A method for force reduction in heavy duty bending

A trend towards thicker and larger sheet metal parts can be observed. This leads to the construction of huge press brakes. A method to reduce the bending force is to preheat locally and quickly the bending area of the thick steel plate. For this purpose a dynamic contact method has been chosen: the steel is heated by being put in contact with preheated 'contact elements'. This method was experimentally tested on low carbon steel plates with a prototype setup. Reported results of the tests include achievable temperature distributions, and associated bending force. An achievable press force reduction of over 50% was demonstrated. The proposed preheating process has been simulated using the Finite Element method. Referring to the measured temperature evolutions, an appropriate value for the heat transfer coefficient could be determined. This allowed simulating the process for other combinations of plate thickness and contact element size.