How to Choose Stepper Motor for CNC Machine?

How to Choose Stepper Motor for CNC Machine?

When choosing a stepper motor for your CNC machine, you can choose according to the following 7 steps, so as to avoid the trouble caused by improper selection. The details are as follows, for reference only.

Step 1. Selection of stepper motor torque.

The holding torque of a stepper motor is similar to what is called “power” by a conventional motor. Of course, there are essential differences. The physical structure of the stepping motor is completely different from AC and DC motors, and the output power of the motor is variable.

Which type of motor is usually selected according to the required torque (that is, the torque of the object to be driven).

Under normal circumstances, if the torque is below 0.8N.m, choose 20, 28, 35, 39, 42 (the diameter or squareness of the motor body, unit: mm); if the torque is around 1N.m, choose 57 motors. When the torque is several N.m or greater, stepper motors with specifications of 86, 110, 130, etc. should be selected.

Step 2. Selection of stepper motor speed.

Special consideration should also be given to the speed of the motor. Because the output torque of the motor is inversely proportional to the speed. That is to say, at low speed (several hundred revolutions per minute or lower, its output torque is relatively large), the torque at high speed rotation (1000 rpm–9000 rpm) is very small. Of course, some working conditions require high-speed motors, and it is necessary to check the coil resistance, inductance and other indicators of the stepping motor.

To measure. Choose a motor with a slightly smaller inductance, as a high-speed motor, you can get a larger output torque. Conversely, when low speed and high torque are required, it is better to choose an inductance of more than ten or tens of mH, and a larger resistance.

Step 3. Selection of stepping motor no-load starting frequency.

The no-load starting frequency of the stepping motor is usually called “no-load starting frequency”. This is an important indicator for choosing a motor. If it is required to start and stop frequently in an instant, and the speed is around 1000 rpm (or higher), usually “accelerated start” is required.

If direct start is required to achieve high speed operation, it is best to choose a reactive or permanent magnet motor. The “idling frequency” of these motors is relatively high.

Step 4. Phase number selection of the stepper motor.

The selection of the number of phases of the stepper motor, this content, many customers pay little attention to it, and most of them buy it casually. In fact, motors with different phase numbers have different working effects. The more the number of phases, the smaller the step angle can be made, and the vibration during work is relatively

smaller. In most occasions, two-phase motors are used more. In the working environment of high speed and high torque, it is more practical to choose a three-phase stepping motor.

Step 5. Use the environment to select.

Select special stepper motors according to the environment in which the stepper motors are used, which can be waterproof and oil-proof, and can be used in some special occasions. For example, underwater robots need water motors. For special-purpose motors, it is necessary to select them in a targeted manner.

Step 6. Whether special specifications are required according to your actual situation.

For stepping motors with special specifications, please communicate with us, and process and order within the range allowed by technology. For example, the diameter, length, extension direction, etc. of the output shaft.

Step 7. If necessary, it is best to further communicate and confirm the model with the technical engineer of the manufacturer.

If necessary, it is best to communicate further with the technical engineer of the manufacturer, so as to confirm whether the stepper motor you want to choose can meet all the indicators you require.

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