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Investigation of complementary use of optical metrology and x-ray computed tomography for surface finish in laser powder bed fusion additive manufacturing

Published

Author(s)

Jason Fox, Felix Kim, Zachary Reese, Christopher Evans

Abstract

The development of additive manufacturing (AM) has allowed for increased complexity of designs over traditional manufacturing; however, increased design complexity leads to greater difficulties in post process finishing of the part surfaces. Additionally, uncertainty surrounding the quality of the complex as-built surfaces hinders wide scale adoption of AM. As such, a strong understanding of the as-built surface texture is required to help determine quality of the resultant part. Complex geometries and internal surfaces create challenges for conventional surface finish metrology, but X-ray Computed Tomography (XCT) has emerged as a candidate since it does not require direct line of sight to the surface being measured. In this work, a comparison of XCT and optical measurements are performed on additively manufactured samples with two main goals: To determine the capability of XCT measurements as a tool for surface finish metrology and to determine if XCT measurements can provide insight into locations of overhangs and undercuts, which are difficult to identify through more conventional surface finish metrology and may have a drastic effect on part performance. Samples made from nickel alloy 625 and 17-4 stainless steel were built using a commercially available laser powder bed fusion (LPBF) system. Laser confocal and XCT measurements are performed on the samples and compared to each other and to SEM images of the parts. The result of this work provides an investigation to the use of XCT for surface finish metrology, as well as the capability of XCT to provide better context for conventional surface finish metrology data near undercut features on the surface of AM parts.
Proceedings Title
Dimensional Accuracy and Surface Finish in Additive Manufacturing
Conference Dates
October 8-11, 2017
Conference Location
Leuven, BE
Conference Title
European Society for Precision Engineering and Technology Special Interest Group

Keywords

Additive manufacturing, laser powder bed fusion, x-ray computed tomography, surface finish

Citation

Fox, J. , Kim, F. , Reese, Z. and Evans, C. (2017), Investigation of complementary use of optical metrology and x-ray computed tomography for surface finish in laser powder bed fusion additive manufacturing, Dimensional Accuracy and Surface Finish in Additive Manufacturing, Leuven, BE, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=923764 (Accessed December 5, 2023)
Created October 10, 2017, Updated April 11, 2022