Introduction
With the increasing development of technology, modern sheet metal processing, especially the bending process, demands increasingly higher standards. There are different technical requirements for equipment and processing efficiency, and both companies and countries have strict control over environmental protection and energy conservation.
Therefore, compared with hydraulic press brakes, press brakes controlled by pure electric servo systems are becoming increasingly accepted by major manufacturers.
Electric press brake versus hydraulic press brake
In recent years, the maturity and cost reduction of electric motors and high-power, high-torque drive technologies have driven the increasing application of related electric drive devices.
The CNC press brake widely used in the sheet metal industry has opened a new trend of pure servo electric main drive replacing the hydraulic main drive, and the tonnage and production of CNC pure servo electric press brake are increasing.
This article describes the advantages of pure servo electric bending machines compared with hydraulic bending machines in terms of energy saving, environmental protection, processing efficiency, bending accuracy and maintenance costs.
1. Significant energy savings
One of the advantages of pure electric servo drive technology is that the motor input power is proportional to the load power, resulting in high energy consumption during bending, low energy consumption when the ram moves upward without load, and virtually no energy consumption when the ram is stationary.
However, in a hydraulic press brake, the main motor and hydraulic pump continue to run even when the slide is not running, consuming energy.
Furthermore, the main mechanical transmission efficiency of a pure electric servo press brake is more than 95%, while the hydraulic transmission efficiency of a valve-controlled servo hydraulic press brake is less than 80%, and its efficiency further decreases after aging. and wear of hydraulic system components.
Taking a 100-ton press brake as an example and based on an 8-hour working day, the power consumption of the main unit of a pure electric servo press brake is about 12 kWh/day, while the power consumption of the hydraulic system of a hydraulic press brake is around 60 kW·h/day.
Therefore, the pure electric servo press brake can save approximately 80% energy compared with a hydraulic press brake.
2. Environmental protection and pollution-free
The pure servo electric press brake does not use hydraulic oil, which eliminates the need for oil changes and component replacement. As a result, there is no need to deal with the hassles associated with oil replacement.
Furthermore, there are no hydraulic oil leaks during the disassembly process or in the hydraulic system during regular use, which means there is no need for waste oil treatment and pollution control.
3. Fast ram speed and high production efficiency
The response speed of the servo motor is faster than that of the hydraulic servo.
Taking 100t pure servo electric bending machine as an example, the ram return and rapid descent speeds are up to 200mm/s, and the working speed is 0-20mm/s;
Most hydraulic press brakes of the same tonnage have ram return and rapid descent speeds below 120 mm/s and a working speed of 10 mm/s.
The hydraulic servo press needs to be started for preheating or stopped for heat dissipation due to the influence of the environment and the heating of the hydraulic system;
Once there is a failure in the hydraulic system, the technical requirements for troubleshooting are high and the time is long.
The pure servo electric bending machine has few components and a low failure rate, which fundamentally eliminates these problems.
Therefore, the processing efficiency of a pure servo electric press brake is almost twice that of a hydraulic press brake of the same tonnage.
4. High bending precision
A pure electric servo press brake has an adjustable bending speed, which can be set to a speed more appropriate for different thicknesses, materials and bending lengths, improving bending accuracy and ensuring high productivity.
The deflection compensation shaft of the pure servo electric press brake uses a VILA structure compensation device, resulting in higher bending accuracy.
The bending angle error of a hydraulic press brake is within ±1 degree, while the main drive of a servo press brake is driven by a servo motor through a ball screw, resulting in higher transmission accuracy.
By measuring the bending angles of various sizes of sheets, the bending angle error can be controlled within ±0.5 degrees.
5. Low maintenance and usage costs
The hydraulic oil in a hydraulic press brake needs to be replaced regularly, and the pump, valve and sealing components are subject to failure and damage.
The hydraulic system is also prone to pollution and it can be difficult to find and eliminate faults. Once the hydraulic system is polluted, cleaning the system can be challenging and can lead to environmental pollution.
In contrast, the transmission system of a pure servo electric press brake is simple and has almost no maintenance costs except for regular lubrication.
The design and manufacturing of a pure servo electric press brake aims at high bending precision, high operating efficiency and high reliability.
Finite element analysis is performed on the base and slide, and the performance of these components is optimized and reinforced.
Based on the analysis of energy consumption, environmental protection, processing efficiency, processing accuracy and cost of pure servo electric bending machines and hydraulic bending machines, the conclusions are shown in the attached table.
Figure 1: Comparison of total daily energy consumption of press brakes
Figure 2: Comparison of fast lifting and lowering speeds of press brakes
Comparison table of hydraulic press brake and pure electric servo press brake
| Comparison category | Hydraulic press brake | Pure electric servo press brake |
| Energy consumption (based on a 100 ton press brake and an 8 hour work day) | Energy consumption: around 60 kWh/d | Energy consumption: around 12 kWh/d |
| Environmental Protection | Possibility of contamination | No possibility of pollution |
| Processing efficiency (based on a 100 ton press brake) | The return speed and rapid descent speed of the ram are below 120mm/s, and the ascent speed is 10mm/s. | The return speed and rapid descent speed of the ram reach 200 mm/s, and the working speed ranges from 0 to 120 mm/s. |
| Bending Accuracy | The bending angle error is within ±1° | The bending angle error is within ±0.5° |
| Cost | A little lower | A little higher |
Efficiency comparison
The improvement in bending efficiency of an all-electric press brake is mainly reflected in the following aspects:
First, the fast travel speed of an all-electric press brake is generally faster than that of an electro-hydraulic servo press brake.
Secondly, the working speed of an all-electric servo press brake is more than twice that of an electro-hydraulic servo press brake.
Third, the acceleration and deceleration capabilities of an all-electric press brake are far superior to those of an electro-hydraulic servo press brake, saving time during speed changes.
Comparative analysis of bending efficiency between fully electric press brake and electro-hydraulic servo press brake
Processing conditions: 80mm fast downward stroke, 10mm working stroke and 90mm upward fast return stroke.
| Universal electro-hydraulic servo press brake | High speed electro-hydraulic servo press brake | Universal Full Electric Servo Press Brake | High Speed All Electric Servo Press Brake | |
| Y axis fast traverse speed (mm/s) | 100-120 | 150-160 | 100-130 | 200 |
| Y axis working speed (mm/s) | 10 | 10 | 20 | 20 |
| Movement time(s) | About 4 | About 3.5 | About 2.8 | About 2.2 |
| Material change time(s) | 0.8 | 0.8 | 0.8 | 0.8 |
| Single push-up time(s) | 4.8 | 4.3 | 3.6 | 3 |
| Number of bending cycles per day | 7500 | 8372 | 10,000 | 12,000 |
| Improved efficiency compared to conventional electro-hydraulic servo press brakes. | 100% | 112% | 133% | 160% |
| Increase in daily bending cycles compared to conventional electro-hydraulic servo bending machines. | 0 | 872 | 2500 | 4500 |
Number of bending cycles per day: Assuming a total working time of 10 hours per day, or 36,000 seconds.
