Experimental investigation on porosity and flexural strength of polymer parts fabricated by fused deposition modeling

Abstract Nowadays, polymer parts are fabricated by fused deposition modeling (FDM) techniques of additive manufacturing for biomedical, sports, and automotive applications. But, functional use of these parts in high‐strength applications is limited due to anisotropic nature of the FDM process. Various researchers have proved that those process variables of FDM affect the mechanical properties of polymer parts. The present paper describes an experimental investigation of porosity and flexural strength of thermoplastic polymer (poly‐lactic acid) parts fabricated by FDM. Influence of three process variables namely nozzle temperature, print speed, and raster width on porosity and flexural strength of parts is studied. Experiments are planned using a central composite design. Specimens are first weighed for density measurements and then tested using three‐point flexural loading on a tensometer. It is found that all three process variables have a significant effect on porosity and flexural strength. Print speed is the most influential parameter for porosity, while raster width is the most significant parameter for flexural strength. Further, regressive models are developed to predict the responses. Also, microstructure of fractured specimens is studied using a scanning electron microscope. Optimization of process variables is performed to minimize porosity and maximize flexural strength using the desirability function approach.