Simulation Analysis And Process Optimization Of PEEK Injection Molding Products With Metal-Inserts

With the rapid development of plastic industry,thermoplastic engineering polymers,such as Poly ether-ether-ketone(PEEK),have been widely used in the fields of automobile manufacturing,aerospace and biomedical etc.,due to their excellent mechanical properties and chemical resistance.Furthermore,polymer material can be combined with metal inserts to create products with more excellent performance.Although this technology has already been widely used in industry,there exist obvious differences both on the modulus and shrinkage between metal and polymer,which can lead to excessive residual stress in the product,even cracking.The structure of some inserts is slender or thin-walled.The stiffness of the insert structure is not enough to endure the uneven pressure field during filling phase,which can easily lead to the unacceptable deformation of the structure,even failing.According to the problems mentioned above,two typical products are selected as the investigation objectives in this dissertation.The first one is a thick-walled PEEK product with a large metal insert(a PEEK/metal pipe),for which the polymer cracking is the main defect.The other one is a PEEK product with slender metal inserts(PEEK electronic connector),for which the excessive deformation of the slender inserts is the main defect.The main purpose is to find the critical reasons of all these defects,and reducing defects by using Kriging surrogate model based optimization method.The main content of this dissertation includes the following two parts:In order to deal with the cracking problem of the PEEK/metal product,firstly,a simulation model was built according to the actual product structure;Secondly,the injection molding simulation was performed by using the actual processing condition to find the main reason of cracking;Thirdly,the process optimization model of the PEEK/metal product was established.All the process parameters of interest were optimized based on the Kriging model and EI function;Finally,the PEEK/metal product was produced in actual factory by using the optimized processing parameters to clarify the optimization result.For the excessive deformation problem of the slender insert in PEEK electronic connector,firstly,this dissertation proposed a modified pressure mapping method in the core shift analyzing process,which has smaller error with experiment than the method in the literature.Secondly,process optimization was performed to reducing the deformation of the slender insert.Finally,the proposed method was applied to the case of PEEK electronic connector.Process optimization was performed as well to improve the quality of the product.The maximum value in the slender insert of the optimized result is 80% lower than the case of Moldflow recommendation process.