Simulation Study On Material Conveying Characteristic Of Disk Volute Screw And Parameter Optimum Design Of Melt Conveving Stage

With the development of micro-product,the requirements of micro-product processing accuracy and shape complexity are also rapidly increasing.Traditional small-sized and medium-sized injection moulding machines cannot meet the requirements.Micro-moulding injection machines emerge as the times require.The disk volute screw,as a core part of a new micro-moulding injection machine,has been successfully applied to market products,but its theoretical research is relatively few.At present,the latest research at home and abroad mainly discuss the feasibility of traditional single-screw structural design method,and preliminary analysis of disk volute screw structural parameters is carried out,but the optimization method of the disk volute screw plasticization performance is lack of in-depth research.In view of the above problems,this paper discusses the optimization method of the plasticizing performance of disk volute screw,and studies the multi-objective optimization method on the plasticizing performance of disk volute screw.The main contents of this paper are as follows:In the first chapter,the research results of disk volute screw structure and numerical analysis at home and abroad are introduced;secondly,it summarizes the research progress of the approximation model method and multi-objective optimization algorithm at home and abroad;finally,the research content of the paper is determined.The second chapter firstly analyzes the working principle of the disk volute screw and constructs the three-dimensional model;secondly,the simulation experiments of solid conveying stage,melting stage and melt conveying stage of disk volute screw are carried out,and the simulation results are discussed respectively,material conveying characteristics of disk volute screw are analyzed.In the third chapter,firstly,the multi-level parameters(structure parameters and process parameters)of the melt conveying stage are analyzed;secondly,based on the simulation results,the plasticizing performance evaluating indexes of the melt conveying stage-mass flow rate,pressure gradient,single production energy consumption,maximum shear stress,are analyzed and quantified;finally,the optimizable parameter set—spiral groove depth,pitch,spiral groove width,and angular velocity,of the melt conveying stage are extracted out based on the orthogonal experimental method.In the fourth chapter,the simulation experiment is carried out based on the optimal latin hypercube experimental method to analyze the design variables' interaction;secondly,based on the normalized experimental data,the response surface model and kriging model of the melt conveying stage are constructed,and the BP neural network model is trained;finally,based on the approximation model evaluation index of error analysis,the BP neural network approximation model is chosen to replace the CFD simulation model of the melt conveying stage,and the plasticization performance optimization of the melt conveying stage is studied based on that approximation model.In the fifth chapter,the optimizable interval of design variables is determined,and the mathematical optimization model of the plasticizing performance of melt conveying stage is designed based on multi-objective optimization theory;secondly,the BP neural network approximation model of the melt conveying stage is optimized by the NSGA-?,and the pareto optimal solution set and pareto frontier are analyzed;finally,a set of optimal solutions are reasonably selected,and by comparing the plasticizing performance indexes before optimization,the feasibility and accuracy of multi-objective optimization method based on approximation model are verified.The sixth chapter summarizes the main research contents and innovations of this paper,points out the shortcomings of the paper,and looks forward to the direction that the paper needs to continue to study in depth.In this paper,the plasticizing performance of disk volute screw during melt conveying stage is analyzed by multi-objective optimization.By comparing the plasticizing performance indexes before and after optimization,it can be seen that the plasticizing performance of disk volute screw has been significantly improved.The feasibility and accuracy of multi-objective optimization design method based on approximation model in the disk volute screw are verified,which provides theoretical guidance for the production practice of disk volute screw.