A model for the screen-printing of Newtonian fluids

White, G. S.; Breward, Christopher; Howell, Peter; Young, Ray

doi:10.1007/s10665-005-9000-7

Cited by 15 publications

(22 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As in [13], we consider a two-dimensional screen with undisturbed height H 0 above a planar substrate, as illustrated in Fig. 2.…”

Section: Problem Formulation and Scalingmentioning

confidence: 99%

“…The flux of paste from one side to the other, F, is taken to be a prescribed function of the pressure difference across the screen. By considering Poiseuille flow of a power-law fluid through a channel (see, for example, Bird et al [17]), we estimate the flux (per unit area of screen) of fluid through an array of periodically spaced pores with open-area fraction φ generated by a pressure difference of p to be [13] where l is the distance between the pores, which have width l − w d and depth 2w d , as shown in Fig. 3.…”

Section: Modelling the Screenmentioning

confidence: 99%

“…Re-printed with permission from [13] None of these models, however, has taken into proper consideration the real geometry of the off-contact screenprinting process. White et al [13] therefore presented a two-dimensional model also based on lubrication theory, but in which the screen is modelled as a permeable membrane, whose position must be found as part of the solution. Although the model is for a Newtonian fluid, it can easily be extended to account for a power-law fluid.…”

mentioning

confidence: 99%

See 2 more Smart Citations

The screen printing of a power-law fluid

et al. 2011

Self Cite

View full text Add to dashboard Cite

We present a two-dimensional large-aspect-ratio model for the off-contact screen printing of a powerlaw fluid. We extend the work of White et al. (J Eng Math 54:49-70, 2005) by explicitly including the fluid/air free surface that is present beneath the screen ahead of the squeegee. In the distinguished parameter limit of greatest interest to industry, the process is quasi-steady on the time-scale of a print and can be analysed in three separate regions using the method of matched asymptotic expansions. This allows us to predict where the fluid transfers through the screen, the point at which it first makes contact with the substrate, and the amount of fluid deposited on the substrate during a print stroke. Finally, we show that using a shear-thinning fluid will decrease the amount of fluid transferred ahead of the squeegee, but increase the amount of fluid deposited on the substrate.

show abstract

“…As in [13], we consider a two-dimensional screen with undisturbed height H 0 above a planar substrate, as illustrated in Fig. 2.…”

Section: Problem Formulation and Scalingmentioning

confidence: 99%

Section: Modelling the Screenmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

The screen printing of a power-law fluid

et al. 2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…White et al [9] state that ink flux through the screen is proportional to the square root of the squeegee tip curvature; provided other factors remain unchanged. Although this is based on modeling using a Newtonian fluid, when screen printing inks are usually shear thinning, worn squeegees should give greater ink transfer as their sharp edges are gradually rounded.…”

Section: Discussionmentioning

confidence: 99%

“…Where volumes are large or the printed inks contain abrasive elements, the squeegee condition will vary over its lifetime and a decision must be made when to replace it. Research to date has focused principally on the effect of process settings [9][10][11][12] and no work has been reported to explore squeegee deterioration during printing.…”

Section: Introductionmentioning

confidence: 99%

A Study of the Abrasion of Squeegees Used in Screen Printing and Its Effect on Performance with Application in Printed Electronics

et al. 2014

View full text Add to dashboard Cite

This article presents a novel method for accelerated wear of squeegees used in screen printing and describes the development of mechanical tests which allow more in-depth measurement of squeegee properties. In this study, squeegees were abraded on the screen press so that they could be used for subsequent print tests to evaluate the effect of wear on the printed product. Squeegee wear was found to vary between different squeegee types and caused increases in ink transfer and wider printed features. In production this will lead to greater ink consumption, cost per unit and a likelihood of product failure. This also has consequences for the production of functional layers, etc., used in the construction of printed electronics. While more wear generally gave greater increases in ink deposition, the effect of wear differed, depending on the squeegee. There was a correlation between the angle of the squeegee wear and ink film thickness from a worn squeegee. An ability to resist flexing gave a high wear angle and presented a sharper edge at the squeegee/screen interface thus mitigating the effect of wear. There was also a good correlation between resistance to flexing and ink film thickness for unworn squeegees, which was more effective than a comparison based on Shore A hardness. Squeegee indentation at different force levels gave more information than a standard Shore A hardness test and the apparatus used was able to reliably measure reductions in surface hardness due to solvent absorption. Increases in ink deposition gave lower resistance in printed silver lines; however, the correlation between the amount of ink deposited and the resistance, remained the same for all levels of wear, OPEN ACCESSCoatings 2014, 4 357 suggesting that the wear regime designed for this study did not induce detrimental print defects such as line breakages.

show abstract

Printing technologies for silicon solar cell metallization: A comprehensive review

Tepner

Lorenz

2023

Progress in Photovoltaics

View full text Add to dashboard Cite

This paper presents a comprehensive overview on printing technologies for metallization of solar cells. Throughout the last 30 years, flatbed screen printing has established itself as the predominant metallization process for the mass production of silicon solar cells. For this reason, we will provide a detailed review on its history, its evolution over time, and how the continuous efforts of the scientific and industrial community for further improvements revolutionized the entire PV industry. Furthermore, we will guide the reader through the physics on silicon solar cell metallization, the fundamentals on contact formation, and what type of challenges and requirements these topics create for printing technologies. The main topic of this review addresses the flatbed screen-printing process mechanics, its different process sequences, corresponding screen technology, and the very important impact of paste rheology on the printing result. Finally, we will compare alternative upcoming printing approaches to flatbed screen printing and discuss how they might solve upcoming challenges in metallization in terms of increasing the throughput rates at an everdecreasing grid line width and reduced silver consumption.

show abstract

A model for the screen-printing of Newtonian fluids

Cited by 15 publications

References 22 publications

The screen printing of a power-law fluid

The screen printing of a power-law fluid

A Study of the Abrasion of Squeegees Used in Screen Printing and Its Effect on Performance with Application in Printed Electronics

Printing technologies for silicon solar cell metallization: A comprehensive review

Contact Info

Product

Resources

About