Deep drawing is one of the most important sheet metal forming processes in which a sheet metal blank is drawn into the die, to deform it into a hollow seamless part. In this process, the blank should be deformed without occurring fracture or any other kind of defects, such as wrinkling, while a very small change of sheet thickness is expected. Hemispherical cups are of the most important product types of this process which have many applications in buoys, submarines, pressure vessels and the cans containing gas-liquid mixture. The main goal of this thesis is to study, numerically and experimentally, deep drawing of a thin hemispherical cup, in room temperature, using a die without blank-holder, to produce a sound product with no excess rim. As we know, eliminating the blank-holder is desirable due to reduction of friction, forming force and final cost, facility of die assembling and also the process would be achievable using a single-action die. Nevertheless this may result in a defective part because of wrinkling or puckering, especially in hemispherical deep drawing. In this, to resolve this problem, a new die has been proposed, based on the tractrix curve. All parts of the die were created using CATIA V5 and ABAQUS 6.13 was employed to conduct finite element simulations. In order to evaluate practically the proposed design, the die was manufactured and experimental tests of deep drawing were conducted, using St13 and Al1050-O blanks. To evaluate the FE simulations, energy criteria and mesh independency were studied. It has been shown that all these criteria are satisfied. Then numerical and experimental results of force-displacement curves were compared and a very good agreement was observed. This clearly shows that simulations are accurate enough to predict the process characteristics. Moreover the results show that a die without blank-holder can be utilized to deep draw a thin blank into hemispherical cup, if a proper curve for the die is designed Key Words: Deep Drawing, Hemispherical Cup, Die without Blank-Holder, Experimental Tests, FE Simulation.
