Design of Experiments Approach to Maximize Process Reliability for Bone Scaffold Fabrication

Micro Robotic Deposition (μRD) is a solid freeform fabrication process in which a colloidal suspension, or ink, is extruded through a nozzle in a defined trajectory to form a three-dimensional structure. The term Micro Robotic Deposition is chosen since the extrusion nozzle is usually positioned by a robotic device with resulting part feature sizes between 1–1000 micrometers. μRD technology has been applied to a variety of applications[1] including hydroxyapatite (HA) bone scaffolds[2]. To date, the majority of the μRD research has focused on developing new materials appropriate for deposition as well as decreasing the feature size. In order to make μRD a reliable and viable manufacturing process the number and severity of fabrication defects must be reduced. However, deposition reliability has received relatively little research attention. The work presented here fills this gap in the literature and will help facilitate the transition of μRD technology from the research bench to a manufacturing environment by developing general guidelines that maximize process reliability.