.

6. The two z-axis smooth rods, seems to be positioned very closely, why is this? - In terms of stability, wouldn't it make more sense to separate them?

The smooth rods in the earlier prototypes were close together for minimizing the dimensions of the Z-axis carriage. They will be a little wider in the production units. If you get them too far apart, you run the risk of the entire Z carriage cocking. Also note that because you don't have the dynamic loads of an extruder moving back & forth on the Z carriage, the Z-axis structure does not have to be nearly as stiff as with a conventional printer design.
To be fair, I was indeed inspecting a picture of an earlier prototype, when I made a comment on the distance of the z-axis smooth rods. It seems fine on the actual release candidate.

Quote Originally Posted by NewMatter View Post
7. I imagine the printer being very sensitive to vibrations, alike, as the bed is only held down by gravity. Have you done any research in terms of how much vibration the printer can handle before skipping steps and thereby ruining prints? - I would hope it's able to handle a kid bumping into the table, while printing?

As mentioned above, it is actually quite difficult to dislodge the build platform. Whacking the printer with a hammer might do the trick, but a kid bumping into the table it sits on it won't be a problem (unless he knocks it over altogether!).
Again a place, where you'd want a heavy table, but assuming you found a good tradeoff, then that's nice. - How about moving the printer during operation, will this be possible?