Simulation And Experiment Study Of 3DP Printing Process Of Sand Mold(Core)

Additive manufacturing technology overcomes the limitations of traditional modeling,has the advantages of saving manufacturing time,reducing cost,and not being limited by model complexity,and has been widely used in recent years.Among them,inkjet 3D printing(3DP)has the advantages of fast molding speed,large molding size,high molding efficiency,and good environmental adaptability,which has become the focus of sand additive manufacturing research.Among them,the influence of 3DP printing sand process parameters on sand(core)performance is particularly important.Currently,3DP printing process parameters are based on workers’ experience or determined through repeated experiments,which is not only costly but also inefficient in production.In this paper,the effect of process parameters on sand laying effect and mechanical properties of sand mold(core)is studied based on the simulation method of discrete element method,and the accuracy of the process parameters obtained by simulation is verified through experiments,which provides practical guidance for the discrete element method in 3DP printing molding sand mold(core).Numerical simulation studies were conducted for four main process parameters of3 DP printing sand patterns,i.e.,four important parameters of sand ratio(silica sand/vitrified sand),sand laying speed,silica sand size,and layer thickness,and relevant experimental verification was carried out.The specific work is as follows: 3DP printing equipment and particle model were designed by using UG,Pro E,and EDEM software and the simulation process of 3DP printing sand laying was completed,and the effects of type sand ratio and sand laying speed on sand laying effect and mechanical properties were analyzed;with the decrease of silica sand content,the pore size first decreases and then increases,and the mechanical properties first increase and then decrease;with the increase of sand laying speed,the pore size keeps increasing and the mechanical properties first increase and then decrease;with the increase of sand laying speed,the pore size keeps increasing and the mechanical properties first increase and then decrease.With the increase of sand laying speed,the porosity increases,the mechanical property increases,and then decreases;several different sets of simulation results obtain the optimal sand ratio and sand laying speed.At the same time,the sand laying model and sand specimen model were established by using Auto CAD and PFC software,and the effects of silica sand size and layer thickness on porosity and mechanical properties of sand(core)were analyzed according to the simulated sand laying results printed by 3DP;with the increase of silica sand size,the porosity first decreases and then increases,and the mechanical properties show a trend of first increasing and then decreasing;with the increase of sand laying layer thickness,the porosity increases,and the mechanical properties decrease.The simulation’s optimum silica sand size and layer thickness were derived through comparative analysis.The effects of sand ratio,sand laying speed,silica sand size,and layer thickness on the porosity and mechanical properties of the sand mold(core)were investigated by the experimental methods of Scanning Electron Microscope(SEM)and flexural and tensile properties testing,and the accuracy of the numerical simulation was verified.According to the simulation results and experimental analysis,the best process parameters are sand ratio 3:7,sand spreading speed 160mm/s,silica sand size 0.18 mm,and layer thickness0.32 mm.This paper verifies the feasibility of applying the simulation method based on the discrete element software EDEM and PFC to the 3DP printing process through a combination of simulation and experiment.According to the simulation results,the parameters can be adjusted in time to make the sand mold(core)performance meet the needs of actual production,simplify the steps of selecting process parameters,improve the production efficiency,provide a certain theoretical basis for the actual process production,and have some practical engineering value for the analysis of the sand mold3 DP printing process method.