Application And Research Of Glass Fiber Reinforced Polypropylene Microcellular Injection Molding On Automotive Structural Parts

Fiber reinforced plastics(FRP)refers to polymer materials which are added fibers as fillers to improve the mechanical strength and mechanical properties of materials.New energy vehicles have gained more and more popularity nowadays.Vehicle lightweight is one of the methods to improve the endurance mileage of new energy vehicles,so the application of new materials and new technology is very important.Based on the traditional injection molding technology,the foaming process is introduced to make the injection products contain micro-bubbles,reduce the weight of products and realize the lightweight of partsIn this paper,the process of injection molding long glass fiber reinforced splines is tested to explore the influence of molding process on the mechanical properties and microstructure of foaming materials.What's more,the joint simulation of injection molding long glass fiber splines is carried out,that is,the results of injection molding are mapped to the dynamic simulation to improve the accuracy of dynamic simulation.After that,the simulation method is applied to the development of the micro foaming automobile gearshift bracket to shorten its development cycle time.Combined with the simulation results,the automobile gearshift bracket mold design is carried out,and finally the final product of the gearshift bracket is obtained by opening the mold,and the related product test is completed.The research results are as follows(1)By adjusting the parameters,the influence of injection molding process on the mechanical properties of four PP materials was studied.The results showed that the mechanical properties of PP materials performed well when the melt temperature was high,the injection speed was low,the mold temperature was high and the SCF concentration was high.(2)The mechanical properties of foamed materials were greatly affected by the micro structure of the materials,including the length of residual glass fiber,the content of glass fiber,the size and distribution of the inner bubbles.The longer the residual glass fiber length was,the better the mechanical properties were.However,there was a contradiction between the retention of the glass fiber length and the even gas mixing in the process of foam injection.How to achieve a proper balance needed further experimental exploration(3)Through the application of Moldex3D mold flow analysis software,the simulation of Microcellular Injection Molding under different process conditions was carried out.The simulation results(mainly the results of bubble distribution and glass fiber distribution)were mapped by digimat composite simulation software,and the results of bubble and glass fiber were mapped to the dynamic model,so that the traditional isotropic dynamic model became anisotropic which was contributive to improve the accuracy of simulation.When modeling composite materials in digimat,the more practical the material model was,the higher the final simulation accuracy was(4)Moldex3D was used to simulate the injection foaming process.In this way,the optimal gate position and grid model of the molding mode were obtained.Combined with the optimal process results of the previous spline stage,the relevant processes were set and the analysis was carried out:symmetrical gate layout was conducive to product filling,improving the distribution and size uniformity of the bubble holes(5)Through the improvement of product structure and forming process,the shift holder with overall weight reduction of 15%was achieved,and the subsequent test results met the relevant test standards of GACIn this paper,Glass fiber reinforced polypropylene microcellular injection molding was deeply discussed,and experiments were carried out to explore the influences of molding process and main technological factors on the mechanical properties and microstructure of foaming materials.The injection foam long glass fiber reinforced spline was simulated to improve the accuracy of dynamic simulation.Finally,the simulation method is applied to the development of the gear shift bracket for injection molded foam cars.This research not only achieved the goal of reducing the weight of the single part of the car shift holder by 15%,but also provided a new method for the realization of the lightweight of the car parts.