In-process control of blank holder force in axi-symmetric deep drawing with degressive gas springs

Design and application of blank holder system with spiral spring in deep drawing of square cups

“…Gunnarsson et al have developed a new blank holder system with degressive gas springs to large process window between fracture and wrinkling in axi-symmetric deep drawing and to increase the LDR [4]. Doege and Elend investigated pliable blank holder to enlarge the safe working area to improve the quality of the produced deep drawing parts and to increase process stability level [5].…”

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

“…Doege and Elend (2001) increase the process stability by using a pliable blank holder compared to a conventional rigid design. Several authors use system designs which are integrated into the tool and are thus independent of the choice of press: Wei et al (2006) use a dual layer blank holder in which a pattern of small pins can be inserted and a static deflection of the blank holder can be achieved; Gunnarsson et al (1998) use a number of interconnected controllable passive gas springs to increase the fracture and wrinkle limits in an axi-symmetric deep drawing; and Yagami et al (2004) show a very finely segmented blank holder with 108 individually controllable actuators.…”

A study of the control of the blank holding force using an MR damper in a drawing press

“…However, time delays and valve dynamics have been found to significantly affect system performance. Gunnarsson et al developed a new blank holder system that consists of inter-connected active and passive gas springs that move in parallel during forming [5]. With this system, retrogressive, constant, and progressive blank holding force trajectories were pre-determined using special software.…”