Electron-optical in-situ metrology for electron beam powder bed fusion: calibration and validation

Christopher Arnold,Carolin Körner

doi:10.1088/1361-6501/ac2d5c

Christopher Arnold, Carolin Körner

Open Access

https://doi.org/10.1088/1361-6501/ac2d5c

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Abstract

A major advantage of metal additive manufacturing is the possibility for tool-free production of complex shaped parts. Currently, the geometrical and dimensional accuracy of these parts can only be reliably controlled by time and cost intensive post-process inspection, e.g. using x-ray computed tomography (XCT). The current investigation demonstrates the first in-situ metrology technique for electron beam powder bed fusion (PBF-EB) using electron-optical imaging (ELO). After a calibration experiment, the approach was validated for a PBF-EB build job by comparing in-situ ELO imaging data to XCT data of an as-built part. The quantitative comparison showed a remarkable high agreement between both imaging techniques. It is demonstrated that ELO imaging is capable of making accurate predictions on the geometrical and dimensional accuracy of the as-build part. This result is the basis of new possibilities for in-situ process and quality control in PBF-EB.

Highlights

Electron beam powder bed fusion (PBF-EB) is an additive manufacturing (AM) technology which applies an electron beam to selectively consolidate layers of metal powder
It was shown that electron-optical imaging (ELO) imaging offers a new possibility for in-situ metrology in PBF-EB and to predict the dimensional accuracy of the as-built part
To demonstrate the capabilities of the ELO imaging approach, a cross-section of an exemplary part was investigated by comparison with computer aided design (CAD) and x-ray computed tomography (XCT) data

Summary

Introduction

Electron beam powder bed fusion (PBF-EB) is an additive manufacturing (AM) technology which applies an electron beam to selectively consolidate layers of metal powder. Due to its characteristic processing conditions, i.e. high temperature and high vacuum, PBF-EB arises increasing interest for the processing of high-performance materials, especially for high-temperature applications. These materials, e.g. titanium alloys, titanium aluminides [1,2,3] or Ni-based superalloys [4], often exhibit a high strength and brittleness which complicates. The as-built manufacturing accuracy of AM technologies like PBF-EB is highly important for their industrial application

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Discussion

Conclusion