Higher step counts do not automatically mean better accuracy or more torque.

A common misconception is that stepmotors offer improved accuracy and better torque. This article discusses important factors that will help machine designers get the best possible accuracy with stepmotors. The step angle is critical in determining how the step motor will function. Half stepping can cause unexpected issues. For example, if a 1.8-degree motor was purchased but it is operated in half-step mode to achieve a 0.9-degree rotation, it will be less accurate than a motor with a 0.9-degree full step. Some designers may try to use the 1.8-degree motor to save on cost, but they will sacrifice accuracy. High torque stiffness also tends to have higher accuracy. This is because the motor’s inertia could cause the rotor to stop out of position. Adding more teeth in the stepmotor will lead to higher torque stiffness, which explains why a 0.9-degree motor has more accuracy than the 1.8-degree version. Variations of the air gaps between rotor and stator poles will also has an affect on stepmotor accuracy, operating speed range, and ability to produce torque. Stepmotors can be found in pick and place systems, medical devices, and other positioning systems.  Read the full article at Machine Design.

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