3D打印石膏粉末流动性的响应曲面优化试验研究

基于响应曲面法的中心复合设计(CCD)法设计了3D打印石膏粉末流动性优化试验,考察疏水性纳米二氧化硅和可溶性淀粉掺量对3D打印石膏粉末流动性的影响,并对优化效果下制备的3D打印粉末进行打印机铺粉、表面形貌和流速的分析、验证。结果表明:在疏水性纳米SiO₂掺量为1%(质量分数)、可溶性淀粉掺量为3%(质量分数)的条件下,石膏流动性能改善效果最佳,相较于未改性的石膏提高了38%,得到了响应变量粉末流动性与疏水性纳米二氧化硅和可溶性淀粉掺量的非线性回归方程,流动性最佳优化预测值与实测值相对误差仅为0.31%;最佳优化条件下,改性石膏粉末流速为3.16 g/s,可连续流动,粉层表面均匀无明显缺陷。本研究提高了石膏基粉末3D打印的精确度,有利于石膏材料在3D打印中的应用。

Experimental Study on Fluidity Optimization of 3 D Printing Gypsum Powder Based on Response Surface Method

Based on the central composite design (CCD) of response surface method, a 3D printing gypsum powder fluidity optimization experiment was designed, and the effect of different dosages of hydrophobic nano silica and soluble starch on the liquidity of 3D printing gypsum powder was analyzed. Tests regarding printer powder coating, surface topography and flow rate for the optimized 3D printing powder were carried out. The results show that the best scheme to improve the fluidity of gypsum is introducing 1% (mass fraction) hydrophobic nano SiO₂ and 3% (mass fraction) soluble starch. Compared with unmodified gypsum, the fluidity of gypsum increases by 38%. The nonlinear regression equation between the fluidity of powder and the content of hydrophobic nano silica and soluble starch was obtained, and the relative error between the best optimized predicted value and the measured value is only 0.31%. Under the best optimized condition, the flow rate of the modified gypsum powder is 3.16 g/s, which flows continuously, and the surface of the powder layer is uniform without obvious defects. This research highly improves the accuracy of gypsum-based powder 3D printing, which is beneficial to the application of gypsum materials in 3D printing.