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The paper describes some advances in the use of grid analysis and forming limit diagram techniques. It is shown that a limited amount of process or tooling related information can be derived from the measurements of the grid distortion at localized areas. It is illustrated that a full three dimensional grid analysis of the part is required for a comprehensive understanding of the interrelation between the state of deformation at different regions and the possible improvement in process.

The theme of this work is the interaction of the part geometry, material properties, forming severity and tooling design for box-shaped stampings. It is shown that the forming severity decreases with the increase of material normal anisotropy and corner radius. The lower the material normal anisotropy, the larger are the required tooling clearances and the thickening of the material under the blankholder. Understanding these relationships is of primary importance in applications requiring a major change in material properties, such as cold-rolled to hot-rolled conversion of products, or product shape redesign. The work also introduces a new type of idealization to metal forming problems. Beside the traditional continuum mechanics axisymmetric and plane strain idealizations, the work introduces the “corner analysis” approximation.