Automated In Situ Placing of Metal Components Into 3-D Printed FFF Objects

Screws are often used to connect 3-D printed parts to other objects. When screwing directly into printed plastic, the reliability is limited, and the connection can wear out over time. For more reliable connections, standard metal nuts are often inserted into slots designed into the object. This article presents an approach where nuts and other ferromagnetic components are integrated directly into the part while printing it. Our prototype machine is a modified Prusa-I3 fused filament fabrication printer with an electromagnetic pick and place tool. We introduce augmented slicing software, where the user can insert generic component models from a library and place them at arbitrary positions in the object. Cavities for the components and additional G-code commands for robotic placing are automatically generated and sent to the printer. A printed component tray is attached to the printbed, allowing different part configurations for each print. The pick and place unit is controlled by our OctoPrint plugin OctoPNP.