Application of Servo Presses to Sheet Metal Forming

Abstract

Mechanical AC servo presses having high flexibility for control of motion have been recently developed. In these presses driven by servo motors, the slide motion is accurately controlled by real-time feedback of ram position measured with sensors like the conventional machine tools, and thus complicated motion is attainable. The application of servo presses to sheet metal forming processes is reviewed in the present paper. The springback in bending was reduced by bottoming and re-striking. In deep drawing, the forming limit of high strength steel sheets was improved by detaching tools from the sheet, and the wrinkling was prevented by applying a stepwise motion. A hot stamping process using rapid resistance heating and a servo press was developed to produce ultra-high strength steel parts.