Numerical Simulation And Analysis Of Injection System Of Rubber Injection Machine

Injection molding is one of the basic molding processes of rubber materials.Compared with molding,it has the characteristics of dense product texture,high dimensional accuracy,high production efficiency and easy to realize automation.It has been widely used.As the rubber material is a typical non-Newtonian fluid,its processing performance changes with the change of temperature and shear rate.During the injection process,the injection process parameters and the structural parameters of the injection system are closely related to the quality and efficiency of injection molding.Therefore,studying the relationship between them and finding out the influence law has important theoretical significance and engineering application value for guiding the design and correct use of the rubber injection machine.Through consulting a large number of domestic and foreign literature,this paper finds that domestic and foreign scholars’ research in this area is relatively small.At present,the research is mainly conducted through experiments and practical use experience,which is lack of systematicness and scientificity.In this paper,the injection system of rubber injection machine is taken as the research object.Through the study of injection mechanism,rheological mechanism and viscosity characteristics of rubber materials,the control equation of injection process,constitutive model,material parameters and boundary conditions of rubber materials are determined,The geometric model of injection system was established by SOLIDWORKS software,POLYFLOW software was used to simulate the injection process of rubber materials under non isothermal conditions.The effects of injection process parameters and injection system structural parameters on the temperature and pressure drop of rubber materials were studied.The optimal solutions of injection system process parameters and structural parameters were obtained by response surface method,The mathematical relation of parameter change is fitted by MATLAB,and the mathematical model is established.The main research work of this paper is as follows:（1）A large number of relevant documents at home and abroad have been retrieved,and the current development and research status of injection molding system,rheological model and injection process numerical simulation technology have been fully studied,and the research route and research plan of this paper have been determined.（2）By studying the mechanism of injection molding,the process parameters,structural parameters and their effects on injection quality were studied,Through the study on the rheological mechanism of rubber materials and the viscosity characteristics of rubber,it is determined that the flow state of rubber in the injection process is steady flow,the flow state of rubber in the injection process is simplified to laminar flow,the temperature change follows Arrhenius law,and the influence of pressure on the viscosity of rubber is ignored,so the control equation of polymer fluid flow is simplified.（3）Through the study of rheological mechanism and viscosity characteristics of rubber materials,it is determined that the constitutive model is Bird-Carreau model,and the Approximate Arrhenius Law equation is selected as the temperature control equation,The material parameters of rubber and the boundary conditions of finite element simulation were determined by consulting the data and combining with the engineering practice.（4）The geometric model of the injection system of the rubber injection machine was established by using SOLIDWORKS software,and the grid division was carried out by using ANSYSMechanical software,and the rationality of the grid division was verified under non isothermal conditions,The grid quality is optimized by ICEM software and the grid independence is verified.（5）The injection process was simulated under non isothermal conditions by orthogonal test method and POLYFLOW software,and the simulation results were analyzed,The changes of pressure and temperature in each section are studied.The influence laws of volume flow rate,barrel temperature and compound temperature on the temperature,pressure,temperature difference and pressure difference in each section of the injection system are obtained through range analysis.The optimal solution of process parameters is obtained by response surface method.The mathematical model of the influence of process parameters on the average temperature of outlet compound and the system pressure drop is established by using MATLAB.（6）The orthogonal test method and POLYFLOW software are adopted,The effects of the length and diameter of the injection channel,nozzle channel and the structure of the nozzle channel on the average temperature of the outlet rubber and the system pressure drop were studied.The optimal solution of the structural parameters was obtained by using the response surface method.The mathematical model of the effects of the structural parameters on the average temperature of the outlet rubber and the system pressure drop was established by using MATLAB.