ANALYSIS OF DIMENSIONAL ACCURACY AND SURFACE ROUGHNESS OF FDM 3D PRINTED PARTS HAVING 100% INFILL DENSITY

Abstract

Fused Deposition Modeling (FDM) is entirely focused on extrusion of thermoplastics and thermosetting-fills. When choosing a thermoplastic polymer to use in an FDM 3D printing process, the properties like part strength, surface quality, accuracy and mechanical properties can be varied to suit a particular application. The thermoplastic filament materials, viz., Polylactic acid (PLA) and Polyethylene terephthalate glycol (PETG) are the best biodegradable filament materials and exhibit good visual quality and mechanical properties of parts produced by 3D printing. This work investigates the surface roughness quality and dimensional accuracy of 100% infill density parts fabricated by FDM process using Carbon fibre PLA and PETG. The cuboid shaped test specimens with dimensions 40 mm× 40 mm×15 mm are considered. The layer thickness, printing speed, nozzle diameter and nozzle temperature for the printing process are set at 0.1 mm, 30 mm/s, 0.4 mm and 220˚C respectively. To check the dimensional accuracy, in particular the warping deformation, a dial vernier caliper is used. The surface roughness of different surfaces is measured by a portable surface roughness tester. According to the experimental results, both carbon fibre PLA and PETG show good dimensional accuracy in 90˚ measuring direction perpendicular to building direction and best surface quality over 10 mm scanned profile. Specifically, the printed parts of both the materials have got low warping and shape distortions due to heat shrinkage. Also on an average scale, carbon fibre PLA filament material comparatively shows a better surface behaviour than PETG. This study can be extended to other advanced and best performing polymers like PEEK, PEEK CF and PEI/ULTEM, which have good mechanical and thermal properties.