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.

Effects of Part Geometry on Spring-Back/Spring-Go Feature in U-Bending Process

2013 ◽  
Vol 549 ◽  
pp. 100-107 ◽  
Author(s):  
Wiriyakorn Phanitwong ◽  
Arkarapon Sontamino ◽  
Sutasn Thipprakmas
Keyword(s):  
Laboratory Experiments ◽  
Fem Simulation ◽  
Work Piece ◽  
Spring Back ◽  
Forming Process ◽  
Bending Angle ◽  
Part Geometry ◽  
Bending Process ◽  
Metal Forming Process ◽  
Simulation Results

The U-bending process is a common sheet-metal forming process widely employed to fabricate sheet parts like channels, beams, and frames of various sizes applied in almost all industrial fields. In recent years, the precision requirements are increased on the U-bent parts. To achieve these requirements, in this study, the effects of part geometry on the spring-back/spring-go feature including work piece length, U-channel width, punch and die radii, and work piece thickness, were investigated by using the finite element method (FEM) and laboratory experiments. The FEM simulation results clearly revealed the influence of part geometry on spring-back/spring-go feature via the changes of stress distribution analyses on the bending allowance zone, the bottom of bent part, and the U-leg of bent part. Specifically, the part geometry affected on the bending characteristic on the bending allowance zone, as well as it affected on the spring-back feature. In addition, the part geometry also affected on the formation of reversed bending characteristic on the bottom and U-leg of bent parts, as well as it affected on the spring-go feature. The bending angle could be achieved by compensating these bending and reversed bending characteristics. Therefore, to meet the required bending angle, the suitable design of part geometry was strongly considered to maintain the balancing of the bending and reversed bending characteristics. The laboratory experiments were carried out to validate the accuracy of the FEM simulation results. The FEM simulation results showed good agreement with the experimental results with reference to the bending angle and bending force.

An Investigation on Effect of Residual Stress on Springback Behavior of High Strength Steel in U-Bending Process

2011 ◽  
Vol 189-193 ◽  
pp. 2864-2868
Author(s):  
Komgrit Lawanwong
Keyword(s):  
Residual Stress ◽  
Fem Simulation ◽  
Sheet Thickness ◽  
High Strength ◽  
Spring Back ◽  
Workpiece Material ◽  
Bending Process ◽  
Commercial Program ◽  
Deform 2D ◽  
Springback Behavior

Bending process is an important process in the metal sheet forming in many industries. The main problem of the bending process is the spring-back phenomenon after removing the punch. This research aims the investigation on effect of residual stress on springback behavior of sheet metal in U bending process. The corner setting technique and bottoming process were designed for experiments. The corner setting technique and bottoming has reduced the thickness in bending area to 5, 10, 15 and 20 percent of the original sheet thickness. Clearance between punch and die of both processes was equal to same the thickness. The residual stress value and springback phenomenal were investigated by commercial program code DEFORM 2D which was able to analyze the effect stress and force in bending area. Electrolytic zinc coated carbon steel grade JIS; SECC, JIS; 440 and JIS; 590 which having the thickness of 1 mm were employed as the workpiece material for all experiments. The result of three materials in conventional U bending die shows larger spring back than the corner setting technique and bottoming process. Moreover, the corner setting technique reduces spring back value in bending process but requires high bending force. Corner setting technique and bottoming process at 15% and 20% shows that the spring go of all parts. The FEM simulation results explained the effect of residual stress to springback phenomenal. Comparisons between experimental and finite element method results were also performed.

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.

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.

Novel U-bending designed setups for investigating the spring-back/spring-go of two-layer aluminum/copper sheets through experimental tests and finite element simulations

2020 ◽  
Vol 234 (8) ◽  
pp. 1142-1153 ◽  
Author(s):  
Ehsan Etemadi ◽  
Abbas Naseri ◽  
Mohsen Valinezhad
Keyword(s):  
Finite Element ◽  
Experimental Tests ◽  
Finite Element Simulations ◽  
Curvature Radius ◽  
Stacking Sequence ◽  
Spring Back ◽  
Effective Parameters ◽  
Bending Process ◽  
Copper Aluminum ◽  
Good Agreement

This paper presents novel U-bending setups in order to investigate the effects of the curvatures created on the punch, die, or both on the spring-back/spring-go of the two-layer aluminum/copper sheets. Comparison of the new U-bending setups with the regular ones showed that the curvatures had important roles in reducing the spring-back/spring-go in the U-bending process. The results further indicated the good agreement between spring-back/spring-go and finite element simulations. Moreover, through finite element simulations, the effects of three effective parameters on reducing the spring-back/spring-go, including the curvature radius ( r) of the punch, the distance between curvature center and the fillet center ( d) in the punch, and the curvature radius at the end of the die ( R) were investigated. In achieving the desired state (90°), the results showed that the distance of curvature center from the fillet center ( d) was a more important parameter compared with the curvature radius at the end of the punch ( r) and the curvature radius at the end of the die ( R). This paper also focuses on the thicknesses of copper and aluminum as well as the stacking sequence of layers. Concerning the thicknesses of the implemented copper and aluminum change, the minimum angle of the spring-back/spring-go relative to the desired state was 75% Al/25% Cu thickness. Furthermore, the spring-back of aluminum/copper was lower than the copper/aluminum layer sheet. The effects of both thickness changing and stacking sequence of aluminum/copper layers on the spring-back/spring-go amounts of different sheets were due to the relocation of the neutral axis.

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.

Study on Hydraulic Deep Drawing of Square Cups

2014 ◽  
Vol 626 ◽  
pp. 334-339
Author(s):  
Te Fu Huang ◽  
Hsin Yi Hsien ◽  
Yan Jia Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Deep Drawing ◽  
Thickness Distribution ◽  
The Finite Element Method ◽  
Experimental Apparatus ◽  
Punch Load ◽  
Simulation Results ◽  
Good Agreement ◽  
Element Method

The friction holding effect and the friction reducing effect occurring during Hydraulic Deep Drawing and the pre-bulging resulting in more plastic deformation on products are applied on sheet hydro-forming. For Hydraulic Deep Drawing of a square cup, the thickness distribution and the relation between the height and the pressure of pre-bulging are simulated with SPCC steels as the specimen by the finite element method. An experimental apparatus of sheet hydro-forming has been constructed to carry out the hydraulic deep drawing experiments of square cups. Experimental thickness distribution and punch load are compared with simulation results. Good agreement was found. The flow patterns of the circular and square blanks with the condition of being firmly pressed against the punch observed from the experiments are in agreement with the predicted results.Keywords:Hydraulic Deep Drawing, sheet hydro-forming, finite element method

Spring-Back Evaluation of Stretch Bending Process Based on Chaboche Combined Isotropic-Kinematic Hardening Laws

2011 ◽  
Vol 204-210 ◽  
pp. 1745-1750 ◽  
Author(s):  
Jing Hu ◽  
Xiao Xing Li ◽  
Kwan Soo Chung ◽  
Rao Yao
Keyword(s):  
Kinematic Hardening ◽  
Spring Back ◽  
Stretch Forming ◽  
Forming Process ◽  
Hardening Law ◽  
Stretch Bending ◽  
User Subroutine ◽  
Bending Process ◽  
Chaboche Model ◽  
Simulation Results

We present a study on spring-back prediction in the stretching bending process using the Chaboche model combined isotropic-kinematic hardening law and Mises yielding criterion, and a material user subroutine (VUMAT, UMAT) program was developed base on the ABAQUS interface for the model. The effects of different hardening law on the spring-back in the stretch forming process was also analyzed and compared. The simulation results show that the combined isotropic-kinematic hardening law has the better spring-back prediction compared with the pure isotropic and kinematic hardening law in the stretch forming process, which is verified by the experimental results.

Study on Spring-Back of CU11000 Clad AL1050 Sheets

2014 ◽  
Vol 941-944 ◽  
pp. 1688-1691
Author(s):  
Shou Fa Liu ◽  
Fei Xue ◽  
Song Lin Wu
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Spring Back ◽  
Bend Radius ◽  
Cu Content ◽  
Element Simulation ◽  
Bending Process ◽  
Clad Metals ◽  
Simulation And Experiment ◽  
Back Angle

This study is aimed to investigate the spring-back angle of clad metal sheet in bending process by using finite element simulation and experiment to meet the growing requires in the application of clad metals. In this study, the clad metals processed into 1mm thick from CU11000 and AL1050 were bent 90o over a die with a bend radius of 1mm. The results show that there is not any relative sliding, crushing or peeling occurred in the junction of the clad material during the bending process, the spring-back angle of the clad metal is always smaller than each single metal and the CU content increasing also caused spring-back angle become small. The configuration of a harder material (CU11000) in tensile side also has a smaller spring-back angle.

scholarly journals Optimization of Spring Back in Air V Bending Processing using Taguchi and RSM Method

Mechanika ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 73-81
Author(s):  
Mustafa özdemir
Keyword(s):  
Experimental Data ◽  
Dual Phase Steel ◽  
Sheet Material ◽  
Optimal Combination ◽  
Dual Phase ◽  
Spring Back ◽  
Signal To Noise ◽  
Surface Method ◽  
Bending Process ◽  
Simulation Results

In this study, springback behaviour of Dp600 (Dual Phase Steel) sheet material was investigated using air V bending technique.  As bending parameters, four different punch tip radii and four different sheet thicknesses were used. The springback values obtained from the experiments were compared with each other. At the same time, the experimental data were analysed with Response Surface Method (RSM) and Taguchi (L16) orthogonal array. The experimental data and the simulation results were found to be consistent. The signal-to-noise (S/N) ratio is used to determine the most appropriate parameter of minimum springback behaviour. Additionally, it is possible to estimate the optimal combination of the bending parameters. The signal-to-noise (S/N) ratio and the design of experiment (DOE) were utilised for the analysis of the experimental results. It was determined that the effect of these parameters on the air V bending process was based on springback behaviours.

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