How to Calculate the Step Size of Lead Screw Stepper Motor?

Economy linear stepper motor is a stepper motor with lead screw, this stepper motor can be used in many high-precision requirements including precision calibration, precision fluid measurement, and precise positional movement, it can directly move linearly, which can make the machine miniaturized. The step size of the linear stepper motor is determined by the step angle of the motor and the pitch of the internally threaded nut and the lead screw. In order to ensure high working efficiency, there must be a certain degree of freedom between the rotor and the lead screw, which requires a certain gap between the two, which is about 0.03 to 0.08 mm backlash.

Do you know how to calculate the step size of lead screw stepper motor? Today we will show you.

Stepper motor and drive

Step angle

For example:

When teh step angle of the stepper motor is 1.8° (Then every time the stepper motor driver receives a driving pulse, the motor rotates 1.8°)
The stepper motor needs to receive the number of pulse for one revolution: N=360°/1.8°=200

Stepper motor and drive

Pulse /rev set up: The motor rotates once every 400 pulse.

At this time, the rotation angle of each pulse motor is: A=360°/400=0.9°

Lead screw

1. Single thread lead screw and multi thread lead screw.
2. Lead ph calculation method: Ph (Pitch), L (Lead), n (Number of thread)

Single thread lead screw: L=Ph

Multi thread lead screw: L=Ph*n

The movement distance of the nut is L for each revolution of the lead screw.

Example

The stepper driver receives 2550 pulses, what is the moving distance of the nut?

Conditions

1. The lead screw stepper motor needs 400 pulses to make one revolution.
2. The single thread screw, the pitch is 4mm.

Calculation

1. Number of rotations of the lead screw stepper motor: 2550/ 400=6.375
2. Nut movement distance: 6.375*4=25.5mm

PLC data storage area address allocation

• D100 Default start frequency storage area
• D200 Accelerated frequency storage area
• D201 Deceleration frequency storage area
• D202 Target frequency storage area low
• D203 Target frequency storage area high
• D204 Target pulse output number storage area low
• D205 Target pulse output number storage area high
• W0.00 RUN-W000
• W0.01 STOP-W001
• W0.02 Angle confirm-W002

Setting the Stepper motor

• Clear the PLC storage area to be used.
• Move the pulse output frequency to D100.
• Pulse output instruction & interrupt output instruction.

Testing the Stepper motor

• RUN & STOP
• Specify the rotation angle.
• Enter 360 and the motor will rotate 360°. Enter 180 and the motor will rotate 180°.

See more details about the stroke caculating of stepper motor. Please check the video.