A feedback control system for a rapid production process based on robotic welding deposition

The Shaped Metal Deposition (SMD) is a novel technique for rapid manufacturing of mechanical parts. It uses a robotic arm and a Tungsten Inert Gas (TIG) arc welding system in order to obtain the desired component final shape adding progressively the needed material. Actually this is the first work, as far as we know, concerning an automatic control system on such a process. After a depth study of several aspects of the process, the fundamental key parameters have been identified. A simplified version of the SMD plant has been equipped both to study and to develop different control algorithms. In order to monitor and to investigate the process several types of sensors have been used during several simpler experimental tests. The experience acquired allowed to develop several basic control laws, so that a closed loop controller has been implemented. This controller takes and maintains the process around a stable working condition, so that the final process results totally automatic.