Stepper Motor Holding Force
Hello,
I have a desktop CNC engraving machine equipped with a NEMA 17 stepper motor. I've set the controller to approximately 1.5 amps, and it's currently working fine. My engraving machine uses a rotary grinder on the Z-axis. The problem is that the motor's holding force seems insufficient; the grinder frequently falls to the bottom of the axis.
My question is, should I increase the stepper motor current? Perhaps this would hold the grinder in the correct position? I'm using a Geko 201 motor, so I can adjust the current slightly. The voltage is 32 volts, and the motor itself isn't very hot.
Alternatively, should I replace the Z-axis stepper motor with a NEMA 23 motor to increase the current and thus enhance the holding force, preventing the grinder from suddenly falling?
RE:
Both countermeasures could work. But before you embark on one of them, please elaborate a bit on what your starting point is. Under which circumstances does the Z drive sag -- during operation? In standby? Also, what is the Z drive mechanism -- belt drive (with what pulley diameter) or lead screw?
NEMA17 motors with that current should have holding torques of a few 10s of N*cm. Hence they should be able to hold a few kg even with a belt & pulley drive if the pulley is small. I am wondering whether the controller reduces the current in holding mode, maybe after a timeout? I would also expect the motor to run quite hot if you actually supply a continuous 32V * 1.5A to it, which apparently it does not?