This paper examines the effect of three different layer thickness, three build direction and five infill percentages for rectilinear pattern on the mechanical properties and build time of 3D printed PLA parts to improve the part strength and minimize the building time. From the results, the strength increased while decreasing the layer thickness, also the “on edge" orientation gave the highest strength, it increased with the infill percentage increase. Regarding the hardness, it increased with the increase of the layer thickness. In addition, the “flat" orientation gave the highest hardness, and it increased while infill percentage was increasing. Regarding building time, it decreased while increasing the layer thickness, also, “flat" orientation appeared to have the minimum building time. In addition, the time decreased while infill percentage decreased. The build direction was the most significant factor affecting the tensile strength. Increasing the layer thickness will decrease the build times without a great significance on mechanical properties.