Three Dimensional Molding Process Of Particle Melt Extrusion Printing

Fused Deposition Modeling(FDM)is currently one of the major 3D printing forming methods.Due to its fastness,ease of use,and low cost,it quickly occupied the desktop 3D printing market.The raw materials used in desktop-class FDM equipment are usually filamentous materials,and the types are limited.The size of the equipment is small,and it is mainly for creating passengers and primary schools.Currently,commercially-available industrial-grade FDM devices are similar to desktop-class devices in that filament-like printing materials are mainly used.Due to the large consumption of printing wire materials,the unit price relative to industrial particle-based materials is high,resulting in higher printing costs.In this paper,the 3D printing process of melt extrusion of granular resin was studied based on screw feeding 3D printing equipment.Acrylonitrile-butadiene-styrene plastic(ABS)and polyvinyl alcohol(PVA)were selected as the experimental objects.The heating extrusion,stack forming and thermal deformation of the material were investigated.Through experiments,the process was continuously optimized,the 3D printing of industrial molds and artistic models was completed,and the prints were tested for 3D scanning.The heating temperature,print speed,and the threading factor are important factors affecting the printing accuracy.In the experimental study,using the differential thermal analysis method and the extrusion experiment,the extrusion heating temperature range of ABS and PVA was 190°C-210°C,and the lower temperature would affect the smoothness of the extrusion,and the higher temperature resin would be excessively ablated.Harmful smoke.Through printing experiments,it was found that the printing ABS speed was less than 80mm/s,the PVA speed was less than 70mm/s,and the printing surface quality was good and the speed was too fast,causing collapse.According to the theoretical formula and experimental measurement results,this paper presents a correction formula for calculating the ratio of spiral feeding filaments.When printing ABS,the proportional coefficient is about 2.5,and the PVA is about 1.68.Ambient temperature,floor temperature,and model structure are important factors that affect deformation.When the hot air temperature is set to 120°C,the deformation of the 3D printing sample is the minimum when the model surface temperature is 90°C,and the average deviation is ±0.28 mm.The porous bottom plate can effectively control the warping deformation of the bottom of the model,and the deformation amount can be heated by the bottom plate.-2.3mm when reduced to-0.11 mm.3D printing requires not only high dimensional accuracy but also surface quality.Wire drawing is a typical surface quality defect printed by FDM.Through theoretical and experimental research,we have found the main cause of wire drawing defects.We have proposed to increase the viscosity of resin material,increase the mechanical structure of the extrusion extrusion hole,and increase the idle movement speed.Measures to overcome wire drawing defects.Based on the experimentally obtained process,three typical samples are printed,and the average deviation of the sample is +0.31mm/-0.62 mm,which can meet the 3D printing of ABS industrial molds and digital sculptures.