Improvement of formability by servo die cushion in deep drawing

Manufacturing process using servo press machines have been highlighted in car manufacturers and other industries in Japan. It is necessary to establish an appropriate press working conditions for manufacturing highly accurate products with great extra value. Our aim is to investigate into effects of variable BHF (blank holding force) on press formability, comparing to using a conventional press machine. In this study, FEM analyses of deep drawing process using a variable BHF system has been conducted to demonstrate the effectiveness of a servo die cushion on formability. We particularly focus the load to mold in deep drawing. According to experimental results obtained with a servo die cushion, it is found that maximum load subjected to dies was reduced by 11.8%, when using a servo press with a servo die cushion comparing to a conventional press.