Raster angle mechanics in fused deposition modelling

Fused deposition modelling is one of the additive manufacturing processes in which a semi-solid polymer material is deposited line-by-line to construct 3D objects direct from computer aided design (CAD) models. Benefits inherent with additively manufacturing allowed effective competition with other traditional methods in specific applications and the process drew sufficient research attention. The nature of material deposition and the mechanics of solid state sintering lead to varying levels of inter-road and inter-layer bonding resulting in a composite structure of voids interspersed in the base material matrix. While there are other parameters also, the raster angle in particular has a direct bearing on the resulting meso-structure and together with the rate of inter-road coalescence plays a significant role in influencing the mechanical characteristics of parts produced. Experimental and analytical attempts were made in the past to evaluate the role of raster angle orientation, but the resulting material properties were taken to be those of the base material. The hypothesis for the current research is that the mechanical properties resulting from fused deposition modelling are structure-sensitive. Experimental and analytical models are developed to test this hypothesis and the results indicate the hypothesis to be true.