X-ray CT and image analysis methodology for local roughness characterization in cooling channels made by metal additive manufacturing

Klingaa, Christopher G.; Dahmen, T.; Baier, Sina; Mohanty, Sankhya; Hattel, Jesper Henri

doi:10.1016/j.addma.2019.101032

Cited by 21 publications

(23 citation statements)

References 32 publications

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“…As a step toward validation of the proposed methodology, the roughness was predicted and applied to the nominal geometry of channels produced at α = 0° and α = 90°. The predicted roughness was compared to X-ray computed tomography (CT) and image analysis results from (Klingaa et al , 2020) and may be seen in Figure 6.…”

Section: Resultsmentioning

confidence: 99%

“…The models used for roughness prediction of any point within a channel were obtained from (Klingaa et al , 2020) where a methodology for obtaining simple roughness prediction models for metal additively manufactured channels was proposed. As a case study, a roughness prediction model was generated for channels made in 17–4 PH stainless steel on an EOS M 290 system.…”

Section: Methodsmentioning

confidence: 99%

“…As a final step of the roughness prediction, the methodology sought to apply the roughness to the point cloud such that the nominal geometry would resemble a realistic post-manufacture geometry. This was done under the assumption that areas of high roughness, also have larger dross formation (Klingaa et al , 2020). Each point true(xyztrue)i, was moved by a distance based on its designated Ra-value, Ra i toward the direction of the point normal, truen⇀i.…”

Section: Methodsmentioning

confidence: 99%

“…This is done under the assumption that the manufactured channels would follow the nominal design and that roughness could be applied according to a roughness table of known subtractive processes. This is not the case for laser powder bed fusion (LPBF) manufactured channels where it has been found that the actual shape and roughness of the channel depends on the orientation of the channel with respect to the build direction (Snyder et al , 2016; Klingaa et al , 2020). As conformal cooling channels inherently may follow a complex pattern in three-dimensional, avoiding bad orientations is not always a possibility.…”

Section: Introductionmentioning

confidence: 99%

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Realistic design of laser powder bed fusion channels

Klingaa

Mohanty

Hattel

2020

RPJ

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Purpose Conformal cooling channels in additively manufactured molds are superior over conventional channels in terms of cooling control, part warpage and lead time. The heat transfer ability of cooling channels is determined by their geometry and surface roughness. Laser powder bed fusion manufactured channels have an inherent process-induced dross formation that may significantly alter the actual shape of nominal channels. Therefore, it is crucial to be able to predict the expected surface roughness and changes in the geometry of metal additively manufactured conformal cooling channels. The purpose of this paper is to present a new methodology for predicting the realistic design of laser powder bed fusion channels. Design/methodology/approach This study proposes a methodology for making nominal channel design more realistic by the implementation of roughness prediction models. The models are used for altering the nominal shape of a channel to its predicted shape by point cloud analysis and manipulation. Findings A straight channel is investigated as a simple case study and validated against X-ray computed tomography measurements. The modified channel geometry is reconstructed and meshed, resulting in a predicted, more realistic version of the nominal geometry. The methodology is successfully tested on a torus shape and a simple conformal cooling channel design. Finally, the methodology is validated through a cooling test experiment and comparison with simulations. Practical implications Accurate prediction of channel surface roughness and geometry would lead toward more accurate modeling of cooling performance. Originality/value A robust start to finish method for realistic geometrical prediction of metal additive manufacturing cooling channels has yet to be proposed. The current study seeks to fill the gap.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Realistic design of laser powder bed fusion channels

Klingaa

Mohanty

Hattel

2020

RPJ

View full text Add to dashboard Cite

show abstract

“…However, their studies were performed on external AM surfaces. More recently, Klingaa et al [30,31] extended the CT analysis to internal surfaces of LPBF channels, by modelling the roughness value depending on the defined global build orientation (α) and local orientation (β). This approach allows establishing novel concepts, like the presented rough belt concept with an angular width, which showed how the angular width directly correlates to the α-orientation.…”

Section: Introductionmentioning

confidence: 99%