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A New In-process Monitoring Technique for Laser Powder Bed Fusion

By Evgueni Todorov on Wednesday, May 17th, 2017


Figure 1: Post process scans of parts with notches simulating tight cracks and holes simulating porosity

Figure 1: Post process scans of parts with notches simulating tight cracks and holes simulating porosity

An EWI innovation team led by  Evgueni Todorov has successfully developed, integrated, and demonstrated a prototype electromagnetic/eddy current (EC) system for layer-by-layer monitoring of  metal additive manufacturing (AM) processes. This system can be adapted to monitor any metal AM process where the material is deposited using a layer-by-layer technique. This technology was developed as part of a research effort to demonstrate the application of electromagnetic and eddy current techniques at all fabrication stages of AM, including (1) evaluation of feedstock (e.g. powder), (2) real-time monitoring during fabrication, and (3) post-process examination of built parts. The demonstration was conducted using EWI’s open-architecture laser powder bed fusion (L-PBF) AM test bed, which was built with funding from the National Institute of Standards and Technology (NIST) to develop, optimize, and test new techniques and tools for real-time process monitoring of L-PBF.

Figure 2: Post process scans of parts with notches simulating lack of fusion with depths of 0.04 mm and 0.12 mm.

Figure 2: Post process scans of parts with notches simulating lack of fusion with depths of 0.04 mm and 0.12 mm.

During the demonstration, process parameters were changed to create discontinuities within the build structure. The system reliably detected and imaged intended and unintended discontinuities and irregular surface conditions using a layer-by-layer approach. Subsurface discontinuities were also detected. This technology has great potential for the development and implementation of real-time AM process control.

To learn more, contact Evgueni Todorov, NDE Technology Leader, at etodorov@ewi.org.

 

 

 

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