Strength and Surface Characteristics of FDM-Based 3D Printed PLA Parts for Multiple Infill Design Patterns

Abstract

Fused Deposition Modeling (FDM) based 3D printers are gaining popularity as cost-effective printers that are changing the life of millions with their capability to manufacture products in the fields of engineering, medical and education. This paper examines the variation in the compressive strength of FDM processed Polylactic acid (PLA) parts for different infill design patterns. The work is performed on 6 infill designs i.e., Hilbert curve, honeycomb, line, rectilinear, Archimedean curve and octagram spiral and compressive strengths are compared for infill densities varying from 20 till 80% in step of 20. It is observed that the Hilbert curve design exhibits maximum compressive strength of 121.35 MPa which is much higher than other designs rectilinear (78.88 MPa), line (73.84 MPa), honeycomb (62.56 MPa), Archimedean (70.07 MPa), octagram spiral (60.01 MPa). Also, with increase in infill density, compressive strength increases for all the considered infill design patterns. The fabricated parts are also investigated for surface roughness values for best 3 compression strengths with different combinations of infill densities. The surface roughness increases with increase in infill densities for rectilinear and hilbert curve but decreases for line pattern. Rectilinear pattern exhibits lowest roughness value as compared to hilbert curve and line design patterns.