Structural Design And Analysis Of The Large-size Dual-thread FDM Printer

With the rapid development of 3D printing technology in recent years,FDM printing technology has been widely used in the fields of product design,parts processing and medical technology.Due to the late start of domestic FDM technology research,there are still some technical limitations on the printing size,printing accuracy and printing speed.To break through the technical limitation,a large-size dual-thread FDM printer was developed and the dynamic characteristics and printing accuracy of the printer was researched.Focusing on the structural design and performance of the large-size dual-thread FDM printer,the main research content and contribution are summarized as follows:1.The structural design of the large-size dual-thread FDM printer was completed.Firstly,the design scheme was determined and the printer was divided into five functional modules.Then,these modules were designed one by one,including extruder module,XY axis module,the platform module,Z-axis module and printer frame module,etc.Finally,static structure analyses of some key parts was completed to verify that the bearing capacity of these parts met the design requirements.2.The optimization of the beam structure was carried out.Firstly,according to the transmission form of the beam,the preliminary structure of the beam was designed.Then,in order to improve the static and dynamic performance of the beam,topo-optimization of the beam structure was completed and a new beam model was established.Next,in order to reduce the mass of the beam,taking the static deformation and the first-order natural frequency as constraints,the mass of the beam as optimization target,the beam is optimized in size.Finally,after analyzing the influence of various dimension parameters on the results,the optimal structure size of the beam is obtained.3.The dynamic characteristics of the beam were analyzed.Firstly,based on Hertz contact theory,equivalent models of the contact surface between guide rails and gears were established by using the spring damping units and the prestressed modal analysis of the structure was completed.Then,the modal test of the beam was completed by using the hammer excitation method.The modal test results verified the accuracy of the finite element model.Finally,the harmonic response analysis of the beam was carried out and the frequency response curve of the printer at each natural frequency is obtained.The result verified that the dynamic stiffness of the beam met the design requirements.4.The dynamic analysis of the rigid-flexible coupling of FDM printer was carried out.Firstly,based on the theory of rigid-flexible coupling dynamics,the rigid-flexible coupling dynamic model of the FDM printer was established by using ANSYS and ADAMS software.Then,based on the Hertz contact theory and Coulomb friction theory,the contact parameters of gears were determined.After the acceleration test,the time and frequency acceleration signals of critical points was obtained and the signals verified the validity of dynamics model.Finally,after the analysis of simulation results,the kinematic accuracy of the printer was obtained and met the design requirements.This paper not only completed the structure design of the FDM printer,but also verified that the performance of the printer met the requirements through the simulations and experiments.This paper is of great significance to the domestic development and research of the super size FDM printer.