Manufacturing Technology Today

B. V. S. Rao ¹, G. Chandra Mohan Reddy ¹, G. Krishna Mohan Rao ², P. V. R. Ravindra Reddy ¹

Affiliations
1 Department of Mechanical Engg., CBIT, Gandipet, Hyderabad, IN
2 Department of Mechanical Engg., JNTU College of Engg., Hyderabad, IN

Abstract

Deep drawing is the process of converting a blank into cup shaped articles like kitchen sinks, utensils, fountain pen caps etc. Wrinkles and fracture are the major defects in deep drawn products. Wrinkles occur at flange as well as the sidewalls of a deep drawn cup. The main reason for wrinkles is inadequate blank holding force. However excessive blank holding force results in fracture. The aim of this work is to arrive at optimum blank holding force in order to produce wrinkle free products. In this work numerical simulations are conducted by considering five different parameters namely punch radius, die radius, clearance, coefficient of friction and Punch diameter using finite element explicit solver LSDYNA. Modeling of the set up is done using hyper mesh. In this work simulations are carried out as per L-27 orthogonal array suggested by Taguchi. A combination of finite element method and Taguchi analysis is used to determine the influence of process parameters in deep drawing.

Keywords

Deep Drawing, Blank Holding Force, Wrinkling, Taguchi Approach, LSDYNA.

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B. V. S. Rao ¹, Chandra Mohan Reddy ², G. Krishna Mohan Rao ³, P. V. Ravindra Reddy ¹

Affiliations
1 Chaitanya Bharathi Institute of Technology (CBIT), Hyderabad, IN
2 Mahatma Gandhi Institute of Technology, Hyderabad, IN
3 J.N.T.U. College of Engineering, Hyderabad, IN

Abstract

Deep Drawing is the process of converting a flat blank into cup shaped articles like automobile panels kitchen sinks, fountain pen caps and shell cases etc. During this process a punch forces the blank to take the shape of the die cavity. If the height of the drawn cup exceeds half its diameter then the process can be termed as deep drawing. One of the primary requirements in drawing operation is estimation of blank area or blank size. It is considered to be critical because even a small variation in estimation can lead to unnecessary wastage of material. If the blank area is underestimated it leads to partially drawn cup due to insufficient material. On the other hand if the blank area is over estimated it leads to wastage in material as the excess material has to be removed by performing trimming operation. Although estimation of blank diameter is done using mathematical formulae these are based on thumb rules which are in turn based on experience. Further for nonstandard and nonaxisymmetric cups there are hardly any readymade formulae available. Hence in this work an effort is made to estimate the blank size required to form nonstandard and nonaxisymmetric cups produced by deep drawing process, both analytically and by using solid works software.

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