Study Of Key Technologies Of 3D Printing For Continuous Carbon Fiber Reinforced Composites

Fiber reinforced composites are increasingly used in the manufacturing industry field due to their superior performance,high specific strength,specific modulus and lightweight properties.However,on account of the limitations of traditional manufacturing processes such as fiber placement,lamination and winding,composite materials are still not available for be the molding of complex structures.3D printing technology is a new additive manufacturing technology in the field of manufacturing industry field,which can realize the forming of complex components without relying on molds.Therefore,combining with the excellent performance of composite materials and the technical characteristics of 3D printing,continuous fiber 3D printing technology is expected to break the limitations of traditional manufacturing processes on the structural design of composite materials and achieve lightweight manufacturing of complex parts.In this paper,a scheme of using thermosetting resin to prepreg continuous fibers and using thermoplastic resin PLA as matrix material for 3D printing is proposed.Based on this,the basic principle of continuous carbon fiber 3D printing technology is studied,and the printing device is designed and built.By testing the mechanical properties of printed components,the influence factors of the mechanical properties is analyzed to verify the effectiveness and feasibility of the printing scheme.The feasibility of using the finite element software Abaqus for simulation and analysis of material properties is explored by means of constitutive analysis of composite materials.Finally,the effect of ply angle and ratio on the torsional deformation resistance of the plate is simulated.The specific work is as follows:(1)Build a 3D printing device of continuous fiber composite materials.First,the printing platform is constructed according to the principles of FDM and Core XY structure.Using the open-source Marlin firmware configuration,it is possible to program instructions to implement personalized settings of printing process parameters and external components.Second,the nozzle has been optimized to prevent the fibers from being cut off by shear forces during printing.Finally,the thermal field of the extrusion mechanism is simulated,a forced heat dissipation scheme is employed,and the structure of the heating device is optimized.Based on the validation of basic printing experiments,the method of co-extruding of thermoplastic resin and prepreg fiber is adopted.The continuous fiber prepreg device is designed to prepreg the continuous fiber with thermosetting resin.(2)Analyze the effect of 3D printing process parameters on the mechanical properties and interfaces of fiber reinforced composites.Through the preliminary exploratory experimental analysis of printing process parameters,the printing temperature T,printing layer thickness L and scanning spacing H are selected as the main study parameters.To verify the effectiveness and feasibility of this scheme,the three-point bending test is used to examine the bending properties of standard part of continuous fiber reinforced 3D printing composite materials,and the influence of various factors on the mechanical properties of fiber composite is analyzed.(3)Measure the engineering constants of 3D printing composite materials and analyze simulation of finite element software.The specimen is printed with the best process parameters and the engineering elastic constants measurement experiment is performed to verify the accuracy of the simulation analysis of the new composite material using the finite element software Abaqus.Based on this,Simulation analysis of torsional deformation of continuous fiber composite 3D printed laminates is performed to study the influence of different ply angles and ply ratios on mechanical properties.