Design And Simulation Of FDM Screw Extrusion 3D Printer

3D printing technology has high utilization rate of materials and low cost of processing complex parts,which has exerted great technical advantages in all walks of life.Fused deposition modeling（Fused Deposition Modeling,FDM）is an important branch of it.Its equipment is convenient to use and maintain,and its post-processing cost is low,and it has been widely used.Traditional FDM-type 3D printing equipment requires secondary melting of filaments,and there are great restrictions on material selection.The extrusion power of the nozzle is limited and it is difficult to achieve continuous production.This project designs and develops a screw extrusion 3D printing equipment,and conducts simulation experiments on the performance of the nozzle.Based on the principle of screw extrusion technology,the design scheme and overall shape of the screw extrusion 3D printer are determined according to the expected product specifications,with a molding space of 265 mm × 265 mm × 255 mm.Through the combination of theoretical analysis and simulation test,a screw extrusion nozzle is designed for the polypropylene（PP）material that is difficult to print through traditional nozzles;The corresponding working platform is designed.The influence of different screw structure parameters on the flow rate was studied by means of orthogonal simulation test,and the influence of screw speed and temperature changes on various parameters of the flow field was explored.regulation.The mixing and plasticizing effect of the nozzle on the material was studied when the screw speed was between 2 rpm and 8 rpm.The simulation test verified that the distribution and mixing effect was close to the ideal state,and the dispersing and mixing performance was continuously enhanced with the increase of the screw speed.Through the simulation analysis of the conveying process of 2 mm granular materials,the reasons for the jam in the feeding process were explored and solved,which increased the throughput of pellets by 77.6% at the same time.The conveying condition of pellets in the feeding section is also affected by the rotational speed,and the simulation verified that the conveying amount of pellets at different rotational speeds can ensure the stable supply of materials.Through the simulation of the temperature field,it can be seen that the application of the heat insulation board can better concentrate the heat in the barrel area,and the laying of the heat dissipation pipes further enables the hopper and the barrel to obtain a reasonable temperature distribution state.By adjusting the flow rate of the pipeline,it can ensure that the installation plate is stable at 30°C,and the temperature of the hopper at the fixed end is 70°C,which avoids the adhesion and blockage of the pellets,and the temperature field distribution is safe and reasonable.The nozzle structure parameters and process temperature that can achieve optimal index printing are explored.