Principles for on-line monitoring of tool wear during sheet metal punching

Significant progress was made in experimental, analytical and numerical modelling of the process of punching/blanking of sheet metal. These models, however, may still not be sufficiently adequate to accurately predict the process in all circumstances. Therefore, researchers have continued to search for methods to monitor and control some key aspects in real time. After an overview of existing literature, some principles of the punching/blanking process are discussed. Detail is added to these principles by the presentation of experimental results, indicating that progressive tool wear can be recognised from progressive changes to the shape of the force-displacement graph of the process. The potential use of such information as input to a monitoring system is demonstrated here.