TRACEABLE GEOMETRIC QUALIFICATION OF ADDITIVELY MANUFACTURED LATTICE STRUCTURES

The manufacture of lattice geometries via Additive Manufacturing (AM) has the potential to impact the production of low-volume, high cost, complex components. However, the qualification of lattice geometries provides several challenges for traditional metrological techniques, limiting the use of these structures within industry. While recent studies in AM part qualification have improved its practice, the measurement of lattice structures unique to additive manufacturing is not well understood and methods to support traceability have yet to be developed. In this dissertation, a methodology to determine measurement uncertainty in the measurement of AM lattice components is developed. A refined sampling registration approach for lattice geometry based on spatially-dependent subsampling is derived and is shown to statistically decrease variation between measurement sources. The importance of sampling location in tactile measurements of components produced using additive manufacturing is investigated and recommends that definition of inspection locations/methods be integrated into the design cycle of AM parts. The substitution method is investigated to determine uncertainty in the measurement of AM lattice structures using X-ray Computed Tomography (XCT). A measurement artifact is developed and measured using the substitution method. The use of reporting measurement uncertainty using uncorrected bias is explored for strut diameter measurements. Components identical to the measurement artifact are manufactured using AM and measured to determine manufacturing variation. The uncertainty in XCT measurement of these AM components is determined using the substitution method and methods to report uncorrected bias. This study provides a methodology to design inspection routines for the qualification of a lattice component, furthers the scientific understanding XCT measurements of AM components, and lays the groundwork for further implementation of the presented method.Ph.D

Adaptive geometry transformation and repair methodology for hybrid manufacturing

With hybrid manufacturing maturing into a commercial scale, industries are pushing to integrate and fully utilize this new technology in their production facilities. Using the capability to interleave additive and subtractive manufacturing, these systems provide an opportunity to perform component repair through additive material deposition and resurfacing via machining. This is particularly attractive to industries which utilize complex, often freeform, components which require a large capital investment, such as the aerospace and mold and die industries. However, in service these components may experience unique distortions or wear, and therefore each require a unique repair strategy. This work seeks to create an adaptive transformation method for part geometry, which can adapt the process to match the needs of an individual component within the context of a commercial hybrid manufacturing system using currently available on machine inspection technology; greatly improving the efficiency of repair processes. To accomplish this, a new methodology for the adaptation of a nominal CAD geometry to a component is presented which combines data registration and reverse engineering strategies for aero engine components. The accuracy of this deformation method is first examined, then simulations are completed to explore the potential efficiency gains in both the additive and subtractive phases of a hybrid repair process.M.S