Stationary and stability analysis of the film casting process

Silagy, David; Demay, Yves; Agassant, Jean‐François

doi:10.1016/s0377-0257(98)00119-0

Cited by 88 publications

(82 citation statements)

References 16 publications

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“…Silagy et al investigated the stability of the cast of film process using different constitutive equations. A membrane model has been considered and both linear stability analysis and direct numerical simulation have been employed [5]. In that case, increasing the drawing distance stabilizes the process.…”

Section: Figure 1 (A) Schematic Of the Coating Process (B) Half Flomentioning

confidence: 99%

“…Interface with air is determined by successive iterations of Newton-Raphson's method (by adjusting the position of the nodes on the interface) to satisfy the kinematic interface transient equation given by: ( 5 ) 050004-2 where is the velocity vector at interface and h is the interface position. This strategy is relatively precise but it is unable to describe transient evolution of the interface.…”

Section: Tracking Strategymentioning

confidence: 99%

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Stability analysis of a polymer coating process

Kallel

Hachem

Demay

et al. 2015

AIP Conference Proceedings

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Abstract.A new coating process involving a short stretching distance (1 mm) and a high draw ratio (around 200) is considered. The resulting thin molten polymer film (around 10 micrometers) is set down on a solid primary film and then covered by another solid secondary film. In experimental studies, periodical fluctuation in the thickness of the coated layer may be observed. The processing conditions markedly influence the onset and the development of these defects and modeling will help our understanding of their origins. The membrane approach which has been commonly used for cast film modeling is no longer valid and two dimensional time dependent models (within the thickness) are developed in the whole domain (upstream die and stretching path). A boundary-value problem with a free surface for the Stokes equations is considered and stability of the free surface is assessed using two different numerical strategies: a tracking strategy combined with linear stability analysis involving computation of leading eigenvalues, and a Level Set capturing strategy coupled with transient stability analysis.

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Section: Figure 1 (A) Schematic Of the Coating Process (B) Half Flomentioning

confidence: 99%

Section: Tracking Strategymentioning

confidence: 99%

Stability analysis of a polymer coating process

Kallel

Hachem

Demay

et al. 2015

AIP Conference Proceedings

Self Cite

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“…-The membrane model is then enriched to capture both development of the dog bone defect and neck-in by considering thickness and mean velocities in stretching and transverse directions to be functions of x and y (e(x,y), u(x,y) and v(x,y)). Direct numerical simulation was used by Silagy et al, (1998). Figure 13 shows the thickness as a function of time for increasing values of the Draw ratio after introducing at t=0 a small arbitrary perturbation of the steady flow (A= 0.5).…”

Section: Influence Of the Neck-in Phenomenonmentioning

confidence: 99%

“…This is not a mathematical artifact and an US patent has been applied (Chambon et al, 1998) to draw films in these super-stable conditions. Silagy et al (1998) and Kim et al (2005) coupled the UCM model with a 2D membrane model accounting for width and thickness reduction. Kim et al (2005) computed the transient thickness and width responses to small perturbations using a time-space numerical scheme.…”

Section: Influence Of the Rheologymentioning

confidence: 99%

An Overview of Molten Polymer Drawing Instabilities

Agassant¹,

Demay²

2014

Film Processing Advances

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Drawing instabilities and rupture are a serious limitation in polymer fibre and film processing. Onset of these defects depends on the processing conditions, on heat transfer, and on the rheology of the polymer even if some may be encountered for Newtonian fluids. The main part of this paper is devoted to the different forms of the draw resonance instability encountered in fibre spinning, cast-film and film blowing. The time dependent equations are presented for the simplified situation of constant width cast-film. Results of the two possible modelling strategies, linear stability analysis and direct simulation, applied to the different fibre and film processes are discussed.

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“…This frequently used model was capable of predicting the dog-bone effect under the stationary conditions. Silagy et al [14] continued and enriched membrane model by a supplementary kinematic hypothesis, which was originally brought Narayanaswamy [15] in his paper on float glass stretching, and carried out the extent isothermal study on the process condition and stability of EFC [16,17]. There has also been done a considerable amount of work on EFC under the non-isothermal conditions by Lamberti et al [18][19][20], Lamberti and Titomanlio [21][22][23][24], and Titomanlio [25].…”

Section: Introductionmentioning

confidence: 99%

Effect of viscoelastic stress state at die exit on extrusion film casting process: Theoretical study

Barborik

Zatloukal

2015

AIP Conference Proceedings

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Abstract. In this work, viscoelastic, isothermal extrusion film casting modeling utilizing 1D membrane model and modified Leonov model was performed in order to understand the role of viscoelastic stress state at the die exit on the polymer melt film stretching in the post die area. Experimental data for LDPE and theoretical predictions based on the eXtended Pom-Pom (XPP) model taken from the open literature were used for the validation purposes. It was found that predicting capabilities of 1D membrane model utilizing XPP and modified Leonov model are comparable for the given processing conditions and material. Consequent theoretical parametric study revealed that increase in the viscoelastic stress state at the die exit, characterized as the ratio of second and first normal stress differences, -N 2 /N 1 , leads to increase in neck-in phenomenon. This suggests that specific attention should be paid to optimization of the extrusion die design in order to stabilize polymer melt film stretching in the post die area.

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Stationary and stability analysis of the film casting process

Cited by 88 publications

References 16 publications

Stability analysis of a polymer coating process

Stability analysis of a polymer coating process

An Overview of Molten Polymer Drawing Instabilities

Effect of viscoelastic stress state at die exit on extrusion film casting process: Theoretical study

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