Vortex formation in a viscoelastic entry flow of asymmetric planar contraction

Anazawa, Tomohiko; Fujisawa, Nobuyuki; Yajima, Takahiro; Yamagata, Takayuki

doi:10.1007/s12650-010-0028-z

Cited by 3 publications

(3 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The OpenSCAD script allows for various design features to be incorporated into the design of the slot die following advanced geometries previously investigated [20][21][22][23][24][25][26]. Dimensional changes to the body of the die, along with the addition of internal features, create the potential for the fabrication of dual cavity slot dies.…”

Section: Slot Die Designmentioning

confidence: 99%

Open-source parametric 3-D printed slot die system for thin film semiconductor processing

Beeker

Pringle

Pearce

2018

Additive Manufacturing

View full text Add to dashboard Cite

Slot die coating is growing in popularity because it is a low operational cost and easily scaled processing technique for depositing thin and uniform films rapidly, while minimizing material waste. The complex inner geometry of conventional slot dies require expensive machining that limits accessibility and experimentation. In order to overcome these issues this study follows an open hardware approach, which uses an open source 3-D printer to both fabricate the slot die and then to functionalize a 3-D slot die printing system. Polymer materials are tested and selected for compatibility with common solvents and used to fabricate a custom slot die head. This slot die is then integrated into a 3-D printer augmented with a syringe pump to form an additive manufacturing platform for thin film semiconductor devices. The full design of the slot die system is disclosed here using an open source license including software and operational protocols. This study demonstrates that functional lab-grade slot dies may be 3-D printed using low-cost open source hardware methods. A case study using NiO2 found an RMS value 0.486 nm, thickness of 17 to 49nm, and a maximum optical transmission of 99.1%, which shows this additive manufacturing approach to slot die depositions as well of fabrication is capable of producing viable layers of advanced electronic materials. Using this method, a cost savings of over 17,000% was obtained when compared to commercial slot die systems for laboratories.

show abstract

Section: Slot Die Designmentioning

confidence: 99%

Open-source parametric 3-D printed slot die system for thin film semiconductor processing

Beeker

Pringle

Pearce

2018

Additive Manufacturing

View full text Add to dashboard Cite

show abstract

“…Although the numerical simulations reproduce the main features of the vortex formation of viscoelastic flows, the quantitative comparison of the flow field has not been studied in literature due to the lack of quantitative experimental data (7) . On the other hand, there are very few studies on the vortex formation in the entry flow of asymmetrical planar contractions (8), (9) , which are often encountered in the practical molding geometry. Such literature survey demonstrates an importance of quantitative experimental data for the entry flow of asymmetrical planar contraction flows.…”

Section: Introductionmentioning

confidence: 99%

“…They found that corner vortices were generated in the entry flow in the upstream of the contraction at higher Weissenberg number. Later, experiments for entry flows in an asymmetrical planar geometry are carried out by Anazawa et al (8), (9) using flow visualization and PIV measurement, because the asymmetrical planar geometry to avoid the vortex formation is essential in slot die coating. Their experimental study focussed on the flow behavior of viscoelastic fluid in the entry channel of asymmetric planar contraction.…”

Section: Introductionmentioning

confidence: 99%

Effect of Contraction Width on the Vortex Formation of Viscoelastic Flow in Asymmetric Planar Contractions

Yamagata

Yajima

Fujisawa

2011

JFST

View full text Add to dashboard Cite

In this paper, the flow behavior of viscoelastic fluid in asymmetric planar contraction geometry is studied by flow visualization and PIV measurement. Experiments are carried out for three channels of different contraction widths. The experimental results indicate that the flow field in the contraction channel is characterized by the Weissenberg number to Newtonian-like flow, transitional flow and vortex formation flow. It is found that the vortex formation flow occurs over the critical Weissenberg number, which is independent of the Reynolds number. However, the critical Weissenberg number decreases with increasing the contraction width due to the influence of velocity acceleration in the entry channel in the upstream of the contraction.

show abstract