The look of a car has become more complicated, and a concern is the sharpness of character lines. However, a sharp character line causes the surface defect called a skid line. Although it is well known that skid lines are caused by inhomogeneous tension, the mechanism of skid line generation is not yet fully understood. In this study, the skid line defect was quantitatively evaluated by a draw forming experiment. The mechanism of skid line formation was clarified by comparing the experimental results with the results of a finite element analysis. The results revealed the effects of the tensile forces caused by blank holder forces on the change in the amount of displacement of the skid line. The results suggest that the skid line surface defect detected could be a concave shape caused in the area initially formed as a character line that shifts from its original location as a result of inhomogeneous tension, and then is subjected to reverse bending by the die.
