America Makes: National Additive Manufacturing Innovation Institute (NAMII) Project 1: Nondestructive Evaluation (NDE) of Complex Metallic Additive Manufactured (AM) Structures

Todorov, Evgueni; Spencer, Roger; Gleeson, Sean T.; Jamshidinia, Madhi; Kelly, S. M.

doi:10.21236/ada612775

Cited by 29 publications

(12 citation statements)

References 49 publications

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“…Removal and inspection techniques were down selected using a Pugh matrix (a tool to qualitatively rank options against criteria [27]). Suitable criteria, such as cost and speed, were 1 3 5 1 1 3 2 1 1 3 5 2 3 5 1 3 3 2 1 2 3 5 3 3 5 1 5 3 2 1 3 3 5 2 1 3 2 2 1 3 5 2 3 3 2 2 2 3 5 2 5 3 2 2 3 3 5 3 1 3 2 3 1 3 5 3 3 3 2 3 2 3 5 3 5 3 2 3 3 3 5 determined from prior reviews of powder removal and inspection techniques [24][25][26]. From these criteria, the following powder removal techniques were chosen: stage 1, a handheld ultrasonic polisher with flexible tooltip; stage 2, ultrasonic bathing and vacuum boiling.…”

Section: Powder Removal and Inspectionmentioning

confidence: 99%

Assessment of trapped powder removal and inspection strategies for powder bed fusion techniques

Hunter

Brackett

Brierley

et al. 2020

Int J Adv Manuf Technol

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The issue of trapped powder within a part made using powder bed fusion additive manufacturing (AM) is one of the 'dirty secrets' of AM, yet it has not received significant attention by the research community. Trapped powders limit the application of AM for complex geometries, including heat exchangers and dies with conformal cooling channels. Being able to detect and remove trapped powder from the build is a necessary step to avoid downstream processing and performance challenges. In this work, 'powder challenge geometries' with complex internal features were fabricated via laser powder bed fusion (L-PBF) and electron beam selective melting (EBSM) and were used to assess the effectiveness of several powder removal and inspection methods. Hand-held ultrasonic polishing was explored as a powder removal technique and was shown to effectively clear extremely elongated channels that grit-blasting (the current industry standard) cannot clear. X-ray computed tomography (XCT) and weighing were used to inspect and quantitatively assess the effectiveness of powder removal techniques on the challenge geometries. Using the lesser known 'vacuum boiling' powder removal process and the more common ultrasonic bathing process, trapped L-PBF powder was easily removed from the deep channels. Conversely, trapped EBSM powder was difficult to remove using ultrasonic polishing as the powder was sintered inside the channels. It was shown that the powder recovered by the ultrasonic polishing process had size distributions, surface chemistry, morphology and porosity similar to the virgin powder. It is suggested, on these bases, that the recovered powder could likely be recycled without detrimental effects on the process operation.

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Section: Powder Removal and Inspectionmentioning

confidence: 99%

Assessment of trapped powder removal and inspection strategies for powder bed fusion techniques

Hunter

Brackett

Brierley

et al. 2020

Int J Adv Manuf Technol

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“…De Chiffre et al also discussed in detail the application of XCT to individual industries, including AM, as well as challenges and barriers to the technology, noting the following as primary concerns: measurement accuracy, large and high density parts, signal-to-noise ratio, reconstruction algorithms, task-specific measurement setups, multi-material measurements, setup time, measurement uncertainty, in-line measurements and high costs. Todorov et al [93] studied NDE methods of complex AM alloy components, discussing defect formation and mitigation, and qualitatively defining design complexity into five groups. Group one, for example, contained simple parts that could be inspected using conventional methods, whereas groups four and five comprised components producible exclusively by AM and requiring new NDE inspection techniques.…”

Section: Relevant Review Workmentioning

confidence: 99%

X-ray computed tomography for additive manufacturing: a review

Thompson

Maskery

Leach

2016

Meas. Sci. Technol.

379

151

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Abstract. In this review, the use of x-ray computed tomography (XCT) is examined, identifying the requirement for volumetric dimensional measurements in industrial verification of additively manufactured (AM) parts. The XCT technology and AM processes are summarised, and their historical use is documented. The use of XCT and AM as tools for medical reverse engineering is discussed, and the transition of XCT from a tool used solely for imaging to a vital metrological instrument is documented. The current states of the combined technologies are then examined in detail, separated into porosity measurements and general dimensional measurements. In the conclusions of this review, the limitation of resolution on improvement of porosity measurements and the lack of research regarding the measurement of surface texture are identified as the primary barriers to ongoing adoption of XCT in AM. The limitations of both AM and XCT regarding slow speeds and high costs, when compared to other manufacturing and measurement techniques, are also noted as general barriers to continued adoption of XCT and AM.

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“…Indeed, despite significant technological advances, the defect ratios are still too high with respect to more conventional production systems. To face this issue, the development of process monitoring methodologies based on insitu sensing as well as novel feedback control strategies was indicated as a priority research area by many recent keynote studies, projects and roadmaps (Mellor et al, 2014;Olakanmi et al, 2015;Mani et al, 2015;Tapia and Elwany, 2014;Everton et al, 2016;Spear and Gold, 2016;Todorov et al, 2014). In-situ sensing and process monitoring are needed to determine the quality and stability of the process during the layer-wise growth of the part.…”

Section: Introductionmentioning

confidence: 99%

Process defects andin situmonitoring methods in metal powder bed fusion: a review

Grasso

Colosimo

2017

Meas. Sci. Technol.

580

246

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Despite continuous technological enhancements of metal Additive Manufacturing (AM) systems, the lack of process repeatability and stability still represents a barrier for the industrial breakthrough. The most relevant metal AM applications currently involve industrial sectors (e.g., aerospace and bio-medical) where defects avoidance is fundamental. Because of this, there is the need to develop novel in-situ monitoring tools able to keep under control the stability of the process on a layer-by-layer basis, and to detect the onset of defects as soon as possible. On the one hand, AM systems must be equipped with in-situ sensing devices able to measure relevant quantities during the process, a.k.a. process signatures. On the other hand, in-process data analytics and statistical monitoring techniques are required to detect and localize the defects in an automated way. This paper reviews the literature and the commercial tools for insitu monitoring of Powder Bed Fusion (PBF) processes. It explores the different categories of defects and their main causes, the most relevant process signatures and the in-situ sensing approaches proposed so far. Particular attention is devoted to the development of automated defect detection rules and the study of process control strategies, which represent two critical fields for the development of future smart PBF systems.

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America Makes: National Additive Manufacturing Innovation Institute (NAMII) Project 1: Nondestructive Evaluation (NDE) of Complex Metallic Additive Manufactured (AM) Structures

Cited by 29 publications

References 49 publications

Assessment of trapped powder removal and inspection strategies for powder bed fusion techniques

Assessment of trapped powder removal and inspection strategies for powder bed fusion techniques

X-ray computed tomography for additive manufacturing: a review

Process defects andin situmonitoring methods in metal powder bed fusion: a review

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