| The Injection Molding Machine is an important production equipment of plastics industry. Along with the progress of science and technology, the Injection Molding Machine control technology is also changing rapidly with the development of industrial technology. At present, there are so many different kinds of Injection Molding Machine control system in the domestic; however, a large number of traditional hydraulic Injection Molding Machine still exists in many enterprises in our country. In the producing process, the power supply power is basically unchanged, due to the difference of the flow and pressure, respectively, in different technological process, the fuel supply of the pump could not change in the pace of different flow and pressure, therefore, a large amount of energy are wasted. In view of the application of the Injection Molding Machine is more and more widely and the demand of energy saving, the mechanical structure, control mode, as well as the optimization design of the least energy consumption, become an inevitable trend, and the modification of existing Injection Molding Machine will be a great theoretical significance and practical value in the engineering.According to the status of fully hydraulic driven Injection Molding Machine, this paper analysis all the possibilities of energy saving, then put forward the reform scheme for energy saving, based on the existing servo driven hydraulic system of Injection Molding Machine. Using high-performance permanent magnet synchronous motor driven by the dosing pump, the purpose of adjusting actuator speed will be achieved, by changing the parameters(torque, speed, etc.) of permanent magnet synchronous motor to control the pump output flow and pressure. The system has advantages of flexible closed-loop control, high control precision, wide speed range, high efficiency, energy saving and low noise, etc. Based on the energy saving of existing full hydraulic injection molding machine, this paper made the thorough research of dynamic performance of the servo-driven hydraulic system, in order to improve the dynamic performance of the system and lay the foundation for the further application.On the basis of consulting related literature domestic and abroad, this paper analyses the composition, working principle and process of the Injection Molding Machine. After the comprehensive analysis about the energy saving system, several schemes are put forward based on the model SZ-100/800 full hydraulic Injection Molding Machine, with stating the model of modified servo-driven hydraulic system and type selection of servo control elements. According to the principle of vector control, the mathematical model were established of permanent magnet synchronous motor, hydraulic pump control actuator, servo-driven hydraulic system and valvecontrolled hydraulic cylinder, and the simulation research were performed for the servo drive system and hydraulic valve controlled cylinder system by use of the MATLAB /Simulink. After analysis all the system dynamic performance influenced by the structural parameters, such as the moment of inertia J, displacement Dp, the mechanism parameters A1,tpC, eb, V1, CP, etc., some improvement measures are proposed(reduce the moment of inertia J, the total leakage coefficient Ctp, the hydraulic cylinder total volume V1, the system load and increase the emissions Dp, the oil bulk moduluseb), and also these measures could satisfy the need of improving dynamic characteristics of the system. Compared with the simulation, experimental results verified the correctness of the model.The results show that it is reasonable that energy-saving modification of the injection molding machine based on the servo-driven hydraulic system, and also the effect is remarkable, up to 37%. Reasonable selection of structural paramet ers of the servo-driven hydraulic system is effective to improve system dynamic performance. |
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