Originally Posted by ger21  It's more complicated than that. There is a formula to figure out how much force a screw will deliver when turned with a given torque. I don't have it handy, though.
The higher the lead, the lower the force. A .5mm lead screw will provide 40 times more force than a 20mm lead screw. The problem, is that steppers lose torque as rpm's increase. Full torque is only available when the stepper is NOT turning. As soon as it starts to spin, it's torque starts to drop. At some rpm, you won't have enough torque to move the machine. Usually that would be under 1500 rpm, but it varies with different motors, and with the voltage applied. Higher voltages will give you more top speed. With larger motors, torque usually drops off faster with rpm than with smaller motors. So, a larger motor may actually have less torque at higher rpm's than smaller ones
You need to see a torque curve chart for your motor to see where the torque drops off. You should gear the motor to stay in the higher torque range of the motor.
One other thing, is that you could be getting binding somewhere as the machine warms up. But I think your trying to spin the stepper too fast. |
I think I agree with your last statement here.
So my plan is to gear my current 400Qz stepper 5:1 and then see what I can do and then if necessary upgrade to the 1600Qz.
I'll rerun the last program at half the feed rate to see if the axis stalls again.