Design And Performance Study Of Rapid Printing Head Of Fused Deposition Modeling (FDM) 3D Printer

With the promulgation and implementation of the“Made in China 2025”plan and the“14th Five-Year Plan”national key research and development plan,the role of 3D printing technology in aerospace,automobile manufacturing,intelligent equipment,biomedicine and other fields will be further enhanced.Fused Deposition Modeling(FDM)3D printing technology,as one of the most widely used forms of 3D printing technology,has attracted more and more researchers'attention.In the current studies on printing head of the FDM 3D printing technology,studies on nozzles with adjustable extrusion size are limited.The nozzle with fixed extrusion size needs to go through dot-line-area-body forming during printing,resulting in slow printing speed and low printing efficiency.In response to this problem,a rapid printing head is designed in this paper,different widths of the printing materials can be obtained by adjusting the length of the extrusion of the rapid printing head's nozzle,this molding method can greatly reduce the number of G codes and the times of the printing head moves back and forth,so as to shorten the printing time and improve the printing efficiency.In this paper,based on the structure and molding characteristics of the FDM 3D printing equipment,a rapid 3D printing platform is parametrically designed using three-dimensional modeling software,including the design of the five modules of the rapid printing head and the XYZ transmission structure of the 3D printer.Draw and process the parts of each module of the rapid printing head,compile the rapid 3D printing platform control program based on the open source firmware,and complete the construction and control of the rapid 3D printing platform.Based on numerical simulation and experimental measurement methods,study the influence of the temperature field distribution of the heating and heat dissipation modules in the rapid printing head on the feeding,melting,and extrusion of the printing filament under different cooling fan wind velocities V_f,and determine the optimal V_f of the rapid3D printing platform is 1.0 m/s?2.0 m/s.Taking polylactic acid(PLA)printing filaments as an example,based on the numerical simulation method,the effect of the die swell phenomenon of PLA polymer melt extruding through the rapid printing head's nozzle on the 3D printing dimensional accuracy is studied.The feasibility of compensating the die swell size based on reverse extrusion simulation and numerical orthogonal experiment is analyzed.Establish a mathematical prediction model for the longitudinal die swell ratio B_c and velocity V_j of the die section entrance,the length L_j of extrusion and the width W_jof extrusion,The optimal printing parameters are obtained as V_j=10.0 mm/s,L_j=1.0mm,W_j=0.4 mm,and W_j of the rapid printing head's nozzle is determined to be 0.4 mm.Based on the rapid 3D printing platform,the printing performance test is carried out to verify the feasibility of the actual printing of the rapid 3D printing platform,the theoretical and actual printing speeds of the rapid printing head and the ordinary printing head with the same model are compared under different printing speed V_p,when V_p=120?3000 mm/min,the theoretical printing speed of the rapid printing head is 2?8 times of the ordinary printing head;when V_p=100?350 mm/min,the actual printing speed of rapid printing head is 5?7 times that of ordinary printing head.Compared with ordinary printing head,the actual printing size accuracy and surface flatness of rapid printing head are lower.