Surface roughness investigation of 3D printed parts via in-situ pellet-filament co-extrusion process
Krishnanand, Mohammad Taufik
Abstract
Material Extrusion (MEX) is a common additive manufacturing (AM) technique using filament and pellets feedstocks to fabricate polymer, elastomer, and composite parts. However, poor surface finish, mainly due to the staircase effect on curved surfaces, limits its industrial applications. Traditional improvements focus on process optimization or post-processing. This study introduces an advanced 3D printing approach by modifying printer hardware for in-situ filament and pellet co-extrusion. A PLA-TPU composite system leverages their melt flow indices (MFI) to fill staircase gaps, enhancing surface quality. A mathematical model estimates roughness based on build orientation and layer height. Surface quality was analyzed using vision systems and roughness measurement tools, with optimization identifying ideal parameters. This method effectively reduces the staircase effect, improving MEX’s applicability.