A Novel Method to Dicing Anodically Bonded Silicon Glass MEMS Wafers Based on UV Laser Technique

2014 ◽  
Vol 511-512 ◽  
pp. 3-7
Author(s):  
Zhi Sheng Jing ◽  
Ze Long Zhou ◽  
Chen Mei ◽  
Xiang Yong Su ◽  
Zhuo Yang ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Bonding Temperature ◽  
Fem Simulation ◽  
Glass Wafer ◽  
Stress Distributions ◽  
Uv Laser ◽  
The Finite Element Method ◽  
Laser Technique ◽  
Novel Method ◽  
Good Agreement

UV laser dicing has many advantages such as mechanical stress-free and dicing shape-free, but it is seldom used to dice multi-layer MEMS wafers because of the deposition of a lot of debris and heat affected zones around the dicing lines. In this paper, a novel UV laser dicing method for anodically bonded wafers is presented. The heat caused split of the bonded silicon and glass around the dicing line is prevented by fabricating recesses on either the glass wafer or the silicon wafer. The Finite Element Method (FEM) in the ANSYSTM software was utilized to analyze the temperature and thermal stress distributions during the dicing process. The thermal stress is minimized sharply due to the fabrication of the recesses beneath the dicing line. The thicknesses of the glass and silicon wafers are 500μm and 250μm, respectively. The anodically bonding temperature is 360oC, and the bonding voltage is 400V. Dicing experiments show that the huge thermal stress caused by the laser can split the originally bonded silicon from glass around the dicing line. After recesses are fabricated along the dicing line, no heat caused split happens. The experiment results are in a good agreement with the FEM simulation. Compared with other methods, this research can provide a more reliable, flexible and cheaper laser dicing process for thick anodically bonded silicon/glass MEMS wafers, especially for multi-layer wafers with free shape.

Comparison of Offset and Wiping Z-Die Designs for Precision Z-Bent Part Fabrication

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Sutasn Thipprakmas ◽  
Pakkawat Komolruji ◽  
Wiriyakorn Phanitwong
Keyword(s):  
Fem Simulation ◽  
The Finite Element Method ◽  
Spring Back ◽  
Bend Radius ◽  
Dimensional Precision ◽  
Bending Process ◽  
Simulation Results ◽  
Bend Angles ◽  
Selection Of ◽  
Good Agreement

In recent years, the requirements for high dimensional precision on Z-bent shaped parts have become increasingly stringent. To attain these requirements, the suitable selection of the Z-die bending type has to be considered much more strictly. In this research, two types of Z-bending processes, offset Z-die bending and wiping Z-die bending, were investigated using the finite element method (FEM) to identify the spring-back characteristics and dimensions of Z-bent shaped parts. In the case of offset Z-die bending, the spring-back characteristics on both bend angles were similar. In contrast, in the case of wiping Z-bending, the spring-back characteristics on both bend angles were different. In addition, the dimensions of the Z-bent shaped parts were investigated. It was found, in the case of wiping Z-bending, that web thinning was generated and the outer bend radius was out of tolerance. To validate the FEM simulation results, experiments were carried out. The FEM simulation results showed good agreement with the experimental results in terms of the bend angles and the overall geometry of the Z-bent shaped parts. To achieve precise Z-bent shaped parts, the suitable selection of Z-die bending type in the Z-die bending process is very important.

A Proposed K1 Solution for Long Surface Cracks in Complex Geometries

1991 ◽  
Vol 113 (1) ◽  
pp. 28-33 ◽  
Author(s):  
A. Chaaban ◽  
A. Chaarani
Keyword(s):  
Stress Field ◽  
Surface Cracks ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Crack Face ◽  
Uniform Tension ◽  
Magnification Factors ◽  
Factor Expression ◽  
Superposition Technique ◽  
Good Agreement

The finite element method is used to derive a general stress intensity factor expression for straight-fronted and circumferential surface cracks subjected to an arbitrary stress field. The superposition technique is used: the stress field normal to the crack face is resolved into uniform tension and linear bending stress distributions. The K1 expression is given in terms of magnification factors that are function of these two types of stress field, the geometry considered and the opening of the crack at the free surface under loading. The results obtained using this method are in good agreement with other numerical and experimental K1 solutions of cracks under simple or complex conditions.

Effects of Draw-Bending Characteristics on Concave Wall Feature in Rectangular Deep-Drawn Parts

2013 ◽  
Vol 549 ◽  
pp. 92-99
Author(s):  
Wiriyakorn Phanitwong ◽  
Sutasn Thipprakmas
Keyword(s):  
Deep Drawing ◽  
Fem Simulation ◽  
Bottom Surface ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Deep Draw ◽  
Concave Wall ◽  
Simulation Results ◽  
Draw Bending ◽  
Major Defect

In recent years, the requirements on the complicated deep-drawn parts with the high dimension precision are increasingly. As the major defect, the concave wall feature which commonly encounter in the complicated deep-drawn parts of the difficult-to-deep draw material is focused. In this research, the effects of draw-bending characteristics on concave wall feature during deep-drawing process are clearly identified. The mechanism of concave wall feature related to the draw-bending characteristic was investigated and clearly identified by using the finite element method (FEM) and the experiments were also performed to validate the FEM-simulation results. On the basis of stress distribution, the effects of draw-bending characteristics on the concave wall feature could be clearly identified via the changes of stress distributions on the wall, convex feature and spring-go feature on the bottom surface, and spring-back feature on the top surface. However, comparing with U-draw bending model, the effects of draw-bending characteristics was decreased and the concave wall feature in the case of deep-drawing model was smaller than that in the case of U-draw bending model. The experiments were carried out in both cases of the deep-drawing and U-draw bending models to validate the FEM-simulation results. The FEM-simulation results showed a good agreement with the experimental results with reference to the distribution of material thickness.

Thermal Stress Analysis and Sealing Performance Evaluation of Pipe Flange Connections With Spiral Wound Gaskets Under Elevated Temperature

2004 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Wataru Maezaki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Performance Evaluation ◽  
Thermal Stress ◽  
Elevated Temperature ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Sealing Performance ◽  
Effects Of Temperature ◽  
Spiral Wound

In this paper, the thermal stress distributions at the interfaces between pipe flanges and the gasket under elevated temperature and internal pressure were calculated by using the finite element method (FEM) taking into account hysteresis in the stress-strain curves of spiral wound gasket. Leakage tests were performed using helium gases. In addition, the effects of temperature on the sealing performance were examined by using an actual pipe flange connection with spiral wound gasket under elevated temperature. By using the calculated contact stress distributions and the results of the leakage tests, the sealing performance was evaluated.

Thermal Stress Simulation of the Surface Grinding

2011 ◽  
Vol 383-390 ◽  
pp. 2211-2215
Author(s):  
Chong Lue Hua ◽  
Gui Cheng Wang ◽  
Hong Jie Pei ◽  
Gang Liu
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Thermal Stresses ◽  
Surface Grinding ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Temperature Dependent ◽  
Finite Element Procedure ◽  
Temperature Dependent Properties ◽  
Stress Simulation

Thermal stresses of grinding plays an important role on the fatigue and wear resistance of the component. A comprehensive analysis of thermal stress induced by surface grinding has been conducted with aid of the finite element method. To obtain a reliable figure of thermal stress induced by grinding, temperature-dependent properties of workpiece materials were taken into account. The developed finite element procedure has also been applied to calculate the surface and sub-surface thermal stress induced by moving source of triangular heat when convection and radiation is occurred over the whole work. Based on an analysis of the effects of wheel velocity on the thermal stress distributions in an elastic-plastic solid, some important conclusions were given.

Application of Back-Up Ring in Fine-Blanking Process

2010 ◽  
Vol 443 ◽  
pp. 140-145 ◽  
Author(s):  
Suthep Yiemchaiyaphum ◽  
Masahiko Jin ◽  
Sutasn Thipprakmas
Keyword(s):  
Flow Analysis ◽  
Fem Simulation ◽  
Material Flow Analysis ◽  
The Finite Element Method ◽  
Fine Blanking ◽  
Die Roll ◽  
Blanking Process ◽  
Cut Surface ◽  
Good Agreement

Considering the advantages of the fine-blanking process, the smooth-cut surface without further operation could be fabricated. However, one of the major problems of the fine-blanking is the occurrence of the die-roll formation. This problem is the main factor which affects the quality of the fine-blanked parts. In this study, to reduce the amount of die-roll formation, the application of back-up ring was proposed. The finite element method (FEM) was used to investigate the effects of back-up ring. In addition, the effects of bridge width were also investigated. The FEM simulation results illustrated that the mechanism of back-up ring and the effects of bridge width could be theoretically clarified base on the material flow analysis. The FEM simulation and experimental results showed the good agreement with each other. Therefore, the application of back-up ring could reduce the amount of die-roll formation on the fine-blanked parts. In this study, the amount of die-roll formation increased as the bridge width increase and it was constant at the bridge width of over 15 mm.

Finite Element Analysis of Thermal Stress at the Interface in Plastic/Brittle Multi-Layer Composite Materials

1990 ◽  
Vol 112 (1) ◽  
pp. 138-142 ◽  
Author(s):  
Sui Lin ◽  
Xichen Yu ◽  
Wieliang Dai
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Brittle Material ◽  
High Stress ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Temperature Distributions ◽  
Layer Composite

The thermal stress of a multi-layer composite of plastic/brittle material was studied by the finite element method. High stress is found to be located on the interfaces between the plastic and the brittle material. 1-D and 2-D approaches for the determination of the temperature distributions in the multi-layer composite were examined. The 1-D approach gives an approximate 80 percent of error in temperature and a maximum of 20 percent of error in thermal stress in comparison with the 2-D approach. This suggests that, for a plastic/brittle composite, a 2-D approach for the determination of the temperature distribution should be taken in order to ensure the validity in the determination of both the temperature and stress distributions.

Reciprocating Shaving Approach to Eliminate Crack and Burr Formations in Pressed Parts

2010 ◽  
Vol 443 ◽  
pp. 201-206 ◽  
Author(s):  
Sutasn Thipprakmas ◽  
Wiriyakorn Phanitwong ◽  
Mutjarin Chinwithee ◽  
Thanaporn Morkprom
Keyword(s):  
Process Parameters ◽  
Metal Cutting ◽  
Fem Simulation ◽  
The Finite Element Method ◽  
Working Process ◽  
Cutting Operation ◽  
The Cost ◽  
Sheet Metal Cutting ◽  
Cut Surface ◽  
Good Agreement

Burrs are unwanted materials remaining not only after the machining operation but also after the sheet metal cutting operation. Burr formations decrease the part accuracy and increase the cost for the deburring operation. In this study, the reciprocating shaving process was proposed to eliminate crack and burr formations in the pressed parts. The finite element method (FEM) was used as a tool to investigate the possibility of this process and its working process parameters as well. The FEM simulation results showed the effects of clearance in shearing operation, shaving allowance, and half-shaving direction on the shaved surface. These results were validated by laboratory experiments, and they showed a good agreement with each other. The FEM simulation could be used as a tool for prediction of the cut surface in the reciprocating shaving process. The results revealed that the reciprocating shaving process could be applied for eliminating crack and burr formations in pressed parts using suitable working process parameters.

FEM Calculations and Evaluation of Sealing Performance in Comparison of Raised Face and Flat Face Flange Connections

2013 ◽  
Author(s):  
Ryou Kurosawa ◽  
Toshiyuki Sawa ◽  
Yuya Omiya ◽  
Takashi Kobayashi ◽  
Kentaro Temma
Keyword(s):  
Internal Pressure ◽  
Fe Analysis ◽  
Displacement Curve ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Flange Connection ◽  
Gas Leakage ◽  
Sealing Performance ◽  
The Relationship ◽  
Good Agreement

The bolted connections inserting gasket such as circular flange connections have been widely used in mechanical structures, which is nuclear and chemical industry, and so on. They are usually used under internal pressure. And they are required the high sealing performance. In the circular flange with non-asbestos compressed sheet gaskets, the two flange surfaces, raised-face and flat-face, are used. The raised-face flange on the sealing performance is examined by many researchers and reported. The flat-face is well known that flange rotation is smaller than that in raised-face flange under the internal pressure. However the sealing performance of the flat-face flange connection isn’t examined. Thus, the sealing performance of the flat-face flange connection is not examined. In this paper, the contact gasket stresses of these connections under internal pressure are analyzed using the finite element method (FEM) of each flange surfaces, taking into account a hysteresis in the stress-displacement curve of the gasket. And then, using the contact gasket stress distributions obtained from FE analysis and the relationship between gasket stress and leak rate obtained from a gasket sealing test (JIS B2490), method for estimating an amount of leakage is examined. The leakage tests were also conducted to measure an amount of gas leakage using an actual circular flange connection with a gasket. The estimated results are in a fairly good agreement with the experimental results.

An Analysis of Thermal Cracking of Carbide Tools in Intermittent Cutting

1979 ◽  
Vol 101 (2) ◽  
pp. 159-164 ◽  
Author(s):  
H. Wu ◽  
J. E. Mayer
Keyword(s):  
Thermal Stress ◽  
Material Properties ◽  
Thermal Loading ◽  
Tool Material ◽  
Thermal Cracking ◽  
Transient Temperature ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Wave Type ◽  
Intermittent Cutting

This paper re-examines the problem of thermal cracking of carbide tools during intermittent cutting. In the paper a two-dimensional tool model is presented. A square-wave type of heat flux is assumed in the model to simulate the thermal loading of the tool during the cutting and non-cutting cycle. The transient temperature and thermal stress distributions of the tools are obtained by the finite element method. Two examples are considered in the paper to illustrate the procedures. It is found that tensile stress near the cutting edge and strong compressive thermal stress may exist in the tool respectively at different cutting cycles. Their magnitudes depend upon the tool material properties and the cutting conditions.

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