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Published September 22, 2020 | Version v1
Conference paper Open

In situ process monitoring by optical microphone for crack detection in Laser Metal Deposition applications

Description

Presented at the 11th CIRP Conference on Photonic Technologies (LANE 2020)

© 2020 The Authors. Published by Bayerisches Laserzentrum GmbH

We introduce an effective application of a novel laser-based optical microphone for in-situ monitoring of cracks during laser metal deposition (LMD) processes. The system relies on XARION’s technology, a membrane‐free optical microphone based on a Fabry–Pérot laser interferometer, that captures broadband airborne acoustic emission up to 1 MHz such as the sudden acoustic emission signals produced by the released energy of cracks. A set of experiments of two different applications, materials and geometries were conducted at AIMEN for evaluation: thin walls of stainless steel and thin deposited layers of tool steel. Through analyzing acoustic STFT-based spectrograms, an approach for identification of cracks and classification of signals is introduced. Process emission of 200 kHz and crack-type signals up to 600 kHz were detected for both cases. NDT methods (X-ray and Eddy Current) and microscopy investigation of defects validate this acoustic sensing system to monitor cracks in laser cladding and other additive manufacturing applications.

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Zenodo_LANE_CP_2020.pdf

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Additional details

Funding

INTEGRADDE – Intelligent data-driven pipeline for the manufacturing of certified metal parts through Direct Energy Deposition processes 820776
European Commission