I would like to use Ball Screws for my Z-Axis, mainly because of less backlash. However, unlike Acme Screws the Ball Screws will evidently let force on the nut turn the screw! (Backdriving).
Question:
So, if you mount a Ball Screw on the Z-Axis won't the weight of the router and other parts cause a continuous motion downwards because of gravity and try to turn the screw? Wouldn't your motor always be having to apply power upwards to counteract that?
From Nook Industries:
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BACKDRIVING
Normally, ball screws are used to
convert rotary motion into linear
motion. Backdriving is the result of
the load pushing axially on the
screw or nut to create rotary motion.
All ball screws, due to their high
efficiency, will backdrive. The
resulting torque is known as
“backdriving torque” and is the
torque required to hold a load
in position.
CAUTION - When using ball screws,
applications should be analyzed to
determine the necessity of a brake,
especially when the possibility of
injury may occur.  |