Extruder dynamics and control in large scale additive manufacturing

Abstract

In Large Scale Additive Manufacturing, there are many part defects, such as bulging at corners and improper part seams that arise due to a lack of information about the extruder. To reduce the number of part defects, it is necessary to understand and control the extruder dynamics. A bead characterization system (BCS) was created to measure the flow rate out of the nozzle. Tests were run to excite the dynamics of the extruder and perform system identification. Models were then created to describe the system and predict the flow rate out of the nozzle. Then a feed forward controller was implemented to maintain a consistent bead geometry, and the results from the controller were evaluated.