Investigation of a Polishing Pad and a Carrier Film for Decreasing Edge Roll Off of Workpiece

2011 ◽  
Vol 325 ◽  
pp. 476-481
Author(s):  
Urara Satake ◽  
Wen Xiao Wang ◽  
Toshiyuki Enomoto ◽  
Norikazu Tabata
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Flat Surface ◽  
Silicon Wafers ◽  
Film Properties ◽  
Polishing Pad ◽  
Fine Fiber ◽  
Hard Polymer ◽  
Polishing Pads ◽  
Carrier Film

Demand for diminishing edge roll off of workpiece has rapidly increased, especially in polishing silicon wafers and glass disks. However, the conventional polishing technologies cannot meet the demand. To address this problem, the influence of carrier film properties and that of polishing pad properties on the stress distribution near the workpiece edge were investigated using finite element methods. Based on the analytical results, double-layered polishing pads having an extra-fine fiber thin layer and a hard polymer layer were developed. Polishing experiments on silicon wafers and glass plates showed that the developed polishing pads achieved high finishing efficiency and extremely flat surface near the edge.

Achieving High Flatness of Workpiece Edge Shape by Considering Polishing Pressure

2010 ◽  
Vol 447-448 ◽  
pp. 71-75
Author(s):  
Takahiro Miyake ◽  
Toshiyuki Enomoto
Keyword(s):  
Semiconductor Devices ◽  
Silicon Wafers ◽  
Polishing Process ◽  
Model Based ◽  
Polishing Pad ◽  
Experimental Analyses ◽  
Polishing Pads ◽  
Polishing Pressure

In recent years, the achievement of further high flatness of workpiece edge shape is strongly required in mirror finishing. Especially, the edge roll off of silicon wafers as the substrates of semiconductor devices is demanded to decrease in the polishing process for raising the yield of IC chips. Many theoretical and experimental analyses for the edge roll off generation have been already done to meet the demand. The analyses, however, cannot fully account for the obtained edge shape in actual polishing. Concretely, the influence of the polishing pressure as one of the key polishing conditions on the edge roll off has not been clarified. In this study, the influence of the polishing pressure on the edge shape was investigated by the polishing experiments and the edge roll off generation analyses using the model based on the viscoelasticity of the polishing pad, which was proposed in the previous study. And it was revealed that an appropriate polishing pressure is needed to be set for achieving high flatness of workpiece edge shape with the consideration of the properties of applied polishing pads.

scholarly journals Studying Maximum Plantar Stress per Insole Design Using Foot CT-Scan Images of Hyperelastic Soft Tissues

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Ali Sarikhani ◽  
Abbas Motalebizadeh ◽  
Sasan Asiaei ◽  
Babak Kamali Doost Azad
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Ct Scan ◽  
Maximum Stress ◽  
Soft Tissues ◽  
Flat Surface ◽  
Uniform Stress ◽  
Heel Height ◽  
Element Method

The insole shape and the resulting plantar stress distribution have a pivotal impact on overall health. In this paper, by Finite Element Method, maximum stress value and stress distribution of plantar were studied for different insoles designs, which are the flat surface and the custom-molded (conformal) surface. Moreover, insole thickness, heel’s height, and different materials were used to minimize the maximum stress and achieve the most uniform stress distribution. The foot shape and its details used in this paper were imported from online CT-Scan images. Results show that the custom-molded insole reduced maximum stress 40% more than the flat surface insole. Upon increase of thickness in both insole types, stress distribution becomes more uniform and maximum stress value decreases up to 10%; however, increase of thickness becomes ineffective above a threshold of 1 cm. By increasing heel height (degree of insole), maximum stress moves from heel to toes and becomes more uniform. Therefore, this scenario is very helpful for control of stress in 0.2° to 0.4° degrees for custom-molded insole and over 1° for flat insole. By changing the material of the insole, the value of maximum stress remains nearly constant. The custom-molded (conformal) insole which has 0.5 to 1 cm thickness and 0.2° to 0.4° degrees is found to be the most compatible form for foot.

The Edge Roll Off Generation Mechanism in Polishing by Considering the Viscoelasticity of Polishing Pads

2009 ◽  
Author(s):  
Takahiro Miyake ◽  
Toshiyuki Enomoto ◽  
Kenji Hirose
Keyword(s):  
Semiconductor Devices ◽  
Measurement Instrument ◽  
Silicon Wafers ◽  
Generation Mechanism ◽  
Polishing Process ◽  
Dynamic Motion ◽  
Polishing Pad ◽  
Experimental Analyses ◽  
Polishing Pads

Recently, the achievement of further high flatness of workpiece edge shape is strongly required in mirror finishing. Especially, the edge roll off of silicon wafers as the substrates of semiconductor devices is demanded to decrease in the polishing process for raising the yield of IC chips. Many theoretical and experimental analyses of the edge roll off generation have been already done and the polishing methods for suppressing the roll off have been proposed to meet the demand. The analyses, however, cannot fully account for the obtained edge shape in actual polishing and the problem about the roll off remains. In this study, the generation mechanism of the edge roll off based on the viscoelasticity of polishing pad was newly proposed. The mechanism considered the horizontal and vertical relative static and dynamic motion between the pad and the workpiece. Moreover, the non-contact viscoelasticity measurement instrument was originally developed to evaluate the viscoelasticity of the polishing pad precisely. A series of polishing experiments for silicon wafers revealed that the edge shape, which was induced from the edge roll off generation mechanism and the measured viscoelasticity of the polishing pad, corresponded well with the obtained edge shape.

scholarly journals A Finite Element Simulation of Nano Effects on Stress Distribution in a Below Knee Prosthetic

2021 ◽  
Vol 1067 (1) ◽  
pp. 012141
Author(s):  
Muhsin J. Jweeg ◽  
H. A. Hamzah ◽  
Muhannad Al-Waily ◽  
Mohsin Abdullah Al-Shammari
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Finite Element Simulation ◽  
Element Simulation

scholarly journals Comparison of one versus two maxillary molars distalization with iPanda: a finite element analysis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Kamontip Sujaritwanid ◽  
Boonsiva Suzuki ◽  
Eduardo Yugo Suzuki
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Alveolar Bone ◽  
Vertical Direction ◽  
Minimal Amount ◽  
Element Analysis ◽  
Molar Distalization ◽  
Second Molar ◽  
Maxillary Molars ◽  
Displacement Patterns

Abstract Background The purpose of this study was to compare the stress distribution and displacement patterns of the one versus two maxillary molars distalization with iPanda and to evaluate the biomechanical effect of distalization on the iPanda using the finite element method. Methods The finite element models of a maxillary arch with complete dentition, periodontal ligament, palatal and alveolar bone, and an iPanda connected to a pair of midpalatal miniscrews were created. Two models were created to simulate maxillary molar distalization. In the first model, the iPanda was connected to the second molar to simulate a single molar distalization. In the second model, the iPanda was connected to the first molar to simulate “en-masse” first and second molar distalization. A varying force from 50 to 200 g was applied. The stress distribution and displacement patterns were analyzed. Results For one molar, the stress was concentrated at the furcation and along the distal surface in all roots with a large amount of distalization and distobuccal crown tipping. For two molars, the stress in the first molar was 10 times higher than in the second molar with a great tendency for buccal tipping and a minimal amount of distalization. Moreover, the stress concentration on the distal miniscrew was six times higher than in the mesial miniscrew with an extrusive and intrusive vector, respectively. Conclusions Individual molar distalization provides the most effective stress distribution and displacement patterns with reduced force levels. In contrast, the en-masse distalization of two molars results in increased force levels with undesirable effects in the transverse and vertical direction.

scholarly journals Three-Dimensional Finite Element Analysis of Stress Distribution in a Tooth Restored with Full Coverage Machined Polymer Crown

2021 ◽  
Vol 11 (3) ◽  
pp. 1220
Author(s):  
Azeem Ul Yaqin Syed ◽  
Dinesh Rokaya ◽  
Shirin Shahrbaf ◽  
Nicolas Martin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Intraoral Scanner ◽  
Element Analysis ◽  
Dental Ceramic ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Ceramic Crown

The effect of a restored machined hybrid dental ceramic crown–tooth complex is not well understood. This study was conducted to determine the effect of the stress state of the machined hybrid dental ceramic crown using three-dimensional finite element analysis. Human premolars were prepared to receive full coverage crowns and restored with machined hybrid dental ceramic crowns using the resin cement. Then, the teeth were digitized using micro-computed tomography and the teeth were scanned with an optical intraoral scanner using an intraoral scanner. Three-dimensional digital models were generated using an interactive image processing software for the restored tooth complex. The generated models were imported into a finite element analysis software with all degrees of freedom concentrated on the outer surface of the root of the crown–tooth complex. To simulate average occlusal load subjected on a premolar a total load of 300 N was applied, 150 N at a buccal incline of the palatal cusp, and palatal incline of the buccal cusp. The von Mises stresses were calculated for the crown–tooth complex under simulated load application was determined. Three-dimensional finite element analysis showed that the stress distribution was more in the dentine and least in the cement. For the cement layer, the stresses were more concentrated on the buccal cusp tip. In dentine, stress was more on the cusp tips and coronal 1/3 of the root surface. The conventional crown preparation is a suitable option for machined polymer crowns with less stress distribution within the crown–tooth complex and can be a good aesthetic replacement in the posterior region. Enamic crowns are a good viable option in the posterior region.

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