Formability limits by wrinkling in sheet metal forming

2016 ◽  
Vol 232 (8) ◽  
pp. 681-692 ◽  
Author(s):  
JPG Magrinho ◽  
CMA Silva ◽  
MB Silva ◽  
Paulo AF Martins
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Effective Strain ◽  
Stress Triaxiality ◽  
Roll Forming ◽  
Blank Holder ◽  
Flexible Roll ◽  
Plane Compression ◽  
Level Of Understanding

This paper presents a new combined experimental and theoretical methodology for determining the formability limits by wrinkling in sheet metal forming. The methodology is based on the utilization of rectangular test specimens clamped along its narrower sides and compressed lengthwise and is aimed at replicating the physics behind the occurrence of wrinkling in deformation regions submitted to in-plane compression along one direction. The methodology draws from a previous development in the field of flexible roll forming, and the overall objectives are to enhance and improve its methods and procedures and to provide a new level of understanding on the onset of wrinkling in sheet metal forming. Experimentation and finite element modelling of cylindrical deep-drawing without blank holder combined with the utilization of the space of effective strain vs. stress triaxiality are employed to discuss the applicability and validity of the new proposed methodology for determining the formability limits by wrinkling.

Modeling and Simulation of Continuous Flexible Roll Forming Process

2013 ◽  
Vol 365-366 ◽  
pp. 549-552
Author(s):  
Zhou Sui ◽  
Zhong Yi Cai ◽  
Ming Zhe Li
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Three Dimensional ◽  
Rigid Bodies ◽  
Roll Forming ◽  
Forming Process ◽  
Flexible Roll Forming ◽  
Flexible Roll ◽  
Roll Forming Process

The continuous flexible roll forming process is a novel sheet metal forming technique for effectively manufacture of three-dimensional surface parts. In this study, two types of finite element (FE) models were developed under the ABAQUS/Explicit environment. The difference of the two models is that the rolls are defined as discrete rigid bodies in model No.1 and are deformable in model No.2. An experiment was carried out using the continuous sheet metal forming setup. The comparison of the numerical computation results with the experimental results shows that the model No.2 can be used for the shape prediction of continuous flexible roll forming process well.

A Flexible Roll Forming on-Line Detection Algorithm Based on Machine Vision

2012 ◽  
Vol 457-458 ◽  
pp. 287-292 ◽  
Author(s):  
Xu Peng Li ◽  
Bo Qian ◽  
Qiang Li
Keyword(s):  
Control System ◽  
Machine Vision ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Detection Algorithm ◽  
Roll Forming ◽  
Loop Control ◽  
Flexible Roll Forming ◽  
Flexible Roll

For the flexible roll forming of the control system, this paper introduces a method that machine vision bind to the flexible roll forming control system. The detection method for sheet metal forming is image acquisition, image processing and other means for the extraction of sheet metal forming in some time section contour curve. Compare extraction section contour curve with the moment theory section contour curve in the control system, get the deviation value and feedback to the control system that interpolation arithmetic to realize closed loop control.

scholarly journals Flexible Roll Forming Technology for Multi-Curved Sheet Metal Forming

2013 ◽  
Vol 22 (5) ◽  
pp. 243-249 ◽  
Author(s):  
J.S. Yoon ◽  
S.E. Son ◽  
W.J. Song ◽  
J. Kim ◽  
B.S. Kang
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Roll Forming ◽  
Flexible Roll Forming ◽  
Forming Technology ◽  
Flexible Roll

Controllable pulsed electromagnetic blank holder method for electromagnetic sheet metal forming

2019 ◽  
Vol 103 (9-12) ◽  
pp. 4507-4517 ◽  
Author(s):  
Yujie Huang ◽  
Zhipeng Lai ◽  
Quanliang Cao ◽  
Xiaotao Han ◽  
Ning Liu ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Blank Holder ◽  
Pulsed Electromagnetic

scholarly journals Die design optimization on sheet metal forming with considering the phenomenon of springback to improve product quality

2018 ◽  
Vol 154 ◽  
pp. 01105 ◽  
Author(s):  
Agung Setyo Darmawan ◽  
Agus Dwi Anggono ◽  
Abdul Hamid
Keyword(s):  
Product Quality ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Die Design ◽  
Forming Limit ◽  
Improve Product Quality ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Improve Product

The process of sheet metal forming is one of the very important processes in manufacture of products mainly in the automotive field. In sheet metal forming, it is added a certain size at the die to tolerate a result of the elasticity restoration of material. Therefore, when the product is removed from the die then the process elastic recovery will end within the allowable tolerance size. Extra size of the die is one method to compensate for springback. The aim of this research is to optimize the die by entering a springback value in die design to improve product quality that is associated with accuracy the final size of the product. Simulation processes using AutoForm software are conducted to determine the optimal parameters to be used in the forming process. Variations the Blank Holder Force of 77 N, 97 N, and 117 N are applied to the plate material. The Blank Holder Force application higher than 97 N cannot be conducted because the Forming Limit Diagram indicates the risk of tearing. Then the Blank Holder Force of 37 N, 57 N and 77 N are selected and applied in cup drawing process. Even though a few of wrinkling are appear, however there is no significant deviation of dimension between the product and the design of cup.

Active Material Flow Control during High-Pressure Sheet Metal Forming

2005 ◽  
Vol 6-8 ◽  
pp. 377-384 ◽  
Author(s):  
Peter Groche ◽  
C. Metz
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Material Flow ◽  
High Pressures ◽  
Active Material ◽  
Sheet Thickness ◽  
Blank Holder ◽  
Rotationally Symmetric ◽  
Material Flow Control

During forming of non-rotationally symmetric sheet metal parts at high pressures nonuniform deformation conditions arise in the flange area. These deformations vary in height and consequently lead to heterogeneous sheet thickness distributions. When using semi-rigid tools, high clamping forces are necessary in order to compensate for the developing sheet thickness variations in the flange area and to avoid leakages of the system or wrinkling. Moreover, the heterogeneous distribution of the clamping force is strengthened by press inaccuracies. This results in a higher surface pressure distribution on one side of the flange and finally in a non-uniform material flow out of the flange area. The development of a segmented active-elastic blank holder enables an active material flow control of the flange movement during sheet metal forming at high pressures. The local elasticity of the active-elastic blank holder is based on an optimized layout of the local tool rigidity. For this purpose, different grooves were integrated below the blank holder surface. This paper provides an overview of the developed technology, advantages with regard to the part’s quality, and recent results comparing the production of non-rotationally symmetric parts with segmented active-elastic tools vs. semi-rigid tools.

Prediction of the Volume Fraction of Retained Austenite in Sheet Metal Forming for Trip Steels

2006 ◽  
Author(s):  
Tikun Shan ◽  
Weigang Zhang ◽  
Zhongqin Lin ◽  
Shuhui Li
Keyword(s):  
Stress State ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Stress Triaxiality ◽  
Transformation Rate ◽  
Transformation Kinetics ◽  
Loading Paths

The dependence of the transformation rate on the multiaxial stress state corresponding to different loading paths is investigated. To achieve different loading paths, single shear uniaxial tension, plane strain and equi-biaxial stretching tests have been carried out for BTR380 steel. On Based of the experimental results, the influence of the stress state on stability of retained austenite is analyzed and an equation of transformation kinetics is developed to predict stress triaxiality-dependence strain-induced transformation. In sheet metal forming, the material undergoes complicated deformation. The prediction of the volume fraction of retained austenite during forming process is essential to estimate the contribution of the TRIP effect to improving formability. To this aim, the volume fraction of retained austenite in the part’s different regions has been calculated using the proposed transformation kinetics equation introduced into finite element method. The calculated results were successfully compared with the experimental data measured in deep drawing experiments.

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