Research On The Extrusion And The Cooling Process Of Molded Parts By Fused Deposition Modeling Technology

Fused deposition 3D printer work process,affected by the smoothness of nozzle extrusion and the reasonable setting of bottom plate temperature,to make the molding quality and dimensional accuracy have greater fluctuations.Regarding the issue above,based on ANSYS thermodynamic analysis module and fluid analysis module,for ABS silk material,firstly simulate the phase change process and flow state of ABS inside the nozzle,then the simulation of the cooling process of the molded parts on the bottom plate after ABS extrusion and the experimental comparative study were carried out,looking for the main parameters for controlling the quality of molded parts,the main work done in this thesis was:(1)Simulate the phase change process of ABS in the stationary state of the nozzle,got temperature fields at different times and the temperature and time curves at different locations,analyzed the reasons for blocking the throat,determined the best fuse temperature and got the best phase change time;(2)Simulate the temperature field,velocity field,and dynamic phase change position point of different ABS speeds during the flow of ABS inside the nozzle,analyzed the influence of different factors on the flow state of the silk material,obtained the key factors that affect the smooth and uniform spitting of the nozzle,get the best spitting speed,and proposed a smooth spitting program;(3)Take the best fuse temperature and spit speed as the conditions for ABS extrusion,simulated the temperature field during the cooling of the molded parts on the bottom plate at different temperatures after ABS extrusion.Summarized the cooling law of molded parts and analyzed the effect of different bottom temperature on the dimensional accuracy of molded parts,the optimum temperature range for the bottom plate is 50°C to 60°C.Thermal-force indirect coupling was used to simulate the corresponding stress and displacement fields,the distribution of the stress field and the amount of warpage of the molded part were obtained,the optimal bottom plate temperature was 50°C as compared to the amount of warpage deformation,and put forward the optimal design scheme of the bottom plate;(4)Done the molded parts cooling measurement experiment,the printer process parameters were set to the optimum fuse temperature and spit rate as analyzed above.The molded parts were printed at 50°C and 60°C respectively,after the molded parts were cooled,then measured them.The results showed that: when the bottom plate temperature was 50°C,the warpage deformation of the molded part was smaller,better dimensional accuracy and surface quality,the experimental results were basically in accordance with the simulation data.This thesis studied the process of silk material extrusion,cooling of molded parts and etc,it provided a valuable reference for the design and use of fused deposition 3D printers.