Additive manufacturing of metallic components – Process, structure and properties

A review of the wire arc additive manufacturing of metals: properties, defects and quality improvement

Effect of inter-layer dwell time on distortion and residual stress in additive manufacturing of titanium and nickel alloys

Additive manufacturing (AM) is increasingly used in the development of new products: from conceptual design to functional parts and tooling. However, today, variability in part quality due to inadequate dimensional tolerances, surface roughness, and defects, limits its broader acceptance for high-value or mission-critical applications. Although process control in general can limit this variability, it is impeded by a lack of adequate process measurement methods. Process control today is based on heuristics and experimental data, yielding limited improvement in part quality. The overall goal is to develop the 630measurement science
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 necessary to make in-process measurement and real-time control possible in AM. Traceable dimensional and thermal metrology methods must be developed for real-time closed-loop control of AM processes. As a precursor, this report presents a review on the AM control schemes, process measurements, and modeling and simulation methods as it applies to the powder bed fusion (PBF) process, though results from other processes are reviewed where applicable. The aim of the review is to identify and summarize the measurement science needs that are critical to real-time process control. We organize our research findings to identify the correlations between process parameters, process signatures, and product quality. The intention of this report is to serve as a background reference and a go-to place for our work to identify the most suitable measurement methods and corresponding measurands for real-time control.

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Measurement science needs for real-time control of additive manufacturing powder-bed fusion processes

Additive manufacturing technologies are increasingly used in the development of new products. However, variations in part quality in terms of material properties, dimensional tolerances, surface roughness and defects limit its broader acceptance. Process control today based on heuristics and experimental data yields limited improvement in part quality. In an effort to identify the needed measurement science for real-time closed-loop control of additive manufacturing (AM) processes, this paper presents a literature review on the current AM control schemes, process measurements and modelling and simulation methods as it applies to the powder bed fusion process, though results from other processes are reviewed where applicable. We present our research findings to identify the correlations between process parameters, process signatures and product quality. We also present research recommendations on the key control issues to serve as a technical basis for standards development in this area. Complimentary deta...

/pdf/a-review-on-measurement-science-needs-for-real-time-control-w9fqvr5382.pdf

Koichi Masubuchi

Papers

Analysis of Welded Structures: Residual Stresses, Distortion, and their Consequences