Deep-drawing tribology

This article is a continuation of [BM7535] , which sets out the issues and general framework of the problem of friction in stamping: material properties, sheet deformation modes and associated contact conditions, and the main test methods for studying and measuring friction. This article deals successively with the following points:

• the main methods for characterizing sheet metal before and after friction, which allows us to begin to define the main characteristics of sheet metal friction;

• microscopic mechanisms responsible for sheet metal/tool interactions (microplastic deformation of the sheet metal, micro-hydrodynamic and hydrodynamic effects, chemical reactivity of lubricant additives);

• the operation of the retaining rings used to control the flow of metal under the hold-down;

• the various models, more or less sophisticated, used to take friction into account in the numerical simulation of stamping operations.