In-situ Sensing of Recoating Force in Metal Binder Jetting and a Preliminary Investigation of Its Relationship to Packing Density

Abstract

Metal binder jetting (MBJ) is an additive manufacturing process that offers advantages such as a wide range of compatible materials, high speed, and low residual stress. A major hurdle in the application of MBJ is the low density of the printed part compared to other additive manufacturing processes. We propose to use closed-loop feedback control in the powder spreading process in MBJ to improve the density of the printed part. To implement the closed-loop feedback control, an in-situ, real-time packing density measurement method needs to be created. This research experimentally verified the hypothesis that there is a positive correlation between packing density and the reaction force from the powder bed during the recoating process (i.e, recoating force) with a modified Desktop Metal Innovent+ 3D printer. However, limitations exist. Anomalies existed in the calibration curve, the recoating force measurement was noisy, and the collected dataset size was small. The future work will focus on taking multi-modal measurements, improving the mechanical design, and taking finer measurements to address the limitations in the current setup.