Quantified Approach for Evaluation of Geometry Visibility of Optical-Based Process Monitoring System for Laser Powder Bed Fusion

Metals, vol. 13, pp. 13

Abstract

The long-term sustainability of the Additive Manufacturing (AM) industry not only depends on the ability to produce parts with reproducible quality and properties to a large extent but also on the standardization of the production processes. In that regard, online process monitoring and detection of defective parts during production become inevitable. Optical-based process monitoring techniques are popular; however, most work has been mainly focused on capturing images of print abnormalities without taking other influencing factors, such as camera and part position, chamber illumination, and print geometry on the resolution of the captured images, into account. In this work, we present a scenario to evaluate and quantify the performance of an optical-based monitoring system in a Laser Powder Bed Fusion (LPBF) machine using the F1 score, considering factors such as scan vector orientation, part geometry (size) and position in a built chamber with a fixed camera position. The quantified results confirm that the F1 score can be used as a reliable means of evaluating the performance of optical-based monitoring systems in the LPBF process for the purposes of standardization. The biggest line width of the test artifact (1000 µm) had the highest F1 score range of 0.714–0.876 compared to the smallest (200 µm) with a 0.158–0.649 F1 score.

Authors 7

1. Song Zhang corresponding Aachen Chair for Digital Additive Production

   RWTH Aachen University

   Affiliation as printed

   Chair for Digital Additive Production, RWTH Aachen University, Campus-Boulevard 73, 52074 Aachen, Germany

2. Frank Adjei-Kyeremeh Aachen Foundry Institute

   RWTH Aachen University

   Affiliation as printed

   Foundry Institute, RWTH Aachen University, Intzestraße 5, 52072 Aachen, Germany

3. Hui Wang Aachen Foundry Institute

   RWTH Aachen University

   Affiliation as printed

   Foundry Institute, RWTH Aachen University, Intzestraße 5, 52072 Aachen, Germany

4. Moritz Kolter Aachen Chair for Digital Additive Production

   RWTH Aachen University

   Affiliation as printed

   Chair for Digital Additive Production, RWTH Aachen University, Campus-Boulevard 73, 52074 Aachen, Germany

5. Iris Raffeis Aachen Foundry Institute

   RWTH Aachen University

   Affiliation as printed

   Foundry Institute, RWTH Aachen University, Intzestraße 5, 52072 Aachen, Germany

6. Johannes Henrich Schleifenbaum Aachen Chair for Digital Additive Production

   RWTH Aachen University

   Affiliation as printed

   Chair for Digital Additive Production, RWTH Aachen University, Campus-Boulevard 73, 52074 Aachen, Germany

7. Andreas Bührig–Polaczek Aachen Foundry Institute

   RWTH Aachen University

   Affiliation as printed

   Foundry Institute, RWTH Aachen University, Intzestraße 5, 52072 Aachen, Germany