Deep drawing is one of the most important operations in sheet metal forming. There are numerous factors, affecting the drawing process, such as the shape of the die, the properties of the material, the shape and size of the blank, the boundary conditions, the friction and lubrication conditions between the die and the blank. Limiting drawing ratio (LDR), which is the ratio of the initial diameter of a blank that can be drawn without failure to the punch diameter is commonly used to provide a measure of the drawability of sheet metal. Due to limitation in LDR, highly deep cups cannot be obtained with a single drawing operation. Disadvantages of redrawing have caused many studies to increase LDR. The method of using anti-lock braking system in deep drawing has recently attracted attention of many researchers. This approach is the same as conventional deep drawing with the exception that the blank holder switches between gripping and releasing the blank in short intervals during forming process. It looks much like the ABS systems used in braking system of autos. Modeling of the drawing instrument was done via Finite Element Analysis software ABAQUS/EXPLICIT. Blank is made of AA5754-O aluminum. Punch, die and blank holder were modeled as rigid bodies. The blank is modeled using a 4-node doubly curved thin shell element with reduced integration, (S4R.). Results show that oscillatory blank holder causes an obvious increase in draw depth and significantly decreases ear heights. Results of the analysis emphasize the fact that blank holder gap and its oscillation amplitude and frequency can significantly influence the benefits of “deep drawing with ABS”. Improvement in cup depth was observed as the frequency increased up to a certain limit after which no further improvement was noticed. On the other hand, pulsation amplitude of the BHG seemed to play a decisive role in the performance of pulsating BHG schemes. Increasing the pulsation amplitude was found to decrease the friction force between the blank and the blank-holder and increase the drawing depth. Aslo increasing amplitude and frequency up to a certain limit decreases the ear heights. There is meaningful relation between dercrease the ear heights and decreases the friction force. It was observed that pulsation the blankholder induced sinusoidal variations in the punch force signal and also noted that these variations were directly proportional to the BHG amplitude. In the case of low frequencies the phase of oscillation is also important. This observation has enabled a strategy to be developed which enables sound parts to be drawn. This is achieved by pulsation the blankholder at an ultra-low frequency and ensuring that the pulsating blank holder gap is asynchronous with the punch force and remains within the process (BHG) limits for the entire width of the critical tearing window. Keywords: Deep drawing, Oscillatory blank holder, Anti-lock braking system, Ultra low frequency.
