Research On Paraffin Wax Fusion Deposition Modeling Process Based On Finite Element Simulation

Investment casting is an important casting method,and the preparation of wax patterns is one of the keys to investment casting.The traditional processing method is used to manufacture the wax mold,which takes a long time and is difficult to form a complicated internal structure.The application of 3D printing technology can quickly obtain wax molds with complex cavities and shorten the development cycle.In the early stage of this research group,a paraffin 3D printer for investment casting was built.In order to improve the printing accuracy of printed parts and obtain high-quality wax molds,it is necessary to study the influence of process parameters on the accuracy of printed parts during the process of fused deposition of paraffin wax for investment casting.In this paper,using paraffin wax for investment casting as raw material,using the 3D paraffin wax 3D printer for investment casting built by the research team,the printing process of paraffin wax fusion deposition molding is divided into three processes: pre-extrusion,extrusion process and molding process,through finite element simulation And the experiment explored the influence of process parameters such as paraffin temperature,heating surface temperature,nozzle diameter,height of the printing nozzle from the base plate,printing speed,nozzle temperature and ambient temperature on the accuracy of printed parts.The main conclusions are as follows:The ANSYS Fluent software was used to simulate the flow process of paraffin wax for investment casting in the nozzle,and the distribution law of the flow field and temperature field during the flow of paraffin wax in the nozzle was obtained.In the nozzle,the temperature of the material inside the same cross-section is slightly lower than the outside temperature;the flow velocity of paraffin on the cross-section of the nozzle gradually decreases from the center to the periphery.In order to maintain good adhesion and easy extrusion of paraffin wax materials,the temperature of the nozzle heating surface should be set within the range of 69?70?.During the extrusion process,the extruded wax filaments shrink due to cold,resulting in the line width of the print being smaller than the nozzle diameter.The nozzle diameter directly determines the line width of the print.The larger the nozzle diameter,the larger the line width of the print.The line width of the print is negatively related to the height of the print nozzle from the bottom plate.The higher the height of the print nozzle from the bottom plate,the line width of the extruded print.The smaller.The python language was used for secondary development based on the ABAQUS software,and the fusion deposition molding process of paraffin wax for investment casting was successfully simulated,and the change law of temperature and stress during the fusion deposition molding process of paraffin wax for investment casting was obtained.During the molding process,the printing speed has a greater impact on the accuracy of paraffin printing,while the temperature of the nozzle and the ambient temperature have less effect on the accuracy of paraffin printing.The faster the printing speed,the lower the accuracy of paraffin printing.The higher the temperature of the nozzle,the higher the deformation of the print.The accuracy of paraffin printing is positively correlated with the ambient temperature.The optimized process parameters based on simulation are: the printing speed is 20mm/s,the nozzle temperature is 68°C,and the ambient temperature is 25°C.The optimized paraffin wax has a maximum deformation of 0.023 mm.The optimized result conforms to the linear size of German investment castings.Tolerance standard requirements.