Computerized Control of the Blankholder Pressure on Deep Drawing Presses

During deep drawing it may be very interesting to vary the blankholder force in a controlled manner. This article describes a system adaptable on conventional presses and designed to allow very fast blankholder force variations. The good dynamic behavior of this system permits closed loop control of the blankholder force at normal drawing speed. From a laboratory point of view the system allows an experimental measure of the minimum blankholder force. In industrial field the system is able to improve drawing performance in respect with severity (i.e. LDR of 2.6 in one draw), appearance, shape fixability.