Visualizing, analyzing, and managing voids in the material extrusion process

A problem with the planning solutions for the additive manufacturing material extrusion process is a lack of optimization strategies to improve upon the standard raster and contour tool paths. Bead deposition tool paths can cause unwanted voids, which in turn creates a set of potential failure points within the finished product. This paper aims to identify, minimize, and manage void regions during the tool path generation. The goal is to minimize voids in each layer and to prevent stacked void regions, i.e., avoid creating an internal chimney. Material extrusion processes, with a wide selection of nozzle sizes (0.4 to 21 mm), are considered suitable candidates for this solution. The mathematical model is established based on the component geometry and the available build options for a given machine-material configuration. A C++ program has been developed to select a set of standard (available) tool path parameters to determine the optimal output process variables (bead width, raster angle, and the overlap percentage). Case studies are presented to show the merits of this approach.