Study On The Process Optimization Of The Mold Opening Microcellular Foam Injection Of Degradable Plastics

In recent years,microcellular foamed materials have attracted more and more attention in the fields of automotive engineering lightweight technology and environmentally friendly household appliances due to their excellent comprehensive performance such as good impact performance and good sound insulation performance.However,the relative complexity of the process,product stability,insufficient foaming ratio,and product surface quality have restricted its further widespread application.The secondary mold-opening microcellular foam injection technology is a research hotspot in the field of polymer molding processing engineering.The foam structure and performance of the foam products prepared therefrom have been significantly improved compared with the traditional microcellular foam injection molding method,showing Great application prospects and potential.Based on this,this article mainly uses simulation to carry out the microcellular foam injection molding process,especially the secondary mold-opening microcellular foam injection molding process research,did the following three aspects of research work.First,taking the air conditioner end cover products of a household appliance manufacturer as the research object,through the design of orthogonal experiments,the key injection and foaming process parameters were simulated to study the maximum warpage deformation,volume shrinkage rate and shrinkage index of the product,and the best results were obtained.Excellent technology combination.Through the establishment of analytical models,meshing and other preliminary treatments,five factors such as mold temperature,melt temperature,melt flow rate,weight loss ratio,and initial gas concentration were selected to establish the maximum warpage deformation and ejection time.The volumetric shrinkage ratio and shrinkage index are orthogonal experimental schemes.Using Minitab data analysis software to quantitatively study the influence of various factors on the above indicators,and then get the optimal process combination.The maximum warpage deformation,shrinkage index and volume shrinkage value of conventional injection molded and injection molded foam products were compared and analyzed.The mechanism of the above key process parameters on the cell structure was explored by single factor method.Secondly,an experimental study was conducted on the effect of initial gas concentration on the cell structure of microcellular foamed injection molded products.Taking injection grade semi-crystalline polylactic acid(3001D)as the research object,standard foaming test splines under different gas injection conditions were prepared,and the relationship between rheological properties,crystallinity,cell structure and mechanical properties was explored.The study found that the addition of supercritical fluid makes molecular chains easier to orient and leads to higher crystallinity;the combined effect of supercritical fluid-induced nucleation of crystals and shear flow in the mold cavity has promoted a certain degree of The cells in the crystalline polylactic acid gas-melted mixture nucleate,thereby preparing a foamed product with a higher cell density and a more uniform cell size.Finally,the simulation and experimental study of the secondary mold-opening microcellular foam injection molding process was carried out.In order to obtain microcellular foamed products with higher foaming ratio and weight reduction ratio,comprehensive consideration of material properties,foaming process,secondary mold opening process characteristics and other comprehensive factors,polypropylene and glass fiber reinforced polypropylene were selected as the research objects.Based on Moldex3D's core-pulling microcellular injection foaming function module,the three-dimensional solid sample model was meshed,flow channel designed,set the moving surface and moving direction and other process steps.The mold temperature,melt temperature and expansion were studied.The influence of key secondary secondary mold opening microcellular foam injection molding process parameters such as rate and expansion distance on the foam cell structure.Thus,experimentally prepared secondary open-cell microcellular foam injection molding samples under different mold opening distance parameters,and constructed a secondary open-mold foam process method with higher foaming ratio and surface quality.