Numerical Simulation And Optimization Of Cold Runner System For Rubber Injection

Injection molding is the main processing and molding method for rubber products.The injection molding process has the advantages of good quality,low energy consumption,high production efficiency and high automation level.With the development of injection molding technology,new technologies are constantly applied,among which cold runner technology for rubber injection is gradually adopted by more and more manufacturers because of its advantages of saving rubber material,shortening operation time and reducing labor intensity.However,at the same time,there is also a difficult design process,the use of the injection pressure loss,temperature control instability and other problems,the main reason is that the rubber material is a typical non-Newtonian fluid,affecting its flow properties of the factors are complex and variable,the application of a variety of occasions,there is no set of perfect scientific and reasonable design methods.Therefore,the study of rubber injection cold runner structure,process parameters and flow characteristics of the rubber material in the runner,the study of the influence of temperature and pressure changes,the establishment of a mathematical model used to guide the design of rubber injection cold runner system,to provide a theoretical basis for the design,application and optimization of rubber injection cold runner system,has important theoretical significance and engineering application value.In this paper,the cold runner system of one-molded four-cavity rubber injection molding is the object of study,and the controlling equations,intrinsic model and boundary conditions of the rubber flow process are determined through the study of the rheological properties and viscosity characteristics of rubber materials.The influence of different runner structures and different process parameters on the temperature and pressure fields of the rubber flow process are studied separately,and the mathematical model of the changes of each parameter is established;the temperature field of the cold runner temperature control system is studied by using the combination of Fluent numerical simulation and orthogonal test,and the response of each parameter of the temperature control system is optimized by using Design Expert software.The main research work done in this paper is as follows:(1)A large amount of domestic and foreign related literature was searched,and the current development and research status of injection molding cold runner technology and injection molding cold runner numerical simulation technology at home and abroad were thoroughly studied,and the research plan and research method of this thesis were determined.(2)The flow mechanism of rubber rubber in the cold runner was studied,and the effect of shear rate and temperature variation on the viscosity of rubber rubber was investigated.The intrinsic model,flow control equation,temperature control equation,and material parameters and boundary conditions used in this study were determined by combining the characteristics of rubber rubber.(3)The overall three-dimensional model of the cold runner system was established by Solidworks software,the geometric model was meshed and the meshindependence of the results was verified,and the overall finite element simulation of the cold runner system was carried out by Polyflow software,and the changes of the pressure and temperature fields of the cold runner system and the influence of the process parameters on the changes of the temperature and pressure of the adhesive were studied by the method of cross-section.(4)Polyflow software was used to simulate the flow of rubber in the primary manifold,secondary manifold,elbow manifold and nozzle,and the effect of different manifold structures and process parameters on the temperature and pressure fields of rubber flow was studied.(5)Using the combination of Fluent numerical simulation and orthogonal test,the influence law of cooling medium orifice diameter,cooling medium inlet velocity and cooling medium inlet temperature on the temperature of cold runner plate was studied;the response optimization of each parameter of the temperature control system was carried out by using Design Expert software,and the mathematical model of the variation law of each parameter was established by Matlab.