Anisotropic Shrinkage of Prismatic and Cylindrical Binder Jetted 316L Parts - Study on the Influence of Printing Parameters by DOE Approach

Metal Binder Jetting (MBJ) is an additive manufacturing (AM) technology increasingly gaining interest due to its capability of producing complex products in medium-large batches, cost-effectively compared to other AM technologies. Nevertheless, dimensional accuracy is still challenging, also considering the significantly anisotropic shrinkage on sintering. The influence of printing parameters on the anisotropic shrinkage of two different geometries is studied in this work. Using fractional factorial Design of Experiments (DOE), four factors at three levels were considered (printhead speed, binder saturation, rake speed, and shell thickness). 30 cubes with squared through-hole, and 30 cylinders with circular through-hole were produced for each experiment using 316L; the shrinkage along different printing directions was derived from the dimensions measured at green and sintered state by Coordinate Measuring Machine. The optimal combination of printing parameters for the different geometries was identified using ANOVA. The effect of printing parameters on the two geometries was highlighted and discussed.