The classical numerical control system multi-coordinate interpolation method can realize to the hole automatic processing. Although the use of NC in the processing of non-circular hole can meet the machining accuracy requirements, but its processing efficiency is low, high cost, processing large quantities of mechanical products, such as piston shaped hole, will reflect its processing economy is poor Disadvantages. As we all know, boring machine processing efficiency and machining accuracy in the machining of machine tools is relatively high, so you can design the boring machine to achieve the special-shaped hole processing.
GMM can convert electromagnetic energy into mechanical energy or wind energy, but also can convert mechanical energy into electromagnetic energy, which is an important energy conversion material. GMM has the advantages of large strain, high energy density, large electromechanical coupling coefficient, fast response and large output force, which makes it show a broad application prospect in the research field of micro-actuator for boring machine.
2. GMM profile
Ferromagnetic materials and ferrimagnetic materials as a result of changes in the state of magnetization, its length and volume will have minor changes, a phenomenon known as magnetostriction. This phenomenon was first discovered by physicist Joule. Later, it was found that magnetite and magnetostrictive effects of nickel, cobalt, iron and their alloys were observed. The material with this effect is called GMM. At present, GMM materials are the most widely used ones, represented by rare earth-iron, rare earth-iron and iron-gallium. Magnetostrictive phenomena have three manifestations: ① along the direction of the size of the external magnetic field relative change, known as the longitudinal magnetostrictive: ② perpendicular to the direction of the external magnetic field size changes in size, known as transverse magnetostrictive: ③ material size The relative change, known as the volume magnetostriction. Magnetostrictive magnetic field before the length of 10, the length of the magnetic field along the H direction increases △ 1.
3. based on the GMM boring rod Arbor magnetostrictive actuator research
The numerical control system of the boring machine calculates the position of the radial offset during machining according to the shape of the special shaped hole to be machined, determines the elongation of the magnetostrictive actuator according to the mechanical actuator, and obtains the excitation magnetic field according to the GMM strain- Size; Finally, the magnetic field deduced the size of the excitation current. The control of the radial position of the tool during the machining process is controlled by controlling the size of the excitation current.
Magnetostrictive actuator structure principle, the excitation coil in the access to a certain current generated after the corresponding magnetic field, GMM in the drive magnetic field generated by telescopic changes, magnetostrictive rod telescopic movement, resulting in strain and stress, the macroscopic performance For the displacement and force output, in order to achieve the conversion of electromagnetic energy to mechanical energy. Then through the mechanical device to achieve the radial position of the tool changes in the hole, in order to achieve special-shaped hole processing.
Giant magnetostrictive micro-displacement actuator feeding up to sub-micron precision, precision and ultra-precision machining for the improvement of automatic control technology to improve product accuracy and speed of response is a generation of products; and boring machine in the process of processing The processing efficiency, low cost, widely used. Therefore, the structural design of GMM for boring machine will undoubtedly be the biggest innovation and its industrial prospect is broad.
Giant magnetostrictive actuator compared with the traditional actuator has the following advantages; telescopic stroke large:
Fast response: less than 1μs; high compressive strength: more than 700MPa; low operating voltage: a few volts to dozens of volts; high reliability: no fatigue aging.
Giant magnetostrictive actuator applications can not be separated from the drive power. The static and dynamic performance of actuators is largely dependent on the performance of the drive power supply. According to the characteristics of GMM drive magnetic circuit, the drive power has the following characteristics: good stability and linearity, high frequency response, constant current source to take digital control of the structure. Usually can be high stability, the circuit is simple and reliable continuous adjustment constant current source as the giant magnetostrictive micro-displacement actuator driven magnetic field controllable constant current source part. The system uses a single closed loop negative feedback PID (proportional, integral, derivative) algorithm control, shorten the rise time, reduce overshoot, reducing the output current deviation. The actuator's feed accuracy can be achieved.
The power of the drive power can be transferred to the field coil via a high-speed mercury slip ring, which solves the power supply problem.
4. the conclusion
The research project leads not only to the application of GMM materials, but also to the numerical interpolation algorithm, interface technology, automatic control technology and power circuit technology if it is to be applied in the industry. The successful development of products will bring special-shaped hole processing spring.
Article from NdFeB Industry Network