Test artefacts for additive manufacturing: A design methodology review

For the past few decades, additive manufacturing (AM) has paved the way to several processes through a wide range of commercially available machines. Benchmark artefacts were developed to set a common reference in order to assess and compare AM machine limitations. In this paper, a review of different AM benchmark artefact design methodologies is presented. More precisely, the evolution of design methods is described. Originally, additive manufacturing machines were assessed by establishing their ability to produce defined features. Indeed, AM benchmark artefact design inherited traditional subtractive manufacturing methods by defining simple geometries. However, due to the AM available freedom, no standard artefact can be sufficiently representative of the diversity of studied criteria. Furthermore, metrology aspects were not considered. Facing the variety of benchmark artefacts available, proposed guidelines then focused on defining systematic design methods rather than standard artefacts. Several methods have been proposed to help designing benchmark artefact suited for considered criteria. Nevertheless, some traditional simple geometries are found incompatible with measuring instruments that can hardly characterise AM free-form surfaces for example. That is why, more recently, significant efforts have been made to consider measurement issues and uncertainties in the artefact design stage. As this paper concludes, benchmark artefacts now tend to be designed in a more metrological way integrating the whole post-manufacturing measurement process relying on statistical modelling and instrument comparisons. Regarding the raised stakes, a final set of recommendations is provided to conciliate both manufacturers' and metrologists' point of view in benchmark artefact design.