Digital control machine tools, abbreviated as numerical control machine tools (NC, Numerical Control), are integrated electromechanical products integrating mechanical, electrical, hydraulic, pneumatic, microelectronics, and information technologies for more than 30 years. They are used in machinery manufacturing equipment. High precision, high efficiency, high automation and high flexibility. This article mainly introduces the advantages of easy-drive ED3000 series inverters on CNC machine tools.
Introduction to CNC Machine Tool The level of technical level of CNC machine tools and their percentages in the output and total ownership of metal cutting machine tools are an important indicator of a country’s national economic development and the overall level of industrial manufacturing. CNC lathe is one of the main varieties of CNC machine tools, and it occupies a very important position in CNC machine tools. It has been receiving widespread attention from countries all over the world for decades and has been rapidly developed. The spindle is an important part of the lathe composition. It plays an important role in improving the processing efficiency, expanding the range of processing materials, and improving the processing quality. Most economical CNC lathes cannot automatically shift gears. When a speed change is required, the machine can only be stopped and then manually shifted. The main drive system of full-function CNC lathes is mostly continuously variable. The continuously variable transmission system mainly includes two types, a servo spindle system and a DC spindle system. A DC or AC spindle motor is generally used. Drive the spindle through the belt drive, or drive the spindle through the belt drive and the reduction gear in the spindle box (for greater torque). Due to the wide speed range of the spindle motor and stepless speed regulation, the structure of the spindle box is greatly simplified.
The main parameters of the CNC lathe and the main parameters and performance indicators for the inverter function requirements:
1) 3.0kW CNC lathe motor parameters: Rated power: 3.0kW, rated frequency: 50Hz, rated voltage: 380V, rated current: 7.8A, rated speed: 970r/min
Mechanical transmission ratio: 1:1.5
Processing Material: 45# Steel Actual Test Performance Index: Spindle Speed: 200r/min (inverter running frequency about 15Hz) Feeding Performance and Speed 2) 5.5kW CNC Lathe Motor Parameters: Rated Power: 5.5kW, Rated Frequency: 50Hz , Rated voltage: 380V, Rated current: 13A, Rated speed: 1400r/min
Mechanical transmission ratio: 1:1.5
Processing material: 45# steel actual test performance index: Spindle speed: 200r/min (inverter operating frequency 9 ~ 10Hz) and spindle speed: 450r/min (inverter operating frequency of about 22Hz) Feeding performance and speed ED3000 series frequency conversion The ED3000 series inverter adopts advanced magnetic flux control technology. The motor has large torque at low speed, high speed accuracy, reasonable price and complete functions. It has the functions of instantaneous power-off processing and speed tracking and restart to ensure that the system realizes continuous operation mechanism to ensure The motor operates at the highest efficiency. Therefore, replacing the spindle AC servo system with the ED3000 high-performance inverter is the best choice for the machine tool industry.
1) The features of the ED3000 inverter are small in size and belong to the mini type product, occupying less space in the control cabinet;
The control method is sine wave SPWM, and the control performance has great performance improvement over the previous VF control method, especially in the low speed torque to meet the requirements of the machine tool spindle, the starting torque can reach more than 100% at 5HZ;
Carrier frequency range 0 ~ 16KHz, reduce the electromagnetic noise of the motor;
Provides a standard 0 to 10V analog interface that is compatible with most CNC system interfaces and has high versatility;
Strong overload capacity, over 150% rated output current exceeds one minute;
Provide multi-functional output terminal signals, such as abnormal signals, running signals, speed arrival signals, fault indications, to meet the system's monitoring of the spindle speed status;
Automatic torque compensation to meet the machining requirements of the machine spindle at low speeds;
2), debugging environment and wiring, debugging methods Customers choose the motor is 3.0KW/50Hz/380V, use the inverter model AMB-ED3000-3R7-T3B, braking resistor 400 watts / 150 ohms.
The AI1/GND terminal of the inverter provides the analog quantity with the numerical control system speed, AI1 is connected with the positive analog signal of the numerical control system interface, GND is connected with the negative signal, the signal is the 0~10V analog voltage signal, and the spindle speed is controlled. FWD/REV/COM is the forward/reverse signal terminal of the inverter. Normally, the forward or reverse signal is sent from the CNC to drive the intermediate relay. The normally open contact of the intermediate relay is connected to the inverter FWD/REV/COM. , to control the frequency converter forward and reverse. The parameter settings are as follows:
1) F005 and F006 are acceleration and deceleration time. According to customer's requirements, F001=5S, F002=1S;
2) F030 and F031 are set according to the motor nameplate, F010=9A, F031=1;
3) F012 upper limit operating frequency selection, corresponding to the output frequency of the inverter when the analog signal is input at 10V, since the speed is within the range of 0-2000rpm, after the mechanical reduction ratio is counted in, this parameter needs to be set to 66. 7Hz;
4) F002 parameters for the operation signal and frequency source settings, set to external terminal signal control (3);
5). Debugging results The spindle motor is driven by ED3000 high-performance inverter to meet the processing requirements and prolong the service life of the tool. Due to the leading flux algorithm, it can evenly output 100% torque even at low speed (low frequency) operation to meet the machining needs of different parts, and can completely replace the traditional rolling bearing spindle structure, and the spindle structure is simple. It is compact and can realize true stepless speed regulation. The speed of this spindle is controlled by an external analog signal to control the output frequency. Different machining processes (such as roughing, finishing, etc.) require different speeds. At this time, the digital control system can output different analog voltage signals to the inverter. The realization of different speeds, at the same time start and stop signals are also controlled by the numerical control system, improve the degree of automation!
CNC machine tool spindle general AC servo system, imported brand vector control inverter and frequency conversion special motor, high purchase cost; easy to drive ED3000 series inverter with its unique performance and superior cost performance, the rapid rise in the application of CNC machine tools, Customers in the machine tool industry have reduced their cost by about one-time, and they have high reliability and create more benefits for customers.
