eng Science and Education Publishing American Journal of Mechanical Engineering 2328-4110 2019-05-13 7 2 87 106 10.12691/ajme-7-2-5 AJME2019725 article Mohammad S. Alsoufi mssoufi@uqu.edu.sa 1 Mohammed W. Alhazmi 1 Dhia K. Suker 1 Wadeea K. Hafiz 1 Sultan S. Almalki 1 Rashad O. Malibari 1 Department of Mechanical Engineering, College of Engineering and Islamic Architecture, Umm Al-Qura University, Makkah, KSA This research paper presents results of a study evaluating the influence of multi-level printing process parameters on 3D printed parts in FDM of PLA Plus. In this study, the effects of printing temperature, printing speed along with skirt/brim with and without top/bottom thickness were considered. The investigations show that the measured dimensions are always more than the CAD dimension along the z-direction (height) but dimensions along x- and y-directions (length and width) are less than the CAD dimension and not necessarily equal. The surface roughness fluctuated over independent printing process parameters along with the density. The results show that the Q-Q (quantile-quantile) plot of density is a very impressive and promising method in 3D FDM printing process parameters optimization. http://pubs.sciepub.com/ajme/7/2/5/ajme-7-2-5.pdf surface roughness density FDM PLA plus skirt brim