Evaluation for forming at T-shaped forming points during press forming

One of the major problems in press forming at Mazda is the deformation of T–shaped joints, specifically the upper part of the central pillar. Analysis of the causes of the deformation and development of a method estimating its effect were conducted so that proper precautions might be taken at the die–design stage. The deformation as analysed in terms of movement and elongation (stress) of the sheet metal in order to express it quantitatively in mathematical formula. These parameters, which are the causes of the deformation, were made computable. This paper deals with the development and application of the method of estimating the deformation.