Measurement of additively manufactured freeform artefacts: The influence of surface texture on measurements carried out with optical techniques

Abstract

Quality control of additively manufactured parts is a crucial topic, since it includes the measurement of freeform geometries, i.e. lattice structures, and parts characterized by surface topographies several times more rough than conventional machining. Freeform surfaces and their related measurands can be effectively assessed via areal optical scanning techniques and X-ray-based systems, while it is still of great interest to evaluate the effect of the surface quality on their measuring performance.In this work, an experimental investigation about the influence of a typical additive manufacturing surface texture on optical measurements was conducted. As test object, the geometry of a standard freeform artefact developed by the NPL Institute was considered and it was realized by using a Material Extrusion Additive Manufacturing (MEX) technology and micro-milling. By comparing results coming from the two realized artefacts, it was possible to evaluate the influence of the AM surface texture on the conducted measurements.