Methodology for geometric characterization and dimensioning of additively manufactured channels

Metal additive manufacturing has the potential to enhance the performance of engineering applications by utilizing its inherent design freedom to create complex geometries such as required for conformal cooling. However, additively manufactured channels show significant form deviations when made by laser powder bed fusion. Thereby, not only process-parameters have an influence, but also design-parameters, such as the assigned build direction and the chosen diameter, matter. From a precision manufacturing point of view, there is a need to understand these interdependencies in order to control the deviations. Hence, this work introduces a standardized methodology to quantify and manage the influence of design-parameters on form deviations under a given set of process-parameters. The methodology utilizes two different kinds of test artefacts that are non-destructively analyzed by X-ray computed tomography and light optical microscopy. The results show a proportional influence of build direction and a degressive influence of diameter on cross-sectional area reductions. A resulting prediction model and lookup table serves as a foundation for design engineers to counteract form deviations by pre-processing the CAD-data accordingly. Moreover, this contribution and its artefacts can be utilized as a standard for benchmarking and process-optimization of additively manufactured channels in the future.