Application of ES800 in Large Vertical CNC Lathe

详细说明

CNC (Numerical Control Machine Tool) is a computer numerical control machine tool (Computer numerical control machine tool) control), which is an automatic machine tool controlled by a program. The control system can logically process the program specified by the control code or other symbolic instructions, and decode it through the computer, so that the machine tool can perform the specified action, and the rough material can be processed into semi-finished parts by tool cutting. During position control, the CNC sends out pulse train commands, and the inverter travels the distance according to how many pulses it receives. Accurate positioning is achieved so that subsequent processes (drilling, cutting) can be carried out without errors.

The requirements of large CNC lathes for frequency converters

1) The low frequency torque is required to be large

Select vector inverter, low frequency (1 ~ 10Hz)

150% rated torque can be produced.

2) Torque dynamic response speed is fast, and speed stabilization accuracy is high

The selection of vector frequency converter can realize very good dynamic

Response effect, according to the change of load, through the output

The change of output torque responds quickly, so as to realize

Now the shaft speed is stable.

3) Decelerate and stop quickly

Usually, the acceleration and deceleration time of CNC machine tools is more than

Shorter, the acceleration time is guaranteed by the performance of the inverter.

Proof, the deceleration time depends on the external braking resistor

or brake unit.

4) Spindle positioning is accurate

According to the pulse command issued by CNC, it can stop accurately and always enable.

5) Frequency command and running command

The frequency command and running command of the frequency converter used on the CNC lathe come from the CNC controller. Generally, there are two kinds of channels, one is the analog value setting, the other is the multi-stage speed setting, and the analog value is given. Based on the voltage type, the inverter needs to switch from the speed control mode to the position control mode during positioning.

Control requirements

Taking the requirements of a large machine tool factory in Shandong as an example to illustrate, the specific requirements are as follows:

1. The motor parameters provided by the customer are shown in the table.

Number of motors, rated power, rated voltage, rated current, rated frequency, encoder lines, rated speed

1 set 37KW380V72A15HZ1024440

The frequency converter needs to control the start and stop control of the spindle motor, control the position through the pulse train command given by the CNC, and switch between the speed mode and the position mode through the mode selection switch. The control commands given to the inverter are: forward rotation start, reverse rotation start, analog frequency given, and position control pulse train given. The output has commands such as inverter fault alarm and inverter ready.

2. Switch between position control and speed control

3. CNC pulse given output

4. After the position control, the motor is enabled

5. Position control accuracy within 0.01mm

System principle and control implementation

The use of servo motor and rotary encoder to control the spindle motor requires position control and spindle positioning. ES800 inverter is a kind of high-speed motor and electric spindle, variable frequency motor, AC servo motor, various synchronous motors, ordinary asynchronous motors, with torque, speed and position control capabilities. It has good torque and speed control performance to ensure stable mechanical operation, rapid response and small torque ripple. The frequency converter has the following technical characteristics:

A. Starting frequency/starting torque at 0Hz/200%

B. Overload capacity: 150% rated current 60s, 180% rated current 10s, 200% rated current 1s

C. Speed ​​ratio: 1:1000

D. Speed ​​control accuracy: ±0.02% maximum speed, response time <10ms>

E. Built-in C3 filter, stronger anti-interference ability

F, with fixed-length control function

G. Position control accuracy: ±1 pulse

Control realization: The inverter needs to control a servo motor, switch the speed control mode and the position control mode according to the terminal, carry out the speed control according to the analog output from the CNC, run at the fastest 50HZ, and carry out the position control according to the pulse train output by the CNC, The pulse train has direction control, the inverter stops to the set position accurately according to the pulse and enables the motor. After the peripheral brake is locked, proceed to the next process.