Fused deposition modeling is one of the most widely used 3-D printing technologies, among other additive manufacturing processes, because it is easy to use, can produce parts faster, and the cost of the finished part is low. Printing processes and finished parts are often studied and characterized using different techniques to collect mechanical, numerical, thermal and dimensional data, with the aim of improving and optimizing the result. The first part of this research is based on the observation of temperature changes with a thermal imaging camera during the fused deposition modeling printing process and during the cooling process after printing. Specimens of polylactic acid and polylactic acid-X improved with second-phase particles were prepared to compare the thermal and dimensional properties of the two materials. The obtained results determined the characteristic temperature behavior of the materials. In the second part of the research, a 3-D optical scanner was used to verify the stability and accuracy of the printed specimens over time. The proposed measurement period showed that stabilization of the parameters takes place, and further follow-up should be performed thereafter.