Application of Frequency Converter in CNC Machine Tool Spindle

CNC machine tools (NC, NumericalControl), is a comprehensive application of three decades of machine, electrical, hydraulic, pneumatic, microelectronics and information and other skills as one of the mechanical and electrical integration products in the machine manufacturing equipment deployment In the high precision, high obedience, high initiative and high flexibility and other advantages. This article important first easy to drive ED3000 series inverter in the NC machine on the good.

The important parameters of the CNC lathe and the demand for the inverter

Important parameters and performance indicators:

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

           Machine drive ratio: 1: 1.5

           Processing material: 45 # steel

           Realistic test performance indicators: spindle speed: 200r / min (inverter operating frequency of about 15Hz) feed performance and speed

Introduction to CNC machine tools

           The ruggedness of the roughness of CNC machine tools and its percentage of production and total possession of metal cutting machines is one of the important marks that weighs the economic growth of a country and the degree of industrial manufacturing. CNC lathe is one of the important varieties of CNC machine tools, it occupies a very important position in the CNC machine tools, for decades to keep the world's vast country, and has been agile growth. Spindle is an important part of the composition of the lathe, to deal with progressive processing obedience, to expand the scope of processing materials, improve the quality of processing has a very important role. Most of the economic CNC lathes can not take the initiative to speed, the need for speed, the machine can only stop, then the back of the variable speed. The full-function CNC lathe main drive system mostly accept stepless speed change. Continuously variable transmission system is mainly servo-spindle system and DC spindle system two, as usual to accept DC or exchange spindle motor. Through the belt drive to rotate the spindle, or through the belt drive and the reduction gear within the spindle box (to get more torque) to mobilize the spindle rotation. As the spindle motor speed range, but also stepless speed regulation, making the layout of the spindle box is greatly simplified.

2) 5.5kW CNC lathe

           Motor parameters: Rated power: 5.5kW, rated frequency: 50Hz, rated voltage: 380V, rated current: 13A, rated speed: 1400r / min

           Machine drive ratio: 1: 1.5

           Processing material: 45 # steel

           Actual test performance indicators: spindle speed: 200r / min (inverter running frequency 9 ~ 10Hz) and spindle speed: 450r / min (inverter operating frequency of about 22Hz) feed performance and speed

           ED3000 series inverter

           ED3000 series inverter to accept the advanced magnetic flux control technology, the motor at low speed torque, high rate of precision, fair price, the effect is complete, with instantaneous power failure handling and rate tracking and restart the effect, to ensure that the system to achieve a continuous operation mechanism to ensure Motor running in the highest state of compliance, therefore, accept the ED3000 high-performance inverter instead of the spindle exchange servo system, the machine tool industry is the best choice.

           1), ED3000 frequency changer characteristic introduction

           Small size, belonging to the mini-products, occupy the control cabinet space is small;

           Control method for the sine wave SPWM, control performance than the previous VF control method has a great improvement on the performance, especially in the low-speed torque on the machine tool spindle needs, 5HZ when the starting torque can reach more than 100%

           Carrier frequency range 0 ~ 16KHz, reduce the motor electromagnetic noise;

           To provide the scale of 0 ~ 10V imitation of the interface, can be probably compatible with most of the NC system interface, versatility;

           Overloaded strength, more than 150% rated output current over one minute;

           Provide a multi-function output terminal signal, such as a very signal, running signal, the rate of arrival signal, hinder instructions, satisfied with the system to deal with the spindle speed state monitoring;

           Active torque compensation, satisfied with the machine tool spindle in the low-speed environment processing needs;

           2), debugging environment and wiring, debugging methods

           Customers optional motor for the 3.0KW / 50Hz / 380V, select the inverter model AMB-ED3000-3R7-T3B, braking resistance of 400 watts / 150 ohms.

           The AI1 / GND terminal of the frequency converter is provided with the analog quantity of the numerical control system. The AI1 receives the digital signal from the digital control system. The signal is 0 ~ 10V imitates the voltage signal and controls the spindle speed. FWD / REV / COM is the forward / reverse signal terminal of the inverter. Normally, the forward signal is usually transmitted by the NC system to drive the center relay. The normally open contact of the center relay is connected to the inverter FWD / REV / COM , Thus controlling the inverter inversion. The parameters are set as follows:

           1) F005 and F006 to speed up the time and deceleration time, according to customer requirements, F001 = 5S, F002 = 1S;

           2) F030 and F031 are set according to the motor nameplate, F010 = 9A, F031 = 1;

           3) F012 upper limit manipulation frequency selection, corresponding to the analog signal 10V input frequency converter output frequency, because it is in the range of 0 ~ 2000rpm speed, the machine reduction ratio after this count, this parameter must be set to 66.7Hz;

           4) F002 parameters for the operation of the signal and frequency source settings, set to external terminal signal control (3);

           5), debugging effect

           Spindle motor to accept ED3000 high-performance inverter drive, satisfactory processing requirements, extend the life of the tool. Due to the acceptance of the leading flux algorithm, even in the low speed (low frequency) operation can also be stable output 100% of the torque to meet the different parts of the processing needs, can replace the traditional rotating bearing spindle layout, and this spindle layout Simple, compact, you can achieve the real stepless speed. The speed of the spindle by the external imitation of the signal to control the output frequency, the difference in the processing of other processes (such as; roughing, finishing, etc.) necessary to the other speed, this time by the NC system output difference to imitate the amount of voltage signal to the inverter, To achieve another speed, while the start and stop signal is also controlled by the NC system, the degree of progress in the initiative!

           CNC machine tool spindle is usually the same as the exchange of servo system, the entrance brand vector control inverter and inverter special motor, the purchase cost is very high; easy to drive ED3000 series inverter with its unique performance and good cost, in the application of CNC machine tools on the rise , For the machine tool industry customers about twice the cost of the cost, and high reliability, for customers to create more benefits.