3D printing technology of PLA granular material based on screw extrusion
Aiming at the problems of unstable filament,low printing speed and limited printing materials in the existing fused deposition modeling(FDM)printing technology,the printing parameters(barrel temperature,screw speed,extrusion ratio and print-ing speed)were continuously optimized.The mechanical properties of the printed parts under different filling methods were compared,and the forming parameters for polylactic acid(PLA)granular materials were finally determined.Based on these forming parameters,the process research was carried out by using the self-made 3D printing equipment for screw extrusion of granular mate-rials.The results show that the stability of spinning and the minimum porosity can be ensured when the barrel temperature is 170℃,the nozzle temperature is 205℃and the extrusion ratio is 0.65 for PLA granular materials.The screw speed with different nozzle diameters is numerically simulated to obtain the fitting formula of the two,so that the screw speed can be quickly determined when different nozzle diameters are selected.Honeycomb filling shows more excellent bending properties,the value of which is 22.49 MPa,which is 16.10%higher than that of grid filling,and the value of which is 24.75 MPa,which is 10.69%higher than that of honeycomb filling.And with the increase of layer thickness,the surface quality of printed parts gradually decrease,the surface roughness from 160.51 μm with h=0.6 mm to 220.38 μm with h=1.0 mm,which is 37.30%.
3D printingscrew extrusionsurface roughnessfilling methodnumerical simulation
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