Space Systems Academic Group
Rapid Prototyping / Additive Manufacturing (3D Printer).
The NPS Space Systems Academic Group procured in 2008 a Fortus 400mc rapid prototyping machine through school funds. The machine employs fused deposition modeling (FDM) for additive manufacturing of three-dimensional parts from computer-aided design (CAD) geometry. This Wiki is intended to provide information for potential users of the machine. The 3D printer is open to the NPS community on a cost-reimbursable basis for appropriate activities, e.g. instructional parts, research, and thesis projects.
How does it work?
CAD models are imported in the stereo lithography (.STL) file format to the printer software. After orienting the part for the build, the software then slices horizontal build planes and creates toolpaths for each slice of the part based on the configuration of the machine and user-selectable parameters. Once print jobs are generated, another software application is used to arrange them on the build area and send them to the machine. In this way, time can be saved by printing a number of parts, as long as they can fit within the envelope of the machine and the build footprint.
The tool path is defined by contour lines that outline the part, and raster, or fill lines. Parts can be made as completely solid, or to save on material and time as a sparse build, where the internal volume is similar to a honeycomb structure. By default, each alternating layer is raster-filled in alternating directions for higher strength. This figure shows the build parameters of a simple block part.