原砂粒度级配对增材制造砂型性能的影响

Effects of Particle Gradation of Base Sand on Performance of Additive Manufacturing Sand Mold

基于Fuller Thompson理论,研究了原砂的连续级配、均匀级配、间断级配对三维打印砂型性能的影响,分别测试了四种粒度级配条件下的粉末床密度、常温24 h和100℃烘干20 min的抗拉强度、X、Y方向常温和100℃烘干20 min的尺寸精度。研究结果表明:连续级配的粉末床密度最低,为1.252 g·cm^(-3),均匀级配的粉末床密度最大,为1.305 g·cm^(-3);均匀级配常温24 h抗拉强度最大,当喷墨量为150%时,其抗拉强度为2.356 MPa,而连续级配的抗拉强度最低,为1.581 MPa;100℃烘干20 min的抗拉强度明显高于常温24 h抗拉强度,当喷墨量为200%时,其烘干强度提高了42.41%;当喷墨量为100%时,连续级配的X、Y方向尺寸精度最高,X方向尺寸误差为+0.21 mm,Y方向尺寸误差为+0.26 mm,而均匀级配的尺寸误差最大,X方向尺寸误差为+0.55 mm,Y方向尺寸误差为+0.67 mm;四种级配烘干之后的尺寸误差明显小于常温24 h的尺寸误差。

Based on Fuller Thompson theory,the effects of continuous gradation,uniform gradation,gap gradation of the base sand on the 3DP sand mold performance are studied.The powder bed density under four particle gradations conditions,the tensile strength of drying at room temperature for 24 h and 100℃for 20 min,and the dimensional accuracy of drying at normal temperature and 100℃for 20 minutes in X and Y directions were tested respectively.The study indicates that the continuous gradation has the lowest powder density of 1.252 g·cm^(-3),and the uniform-gradation has the highest powder density of 1.305 g·cm^(-3);The uniformgradation has the highest tensile strength at room temperature of 24 h,when the inkjet volume is 150%,the tensile strength is 2.356 MPa,and the continuous gradation has the lowest tensile strength of 1.581 MPa;the tensile strength of drying at 100℃for 20 min is significantly higher than that at room temperature of 24 h,when the inject volume is 200%,the drying strength is increased by 42.41%;when the inject volume is 200%,the continuous gradation has the highest dimensional accuracy in the X and Y directions,the dimensional error in the X direction is+0.21 mm,and the dimensional error in the Y direction is+0.26 mm;the uniformgradation has the highest dimensional error,the dimensional error in the X direction is+0.55 mm,and the dimensional error in the Y direction is+0.67 mm;the dimensional error of four particle gradations after drying is obviously smaller than that of 24 h at normal temperature.