Modelling of Cusp Geometry in Additive Manufacturing Parts Using a Piece-Wise Polynomial

Abstract

The final dimensional and geometric inaccuracies, and the resulting high surface roughness of the products have been the major problems in employing Additive Manufacturing (AM) technologies. Most of commonly used Additive manufacturing (AM) technologies are developed based on a layer-based manufacturing process to fabricate 3D models. The main critical issue in AM which reduces the surface integrity of the final products is the stair case error which happens due to layer by layer manufacturing process. A new method is presented to model the surface roughness of FDM parts based on considering a new geometry for the cusps. Variety of observations were conducted to model the exact geometry of the cusp. Considering that cusp geometry affects the surface roughness directly, the new geometry was used to predict the surface roughness distribution as a function of layer thickness and surface angle of the final FDM products. The model was validated by designing a set of experiments using 3D measurements of the surface roughness under high resolution surface topography device and the predicted model was in a good agreement with the experimental results.