A comparative analysis of non-destructive surface topography measurement techniques for additively manufactured metal parts

Surface characterization of additively manufactured specimens is confounded by their intricate geometries and the presence of various features, including asperities, undercuts, and deep, sharp valleys. Despite the need to understand the impact of surface features on many practical applications, there is a lack of consensus regarding the variability inherent in measurement techniques. Here the topography of as-built Ti-6Al-4V specimens is examined through the utilization of four techniques: contact stylus profilometers, white light interferometers, focus variation microscopy, and X-ray computed tomography. Identification of discrepancies across measurement techniques was made possible through qualitative and quantitative analyses of measured surfaces. Conventional surface texture parameters were used to differentiate the methods and provide guidance for effective scan parameters and measurement technique selection.