This work implements for the first time a dimensional qualification procedure for an open access 3D printer, the authors propose a new methodology to measure the prototype part as a mean to achieve the qualification procedure. Experimental results are compared with the specifications of the designer from a Fused Deposition Modelling (FDM) 3D printing. The quality of the machine recommended by the manufacturer and data are used to obtain its qualification. Then, this work aims to evaluate the quality of the machine through a comparison between the design’s data and the measurements taken from the prototype part (the piece test). So, the results have confirmed and validated the dimensional quality of the machine that was randomly taken from a series of commercial printers.