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A tensile strip test has been developed for evaluating friction under conditions which simulate the stretching of sheet over the punch corner radius in forming a shallow stamping in a typical draw die. Preliminary results are presented for the aluminum alloys 5182-0, 2036-T4, 6009-T4 and 6010-T4,which are used for automotive applications. Tests were conducted with various lubrication conditions, different corner radii and with prestrained sheet. For given friction conditions, the maximum strain obtained over the face of the punch was significantly affected by small amounts of prestrain or small changes in the tensile/yield ratio of the sheet.

Stretching a circular blank over a circular domed punch is modelled using the ABAQUS finite element code. Hemispherical, elliptical and flat-bottomed punches are investigated as well as the effect of strain hardening, friction, blank diameter, blankholder pressure and die radius. The results are illustrated using forming limit and other diagrams and summarized in a table that illustrates how strain in the different regions of the blank can be controlled and redistributed.

Stress and strain distributions developed in a tube during the tube bending operation is important in estimating the limit bending radii, springback and structural properties of the tube. In this paper, A new strain distribution model for tube bending, considering stretching, circumferential strain and cross section flattening, is presented. The axial, circumferential, thickness and effective strains on the outer surface, inner surface and mid-surface of a bending tube were calculated from grid measurement, and are shown in different ways. Thickness strain was also obtained from thickness measurement. Comparison is made among the results from measurement and modeling and a very good agreement is obtained between the new model and the measurement.

An important extension to the process of roll forming is the production of embossments by a secondary stamping operation. In this paper, a system is described for transforming stamping profiles to roller profiles, thus eliminating the need for the secondary stamping operation. Included in the system are techniques for identifying and avoiding interference between the rollers, and for calculating torque and power requirements. The system is illustrated by describing how the process was used to design a pair of rollers for embossing a profile generated by the LaBarge method [1].