Springback Compensation by Superposition of Stress in Air Bending

2009 ◽  
Vol 410-411 ◽  
pp. 621-628 ◽  
Author(s):  
Andres Weinrich ◽  
Nooman Ben Khalifa ◽  
Sami Chatti ◽  
Uwe Dirksen ◽  
A. Erman Tekkaya
Keyword(s):  
Sheet Metal ◽  
New Method ◽  
Lightweight Construction ◽  
Springback Compensation ◽  
Air Bending ◽  
Forming Technology ◽  
Bending Process ◽  
The Common ◽  
Metal Processing Industry ◽  
Free Bending

In the sheet metal processing industry bending is one of the common metal forming processes. Depending on the process state, a differentiation has to be made between free bending (air bending) in the die and coining (die bending). Because of its flexibility the air bending process is nowadays one of the widely applied processes for sheet metal bending, but the springback phenomenon is still a great challenge for the industrial application. At the Institute of Forming Technology and Lightweight Construction (IUL) of the Technische Universität Dortmund, Germany, a new method has been developed allowing the compensation of springback effects in air bending of sheet metals. This method is based on the incremental and local superposition of stresses in the forming zone. The superposition occurs after the bending operation but before unloading along the sheet metal width. The advantage of this new method is that a minimal force is required to compensate the springback. This paper describes the springback compensation method in detail and presents first experimental results.

Intelligent Control Experiment Study for V-Shape Free Bending of Wide Sheet Metal

2008 ◽  
Vol 575-578 ◽  
pp. 186-191
Author(s):  
Jun Zhao ◽  
Chun Jian Su ◽  
Ying Ping Guan
Keyword(s):  
Sheet Metal ◽  
Intelligent Control ◽  
Control Experiment ◽  
Bending Process ◽  
Prediction And Control ◽  
The Neural Networks ◽  
Die Material ◽  
Object Of Study ◽  
And Control ◽  
Free Bending

The main problem in bending process of sheet metal is that it is difficult to control bending springback accurately. Springback produced from the unloading of bending makes the shape and size incongruent between bending workpiece and working portion of die. Because the final shape of bending workpiece is related with the whole deformation process, the geometric parameter of die, material performance parameter will have great effect on springback. Therefore, the springback problem is very complicated and the prediction and control of springback is the key to improve the accuracy of bending workpiece. Taking the V free bending of wide sheet as an object of study, the neural networks technology and data acquisition system based on LabVIEW are used to establish intelligent control experiment system for V free bending of wide sheet metal. The control accuracy of system is high and it provides the basis for the realization of intelligent control for V-shape free bending of wide sheet metal in practice in future.

Total Flexibility in Forming Technology by Servo Presses

2014 ◽  
Vol 907 ◽  
pp. 99-112 ◽  
Author(s):  
Jörg Avemann ◽  
Stefan Calmano ◽  
Sebastian Schmitt ◽  
Peter Groche
Keyword(s):  
Mass Production ◽  
Degrees Of Freedom ◽  
Sheet Thickness ◽  
The Other ◽  
Adaptive Control System ◽  
High Productivity ◽  
Forming Technology ◽  
Bending Process ◽  
Product And Process ◽  
Free Bending

In forming technology, uncertainty can arouse from fluctuations in demand scenarios on one hand and in properties of semi-finished parts on the other. These technologies are usually characterized by a high productivity in mass production. However, high development efforts and investment costs for processes and machines lead to a rigid product and process spectrum. One approach to encounter these uncertainties is the introduction of flexibility into forming technologies by enlarging the number of degrees of freedom without drastically reducing productivity. The 3D Servo Press fulfils the mentioned requirements by exceeding free ram motion of conventional servo presses by two rotational ram DoFs. The adaptive control system coordinates the machine motion and controls product properties by model-based algorithms. Possibilities of this approach are demonstrated in a free bending process of a heat dissipater, resulting in uniform product quality despite variations in material, sheet thickness and desired geometry.

INNOVATIVE FORMING TECHNOLOGY AS A KEY FOR THE EFFECTIVE MANUFACTURING OF LIGHTWEIGHT STRUCTURES

2008 ◽  
Vol 07 (01) ◽  
pp. 37-40
Author(s):  
ERMAN TEKKAYA ◽  
MICHAEL TROMPETER ◽  
WERNER HOMBERG
Keyword(s):  
Sheet Metal ◽  
Traffic Engineering ◽  
Research Work ◽  
High Strength ◽  
Special Focus ◽  
Lightweight Construction ◽  
Lightweight Structures ◽  
Forming Technology ◽  
The Face ◽  
Volume Production

Current tends in car body or rail traffic engineering aim at the realization of modern lightweight structures. In this context, demanding technological and economical requirements like the use of high strength materials, the forming of very complex geometries, and the reduction of costs, particularly with regard to low volume production, must be achieved. Novel approaches in the field of sheet metal hydroforming are able to overcome existing limitations of conventional forming technologies and feature a higher potential for an effective manufacturing of lightweight structures. This paper shows the current research work at the Institute of Forming Technology and Lightweight Construction (IUL) in the face of sheet metal hydroforming with a special focus on the design of tool systems.

Forming Limit Extension of High-Strength Steels in Bending Processes

2014 ◽  
Vol 611-612 ◽  
pp. 1110-1115 ◽  
Author(s):  
Mohamed El Budamusi ◽  
Andres Weinrich ◽  
Chrstioph Becker ◽  
Sami Chatti ◽  
A. Erman Tekkaya
Keyword(s):  
Hydrostatic Pressure ◽  
Metal Forming ◽  
Fem Simulation ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Limit ◽  
Forming Limits ◽  
Air Bending ◽  
Forming Technology ◽  
Bending Process

Bending is a commonly used forming technology in metal forming. The occurring springback and low forming limits of high-strength steels especially during air bending are the main disadvantages. In this paper, the conventional air bending process is applied with a hydrostatic pressure in the bending zone. This was done using an elastomer tool. The advantage of this method is that the flexibility of air bending is maintained by reducing the springback while the forming limits are extended. Furthermore, different geometries for the elastomer tool were investigated by means of a FEM simulation. The investigation leads to a reduction of the process forces by minimizing the springback and to an extension of the forming limits.

Springback Compensation of Sheet Metal Bending Process Based on DOE & ANN

2008 ◽  
Vol 32 (11) ◽  
pp. 990-996 ◽  
Author(s):  
Jae-Hong An ◽  
Dae-Cheol Ko ◽  
Chan-Joo Lee ◽  
Byung-Min Kim
Keyword(s):  
Sheet Metal ◽  
Springback Compensation ◽  
Bending Process ◽  
Sheet Metal Bending

Springback control of sheet metal air bending process

2008 ◽  
Vol 10 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Jyhwen Wang ◽  
Suhas Verma ◽  
Richard Alexander ◽  
Jenn-Terng Gau
Keyword(s):  
Sheet Metal ◽  
Air Bending ◽  
Bending Process ◽  
Springback Control

A New Method of Producing Bend Angle by Applying Sheet Forging to V-Bending Process

2015 ◽  
Vol 651-653 ◽  
pp. 1066-1071 ◽  
Author(s):  
Takayuki Aso ◽  
Takashi Iizuka ◽  
Tomoyuki Ota
Keyword(s):  
Plastic Deformation ◽  
Sheet Metal ◽  
Final Stage ◽  
Empirical Method ◽  
New Method ◽  
Bend Angle ◽  
Bending Process ◽  
Punch Displacement ◽  
Bend Angles

In actual manufacturing, some empirical method such as the bottoming technique is generally used in order to adjust the bend angles of products. In this study, a new method for controlling the bend angle in the V-bending process was attempted by applying sheet metal forging. In the experiments, three punches with lumps at the punch tip were used. These lumps were pushed into a bent section at the final stage of bending and were able to stretch the inside plane of the bent section. In both cases examined (using punches with one or two lumps at the tip), the bend angle decreased with an increase in punch displacement. This result shows new possibilities for controlling the bend angle by introducing plastic deformation to the bent section.

Enhanced Semi-Analytical Process Simulation of Air Bending

2005 ◽  
Vol 6-8 ◽  
pp. 729-736 ◽  
Author(s):  
N. Ridane ◽  
D. Jaksic ◽  
Matthias Kleiner ◽  
B. Heller
Keyword(s):  
Sheet Metal ◽  
Process Simulation ◽  
Simulation Software ◽  
Thick Sheet ◽  
Process Data ◽  
Air Bending ◽  
Bending Process ◽  
Sheet Metal Bending ◽  
Punch Displacement ◽  
Analytical Approaches

The air bending process is one of the most widely used process for the manufacturing of sheet metal bending parts made of thin as well as of thick sheet metal. Although the air bending process offers a very high production potential due to its great flexibility, it is associated with certain problems which can negatively influence the shape and dimensional accuracy of the bending parts. Examples for such negative influences are the springback of the material, the batch variations, or the deflections of the bending machine and tools. These differences have to be considered either in the determination of the process parameters or they have to be compensated later on in the manufacturing process itself. A well established approach to calculate process data for forming processes is the use of a process simulation. At the Institute of Forming Technology and Lightweight Construction (IUL) a simulation software called Sheet Metal Bending Simulation (SMBS) has been developed and successfully been tested for the field of sheet metal bending, based on semi-analytical approaches. Although it already provides very satisfactory results in general, disturbances such as material and batch variations as well as the deflections of C-frame, machine table, and press brake ram can still negatively affect the prediction of the punch displacement necessary to achieve a certain bend angle. While material and batch variations cannot properly be considered in a process simulation at present, the afore mentioned influences offer a promising potential for improvements. Therefore, in order to further improve the accuracy of predicted quantities such as punch displacement and bending angle, a new module describing the elastic machine behaviour of press brakes has been developed and successfully been integrated in the process simulation SMBS. Experimental investigations have been carried out on a conventional CNC press brake to verify the efficiency of the newly implemented approach.

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