A Novel Approach for Trouble-Shooting Stamping Problems Based on The Concept of Process Signatures

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. The understanding of this new concept will be an asset in the effective troubleshooting of stamping problems, and in the isolation of process as opposed to product, material, lubricant or tooling related problems. Several practical examples are illustrated to demonstrate the applicability of this methodology.