Experimental investigation of friction in deep drawing

Investigation of friction is carried out in the radial drawing region between the die and blank holder and also in the stretching zone over the punch in deep drawing. Two methods are developed to calculate the coefficient of friction in each zone using the experimentally determined data such as punch force diagrams and strain distributions obtained by an optical scanning system. The current methods differ from the existing techniques which are obtained in simulative tests. The proposed methods can be applied in room temperature and at elevated temperatures. Comparisons of friction coefficients are made with those obtained by other techniques.