Hi,
steppers losing steps is the never ending hazard of steppers.
All stepper motors lose torque the faster they go, it just plain physics, there is no avoiding it. One of the specifications of a stepper is its
inductance, and the lower its inductance the better. This is because the degradation in torque is least with low inductance motors.
Manufacturers of steppers try to make the highest torque motors, but they also have the highest inductance. First time buyers don't
know about inductance and get trapped with steppers of great torque at low speeds but can scarcely get to 500 rpm.
What is the inductance specs of your motors?
Ideally 23 sized motors would be 1mH-2mH, 1mH preferred and reject anything over 2mH.
17 size steppers should be 1mH-1.5mH.
The classic way to counteract the negative effects of inductance is to use the highest possible voltage drivers you can get.
What is the maximum voltage your drivers can tolerate? What voltage are you actually using?
Craig