Tooling design accomodating springback errors

Abstract Tooling design and development for sheet metal forming is an expensive process in terms of both time and current manufacturing cost. In the present work it is shown that Finite Element Analysis can be used in tooling design procedures by accurately predicting and accomodating for errors due to springback in sheet metal forming operations. To design the appropriate tooling, traction distributions on the sheet in the fully loaded deformed state are computed using the Finite Element Method. The calculated tractions are then used to elastically load the desired part shape. The deformed shape is then taken to be the die shape as it now contains the springback error. The traction-based design algorithm is examined for materials covering a range of steel strength and hardening and is found to produce parts with negligible error. The success of the method indicates that it can replace the current hardware steps of trial and error tooling design procedures, thereby greatly reducing the cost of tooling development and the experience required for such development.

[1]  Yuji Umehara,et al.  Technologies for the more precise press-forming of automobile parts , 1990 .

[2]  Mary C. Boyce,et al.  Finite Element Analyses of Real-Time Stability Control in Sheet Forming Processes , 1992 .

[3]  H. D. Hibbitt,et al.  Finite element analysis of sheet forming processes , 1990 .

[4]  M. Domroese,et al.  Real-Time Control of Twist Deformation , 1987 .

[5]  David E. Hardt,et al.  Sheet Metal Die Forming Using Closed-Loop Shape Control , 1982 .

[6]  Kim A. Stelson,et al.  Finite Element Method for the Analysis of a Material Property Identification Algorithm for Pressbrake Bending , 1988 .

[7]  Y. Liu,et al.  The Effect of Restraining Force on Shape Deviations in Flanged Channels , 1988 .

[8]  Shiro Kobayashi,et al.  Metal forming and the finite-element method , 1989 .

[9]  David E. Hardt,et al.  Closed Loop Control of a Roll Straightening Process , 1984 .

[10]  Tongxi Yu,et al.  On the range of applicability of results for the springback of an elastic/perfectly plastic rectangular plate after subjecting it to biaxial pure bending—II , 1981 .

[11]  Yasuhisa Tozawa,et al.  Forming technology for raising the accuracy of sheet-formed products , 1990 .

[12]  David C. Gossard,et al.  An Adaptive Pressbrake Control Using an Elastic-Plastic Material Model , 1982 .

[13]  Mary C. Boyce,et al.  Tooling design in sheet metal forming using springback calculations , 1992 .

[14]  Robert A. Ayres,et al.  SHAPESET: A process to reduce sidewall curl springback in high-strength steel rails , 1984 .

[15]  Tongxi Yu,et al.  Springback after the biaxial elastic-plastic pure bending of a rectangular plate—I , 1981 .

[16]  David E. Hardt,et al.  A Transfer Function Description of Sheet Metal Forming for Process Control , 1991 .