Abstract: With the advancement of technology and the increase of labor costs, the current sheet metal processing, especially the bending processing equipment, has higher and higher requirements for processing efficiency and product quality, and in recent years, the country’s requirements for environmental protection have become higher and higher. This article briefly discusses the advantages of pure electric servo press brakes compared to hydraulic press brakes.
In recent years, the maturity and cost reduction of high-power, high-torque servo motors and drive technologies have promoted more and more applications of related electric servo drives. The CNC bending machine widely used in the sheet metal industry has opened a new trend of pure electric servo main drive to replace the hydraulic main drive. The tonnage and output of pure electric servo CNC bending machine are increasing. This paper expounds the advantages of pure electric servo bending machine compared with hydraulic bending machine from the aspects of energy saving, environmental protection, processing efficiency, bending accuracy and maintenance cost.
1. Significant energy saving
One of the advantages of pure electric servo drive technology is that the input power of the motor is proportional to the load power, the power consumption is large when bending, the power consumption is small when the slider is no-load and the power consumption is basically not when the slider stops. However, the main motor and hydraulic pump of the hydraulic servo bending machine continue to run even if the slider does not work, consuming electricity. In addition, the mechanical main transmission efficiency of the pure electric servo bending machine is above 95%, the hydraulic transmission efficiency of the hydraulic servo bending machine is below 80%, and the efficiency of the hydraulic system components is lower after aging and wear.
Taking a 100t bending machine as an example, based on 8 hours of work a day, the main power consumption of the pure electric servo bending machine is about 12kW h/d, while the power consumption of the hydraulic system of the hydraulic bending machine is about 60kW h/d. The servo bending machine saves about 80% of energy.
2. Environmentally friendly and pollution-free
The pure electric servo bending machine does not use hydraulic oil, and there is no trouble in replacing hydraulic oil and hydraulic components, so there is no hydraulic oil leakage during the replacement, replacement process and the daily system of the system, and there is no waste oil treatment and pollution.
3. The slider speed is fast and the production efficiency is high
The response speed of the servo motor is faster than that of the hydraulic servo. Take the 100t pure electric servo bending machine developed by Kaifeng CNC as an example. Tonnage hydraulic press brake slider return and fast down speeds are below 120mm/s, and the working speed is 10mm/s. The hydraulic servo bending machine is affected by the environment and the heat of the hydraulic system, and needs to be preheated or stopped to dissipate heat; once the hydraulic system is faulty, the technical requirements for troubleshooting are high and the time is long. The pure electric servo bending machine has few components and low failure rate, and these problems do not exist fundamentally.
Therefore, the processing efficiency of pure electric servo bending machine is nearly 1 times higher than that of hydraulic bending machine of the same tonnage.
4. High bending accuracy
The bending speed of the pure electric servo bending machine can be adjusted. It can be bent according to different thicknesses, different materials and different bending lengths, and a more suitable bending speed can be set to improve the bending accuracy and maintain high productivity. The deflection compensation shaft of the pure electric servo bending machine adopts the VILA structure compensation device, and the bending accuracy is higher.
The bending angle error of the hydraulic bending machine is within ±1°, and the main drive of the servo bending machine is driven by the servo motor to drive the screw, and the transmission accuracy is higher. It is good to ensure that the bending angle error is within ±0.5°.
5. Low maintenance and use cost
The hydraulic oil of the hydraulic bending machine needs to be replaced regularly; pumps, valves and seals are prone to failure and damage, and the hydraulic system is prone to pollution, and it is difficult to find and eliminate faults. Once the hydraulic system is polluted, it will be difficult to clean the system, and will cause environmental pollution. The drive system of the pure electric servo bending machine is simple, there is basically no maintenance cost, and only regular lubrication is required.
The design and manufacture of the pure electric servo bending machine aims at high bending precision, high operation efficiency and high reliability. The finite element analysis of the bed and the slider is carried out, and the rigidity of the bed and the slider is optimized and strengthened.
According to the analysis of pure electric servo bending machine and hydraulic bending machine in terms of energy consumption, environmental protection, processing efficiency, processing accuracy and cost, the conclusions are shown in the attached table.
Comparison table of hydraulic press brake and pure electric servo press brake
Comparative category Hydraulic press brake Pure electric servo press brake energy consumption (100t press brake as an example, based on 8 hours of work a day) Power consumption is about 60kW·h/d Power consumption is about 12kW·h/d Environmental protection may be polluted and may not be polluted Processing efficiency (take a 100t bending machine as an example) the slider return and fast down speed are below 120mm/s, the working speed is 10mm/s, the slider return and fast down speed are as high as 200mm/s, and the working speed is 0～20mm/s. Machining accuracy The bending angle error is within ±1° The bending angle error is within ±0.5° The cost is slightly lower and higher