Journal of Engineering and Applied Sciences

Year: 2007
Volume: 2
Issue: 5
Page No. 849 - 853

Comparative Study of Springback for Expansion and Retreint Deep Drawing

Authors : A. Soualem , E. Ouakdi and G. Ferron

Abstract: The design of multi-stage deep drawing processes requires the evaluation of many process parameters such as the intermediate die geometry, the blank shape, the sheet thickness, the blank-holding force, friction, lubrication etc� These process parameters have to be determined for the optimum forming condition before the process design. In general sheet metal forming may involve stretching drawing or various combinations of these basic modes of deformation. It is important to determine the influence of the process variables in the design of sheet metal working process. Especially, the punch and die corner for deep drawing will affect the formability. At the same time the prediction of sheet metal�s springback after deep drawing is an important issue to solve for the control of manufacturing processes. Nowadays, the importance of this problem increases because of the use of steel sheeting with high stress and also aluminium alloys. The aim of this study is to give a better understanding of the springback and its effect in various sheet metal forming process such as expansion and retreint deep drawing, by varying diameter die, lubricant for 2 commercially available materials e.g., galvanized steel and aluminium sheet. Expansion deep drawing occurs when the metal between the die and the blank holder is blocked, which prevent the metal flow during this test. This lead at the end of the test, a decrease in thickness. Retreint deep drawing occur when the metal between the die and the blank holder is not blocked, which permit the metal flow during this test and then obtaining final draw product with high thickness. To measure the springback, an experimental apparatus was built especially for deep drawing in our laboratory, to incorporate a number of new features that were motivated by the theoretical analysis. This apparatus was composed of the die and of a punch, which is adapted to traction machine Fu 1000e. A displacement detector pass through an opening under the die. This detector is bended at a recorder. The propose method can be further improved to determine and measure the springback. Thus, the sequence calculus of the springback consists of 3 steps. At the first step, we take the initial value on the recorder as reference, at the second step, we applied a load on the punch and we take then the final value of deformation. At the third step, we unload the punch and take also the residual value of deformation. The springback value is evaluated as the difference between 2 values indicated in steps two and three. Furthermore, the punch depth is evaluated as the difference between 2 values indicated in steps 1 and 2. For expansion deep drawing, the springback decreases rapidly with an increase of deformation (or a decrease of thickness), but the retreint deep drawing, the springback increases with an increase of thickness. As discussed previously, the magnitude of the springback is influenced by the amount of plastic deformation and unloading residual stresses.

How to cite this article:

A. Soualem , E. Ouakdi and G. Ferron , 2007. Comparative Study of Springback for Expansion and Retreint Deep Drawing . Journal of Engineering and Applied Sciences, 2: 849-853.

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