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Purpose - The paper aims to predict the surface roughness of fused deposition modelling prototypes. Since average roughness is not comprehensive, this study aims to extend the characterization to all the roughness parameters obtainable by a profilometric analysis. Design/methodology/approach - A theoretical model of the 3D profile is supplied as a function of process parameters and part shape. A suitable geometry was designed and prototyped for validation. Data were measured by a profilometer and complemented by microscopic analysis. A methodology based on the proposed model was applied to optimise prototype fabrication in two practical cases. Findings - The proposed profile is effective in describing the micro-geometrical surface of fused deposition modelling prototypes. The third dimension enables the calculation of amplitude, spatial and hybrid roughness parameters. Research limitations/implications - Because of mathematical assumptions and technological aspects, the validity of the model presents limitations related to the deposition angle. Practical implications - The method is an effective tool in the process planning stage: it enables knowing in advance how to assure part specifications delivering a set of technical choices. Two practical applications point out the usability in the product development and process parameters optimisation. Originality/value - This work fulfils an identified need to predict a complete surface characterization of fused deposition modelling technology

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

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Physical and mechanical properties of metallic foams derive from their micro- and macrostructure. Unfortunately these foams have a very heterogeneous structure so that their properties may show a large scatter. In this paper image analysis has been used to determine size, morphology and distribution of cells in three aluminium alloy foams produced by means of different manufacturing processes. The study highlighted that difficulties deriving from cell cavity coalescence can be overcame by using the assistedwatershed method. The morphometric analysis of cells showed that cell size, shape and distribution are strictly related to the manufacturing process. The proposed and analysed method appears to be a useful tool to correlate cell morphology with the manufacturing parameters and then to tailor foam properties to given applications. © 2012 Taylor & Francis Group

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