The working principle of the four-column hydraulic press machine
The four-column hydraulic press machine is a device that uses liquid to transmit pressure: when the liquid transmits pressure in a closed container, it follows Pascal’s law. The hydraulic transmission system of hydraulic equipment consists of power mechanism, control mechanism, actuator, auxiliary mechanism and working medium. Power mechanism Usually an oil pump is used as the power mechanism, generally a positive displacement oil pump. In order to meet the requirements of the movement speed of the actuator, choose one oil pump or multiple oil pumps. Gear pump for low pressure (oil pressure less than 2.5MP); vane pump for medium pressure (oil pressure less than 6.3MP); plunger pump for high pressure (oil pressure less than 32.0MP).
The four-column hydraulic press machine is composed of two hydraulic cylinders of different sizes, which are filled with water or oil. The one filled with water is called “hydraulic press”; the one filled with oil is called “hydraulic press”. There is a sliding piston in each of the two liquid cylinders. If a certain amount of pressure is added to the small piston, according to Pascal’s law, the small piston transmits this pressure to the large piston through the pressure of the liquid, and pushes the large piston up. Let the cross-sectional area of the small piston be S1, and the downward pressure on the small piston is F1. Therefore, the small piston pair can be transmitted in all directions by the liquid with the same magnitude.” The pressure on the large piston must also be equal to P. If the cross-sectional area of the large piston is S2, the upward pressure generated by the pressure P on the large piston is equal to P. The pressure cross-sectional area is a multiple of the cross-sectional area of the small piston. From the above formula, if a small force is added to the small piston, a large force will be obtained on the large piston. For this reason, a hydraulic press is used to press plywood and oil , Extracting heavy objects, forging steel, etc.
Four-column hydraulic press with ejector cylinder
Why should a four-column hydraulic press machine have an ejector cylinder? If you look closely, you will find that most hydraulic press equipment is equipped with an ejector cylinder. Then, why do you need an ejector cylinder? This is because many times our processed products need a component to eject the product from the mold, and at this time, an ejector cylinder needs to be installed.
The function of the ejector cylinder is very simple. Generally speaking, it is used for demoulding, and the workpiece is lifted from the die. However, the price of a four-column hydraulic press machine with an ejector cylinder is more expensive than that of an ordinary four-column hydraulic press machine. Because the oil cylinder is an important part of the four-column hydraulic press machine, the cost of adding an oil cylinder is very high.
The first step in the working process of the ejector cylinder is to eject the workpiece. The specific implementation is to press the ejection button after the return stroke of the master cylinder stops, and the corresponding 3 electromagnets are energized, 2 of which are opened, and 2 of them are turned on. The hydraulic oil enters the lower chamber of the ejector cylinder through the valve cartridge, and the oil in the upper chamber flows back to the oil tank through the valve, and the workpiece is ejected. The second step is to return the ejector cylinder. First press the return button, the electromagnet is de-energized, the other electromagnets are energized, the cartridge valve is opened, the hydraulic oil enters the upper chamber of the ejector cylinder through the valve, and the oil in the lower chamber passes through the valve. The valve flows back to the tank, ejecting the cylinder back. When these steps are completed, the next step begins, and then a circulatory system is formed to maintain the continuous movement of the four-column hydraulic press machine.
Precautions for safe operation of hydraulic presses
The main contents of the precautions for the safe operation and use of hydraulic presses are as follows:
1. Without understanding the structure and working performance of the hydraulic press and the premise of operating specifications, the machine should not be operated without authorization.
2. During the working process of the hydraulic press, the overhaul and adjustment of the mold should not be carried out, and the maintenance during the operation of the equipment is very dangerous.
3. When the machine finds serious oil leakage or other abnormalities (unreliable action, loud noise, vibration, etc.), it should stop immediately, analyze the reasons, try to eliminate it, and never allow it to be put into production with illness.
4. The fast single-column hydraulic press shall not be overloaded or used beyond the maximum eccentric distance.
5. It is strictly forbidden to exceed the maximum stroke of the slider, and the minimum closing height of the mold shall not be less than 600mm.
6. The grounding of the electrical equipment of the hydraulic machine must be firm and reliable, and the grounding does not allow the wrong access to the electrical box.
7. At the end of each day’s work, the slider should be placed at the lowest position.