Towards the Real-Time Piloting of a Forging Process: Development of a Surrogate Model for a Multiple Blow Operation

Forging processes are defined by variables related to the workpiece, the tools, the machine, and the process itself, and these variables are called process variables. They have a direct impact on the quality of the finished product, so it is important to accurately define them at the very beginning of the process design. Nowadays, the design stage is supported by numerical simulations, however, these simulations are made under ideal process conditions and do not consider the dynamics of the forging machine or the variabilities that may occur in production (e.g., variabilities in the dimensions of the billet). This suggests that among the different process variables, those defined for piloting the process (such as the blows energies, for example) are fixed under nominal conditions and are not calibrated for each part produced. This study exploits a methodology in four steps to create a surrogate model and implement it into a machine-behavior model for real-time piloting of a forging operation with a screw press. This model supports the piloting of the operation, providing a value for the energy setpoint, according to the current state of process variables, these being the input of the model. The methodology is detailed for a multiple-blow cold upsetting of a copper billet.