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The effect of binder shape on the formability of metal stampings is addressed in this work. The paper starts with a discussion of a binder development approach for developable or near developable binders. An FEM based test for closeness to developable surfaces is also presented. In this case, the binder surface is meshed using standard FEM discretization techniques. The test is used as an evaluator for the proneness of wrinkle formation at the binder closing stage under the binder surface. The formability of a door outer panel is evaluated and the forming severity related to binder shape. It is shown that addendum and binder designs are key process variables that have to be designed up front and related to product characteristics.

A simultaneous Design/Process/Material engineering approach for the analysis of automotive structural cross member designs is presented. It is shown that it is possible at the product design stages to evaluate i. forming severity, ii. blank shape and nestability, iii. spotting requirements, and iv. structural analysis based on yield stress and thickness distributions after forming. The approach allows the reduction of material content in the part (by nesting and possible weight reduction), a better estimate of part performance during stamping, the evaluation of the effect of the material properties, the construction of the blanking die at the same time as production form tooling, and the reduction of a significant portion of the product design/manufacturing cycle. A production cross member is used to validate the approach. The production cross member information also served as a basis for a new prototype cross member.

This paper presents several guidelines useful when applying axisymmetric solution techniques to the problem of estimating the forming severity of complex three dimensional stampings. Although the axisymmetric solutions are seemingly restricted in their number of applications, these two dimensional techniques can be used to analyze a wide variety of stamping configurations. However, great care must be taken to ensure that the underlying requirements of Axisymmetry are not “seriously” violated. Presented in this paper are several guidelines, including a discussion of the rationale behind them, suggesting how to apply AS solutions to stretch and shrink flanging stamping operations.

The paper introduces the concept of process signatures, the main intention being to change the grid analysis from a merely data processing activity to a knowledge based methodology. The process signature is the shape of the strain envelope, which depicts the strain state of contiguous elements on the surface of a stamping. The signature is strongly influenced by the tooling geometry, process induced modes of deformation, and to a lesser extent by the lubricating conditions, material characteristics, etc. Essentially the deformation of the whole part can be analysed by subdividing it into the fundamental modes. It is shown that the total response of a stamping depends on certain combination of these basic fundamental signatures. Distinct areas on the signature correspond to the punch and die actions. The work demonstrates that the process signatures respond in a predictable fashion to changes in tooling, material and set up.