A comparative estimation of the forming load in the deep drawing process

The deep drawing process is one of the important sheet-metal forming processes. Using this operation, many parts are manufactured in various industries. In this paper, different methods of analysis such as analytical, numerical and experimental techniques are employed to estimate the required drawing force for a typical component. With this regard, the numerical simulations were conducted using the finite-element (FE) method. In these simulations, the effects of the element type on the forming load and the variation of the thickness strain were studied. Moreover, the influences of the friction coefficient on the load–displacement curve of the process and maximum drawing force were quantitatively investigated for both the analytical and FE methods. A die set including a blankholder was designed to carry out the experiments on a 600 kN Instron testing machine. Different analytical relationships suggested by different researchers were also used to calculate the maximum drawing force. The results obtained from these methods together with the numerical results were compared with the experimental findings. Based on this comparison, it was concluded that Siebel’s formula predicts more accurate results, compared with other analytical relationships. It was also found that this formula is more sensitive to the friction coefficient than the finite-element simulations. On the other hand, the shell elements are more suitable than four-node solid elements for the numerical analyses because the relevant FE predictions present much better agreement with the experimental results.