Research On Hydraulic System Of Two-platen Injection Molding Machine

In recent years, the plastic products because of its low cost, lightweight, style and diverse, has widely used by the favor of the majority of people, and the injection molding machine, key equipment in the production of plastic products in the mechanical field, can not be ignored. The paper, based on large mechanical- hydraulic compound two-platen injection molding machine, designed and researched hydraulic circuit, and simulated and optimized of the design of the system, by the hydraulic simulation software AMESim and dynamic system simulation software Simulink.Compared the advantages and disadvantages of several hydraulic drive schemes, and confirmed a more suitable control scheme for the large-scale injection molding machine, servo control system, as the main hydraulic system control scheme. Analysed servo valve control scheme and servo pump control scheme for the design of the hydraulic control system, and ultimately selected the servo pump control scheme, and established a mathematical model of servo pump control system.Because of requirements of mold protection, low shock and vibration, high production efficiency in shift mold stage, cartridge valve group was introduced into the shift mold loop, to design the shift mold loop. Without increasing the hydraulic pump oil pressure, design the boost circuit and mode locking loop, in order to increase partial pressure and reduce the leakage. For the problem that in high pressure system, system produces a shock and vibration due to a sudden change, so the injection molding machine action is not smooth, designed a special pressure releasing loop, let the pressure of high pressure lock cavity discharge slowly at first, then quickly. Designed hydraulic system of the injection molding machine, and meet moving requirement of the injection seat shift. For solving the problem of the screw being forced to move because the screw encounters resistance of melting plastics in the melting stage, increased a proportional pressure valve and several cartridge valves in the oil loop to improve the design of injection and melting loop. In addition, in order to achieve the required flow and pressure of the system, a number of hydraulic pumps and servo motors were chosen to do the perfect match between the hydraulic pumps and servo motors. Finally, selected the main components according to the requirements of the system, and drew hydraulic principle diagram of the hydraulic system of mechanical- hydraulic compound two-platen injection molding machine.Selected Simulink and AMESim software to establish simulation model of important components and system of the clamping hydraulic system of the injection molding machine, and set the parameters of each element, and co-simulate and optimize. The analysis shows that the designed system is in agreement with the theoretical expectation, which provides a theoretical basis for the practical application of the hydraulic system.