The Film Thickness Variation in the Work Zone of Hydrodynamically Lubricated Continuous Deformation Processes

1973 ◽  
Vol 95 (4) ◽  
pp. 541-543 ◽  
Author(s):  
W. R. D. Wilson
Keyword(s):  
Film Thickness ◽  
Work Zone ◽  
Thickness Variation ◽  
Continuous Deformation ◽  
Deformation Processes

Hydrodynamic Lubrication of Hydrostatic Extrusion

1976 ◽  
Vol 98 (1) ◽  
pp. 27-31 ◽  
Author(s):  
W. R. D. Wilson ◽  
S. M. Mahdavian
Keyword(s):  
Film Thickness ◽  
Castor Oil ◽  
Hydrodynamic Lubrication ◽  
Film Formation ◽  
Hydrostatic Extrusion ◽  
Work Zone ◽  
Thickness Variation ◽  
Viscous Heating ◽  
Theoretical Predictions ◽  
Good Agreement

An analytical model for the hydrodynamic lubrication of hydrostatic extrusion is developed. This includes the effect of viscous heating on the film formation process and the effect of viscous and plastic heating on the friction and film thickness variation in the work zone. Theoretical predictions of film thickness and extrusion pressure show good agreement with experimental measurements for aluminum billets lubricated with castor oil.

Application of dynamic mesh technology in the oil film flow simulation for hydrostatic bearing

2019 ◽  
Vol 71 (1) ◽  
pp. 146-153
Author(s):  
Yanqin Zhang ◽  
Zhiquan Zhang ◽  
Xiangbin Kong ◽  
Rui Li ◽  
Hui Jiang
Keyword(s):  
Film Thickness ◽  
Flow Velocity ◽  
Manufacturing Industry ◽  
Dynamic Mesh ◽  
Lubricating Oil ◽  
Thickness Variation ◽  
Content Type ◽  
Oil Film ◽  
Rotating Speed ◽  
Hydrostatic Bearing

Purpose The purpose of this paper was to obtain the lubrication characteristics of heavy hydrostatic bearing in heavy equipment manufacturing industry through theoretical analysis and numerical simulation. Design/methodology/approach This paper discusses the influence of oil film thickness variation on velocity field, outlet-L and outlet-R flow velocity under the hydrostatic bearing running in no-load 0 N, load 400 KN, full load 1,500 KN and rotating speeds of 10 r/min, 20 r/min, 30 r/min, 40 r/min, 50 r/min and 60 r/min, by using dynamic mesh technology and FLUENT software. Findings When the working table rotates clockwise, in the change process of oil film thickness, the fluid flow pattern of the lubricating oil at the edge of the sealing oil is the rule of laminar flow, and the oil cavity has a vortex. The outlet-R flow velocity becomes higher and higher by increasing the bearing load and working table speed, and the flow velocity increases with the decrease in oil film thickness; the outlet-L flow velocity increases with the decrease in oil film thickness under low rotating speed (less than 10 r/min) condition and decreases with the decrease of oil film thickness under high rotating speed (more than 60 r/min) condition. Originality/value The influence of the oil film thickness on the flow state distribution of the oil film was analyzed under different working conditions, and the influence rules of oil film thickness on the flow velocity of hydrostatic bearing oil pad was obtained by using dynamic mesh technology.

scholarly journals Effect of the Thickness of Insulator Polymeric Films on the Memory Behavior: The Case of the Polymethylmethacrylate and the Polystyrene

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
J. A. Avila-Niño ◽  
A. O. Sustaita ◽  
M. Reyes-Reyes ◽  
R. López-Sandoval
Keyword(s):  
Film Thickness ◽  
Differential Resistance ◽  
Polymeric Films ◽  
Thickness Variation ◽  
Pmma Film ◽  
Organic Layer ◽  
Organic Film ◽  
Aluminum Particles ◽  
Conductivity Switching ◽  
Type Of Behavior

The effect of thickness variation on the memory behavior of the polymethylmethacrylate-(PMMA)-based devices has been investigated. The PMMA film thicknesses have been varied between 5 to 300 nm, and we have found that the film thickness determines the type of behavior: ohmic, write-once-read-many-times (WORM) memory with two ON states, WORM memory with a negative differential resistance (NDR) region, and WORM memory without NDR region. The fact that similar results were obtained using different solvents to dilute PMMA (chlorobenzene, chloroform, and dimethyl sulfoxide), as well as using an other insulating polymer such as polystyrene (PS), leads to the conclusion that the phenomenon of memory depends on the aluminum electrodes, organic film thickness, and the compliance current used during the electroformation whereas the type of organic layer (PMMA or PS) has minor influence. From here, we conclude that the conductivity switching of the insulator organic film is due to the injection of aluminum particles into the film during the first voltage cycle.

Effect of Stiff Coatings on EHL Film Thickness in Point Contacts

2007 ◽  
Author(s):  
Yuchuan Liu ◽  
Q. Jane Wang ◽  
Dong Zhu
Keyword(s):  
Film Thickness ◽  
Working Conditions ◽  
Coating Thickness ◽  
Point Contact ◽  
Thickness Variation ◽  
Point Contacts ◽  
Lubricant Film Thickness ◽  
Wide Range ◽  
Minimum Film Thickness ◽  
Coating Material Properties

This study investigates the influences of coating material properties and coating thickness on lubricant film thickness based on a point-contact isothermal EHL model developed recently by the authors. The results present the trend of minimum film thickness variation as a function of coating thickness and elastic modulus under a wide range of working conditions. Numerical results indicates that the increase in minimum film thickness, Imax, and the corresponding optimal dimensionless coating thickness, H2, can be expressed in the following formulas: Imax=0.766M0.0248R20.0296L0.1379exp(−0.0245ln2L)H2=0.049M0.4557R2−0.1722L0.7611exp(−0.0504ln2M−0.0921ln2L) These formulas can be used to estimate the effect of a coating on EHL film thickness.

Partial Film Lubrication Characteristics of Inlet Zone in Cold Strip Rolling

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Kuo Fu ◽  
Yong Zang ◽  
Zhiying Gao
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Contact Area ◽  
Friction Stress ◽  
Area Ratio ◽  
Work Zone ◽  
Zone Length ◽  
Inlet Zone ◽  
Pressure Stress ◽  
Contact Area Ratio

According to the average flow Reynolds equation and rolling theory, a partial film lubrication model of inlet zone has been developed. The model mainly simulates and reflects the influence of surface topography on the inlet film thickness and inlet zone length. Based on the surface topography analysis, a method to judge the friction condition was proposed. All the calculation was conducted by a numerical method. The result shows that the transverse stripe increases the inlet film thickness and the inlet zone length, while the longitudinal stripe decreases them. The surface roughness will enhance this effect. The surface roughness and the stripe direction also have a significant influence on the contact area ratio and the distribution of stress and film thickness in work zone. Transverse stripe increases the lubricant film thickness and separates the roll and the sheet with a larger distance in work zone. It also decreases the contact area ratio, the pressure stress and friction stress of the work zone. Whereas longitudinal stripe decreases the film thickness and increases the contact area ratio, pressure stress and friction stress. The surface roughness increases the contact area ratio, pressure stress and friction stress.

Wafer Nanotopography Effects on CMP: Experimental Validation of Modeling Methods

2001 ◽  
Vol 671 ◽  
Author(s):  
Brian Lee ◽  
Duane S. Boning ◽  
Winthrop Baylies ◽  
Noel Poduje ◽  
Pat Hester ◽  
...  
Keyword(s):  
Film Thickness ◽  
Measurement Data ◽  
Relative Length ◽  
Experimental Results ◽  
Thickness Variation ◽  
Length Scale ◽  
Modeling Approaches ◽  
Measurement Analysis ◽  
Thickness Variations ◽  
Film Thinning

ABSTRACTNanotopography refers to 10-100 nm surface height variations that exist on a lateral millimeter length scale on unpatterned silicon wafers. Chemical mechanical polishing (CMP) of deposited or grown films (e.g., oxide or nitride) on such wafers can generate undesirable film thinning which can be of substantial concern in shallow trench isolation (STI) manufacturability. Proper simulation of the effect of nanotopography on post-CMP film thickness is needed to help in the measurement, analysis, diagnosis, and correction of potential problems.Our previous work has focused on modeling approaches that seek to capture the thinning and post-CMP film thickness variation that results from nanotopography, using different modeling approaches. The importance of relative length scale of the CMP process used (planarization length) to the length scale of the nanotopography on the wafer (nanotopography length) has been suggested.In this work, we report on extensive experiments using sets of 200 mm epi wafers with a variety of nanotopography signatures (i.e., different nanotopography lengths), and CMP processes of various planarization lengths. Experimental results indicate a clear relationship between the relative scales of planarization length and nanotopography length: when the planarization length is less than the nanotopography length, little thinning occurs; when the CMP process has a larger planarization length, surface height variations are transferred into thin film thickness variations. In addition to presenting these experimental results, modeling of the nanotopography effect on dielectric CMP processes is reviewed, and measurement data from the experiments are compared to model predictions. Results show a good correlation between the model prediction and the experimental data.

Sign in / Sign up

Export Citation Format

Share Document