Modelling micro geometrical profiles in fused deposition process

Fused deposition modelling is an established additive manufacturing technique for creating functional prototypes from three-dimensional computer-aided design models. Despite of the potential advantages of this technology, surface roughness is a substantial problem and some attempts have been made to predict the average roughness R (a). As well known, the surface quality characterization of a part is not limited to R (a) but involves many other roughness parameters. The knowledge in advance of these parameters is a critical point especially in the product design stage both for rapid prototyping purpose and finished part manufacturing. In this work, a novel approach aimed to the geometrical description of roughness profile is reported. By means of an analytic formulation it is possible to calculate custom set of roughness parameters. An experimental analysis, based on design of experiments technique, is carried out to investigate the effects of several factors on shape profile. The achieved results permit to define the domain in which the presented model depends only on two parameters. A profilometric analysis has been performed on specimens properly designed to validate the method. Statistical tests show a good accordance with predicted values for the made assumptions and the calculated roughness parameters.