Views: 16 Author: Site Editor Publish Time: 2023-07-14 Origin: Site
A stepper motor is a digitally controlled motor that receives a control pulse signal and rotates a certain angle accordingly. In practical application, the stepping motor and the controller are an inseparable whole. The control pulse signal generated by microcontrollers such as single-chip microcomputer and DSP is a weak current signal, which can only be applied to the winding of the motor after the power of the driving circuit is amplified. Power on in a certain order. As long as the windings of each phase are energized in turn in a predetermined order, the stepper motor can produce the required stepping motion.
Because of its high resolution in open-loop control, stepper motors are widely used in CNC machinery as the core of economical CNC machine tools. After long-term development, stepper motors have been applied in many fields of digital control. As control motors or drive motors, there are many application examples in the fields of office automation equipment, computer peripherals and industrial machinery. In recent years, the rapid development of microelectronics technology, high-power power electronic devices and drive technology has further promoted the development of stepper motors.
The stator of the reactive stepper motor is made of silicon steel sheets, and the opposite two magnetic poles are wound with the same winding with different winding directions. When energized, a pair of N and S poles are formed, and there is no winding in the motor rotor. The rotor of the motor is made of soft magnetic material. There are many small teeth with the same size and the same spacing on the outer surface of the rotor pole and the inner surface of the stator pole. Electromagnetic force is the driving force for the reactive stepper motor to move. Under the action of electromagnetic force, the rotor will move to the position of maximum magnetic permeability (or minimum magnetic resistance) and be in a balanced state.
The material of the rotor of the permanent magnet stepper motor is permanent magnetism, the number of poles of the rotor and the stator is the same, the output torque of the motor is large, and the step angle is relatively large, but the working performance is good.
The structure of the hybrid stepper motor stator is the same as that of the reactive stepper motor. The rotor is divided into two sections in the axial direction. The same number and size of small teeth are evenly distributed in the circumferential direction of the iron core of the two sections, but they are misplaced by half the tooth pitch. A permanent magnet is embedded in the middle of the two iron cores, so that the iron core at one end of the rotor is N pole and the iron core at the other end is S pole, as shown in Figure 1.1. The N and S polarities of the rotor remain unchanged, and the sequential change of the N and S polarities of the stator magnetic poles is realized by controlling the stator winding current, and a corresponding force is generated on the N and S poles of the rotor to push the rotor to rotate as required. Because the permanent magnetic field of the rotor of the hybrid stepper motor also generates part of the torque, it is larger than the torque generated by the stator magnetic field of the reactive stepper motor.
Picking a stepper motor for CNC is about understanding your torque and RPM (speed) requirements.
The best stepper motor will be capable of delivering your required torque while also being fast enough.I tell you my best picks depending on the category of the stepper motor:
CNC stands for “computer numerical control.” These machines represent a manufacturing process used to control a wide range of complex tasks.CNC machining is used in many different industries. It’s most prevalent in metal and plastic production.Basically, CNC machining is a manufacturing process. Computer software is pre-programmed to tell a machine how to move factory tools and machinery.A CNC machine allows for three-dimensional cutting tasks to be accomplished with a single set of prompts. This means that it requires very little input from human operators.Once the programming is put into the machine, a CNC machine will operate on its own. The speed and position of machinery and involved tools are run through software. CNC machines operate like robots.
Stepper Motor for CNC
Stepper motors are widely used in various fields of production practice. Its biggest application is in the manufacture of CNC machine tools, because stepper motors do not require A/D conversion and can directly convert digital pulse signals into angular displacements, so they are considered ideal executive components for CNC machine tools. The output torque of the early stepper motors was relatively small, which could not meet the needs. In use, it was used together with the hydraulic torque amplifier to form a hydraulic pulse motor. With the development of stepping motor technology, stepping motors have been able to be used alone in the system and have become irreplaceable actuators. For example, the stepper motor is used as the drive motor of the feed servo mechanism of the CNC milling machine. In this application, the stepper motor can complete two tasks at the same time, one is to transmit torque, and the other is to transmit information. The stepper motor can also be used as the drive motor for the synchronous system of the CNC worm wheel grinding machine. In addition to the application on CNC machine tools, stepper motors can also be used in other machinery, such as motors in automatic feeders, motors in general-purpose floppy disk drives, and printers and plotters.
