To recap the setup so far, there are 55 oz-in
motors on all axii. I run X and Y with a rapid
of 15 ipm, Z set slightly slower. When the mill
is adjusted and lubricated properly, it will reliably
travel faster. However, 15 ipm is a conservative
setting to allow for a 'safety margin'.
X and Y share a 24V power supply, Z has two supplies
for a total of 41 volts (the maximum for the Allegro
SLA7042 driver IC is 46V).
Driver for all three axii is a microstepping,
chopping unipolar-style (not to be confused
with those cheap 4-transistor unipolar drivers).
For some Z-axis experimentation, I got a Gecko
G201 bipolar driver, a 48V switching supply, and
a low-inductance 3A Vexta motor.
The motor is small, about the same size as the
55 oz-in motor, but square instead of round.
After removing the handleweel (it was making the
whole mill shake), I was able to achive 60 ipm
rapid on Z! Yes, 1200 rpm. Very fast!
And there was still some torque at that speed.
I couldn't stall the motor by pressing down on
the headstock as it was rising.
If I keep this on Z, I will probably limit it
to 28-30 ipm, both to have a safety margin, and
also so the mill doesn't shake itself apart.
|