Hybrid CNC bending machine
In fact, from the essence of CNC bending machine synchronization, it can be divided into three types.
1.Torsion shaft synchronization
2.Hydraulic proportional valve synchronization (also called electro-hydraulic synchronous CNC bending machine)
3.Dual servo pump control synchronization (also known as hybrid CNC bending machine).
Torsion axis synchronization: Forced mechanical synchronization by torque.
Hydraulic proportional valve synchronization: The stroke position of the left and right oil cylinders is transmitted to the computer through a grating ruler or a magnetic grating ruler, and the computer controls the synchronization of the left and right oil cylinders through the electro-hydraulic proportional valve.
Dual-servo pump control synchronization: The stroke position of the left and right oil cylinders is transmitted to the computer through grating ruler or magnetic grating ruler. Synchronization of left and right cylinders.
More and more customers will choose dual-servo pump-controlled synchronous CNC bending machine in the future, and use the servo motor variable speed to change the output flow of the oil pump to meet the speed requirements of various load conditions, reduce energy loss and improve system performance. Efficiency, relative to reduce energy consumption, reduce the user’s cost of use.
The Principle and Existing Problems of Electro-hydraulic Synchronous Numerical Control (Valve Control) System
The electro-hydraulic synchronous CNC bending machine uses ordinary three-phase asynchronous motors to control the quantitative hydraulic pump, and changes the flow through the proportional pressure valve by throttling the overflow valve, so as to realize the double-cylinder synchronization and finally meet the accuracy requirements of the bending process. for “valve control”. This technology has the defects of energy loss and excessive heat generation. The energy loss of the hydraulic system will reduce the overall efficiency of the system, increase the oil temperature, and deteriorate the oil, which will lead to the failure of the bending machine.
In order to maintain the heat balance of the oil, the method of increasing the amount of hydraulic oil is usually adopted. At the same time, the problem is the increase in the cost of waste oil disposal and the possible pollution impact on the environment.
Principle of Hybrid Numerical Control (Pump Control) System
The hydraulic-electric hybrid numerical control (pump-controlled) bending machine includes a power unit and a control valve group connected with the numerical control system. The power unit includes a servo motor, a one-way quantitative pump connected with the servo motor, and an independent fuel tank; the control valve group includes overflow. Flow valve, unloading valve, check valve, reversing valve, back pressure valve, poppet valve, safety valve and filling valve. The speed of the servo motor of the power unit is controlled by the numerical control system, and then the displacement of the oil pump connected to it is controlled, so as to realize the displacement speed control of the actuator (double-rod oil cylinder). Through the numerical control system to set the torque of the servo motor, the control of the output force of the left and right actuators (double-rod oil cylinder) is realized.
Double servo pump control CNC bending machine
The dual-servo pump-controlled hydraulic system is independently developed by HOGI. The system integrates servo technology, high-pressure two-way pump technology, and precision hydraulic technology. It adopts servo motor + high-pressure two-way servo pump + imported valve group, and changes the speed of the servo motor through the numerical control system. Control the running speed of the slider, change the running direction of the servo motor to control the running direction of the slider.
No reversing valve is needed, and the precise speed control, position control and high dynamic response performance of the servo motor are used to ensure the high synchronization performance and positioning accuracy of the bilateral motion of the slider. It is a closed-loop advanced technology without overflow and throttling loss. The control method has the characteristics of high efficiency, energy saving, fuel saving, low noise and stability.
Advantages of Hybrid Drive (Pump Control) System
Since the motor does not rotate when the hybrid CNC bending machine is in standby, the machine is in a state of zero noise when it is not working; because the oil consumption of the hybrid CNC bending machine is only 1/3 of that of the electro-hydraulic synchronous bending machine, And the oil temperature is controllable, so it is generally not necessary to replace the hydraulic oil within 3 years; Because the frequency response of the servo motor is much higher than that of the proportional valve, the time of one bending cycle of the hybrid CNC bending machine is 30% faster than that of the electro-hydraulic synchronous CNC bending machine.
Through the comparison of the two control methods, we can clearly see that the oil-electric hybrid numerical control (pump control) system has the characteristics of high efficiency and energy saving, high precision, low noise, and environmental protection.
The pump control technology replaces the conventional valve control technology, eliminates the throttling loss, has no overflow loss, and saves energy significantly; the servo motor can be significantly overloaded in a short time, and the actual installed power is only 50% of the theoretical installed power; the fuel tank volume is reduced by 75% , greatly reducing the use of hydraulic oil;
The thermal equilibrium temperature is low, no cooling device is required, and the life of hydraulic components is prolonged;
Noise is significantly reduced in idle, fast exit, pressure-holding, and return trips, improving the working environment;
The response speed of the servo motor is faster than that of the ordinary motor, and the pressure and flow switch are faster in emergency situations; the sensitivity of oil particles is reduced, from NS7 to NS9;
The temperature sensitivity is reduced, and the working temperature is extended from -10 to 60°C to -10 to 80°C;
Under certain conditions, the maximum speed of fast down and return can reach 300mm/s;
The working speed can be greatly improved, up to 20 ~ 25mm/s.
The oil-electric hybrid CNC bending machine has better synchronization, real energy saving and high efficiency, simple structure and faster speed, but the price is high, how to achieve reasonable cost and stable performance, that is, the higher cost performance is the formation of batches by enterprises. production and the premise of market acceptance.
