Study On The Technique Of Polyamide And Glass Fabricated By Fused Deposition Modeling

Currently,the type of filaments commercially available for Fused Deposition Modeling is still somewhat limited which hindering overall growth of this technology for manufacturing final products.Therefore,in order to expand the application fields of FDM technology,develop new materials suitable for FDM and improve the quality of FDM parts,the feasibility of polyamide 12 and soda-lime glass used in FDM was discussed by retrofitting commercial FDM machine in this thesis.Besides,the relationship among the properties of materials,process parameters and the quality of parts was also discussed.The main results of this thesis are shown as followed:(1)According to mechanical test,rheological measurement and fractographic analysis of the FDM parts,FDM process was followed by Frenkel–Eshel viscous sintering model.In low shear rate condition,melt-state viscosity were found significant for ensuring the good bonding quality between filaments intra and interlaminar.The rheological results showed that the melt-state viscosity of PA12 was more sensitive to temperature than ABS which is the most common materials used in FDM.Therefore,the bonding quality of PA12 parts could be controlled by printing temperature,and parts with 91.8% mechanical strength compared to injection part could be obtained by FDM using PA12.(2)The effect of different process parameters on surface roughness of PA12 FDM parts with different geometries was discussed by single factor experiment.It was found that the parameters related to the slice pattern,such as layer thickness and building orientation,played an important role on surface roughness of FDM parts.The change rate of surface roughness to layer thickness could be 269.4% in this thesis.Specimens with smaller layer thickness and smaller angle between the contour and Z axis could obtain better surface condition.Besides,the increase of printing temperature would lead to the increase of surface roughness,but the change of printing speed has no obvious influence on surface roughness.(3)By analyzing the relationship between viscosity and temperature of glass materials,the automatic feeding device,the printing nozzle assembly and the molding chamber of the FDM equipment used for glass materials were designed.Moreover,the suitable printing temperature and the temperature of molding chamber were determined as 1100-1150 ℃ and 450 ℃ respectively for the self-developed glass FDM equipment,resulting in translucent and non-cracked glass FDM parts with different structures.In conclusion,the feasibility of PA12 and soda-lime glass used in FDM was proved by developing FDM equipment.By using the rheological measurement,mechanical test and fractographic analysis of the FDM parts,it was concluded that the density and the mechanical strength relative to injection part of PA12 FDM parts were better than ABS FDM parts.Furthermore,this thesis suggested the optimized parameters used for PA12 FDM process in different conditions.The above conclusions are of great significance to the development of new materials for FDM technology and to the optimization of process parameters for PA12 FDM parts with different structures.