International Conference on Mechanical, Industrial and Energy Engineering 2012 01-02 February, 2013, Khulna, BANGLADESH * Corresponding author. Tel.: +88-017141180938 MIE12-014- 1 E-mail address: aupatwari@hotmail.com MIE12-014 Prediction of forming defects in Deep Drawing process by Finite Element Simulation. Anayet U. Patwari * , Adib Bin Rashid, Ashiqur Rahman Department of Mechanical and Chemical Engineering Islamic University of Technology (IUT), Dhaka, Bangladesh ABSTRACT Deep drawing is widely used in industries for producing automobile & aircraft body parts, household application and auxiliary parts in construction field. The method is very suitable for large amount of small shaped parts like cups, cans, vessels etc. There may be some forming defects like wrinkling, material erosion etc occurred within the finished products. This paper shows the Finite Element Simulation of the Deep Drawing process for the prediction of the defects. A CAD model of upper die, lower die & blank was generated and assembled using Solidworks. Then a mesh file was created by FEM software and analyzed the model by Static Structural Analysis. Simulation parameters and boundary conditions were considered from experimentation. Simulation results were obtained in terms of Shear stress, Shear strain; Equivalent von misses Stress, Equivalent strain, Maximum principal stress, and Maximum principal strain. The calculated distortion of the element mesh considering deformation pattern predicts the formation of forming defects like wrinkling, erosion etc. of material in the blank. Keywords: Deep drawing, wrinkling, Punching press, Finite Element Simulation 1. Introduction Deep drawing is a manufacturing process in which sheet metal is progressively formed into a three-dimensional shape through the mechanical action of a die forming the metal around a punch. The deep drawn metal stamping process work hardens the metal, resulting in a seamless finished part that is stronger than the base material. Deep drawing can produce precise and intricate parts, including both symmetrical and asymmetrical parts. When the length of a stamped part is equal to or greater than ½ of its diameter it is generally termed as being "deep drawn." In deep drawing process, flat sheet or metal (called blank) is placed over the die, and with the help of the punch, blank is pressed over the die cavity. Blank holder applies pressure to the blank in the flange region during the deep drawing process. The basic deep drawing process [1] is illustrated in the figure1.1 Fig1.1: Deep drawing process The success of forming is in relation to two things, the flow and stretch of material. As a die forms a shape from a flat sheet of metal, there is a need for the material to move into the shape of the die. The flow of material is controlled through pressure applied to the blank and lubrication applied to the die or the blank. If the form moves too easily, wrinkles will occur in the part. The flange region (sheet metal in the die shoulder area) experiences a radial drawing stress and a tangential compressive stress due to the material retention property. These compressive stresses (hoop stresses) result in flange wrinkles (wrinkles of the first order). Different types of wrinkles are shown in the Fig 1.2 Fig1.2 1) flange wrinkling, 2) Wall wrinkling, 3) Part wrinkling. [2] Wrinkles can be prevented by using a blank holder, the function of which is to facilitate controlled material flow into the die radius. Again, more pressure or lubrication can be applied to the blank to limit the flow of material and cause the material to stretch or thin. If