The Application of Frank FRB6000 Series Frequency Converter in the Spindle of CNC Machine Tools
May 15, 2023
In recent years, with the rapid development of the economy, the machine tool industry has also witnessed rapid development: it is reflected in the extensive application of new technologies and the significant improvement in corporate profits. At present, the mainstream of machine tool industry consumption is CNC machine tools. From the perspective of the demand for CNC machine tools at home and abroad, the CNC machine tool market has the following features: First, economical CNC machine tools are the mainstream products in the future. Second, adopting new technologies, reducing costs, and improving product stability are the key to business survival. Below we take the Francois frequency converter in the Jinan Yudong Machine Tool Factory for example:
First, the main machine spindle drive characteristics:
Under normal circumstances, the drive system of the machine tool is driven by the motor to drive and speed the gear box. It has the following features:
1. The original system
A load - constant power nature When a gearbox is changing speed, the change in torque is inversely proportional to the change in speed. If the loss of the gearbox is not taken into account, it has constant power characteristics in the full power range.
1) Speed grade The speed regulation box has 8 speeds: 75, 120, 200, 300, 800, 1200, 1500, 2000r/min.
2) Motor's main rated parameters Rated capacity: 7.5kw Rated speed: 1440r/min Load characteristics: Constant power
3) Control mode The combination of the four clutches is controlled by the eight positions of the handle combination, and 8 combinations of gears are obtained to obtain the 8th speed.
B. When the overload capacity at low speed is strong and low speed, the rated torque of the drive system after gear speed reduction by the gear box will be much larger than the maximum working torque of the load, and there is a strong overload capacity.
Second, the basic considerations when using frequency converter speed regulation:
1. The adjustment range of frequency conversion speed regulation is very wide, general general-purpose frequency converter can realize stepless speed regulation in the range of 0-400HZ.
2. Considering that the machine tool requires hard mechanical properties. In line with the inverter + ordinary motor (or variable frequency motor) transmission has a hard mechanical characteristics. Can generally provide 150% load torque at low frequencies
3. Consider that the machine tool needs a powerful overload capability at low speeds. The inverter can provide 150% overload protection (60S) to meet the requirements of the equipment.
4, after the use of frequency control, can simplify the original gear transmission and other complex mechanical drag mechanism, a high degree of automation, simple operation and easy maintenance.
5, the inverter has a voltage (DC0-10V), current analog input interface, can be a good match with the control signal of the CNC system.
Third, the specific application of Franck frequency converter in the industry.
1. After the transformation of the system structure:
A In this system, the inverter adopts external terminal control. The DC0-10V signal sent from the CNC system is sent to the inverter through the inverter's control terminal to realize the digital variable speed control of the analog frequency output. The speed of the motor is controlled by the magnitude of the voltage signal output from the digital control system.
B The forward and reverse running of the motor is controlled by the FWD, REV and CM terminals of the inverter.
C Various protection signals are controlled by the normally open contacts of the inverter, which can realize over-current, over-voltage, overload, overheat, negative pressure, and missing equal protection.
2 related parameter settings:
According to the requirements of numerical control system and machine tool design, the setting of appropriate parameters can improve the original product performance:
3 Comparison with the original performance after the transformation Machine speed range: 0--400HZ adjustable (Most machine tools work under 3000 revolutions)
Acceleration and deceleration time: 0.1 - 30S adjustable processing speed: 100-3000r Continuously controllable protection function: perfect, and fault display overload capacity: 100% - 180% adjustable
4. The actual use of the customer's effect: In the actual processing speed, after repeated testing, fully meet the design requirements, and achieved satisfactory results.
5. Possible Problems - Low Voltage Causes Drive Protection
