Exploring Registration of Optical, CMM and XCT for Verification of Supplemental Surfaces to Define AM Lattices: Application to Cylindrical and Spherical Surfaces

Abstract

Abstract The use of lattice structures produced using additive manufacturing (AM) is of great interest to the aerospace and medical industries because of their potential for strength/weight optimization. However, their use is often limited due to challenges in qualification. Recent standards proposed for the definition and verification of lattice structures created using AM attempt to address these gaps. In this work, a lattice component is designed using a repeated unit cell and theoretical supplemental surfaces (TSS), brought forth in ASME Y14.46, are used to define the bounding geometry of the component. Two planes and a sphere are used to define a datum hierarchy that will be used to qualify the component. A measurand is defined by a spherical TSS and is later used to evaluate the quality of datum registration. The component is produced using a laser powder bed fusion process and then measured using focus variation microscopy, X-Ray computed tomography, and a coordinate measuring machine (CMM). The three data sources are then registered using a refined sampling registration based on the CMM points. The effect of CMM data acquisition strategy on the quality of the registration is then examined. Results show that CMM planning based on optical measurements of the component, as opposed to the designed geometry, show significant improvement in the quality of registration. This work highlights the importance of sampling location in tactile measurements of components produced using additive manufacturing and recommends that definition of inspection locations/methods be integrated into the design cycle of AM parts.