Multi-objective optimization of slurry impact parameters to improve surface roughness in MEX-3D printed PLA using WGRA-Taguchi approach

Purpose Material extrusion-based-3D (MEX-3D) printing technology is popular for its simplicity and low cost; however, fabricated parts often exhibit high surface roughness. This study aims to minimize surface roughness in both longitudinal and transverse directions of MEX-3D printed poly (lactic acid) (PLA) parts using a slurry impact technique. Design/methodology/approach An L9 orthogonal array is constructed within a Taguchi framework coupled with weighted grey relational analysis (WGRA-Taguchi) to handle the multi-response nature of surface roughness data. PLA specimens are printed using a MEX-3D printer of three parameters at three levels, namely, build orientation at (0°, 45°, 90°) and layer thickness at (0.1, 0.2, 0.3 mm) before being subjected to slurry impacts at angles (15°, 45°, 90°). Analysis of variance (ANOVA) is performed on the weighted grey relational grades to evaluate and rank parameter significance. Findings The optimal parameter set for minimizing surface roughness is 0° build orientation, 0.1 mm layer thickness, and 90° slurry impact angle. ANOVA results reveal that layer thickness exerts the dominant influence on surface finish in both principal directions, followed by impact angle and build orientation. Originality/value To the best of the authors’ knowledge, this study is the first to implement the WGRA–Taguchi approach to achieve minimum surface roughness in MEX-3D printed parts by considering printing parameters alongside slurry impact parameters, aiming to achieve superior surface quality.