Purpose This paper aims to evaluate the influence of the parameters of the Fused Filament Fabrication (FFF) process on the mechanical properties and on the mass of parts printed in Polylactic Acid (PLA). In addition, the authors developed predictive models for the analysed responses. Design/methodology/approach A full Factorial type of experimental planning method was used to define the conditions for manufacturing parts according to the variation of the construction parameters, extrusion temperature and print speed. Samples were printed for tensile, flexion and compression tests. Their mass was measured. Multiple regression methods, based on power equations, were used to build the forecasting models. Findings It was found that the extrusion temperature was the parameter of greatest influence in the variation of the analysed responses, mainly because it generates behaviour patterns and indirectly demonstrates thermal/rheological characteristics of the material used. Print speed affects responses, however, with variations dependent on part geometry and printer hardware/software. It was possible to establish prediction models with low error rates in relation to the experimental values. Originality/value The study demonstrates a good relation between the use of a structured experimental planning method as the basis for the development of predictive models based on mathematical equations, the same structure of which can be used to describe different responses.