Statistical Modeling and Optimization of Surface Roughness for Acrylonitrile Butadiene Styrene Parts Fabricated By Fused Filament Modeling Process

Abstract

3D Printing is a layered manufacturing process that builds prototypes by depositing material in layered form using heaters. Prototypes made by 3D Printing are widely used in product development as they can be used for product testing. 3D Printing prototypes should have a very good surface finish for functional performance as well as aesthetics. The surface quality in 3D printing depends upon different process parameters, namely Nozzle Diameter, Part Bed Temperature, Layer Thickness, Speed of Deposition, Raster Angle of Deposition, Raster Width and Orientation of the parts. In this present work an attempt has been made to improve the surface roughness of prototypes of acrylonitrile butadiene styrene fabricated using Fused Filament Modelling process of 3D Printing. Experiments have been performed according to Central Composite Rotatable Design (CCRD) considering four parameters namely nozzle diameter, part bed temperature, layer thickness and orientation at three levels. Two different surfaces, up facing surface and down facing surface have been used in the study. Analysis of variance (ANOVA) has been used to test the significance of process variables on surface roughness. In case of up facing surfaces, build orientation and layer thickness has been found to be significant. In down facing surfaces, build orientation, layer thickness and part bed temperature have been found to be significant. Empirical statistical models have been developed for predicting the surface roughness of the parts. Optimization of the surface roughness for up and down facing have been done using trust region based MATLAB technique and confirmation of statistical model have been done by performing experiments at different parameters other than experiments in DOE.