Design And Simulation Of Conveying Section Of Disc Type Micro Injection Molding Machine

Micro injection molding has the advantages of high precision,low cost and easy mass production.It is widely used in aerospace,automotive industry,electronic products and medical technology.The micro injection molding machine is the key to achieving micro injection molding.Due to the small amount of plasticization in each injection cycle of micro injection,the accuracy of plasticization of the traditional screw micro injection machine and the strength problems caused by reducing the size of the screw limit the development of screw micro injection.In order to overcome the above shortcomings,this paper develops a disc type micro injection molding machine,the plasticizing unit has the characteristics of small space occupation and excellent plasticizing performance,and studies the conveying mechanism and conveying performance of its melt conveying section.The main research work is as follows:(1)Based on the requirements of micro injection,the performance parameters of the designed disc type micro injection molding machine are determined,and the structural scheme design is completed;the finite element analysis of the pull rod and the moving template is carried out,and the design of the moving template is optimized to reduce its deformation;the selection of the rolling bead screw pair,servo motor and reducer is carried out according to the requirements of disc type micro injection molding machine.(2)The mechanism of the melt transport of the disc is studied to obtain the velocity distribution and volume flow rate of the fluid in the flow path of the disc.Using PLOYFLOW to study the conveying characteristics of the melt conveying section of the disc,the three-dimensional non-isothermal numerical simulation of the flow field of the melt conveying section of the disc was carried out.Analyze the pressure and temperature distribution of the melt cross section along the length of the spiral groove;and discuss the velocity,viscous heat generation,shear rate,shear stress and mixing index of the melt conveying section of the disc.(3)Based on the agent model,the multi-objective optimization of the geometric structure parameters of the disc is carried out.The depth,width and spacing of spiral grooves are selected as design variables,and the volume flow rate,cumulative residence time and temperature difference along the path are taken as optimization objectives.The optimal Latin hypercube test design method is used to select different sample points,the agent model and the multi-objective particle swarm optimization algorithm are used to optimize the geometric structure parameters of the disc.(4)Based on POLYFLOW,the influence of process conditions and disc gap on melt conveying performance was studied.The distribution rules of the pressure,temperature,volume flow rate,shear rate,weighted average shear stress and cumulative residence time of the materials in the melt conveying section under different disc speeds,fixed disc temperature and disc gap are obtained.