Improvement of Web Spacing and Friction Characteristics by Two Types of Stationary Guides

2000 ◽  
Vol 123 (3) ◽  
pp. 509-516 ◽  
Author(s):  
Hiromu Hashimoto ◽  
Haruyasu Nakagawa
Keyword(s):  
Hydrostatic Pressure ◽  
Friction Coefficient ◽  
Hydrodynamic Pressure ◽  
Back Surface ◽  
Gaussian Distributions ◽  
Reflected Light ◽  
Experimental Apparatus ◽  
Entrained Air ◽  
The Web ◽  
Web Tension

In this paper, two types of stationary guides are presented to improve the web spacing characteristics; hybrid hollow porous guide for maintaining the sufficient web spacing and grooved guide for removing the entrained air. In the hybrid hollow porous guide, the pressurized air is added to the lubrication air flow between web and guide from inside the guide. Then, the web spacing characteristics are improved by the hybrid effects of hydrodynamic pressure due to web movements and hydrostatic pressure due to pressurized added air through the guide. The relations between web spacing and web velocity are measured under various supply pressures. Moreover, the relations between web spacing and web tension are examined. The contactless optical sensor, which can measure the variation of the quantities of reflected light from the back surface of web according to the variation of web spacing, is used to obtain the web spacing under various conditions. In the grooved guide, the method for the estimation of web spacing by using the concept of equivalent spacing between web and guide is presented, and the web spacing is measured by the same experimental apparatus used in the case of hollow porous guide. From the calculated and measured results obtained, the effectiveness of two types of guides on the web spacing is clarified. Finally, based on the assumptions of Gaussian distributions of asperities, the simple relations to predict the friction coefficient between web and guide surfaces are formulated, and the variation of friction coefficient with velocity is shown for various values of web tension.

The Effect of Web Permeability and Side Leakage on the Air Film Height Between a Roller and Web

1998 ◽  
Vol 120 (3) ◽  
pp. 559-565 ◽  
Author(s):  
K. S. Ducotey ◽  
J. K. Good
Keyword(s):  
Constant Pressure ◽  
Separation Distance ◽  
Foil Bearing ◽  
Pressure Region ◽  
Entrained Air ◽  
Web Quality ◽  
Air Film ◽  
Roller Radius ◽  
The Web ◽  
Web Tension

Air entrained between a web and roller can cause a loss in traction that can affect web quality. The entrained air causes an air layer to form which separates the web from the roller. Insufficient traction exists at this point and an idler roller will be unable to be driven by the web. Other applications, however, such as newsprint moving around a turnbar, require complete clearance. An equation for predicting the air film height between a permeable web and roller was developed using foil bearing theory. The separation distance (h) between the roller and web is a function of the roller radius (R), web tension (T), air viscosity (η), summation of the web and roller velocities (U), and the web permeability (α). The air film height was found to decrease linearly around the circumference (θ) of the roller in the constant pressure region. Therefore, the air film height can be expressed simply as, h=0.643R[(6ηU)/T]2/3−2[(αT)/U]θ The slope of the air film height is a function of the web/roller velocity, web tension, and the permeability of the paper. A correction factor for side leakage was also incorporated into the result.

Measurements of the Static Friction Coefficient Between Tin Surfaces and Comparison to a Theoretical Model

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Rebecca D. Ibrahim Dickey ◽  
Robert L. Jackson ◽  
George T. Flowers
Keyword(s):  
Theoretical Model ◽  
Friction Coefficient ◽  
Human Error ◽  
Surface Profile ◽  
Static Friction ◽  
Quantitative Agreement ◽  
High Plasticity ◽  
Static Friction Coefficient ◽  
Experimental Apparatus ◽  
Rough Surface Contact

A new experimental apparatus is used to measure the static friction between tin surfaces under various loads. After the data is collected it is then compared to an existing theoretical model. The experiment uses the classical physics technique of increasing the incline of a plane and block until the block slides. The angle at the initiation of sliding is used to find the static friction coefficient. The experiment utilizes an automated apparatus to minimize human error. The finite element based statistical rough surface contact model for static friction under full stick by Li, Etsion, and Talke (2010, “Contact Area and Static Friction of Rough Surfaces with High Plasticity Index,” ASME Journal of Tribology, 132(3), p. 031401) is used to make predictions of the friction coefficient using surface profile data from the experiment. Comparison of the computational and experimental methods shows similar qualitative trends, and even some quantitative agreement. After adjusting the results for the possible effect of the native tin oxide film, the theoretical and experimental results can be brought into reasonable qualitative and quantitative agreement.

Modeling of Web Slip on a Roller and Its Effect on Web Tension Dynamics

2005 ◽  
Author(s):  
Ramamurthy V. Dwivedula ◽  
Prabhakar R. Pagilla
Keyword(s):  
Numerical Computation ◽  
Dynamic Models ◽  
Simple Approach ◽  
Roller Surface ◽  
Perfect Adhesion ◽  
The Web ◽  
Web Tension

This paper considers the effect of web slip over the rollers on the span tension dynamics. In classical development of the web span tension dynamics, it is assumed that there is strict adhesion between the web and the surface of the roller and thus, there is no slip-page between the web and the roller. As a result of this assumption, effect of tension disturbances in downstream spans on the upstream span tension is precluded. However, in practice, perfect adhesion between the web and roller surface is seldom achieved and tension disturbances propagate upstream also. Though web span tension dynamic models that include slippage between web and roller are proposed, these models rely to a great extent on numerical computation of slip arc angles and are prohibitively complex to be of practical use. This paper proposes an alternative, simple approach for developing web span tension dynamics to include the effect of web slip.

scholarly journals Study on Friction and Lubrication Characteristics of Surface with Unidirectional Convergence Texture

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 780 ◽  
Author(s):  
Chenchen Li ◽  
Xuefeng Yang ◽  
Shouren Wang ◽  
Yanjun Wang ◽  
Chongyang Lu ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Abrasive Wear ◽  
Simulation Analysis ◽  
Dynamic Pressure ◽  
Contact Fatigue ◽  
Hydrodynamic Pressure ◽  
Surface Friction ◽  
Textured Surface ◽  
Fatigue Wear ◽  
Lubrication Performance

In order to study the influence of texture on the wear and lubrication performance of the surface of the tools, three kinds of textures with unidirectional convergence morphology were processed on the surface of the samples, and each texture was designed with different area occupancy ratios. Simulation analysis shows that, owing to the reflow and convection effect of liquid in the texture, the lubricating film flowing through the textured surface has a high hydrodynamic pressure value, and the semicircular ring texture is the most prominent. By comparing the friction coefficient, when the area occupancy ratio of texture on the surface is 10%, the surface of the samples with different morphology has the lowest coefficient of friction; the friction coefficient of the semicircular ring textured surface is especially very low. Surface textures reduce the direct contact area between the friction pairs, and generate dynamic pressure lubrication and secondary lubrication, so that the surface friction coefficient of the samples is obviously reduced. The surfaces of the non-textured samples have abrasive wear and contact fatigue wear, and the surfaces of the textured samples have adhesive wear, abrasive wear, and cavitation.

Friction Behavior in the Cup Ironing Process of Aluminum Sheets

1992 ◽  
Vol 114 (2) ◽  
pp. 175-180 ◽  
Author(s):  
N. Kawai ◽  
K. Dohda ◽  
M. Saito ◽  
N. Hayashi ◽  
Z. Wang
Keyword(s):  
Friction Coefficient ◽  
Friction Behavior ◽  
Surface Flattening ◽  
Aluminum Sheets ◽  
Experimental Apparatus ◽  
Die Surface ◽  
Lubricating Mechanism

The object of this paper is to clarity the surface flattening mechanism in the cup ironing process based on the lubricating mechanism. A new experimental apparatus for the ironing process was made and experiments on ironing were carried out with aluminum cups using various lubricants and reductions in thickness. The experiments revealed that on the die surface the friction coefficient becomes minimum under the appropriate conditions of viscosity of lubricant and reduction in thickness. It was also confirmed that the cup surface is best flattened under conditions where the minimum friction coefficient appears.

Advanced Optimization of Industrial Large-Scale Roll-to-Roll Systems Under Parametric Uncertainties

2012 ◽  
Author(s):  
J. Frechard ◽  
D. Knittel
Keyword(s):  
Young’S Modulus ◽  
Large Scale ◽  
Young's Modulus ◽  
Robust Design Optimization ◽  
Parametric Uncertainties ◽  
Optimization Approach ◽  
Roll To Roll ◽  
Polymer Metal ◽  
The Web ◽  
Web Tension

In industrial plants some parameters can not be evaluated properly or they are varying with time. These parametric uncertainties has to be taken into account during the design process of industrial systems. In this work, the developped optimization approach is applied on an industrial roll-to-roll sytem. Such systems are commonly used to handle materials as polymer, metal, paper and textile. The key challenge is to move the web at the expected speed while maintaining the web tension in an acceptable range around its reference. Moreover, the Young’s modulus of the web is difficult to evaluate and it is varying with time due to temperature and moisture variations. This paper deals with the web tension controller synthesis on a large-scale roll-to-roll system with uncertain Young’s modulus. To synthesize web tension controllers, an H∞ approach is applied and adapted to the system with parametric uncertainties using multi-objective robust design optimization.

Numerical Investigation on the Mixed Lubrication Performance of Water-Lubricated Coupled Journal and Thrust Bearings

2019 ◽  
Author(s):  
Yanfeng Han ◽  
Guo Xiang ◽  
Jiaxu Wang
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Thrust Bearing ◽  
Journal Bearing ◽  
Load Capacity ◽  
Hydrodynamic Pressure ◽  
Mixed Lubrication ◽  
Eccentricity Ratio ◽  
Thrust Bearings ◽  
Lubrication Performance

Abstract The mixed lubrication performance of water-lubricated coupled journal and thrust bearing (simplified as coupled bearing) is investigated by a developed numerical model. To ensure the continuity of hydrodynamic pressure and flow at the common boundary between the journal and thrust bearing, the conformal transformation is introduced to unify the solution domain of the Reynolds equation. In the presented study, the coupled effects between the journal and thrust bearing are discussed. The effects of the thrust bearing geometric film thickness on the mixed lubrication performance, including the load capacity, contact load and friction coefficient, of the journal bearing are investigated. And the effects of the journal bearing eccentricity ratio on the mixed lubrication performance of the thrust bearing are also investigated. The simulated results indicate the mutual effects between the journal and thrust bearing cannot be ignored in the coupled bearing system. The increasing thrust bearing geometric film thickness generates a decrease in load capacity of journal bearing. There exists an optimal eccentricity ratio of journal bearing that yields the minimum friction coefficient of the thrust bearing.

Longitudinal and Out-of-Plane Stiffness of a Web in an Air-Flotation Oven

1999 ◽  
Author(s):  
Young B. Chang ◽  
Ronald P. Swanson ◽  
Peter M. Moretti
Keyword(s):  
Analytical Model ◽  
Experimental Results ◽  
Photographic Film ◽  
Longitudinal Stiffness ◽  
Out Of Plane ◽  
Air Cushion ◽  
Air Flotation ◽  
Low Tension ◽  
The Web ◽  
Web Tension

Abstract Air-flotation ovens are used for non-contact drying of coated web materials such as photographic film, magnetic media, and paper. In a typical air-flotation oven, the air bars are arranged in such a way that the path of web is nearly sinusoidal. When web tension fluctuates, the distance between the web and the air bars also changes. This phenomenon affects the longitudinal dynamics and tension control of an air-floated web. In some cases, tension fluctuations can cause the web to touch the air bars, resulting in damage to the coating and the web. This paper discusses an analytical model of the extensional resiliency of an air-floated web. The analysis shows that at low tension the longitudinal stiffness of an air-floated web is small, being dominated by the air cushion effects. At higher web tension, however, the effects of material deformation become more important than the air cushion effects. The analysis is compared with the experimental results obtained in a pilot air-flotation oven. The analytical and experimental results show the same trends, though the analytical model tends to underpredict the longitudinal stiffness of air-supported webs.

Bahnzugkraftregelung in der Batteriezellfertigung*/Web tension control in battery cell production

2018 ◽  
Vol 108 (07-08) ◽  
pp. 519-524
Author(s):  
H. Weinmann ◽  
F. Lang ◽  
J. Hofmann ◽  
J. Fleischer
Keyword(s):  
Dimensional Accuracy ◽  
Tension Control ◽  
Selection Function ◽  
Battery Cell ◽  
Cell Production ◽  
Material Parameters ◽  
Single Sheet ◽  
The Web ◽  
Web Tension

Viele Maschinen- und Materialparameter sind für die Qualität eines Elektroden-Einzelblattes verantwortlich. Relevant für Vereinzelung und Stapelbildung ist etwa die Bahnzugkraft, mit der die Elektrodenbahn während des Stanzvorgangs beaufschlagt wird. Diese wurde in der Versuchsanlage des wbk Institut für Produktionstechnik regelbar ausgeführt, um Zusammenhänge bei der Einzelblattstapelbildung zu untersuchen. Dieser Artikel stellt Auswahl und Funktion sowie die Integration der Lösung in die Versuchsanlage und die Auswirkung verschiedener Bahnzugkräfte auf die Maßhaltigkeit der gestanzten Einzelblätter vor.   The quality of an electrode single-sheet is affected by a multitude of machine and material parameters, such as the web tension force for separating and stacking applied to the electrode web during die cutting. As an adjustable force it was analyzed in a demonstrator at the wbk Institute of Production Science to identify interdependencies during single-sheet-stacking. This article presents the selection, function and integration of the solution into a demonstrator and how different web tension forces affect the dimensional accuracy of die-cut sheets.

Sign in / Sign up

Export Citation Format

Share Document