Fused deposition modeling (FDM) is one of the most additive manufacturing techniques that adopted to produce prototypes and/or final parts, particularly under geometrical complexity restrictions. One of the most challenging aspects of FDM technology is the attainable roughness. In this paper, a hot-air jet was applied simultaneously during the printing process of FDM products to investigate the effect of its factors on surface roughness. Experimentally, a test rig was utilized to evaluate the effect of these factors on surface roughness. Two main factors were addressed: air jet temperature; and nozzle translational velocity over the part surface and investigated their effect on the roughness. Statistically, ANOVA and regression analysis were conducted to study the contribution of the individual factors to the process response and to introduce regression model to predict the resulting surface roughness in terms of different …