Working principle and precautions of hydraulic system of injection molding machine
Working principle and precautions of hydraulic system of injection molding machine
Injection molding machine hydraulic system of hydraulic transmission, based on the hydraulic oil as working medium, through the power components (pump) will be prime mover's mechanical energy into hydraulic oil pressure can, again through the control element, and then with the help of executive components (cylinder or oil motor) will pressure can be converted into mechanical energy, driving load to realize linear or rotary movement, and through the control element of remote controlling and regulating flow, setting the force and speed of the actuators. When there is disturbance to the above system, the output of the actuator normally deviates from the original setting value, resulting in a certain error.
Hydraulic control of hydraulic system of injection molding machine:
A. Hydraulic control of the injection molding machine is the same as hydraulic transmission. The system also includes power components, control elements and actuators, which are also transmitted by oil. The different point is the hydraulic control with feedback device, the effect of feedback device output components is the implementation of the (displacement, speed, strength and other mechanical quantity) feedback back to the input quantity (can be change, also can be a constant), comparison with the deviation of control system, the components of the output of the changes over the amount of input or constant. It is a hydraulic transmission system that forms a closed-loop circuit, also called hydraulic servo system or hydraulic servo system.
B. The hydraulic transmission system USES the pass-through or logic control elements, which control the purpose to maintain the stable or simple transformation direction of the fixed value, also known as the fixed value and sequence control elements.
C. servo control element is used in the hydraulic control system, with feedback structure, and electrical devices to control has higher control precision and response speed, the control of pressure and flow of constant change. The output power can be amplified.
D. proportional control is a control between the above two, the proportional control valve is used in the on-off control element and servo control element on the basis of the developed a kind of electric - hydraulic control elements, some of the characteristics of both the above two kinds of components, is used to control the on-off type with the hand can't meet the requirements, but also do not need the servo valve on the hydraulic system as strict pollution control requirements of the occasion.
The injection molding machine hydraulic system should pay attention when using:
1 the user should understand the working principle of the hydraulic system, be familiar with the operation and adjusting the position of the handle and the rotation direction, etc.
2 check before driving system on the handles, the handwheel is irrelevant personnel move, the location of the electrical switch and travel switch is normal, host tools installation is correct and strong, to guide and exposed portion of the piston rod to wipe, and then to drive.
3. When driving, first start the hydraulic pump that control the oil circuit, and when the hydraulic pump is not dedicated, the main hydraulic pump can be started directly.
4. The hydraulic oil should be checked regularly, and the hydraulic equipment for the new investment should be cleaned and new oil should be cleaned in three months or so. Once every six months to 1 year for cleaning and oil change.
5 work should pay attention to the oil at any time, normal work, the oil temperature in the tank should be less than 60 ℃. Excessive oil temperature should be managed to cool down and use a more viscous hydraulic oil. When the temperature is too low, it should be preheated or intermittently run before operation, which will gradually increase the oil temperature and then enter into the official operation status.
Check the oil surface to ensure that the system has enough oil.
The system of the exhaust device should be exhaust, and the system of the exhaust device should be repeatedly run repeatedly, so as to exhaust the gas naturally.
8 fuel tank should be sealed and air filter should be installed in the air hole above the fuel tank to prevent the intrusion of dirt and moisture. When refueling, it should be filtered to clean the oil.
The system should be equipped with coarse and fine strainer according to need, and the filter should be checked, cleaned and replaced regularly.
The adjustment of pressure control elements is generally adjusted first to adjust the system pressure control valve, the overflow valve, to adjust the pressure from pressure to zero, and gradually increase the pressure to reach the specified pressure value; Then adjust the pressure control valves of each circuit in turn. The adjustment pressure of the safe overflow valve of main hydraulic pump is generally greater than 10% to 25% of the operating pressure of the actuator. The pressure valve of the fast moving hydraulic pump is usually more than 10% - 20%. Pressure should be maintained at 0.3 to 0.6mpa if the unloading pressure supply is used to control the oil and oil roads. Pressure relay adjustment pressure generally should be lower than the supply pressure 0.3-0.5mpa.
The flow control valve should be transferred from small to large flow, and should be adjusted gradually. The flow control valve shall be adjusted simultaneously to ensure the stability of the motion.
