NDE in-process for metal parts fabricated using powder based additive manufacturing

Abstract

Ensuring adequate quality for additive manufactured (AM) materials presents unique metrology challenges to the on-line process measurement and nondestructive evaluation (NDE) communities. AM parts now have complex forms that are not possible using subtractive manufacturing and there are moves for their use in safety criticality components. This paper briefly reviews the status, challenges and metrology opportunities throughout the AM process from powder to finished parts. The primary focus is on new acoustic signatures that have been demonstrated to correlate process parameters with on-line measurement for monitoring and characterization during the build. In-process, quantitative characterization and monitoring of material state is anticipated to be potentially transformational in advancing adoption of metal AM parts, including offering the potential for early part rejection, part condition guided process control or even potentially in-process repair. This approach will enable more effective deployment of quality assessment metrology into the layer-by-layer material build with designed morphology. In this proof-of-concept study acoustic-based process monitoring signals were collected during the Direct Energy Deposition (DED) AM process with different process conditions to investigate and determine if variations in process conditions can be discriminated. A novel application of signal processing tools is used for the identification and use of metrics based on temporal and spectral features in acoustic signals for the purpose of in-situ monitoring and characterization of conditions in an AM process. Results show that the features identified in signatures are correlated with the process conditions and can be used for classifying different states in the process.

Failures and Flaws in Fused Deposition Modeling (FDM) Additively Manufactured Polymers and Composites

“…However, in using surface mating techniques and applying NDT methods to several faces, the ultrasound readings could effectively produce a 3D image of the part in question. This would then allow the researcher to break the part down to a layer level and detect where any defects occurred when compared to the digital slicing software layer models [49,50].…”

Critical Features in the Microstructural Analysis of AISI 316L Produced By Metal Additive Manufacturing

“…This process allows producing precise geometric shapes in the bottom-up method [3]. In recent years, there has been an increasing interest in AM technology to be used in different industries, such as automotive, aerospace and medicine [4,5]. The motivation for this interest is because of the flexibility in design and rapid productivity of metal AM technologies in the building of the complex and high-value parts in a single step [6].…”