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The torque of a stepper driver is not linear over the number of revolutions per second. It is nearly linear in the beginning but drops down at a specific point for each motor until it reaches zero.
 
The torque of a stepper driver is not linear over the number of revolutions per second. It is nearly linear in the beginning but drops down at a specific point for each motor until it reaches zero.
In our current setup we use Sanyo Denki 103h7126-0740 Motors, which are linear until about 1000 to 2000 steps/second. We are using 8 Microsteps, so the normal 200 steps per revolution (1.8 Degree step size) must be multiplied by 8, which gives 1600 steps per revolution.
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In our current setup we use Sanyo Denki 103h7126-0740 Motors, which are linear until about 1000 to 2000 pulses/second. We are using 8 Microsteps, so the normal 200 steps per revolution (1.8 Degree step size) must be multiplied by 8, which gives 1600 steps per revolution.
Now we can calculate the maximum speed for a axis by taking the steps needed per mm (266,6 on our machine) and divide it by the maximum steps per second we can do: 1600 [st/s] / 266,6 [st/mm] ~ 6mm/s with maximum torque.
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Now we can calculate the maximum speed for a axis by taking the maximum pulses/second and divide it by the steps needed per mm (266,6 on our machine):
We can of course run much quicker (for example for G0 commands) but then the mill should not be in action!
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<math>2000 pulses/s * 8 pulses/step / 266 steps/mm = 60 mm/s = 3600 mm/min</math>
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We need the factor 8 here because of the microstepping.
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This aspect of a stepper motor means also: lower microstep setting allows higher speed and vice versa.
 
This aspect of a stepper motor means also: lower microstep setting allows higher speed and vice versa.

Version vom 8. Januar 2015, 18:56 Uhr

This page descibes technical aspects of the CNC machine in more detail.

Stepper Torque

The torque of a stepper driver is not linear over the number of revolutions per second. It is nearly linear in the beginning but drops down at a specific point for each motor until it reaches zero. In our current setup we use Sanyo Denki 103h7126-0740 Motors, which are linear until about 1000 to 2000 pulses/second. We are using 8 Microsteps, so the normal 200 steps per revolution (1.8 Degree step size) must be multiplied by 8, which gives 1600 steps per revolution. Now we can calculate the maximum speed for a axis by taking the maximum pulses/second and divide it by the steps needed per mm (266,6 on our machine): We need the factor 8 here because of the microstepping.

This aspect of a stepper motor means also: lower microstep setting allows higher speed and vice versa.