Helmet RTM Process Mold Design And Charging Imitation True Analysis

Resin Transfer Molding(Hereinafter referred to as RTM)as a low-cost composite molding process,the fiber composite materials produced and manufactured by it have high specific strength and specific stiffness,small density,corrosion resistance and other excellent properties.At present,domestic helmets are mainly injection molded by thermoplastics,the production process is simple,and the mold shrinkage of the obtained parts is large and the wear resistance is poor.In order to improve the molding quality of helmet parts,the RTM process is applied to the production and manufacture of helmets on the head,which can effectively reduce the quality of helmets and improve the industry competitiveness of enterprises under the premise of ensuring the mechanical properties of the parts such as strength and stiffness.This project takes the helmet as the research object,analyzes and studies the RTM process,completes the mold design of the helmet fiber preform based on numerical simulation,and performs the imitation true analysis of the resin molding process,which has important guiding significance for the actual molding process.The specific research content of this article is as follows:(1)Based on numerical simulation,complete the design of helmet RTM molding injection scheme.Analyze the resin molding process of the RTM process and establish a mathematical model of the filling process.According to the design principle of the glue injection nozzle,the helmet RTM molding process is designed for the injection scheme,and a process performance index that can evaluate the advantages and disadvantages of the injection scheme is established in combination with the actual situation,and the results of the simulation of the ten injection schemes are evaluated,and the best glue injection scheme is obtained by comparative analysis to guide the mold structure design.(2)According to the best glue injection scheme determined,complete the helmet RTM process mold design.According to the helmet structure characteristics and molding requirements to complete the mold material selection and parting surface determination,combined with the flat plate theory to calculate the thickness of the mold template,complete the mold cavity layout,according to the best glue injection scheme determined,the mold pouring system,ejection mechanism,reset device and guide positioning of the mold,and design a mold with reasonable structure.(3)The influence of process parameters on the molding process is discussed in combination with flow simulation analysis.Based on the PAM-RTM,the influence of permeability,injection pressure and injection flow on resin filling time is discussed,and it is concluded that the permeability is negatively linearly correlated with the filling time,and increasing the injection pressure and increasing the injection flow can effectively shorten the filling time.In the case of the same filling time,the pressure change at each injection port is used for constant pressure injection and constant current injection,respectively,and it is more reasonable to select the constant current injection and then choose the constant current injection.Finally,the three process parameters of mold curing temperature,resin injection temperature and packing pressure were selected,and the average volume shrinkage and warpage deformation were selected as the evaluation indicators,and the curing molding of helmet parts was simulated and optimized based on moldflow design orthogonal test,and the optimal process parameter combination was determined.