In this paper an analytical dimensional performance evaluation and comparison is illustrated, done on benchmarks manufactured using two different 3D FDM printers: an industrial system, and an open-source one (a modified Fab@Home Model 1 printer).Using a factorial analysis design of experiment (DOE), optimum process parameters were found to improve dimensional accuracy on rectangular test specimens, minimizing changes in length, width and height. Fab@Home printer demonstrated to be a good platform, simple, flexible and inexpensive.