Research On LFT-D Compression Molding Process Of Vehicle Seat Backrest

With the environment and energy problems becoming more and more serious,the vehicle industry is developing in the direction of light weight,energy saving and low carbon.The composite material formed by LFT-D(long-fiber thermoplastic composite direct in-line compression molding process)is recyclable,lightweight,high-strength,etc.by directly adding a certain proportion of reinforcing fiber in the resin matrix and hot-pressing in a mold.The characteristics have been obtained in batches in the vehicle industry,but the lack of research on the compression molding process has restricted its further application.Based on the compression molding process of LFT-D composite materials,this paper conducts systematic research on the structural design,analysis of molding process,design and optimization of mold cooling system,optimization of molding process parameters of vehicle seat backrest.The main work of the project is as follows:First,based on the LFT-D molding process,an new kind of LFT-D composite vehicle seat backrest is designed.Analyze the modal and static strength characteristics of the seat backrest,and combine the stress and strain conditions used to verify the rationality of the structure and meet the relevant industry specifications.Secondly,combined with the LFT-D forming characteristics,the forming process law of the seat backrest is analyzed.Establish a numerical model of the seat backrest,analyze the filling flow state of the composite melt,research on the influence law of key parameters such as filling time,compression completion time,compression force distribution,suture and warpage deformation;combined with the filling mold flow process of the compression molding material during the mold closing process,obtain the temperature,velocity and pressure distribution characteristics of the compression molding material during the filling process of the molded part under typical process.Then,combined with the heat transfer law of the mold cooling system,the design analysis and optimization of the cooling system are carried out.Analyze the influence law of key factors of cooling system,and optimize the cooling waterway layout and coolant temperature field conditions to improve the molding performance of the product;combined with the optimized analysis results of the cooling system,design the cavity edge zone cooling waterway and the cavity bottom baffle channel waterway to optimized cooling system,to improve the compression molding quality of LFT-D products.Finally,combined with the orthogonal test method,the key parameters of the LFT-D molding process are further optimized.Based on the orthogonal test method,the influence of key parameters of the molding process on the warpage deformation of the molded parts was studied,and the optimal molding process parameter combination was determined;Combined with the single factor test method,analyze the variation law of the key parameters of the process on the warpage of the product,and the molding quality of the compression molding part under the optimized parameters,to verify the effectiveness of the optimized value obtained.The innovation of this paper is based on a new type of LFT-D composite vehicle seat backrest,around the flow and temperature field characteristics of composite materials of the forming process,systematically conduct the optimization of the mold cooling system and the influence of the key parameters of the molding process on the warpage of the compression molding parts,and based on this,the optimal combination of parameters for improving the quality of the compression molding parts is proposed.In this paper,the research on the systematic compression molding process based on LFT-D technology has positive significance for promoting this technology and its more extensive high volume applications in the field of vehicle lightweigh.