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.

Cut Surface Features in Various Die-Cutting Processes

2016 ◽  
Vol 719 ◽  
pp. 127-131 ◽  
Author(s):  
Arkarapon Sontamino ◽  
Sutasn Thipprakmas
Keyword(s):  
Process Parameters ◽  
Fem Simulation ◽  
Cutting Process ◽  
Working Process ◽  
Surface Features ◽  
Straight Portion ◽  
Simulation Results ◽  
Cutting Processes ◽  
Blanking Process ◽  
Cut Surface

Currently, the shaped parts combined with straight, concave, and convex portions are increasingly fabricated. To produce the straight portion, the shearing theory is usually applied. As well as, to produce the concave and convex portions, the punching and blanking theories are usually applied. However, with the same die-cutting process parameters, the comparison of cut surface features of straight, concave, and convex portions has not been investigated yet. Therefore, in the present research, the comparison of the cut surface features in various die-cutting processes, including shearing, blanking, and punching processes are investigated. The finite element method (FEM) was used as a tool to investigate these cut surface features. The cut surface features were investigated and clearly identified via the changes of the stress distribution analyses. The results elucidated that with the same die-cutting process parameters, the different cut surface features were obtained. Specifically, the crack formations were easily generated in the case of blanking process, following by the shearing and punching processes, respectively. Therefore, the smooth cut surface was smallest in the case of blanking process, following by the shearing and punching processes, respectively. The laboratory experiments were carried out to verify the accuracy of the FEM simulation results. Based on the cut surface features, the FEM simulation results showed good agreement with the experimental results in terms of the cut surface features. Therefore, to design the die-cutting process parameters to meet the product requirements of complicated shapes, the understanding on these working process parameters being upon the shaped parts is necessarily.

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.

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 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.

Prediction of Trimming Process Parameters in Aluminum Sheet Materials Using FE Method

2004 ◽  
Author(s):  
Quan Situ ◽  
Mukesh K. Jain ◽  
Don R. Metzger
Keyword(s):  
Process Parameters ◽  
Fracture Initiation ◽  
Material Model ◽  
Aluminum Sheet ◽  
The Finite Element Method ◽  
Fe Method ◽  
Cut Edge ◽  
Sheet Materials ◽  
Material Separation ◽  
Good Agreement

The trimming process is an important step to achieve good dimension and shape of a final product. However, it requires a systematic study of the various parameters involved in material separation. The finite element method was utilized to simulate the trimming process of aluminum sheet materials in aspects of material properties, tooling conditions and process parameters, including different tool configurations, clearances and punch speeds. Punch load versus displacement diagrams and cut edge morphologies obtained from representative clearances and tool configurations were investigated. A two-dimensional plane strain trimming was analyzed using a rate independent material model. An experimentally measured fracture strain was utilized in FE modeling for fracture initiation and development using element deletion technique. A thermally coupled material model was tentatively tested. Results from simulations were compared with experiments and good agreement was obtained for most of the studied conditions. Optimal trimming process parameters such as specific tool configuration, clearance and punch speed are suggested.

Application of FEM Simulation and Abductive Network to Predict the Springback of U-Shaped Bending Process with Counter Force

2012 ◽  
Vol 579 ◽  
pp. 32-41
Author(s):  
Tung Sheng Yang ◽  
Jen Chuan Yeh ◽  
Sheng Yi Chang
Keyword(s):  
Finite Element ◽  
Process Parameters ◽  
Fem Simulation ◽  
Data Sets ◽  
The Finite Element Method ◽  
Blank Holder Force ◽  
Element Analysis ◽  
Blank Holder ◽  
Bending Process ◽  
Abductive Network

This study applies the finite element method (FEM) in con-junction with an abductive network to predict springback’s angle during the U-shaped bending process with counter force. To verify the prediction of FEM simulation for springback, the experimental data are compared with the results of current simulation. Bending force, effective stress distribution and springback are investigated for different process parameters, such as profile radius of die, blank holder force and counter force of U-shaped bending process, by finite element analysis. The abductive network is then utilized to synthesize the data sets obtained from numerical simulations. Finally, prediction model is established for predicting springback’s angle under a suitable range of process parameters.

Die Design in Fine-Piercing Process by Chamfering Cutting Edge

2010 ◽  
Vol 443 ◽  
pp. 219-224 ◽  
Author(s):  
Suthep Yiemchaiyaphum ◽  
Masahiko Jin ◽  
Sutasn Thipprakmas
Keyword(s):  
Process Parameters ◽  
Flow Analysis ◽  
Fem Simulation ◽  
Material Flow Analysis ◽  
Cutting Edge ◽  
Die Design ◽  
The Finite Element Method ◽  
Sheet Metal Parts ◽  
Secondary Operations ◽  
Die Roll

The hole quality on sheet metal parts is directly dependent on the die design and process parameters. In conventional piercing process, the secondary operations such as shaving, reaming and grinding are needed for manufacturing the precise-dimensioned holed parts without any cracks, resulting in the increase of both production time and costs. The fine-piercing process, referenced to the fine-blanking principle, is used to produce the precise-dimensioned holed parts with smooth-cut surfaces over the whole material thickness in a single operation. However, it is difficult to achieve the suitable die design and process parameters for meeting the part requirements. In this study, the die design by chamfering punch cutting edge was investigated on both the experiments and the finite-element method (FEM). The results were compared with the results obtained when the conventional die design with the punch cutting-edge radius was used. The FEM-simulation results showed the amount of die-roll, smooth-cut surface, and cracks agreed well with the experimental results. The results showed that an application of punch cutting-edge chamfer results in a superior fine-pierced hole surface could be achieved. Furthermore, the mechanism and effects of the punch cutting-edge chamfer have been theoretically clarified on basis of the material-flow analysis and stress distribution.

Finite Element Modeling of Shear-Slitting Process

2012 ◽  
Vol 459 ◽  
pp. 3-6 ◽  
Author(s):  
Mang Ding ◽  
Di Ping Wu ◽  
Qin Qin
Keyword(s):  
Finite Element ◽  
Metal Cutting ◽  
Shear Failure ◽  
Element Model ◽  
Failure Criteria ◽  
Mass Scaling ◽  
Dimensional Finite Element ◽  
Material Separation ◽  
Sheet Metal Cutting ◽  
Good Agreement

Shear-slitting is a sheet metal cutting process used for dividing coiled sheet into narrower coils. In this paper, a two-dimensional finite element model was developed for the calculation of the shear-slitting process by using ABAQUS/Explicit. The shear failure criteria and the element-delete method were adopted to model the material separation. Mass scaling was used to reduce the solution time. The effect of clearance on the burr height was investigated. The simulation results show good agreement with experimental results. The critical clearance values was suggested for decreasing the burr.

Analysis of the Contact Deformation of Tread Blocks

1992 ◽  
Vol 20 (4) ◽  
pp. 230-253 ◽  
Author(s):  
T. Akasaka ◽  
K. Kabe ◽  
M. Koishi ◽  
M. Kuwashima
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Deformation Behavior ◽  
Contact Deformation ◽  
The Finite Element Method ◽  
The Road ◽  
Loss Of Contact ◽  
Tread Rubber ◽  
Good Agreement ◽  
Rubber Block

Abstract The deformation behavior of a tire in contact with the roadway is complicated, in particular, under the traction and braking conditions. A tread rubber block in contact with the road undergoes compression and shearing forces. These forces may cause the loss of contact at the edges of the block. Theoretical analysis based on the energy method is presented on the contact deformation of a tread rubber block subjected to compressive and shearing forces. Experimental work and numerical calculation by means of the finite element method are conducted to verify the predicted results. Good agreement is obtained among these analytical, numerical, and experimental results.

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