Anybody hear of this - 3D printers for every FIRST team

[Bald & Bearded]

Originally Posted by techhelpbb

Thanks I like the effort put into the comparison.

I am not sure one actually needs to have dual Z motors as a "critical feature" (page 4) as long as they can achieve the resolution and movement with one: does it really matter?

After all: often times the dual Z stepper motors are in parallel (with respect to a RAMPS 1.4 system for example...not in the general sense of stepper motor windings) and you are actually sending less power to both motors. For something like a Prusa I3 it makes sense because the dual Z lifts the carriage over the width of the printer. In a design like the MakerBot, Duplicator 4, or others of that type the table moves the print in the Z axis of the printer instead of the potentially heavier head assembly. Keeping in mind the head assembly moves in the X from side to side so at any one time the increased weight of the head is on one side of the other of the Prusa I3 design. That issue does not exist in the other design: the prints weigh less and really should not extend over the bed, while the extruder may extend out over the bed surface increasing the leverage of the head weight in the Prusa I3 system.

Good point on the other designs. I should have noted that designs that move the bed vs the X-carraige in the Z would not need dual motors. My main concern was both the weight of the Xcarraige and the resonance/vibration from the unsecured end as the carriage moves.
Rostocks are yet another example where the Z motor does not apply.

The reality is that the overall stability of the entire system is the key. Rod driven versus belt driven systems tend to have better absolute resolution in the X and Y.