Large scale fused deposition modeling : the effect of process parameters on bead geometry.

The field of Fused Deposition Modeling (FDM) continues to grow, with focus turning from small scale applications such as modeling and prototyping to large scale parts intended for industrial use. The purpose of this study is to examine the parameters related to scaling FDM with an emphasis on polymer bead geometry. Using an Exon8 single screw extruder capable of outputting 13pph HDPE and an 18”x18” build platform, four parameters, specifically nozzle height, screw RPM, platform speed, and polymer type, were manipulated to study effects on different aspects of bead geometry to obtain an understanding of appropriate conditions for various desired outputs. In studying these effects, data is acquired that can be compared to small-scale data in an effort to determine optimal geometries for different print requirements. Ideally, bead shape should be rectangular to avoid creating voids between layers, as well as appropriately sized to the resolution needed in the print.