Investigation of Sintering Shrinkage in Binder Jetting Additive Manufacturing Process

Binder jetting process is an additive manufacturing technology that produces objects layer by layer from 3D digital data. After printing process, the secondary post-processing operations, including curing and sintering, are used to solidify the object. The linear dimensional accuracy is one of the most important end-product qualities in manufacturing process. However, it is not easy to control it since the whole process combines several steps and covers different disciplines. Sintering process can affect the shrinkage rate significantly through using different sintering profiles. This project focuses on investigating the effect of sintering parameters on linear dimensional accuracy with stainless steel 316L. The Taguchi method is used to design 9 groups of orthogonal experiments. After that, the results are converted to signal-to-noise (S/N) ratio and using analysis of variance (ANOVA) to analyze. There are 3 sets of recommended sintering parameters to achieve the best dimensional accuracy for each axis and there is also 1 set of recommended sintering parameters which considers dimensional accuracies of all 3 axes. Comparing with the shrinkage rates measured using default sintering profile, the dimensional accuracies are improved.