Closed loop control of the friction force. Deep drawing process

Effect of alternating blank holder motion of drawing and wrinkle elimination on deep-drawability

“…The reduction of friction can also be induced by variable BHF control technique. Some researchers showed that formability improves by oscillating BHF at high frequency with an ultrasonic device [4] or at low frequency using conventional hydraulic actuators [5].…”

A novel feedback control system – Controlling the material flow in deep drawing using distributed blank-holder force

“…punch force (Damborg and Jensen, 2000), wrinkle height (Siegert et al, 1997), material flow into the die cavity (Lo and Yang, 2004) and flange draw-in (Siegert et al, 1997). The last one will be used as control variable in this work, as the draw-in is closely related to the two main failure modes; necking and wrinkling.…”

Experimental verification of a deep drawing tool system for adaptive blank holder pressure distribution

“…This system is further improved by Siegert et al (1997) to investigate the influence of lubrication on the in-process forces. They use a segmented rigid blank holder compared to the rigid one-piece design which Ahmetoglu et al (1992) propose.…”