Preliminary Design Method Accounting for Shape Distortion in Metal Binder Jetting Parts: A Case Study

Additive Manufacturing (AM) technologies theoretically allow the production of complex products without any geometrical restriction. Nevertheless, production process delineates some limitations on the resulting dimensional and geometrical precision. This is a critical issue mainly for Metal Binder Jetting (MBJ) process, on the reason of anisotropic dimensional change and distortion on sintering. Literature reports fairly reliable models for predicting the deformation on sintering. However, the application of such methods might be time consuming from industrial perspective, because of the extensive experimental analysis required to assemble a robust material database. For that reason, this work aims at proposing an alternative approach for compensating dimensional and geometrical change on sintering. Two complex geometries, having similar geometrical features with different sizes, were printed and measured by a coordinate measuring machine before and after sintering process. The analysis of cylindricity form errors reveals an excellent geometrical stability of smaller geometry. Therefore, dimensional change along printing direction was derived in order to obtain a precise scaling factor for improving the dimensional and geometrical precision. By contrast, bigger samples encountered a dramatic distortion, which required a complete redesign. The shape of the distorted cylinder was approximated with an ellipse and a corrective function has been proposed for compensating green geometry.