Messverfahren für die pulverbettbasierte additive Fertigung zur Sicherstellung der Konformität mit geometrischen Produktspezifikationen

Description

Due to insufficient standards for in-process manufacturing and quality control, decisive prerequisites are still missing in additive manufacturing that are necessary for industrial series production. In addition to numerous efforts of various standardisation committees to standardise the additive manufacturing process gradually, the present work also deals with basic scientific methods for referenced in-process monitoring as well as derived approaches for the analysis of geometric manufacturing and measurement deviations. The aim is to contribute to a consistent procedure for process monitoring to ensure the conformity of geometric product specifications in additive manufacturing. In order to correct the detected geometric deviations during the process with appropriate control strategies, an exact allocation is necessary to be able to assign the measurement data precisely at any time of the manufacturing process in addition to a sufficient controllability. For a better assessment of the required comprehensive observability of the measured variables, a novel referencing concept for the position determination of the melt pool contours is provided, based on a powder bed based selective laser beam melting process. The acquisition of four referencing pipes, integrated in the powder bed, cause a shortening of the measuring circuit and increase the accuracy of the measurement data acquisition. This allows a better allocation of the causes of manufacturing and measurement deviations. Based on the referenced contour analysis of the melt pool and the detection of the shining heat radiation of the component contours after powder application, a metrological verification of lateral contour displacements is provided.