Research On Injection Molding Machine Energy-saving System Based On Load-sensing Theory

In recent years, with the rapid development of plastics industry, the manufacture of plastics processing equipment has been increasingly paid attention to. In the plastic molding processing, injection plays an important position, and the processing equipment of injection is injection molding machine. The main part of energy consumption in injection molding machine is power drive system. Injection molding machine hydraulic system requires multi-level pressure-flow control, the traditional quantitative pump hydraulic system used in injection molding machine has a lot of run-off loss and throttling loss in a production cycle. Therefore, the research on energy-saving hydraulic system used in injection molding machine has increasingly become the focus of attention. The emergence of load-sensing system makes this issue to be resolved. The load-sensing system not only can adaptively meet the requirements of load pressure and load flow in order to make adaptive between the output power of pump and the power consumed by the load, but also can combine with proportional pressure valve and proportional throttle valve to achieve pressure and flow proportional control, which forms electro-hydraulic proportional load-sensing system. According to the modern injection molding machine hydraulic system’s requirements, a new electro-hydraulic proportional load-sensing system scheme is designed, combined with electro-hydraulic technology and load-sensing technology. The system is researched in-depth and the main research contents are as follows:1) A new electro-hydraulic proportional load-sensing system scheme is designed. Working principles and structures of various components of the system are analyzed.2) Modeling theory of the system is researched to analyze the dynamic characteristics of every part of the system in depth. Dynamic equation of every part of the system is worked out. And then Transfer function block diagram of every part of the system is worked out by laplace transform. Finally transfer function block diagrams of every parts of the system are combined properly to establish flow regulation process transfer function block diagram and pressure regulation process transfer function block diagram in order to analyze impacts of parameters of the system on dynamic characteristics and steady-state characteristics. 3) Simulation model of every part the system is established using AMESim software and the parameter of every part of the system is set. Simulation analysis of each model’s function is analyzed. Finally the AMESim models of every parts of the system are combined properly to establish the whole AMESim simulation model of the new electro-hydraulic proportional load sensing system.4) Regulation principle、flow-pressure regulation characteristic and impacts of important parameters on dynamic characteristics are researched by simulation. Finally Simulation of the system is researched according to the working condition’s requirements.of injection molding machine.Conclusions are as follows:①The system can provide constant flow according to the requirements of the load without accepting influence of load pressure changes and the system has a good constant current characteristic.②The output power of pump is always adaptive with the power consumed by the load to achieve a power match. The system has a good energy-saving effect.③pressure and flow of the system can achieve stepless adjustment in a large range.④When the system is in holding pressure state, the system can be in the high-pressure and small flow state. The system can also achieve holding pressure stepless adjustment.⑤The system has good dynamic and steady-state performance.⑥parameters of the system have important impacts on the dynamic and steady-state performance.⑦the system is able to meet the requirements of energy-saving in injection molding machine. Parameters of the system can be selected properly according to the specific requirements to make the system have good steady-state and dynamic control characteristics in order to meet the working conditions of injection molding machine.