Powder bed fusion metrology for additive manufacturing design guidance

Allison, Jared Austin
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The benefits afforded by the use of additive manufacturing (AM) are diminished due to limited understanding of the various AM processes. Design for additive manufacturing (DFAM) guidelines can be generated through metrology studies using test parts to characterize specific processes and inform designers. Polymer selective laser sintering (SLS) is an AM process that can be used to create geometrically complex, end-use parts. However, no DFAM guidelines exist for polymer SLS that are both comprehensive and statistically robust. A test part is designed for polymer selective laser sintering (SLS) that incorporates an array of geometric features. The part is comprehensive, including a variety of different features of interest to a designer. Many copies of the test part are built in a factorial-style metrology study, while varying different input parameters. The part is built in multiple materials, build orientations, locations within the build chamber, and on different machines to assess the variation attributed to each processing parameter. Multiple replicates are created at each point in the experimental design to add statistical robustness to the results. Both resolution and accuracy are investigated based on the features of the test part. Upon measurement of the test parts, tolerances and design allowables could be established and compiled into a set of design guidelines for SLS. The design guidelines are structured to include varying levels of detail depending on the intent of the designer implementing them. Lastly, the guidelines are assembled into an online web-based tool that allows them to be accessed freely. Using the web tool, designers can realize parts with fewer mistakes and iterations in the design process.