boozeroo84:How to prevent the coolant from entering the the stepper motor? Currently the cooloant will enter into the motor through the shaft. Any suggestion?
I'd recommend looking into a sealed step motor, boozeroo84. A motor with an IP65 rating not only protects against dust but should withstand low pressure jets of water sprayed at pressures up to 30 kPa at 12.5 l/min from all directions from a distance of 3 meters. Assuming the coolant isn't spraying directly on the motor, that should suffice. However, you can always explore motors with the higher IP67 rating.
Machine Design Associate Editor