1. Overview of the working principle of the hydraulic system
The hydraulic system of the CNC bending machine is mainly composed of hydraulic pumps, hydraulic cylinders, hydraulic valves and other components. As a power source, the hydraulic pump converts mechanical energy into hydraulic energy and provides high-pressure oil for the entire system. The oil is transported to the hydraulic cylinder through a pipeline, and the hydraulic cylinder is an actuator. The reciprocating motion of the piston realizes the up and down movement of the upper die of the bending machine, thereby completing the bending operation of the plate. In this process, the hydraulic valve plays a key role in controlling the flow direction, pressure and flow of the oil. For example, the reversing valve can change the flow direction of the oil so that the piston of the hydraulic cylinder can rise or fall; the overflow valve can control the maximum pressure of the hydraulic system to prevent excessive pressure from causing damage to the system.
2. The relationship between bending force and hydraulic system pressure
The magnitude of the bending force depends directly on the pressure of the hydraulic system. According to Pascal's law, in a closed hydraulic system, the pressure is equal everywhere and transmitted in all directions. When the oil pressure output by the hydraulic pump acts on the piston of the hydraulic cylinder, the piston will generate a thrust, which is transmitted to the sheet through the upper die, thereby generating a bending force. For example, if the pressure set by the hydraulic system is P and the effective area of the hydraulic cylinder piston is A, the bending force F = P×A. Therefore, to control the bending force, it is necessary to accurately adjust the pressure of the hydraulic system. In the CNC bending machine, the pressure of the hydraulic system is monitored in real time by the pressure sensor and fed back to the control system. The control system adjusts the output power of the hydraulic pump or adjusts the opening pressure of the overflow valve according to the preset bending force requirements, thereby achieving precise control of the bending force.
3. The influence of flow control on bending speed and force
The flow control of the hydraulic system also has an indirect relationship with the bending force. The flow determines the movement speed of the hydraulic cylinder piston, that is, the downward speed of the upper die. When the flow is large, the downward speed of the upper die is fast, and the deformation speed of the sheet will also increase during the bending process. This may cause the bending force to rise rapidly in a short period of time, causing a greater impact on the sheet and the die. On the contrary, if the flow rate is too small and the bending speed is too slow, it will not only affect the production efficiency, but also may cause local deformation or cold hardening of the plate due to long-term pressure, thus affecting the bending quality. Therefore, the hydraulic system of the CNC bending machine needs to reasonably control the flow rate according to different plate materials, thicknesses and bending process requirements, optimize the bending speed under the premise of ensuring bending accuracy and quality, so that the bending force can act on the plate smoothly.
4. The importance of hydraulic system stability to bending force control
The stability of the hydraulic system is crucial for the precise control of the bending force. If there are problems such as leakage in the hydraulic system, oil temperature fluctuations or unstable performance of hydraulic components, it will cause fluctuations in hydraulic pressure, making the bending force unstable. For example, hydraulic oil leakage will cause the system pressure to drop and fail to provide sufficient bending force; excessive oil temperature will reduce the viscosity of the hydraulic oil, affecting the transmission efficiency of the hydraulic system and the accuracy of pressure transmission. Therefore, the CNC bending machine needs to be equipped with a complete hydraulic oil filtration and cooling system, and the hydraulic components should be regularly maintained and inspected to ensure the stability of the hydraulic system, so as to achieve reliable control of the bending force, ensure the accuracy and consistency of the bending process, meet the requirements of various complex bending processes, and improve the processing quality and production efficiency of the product.
