Development of an Interactive Digital Twin for Directed Energy Deposition (DED) Process

Due to inherent drawbacks of metal 3D printing process such poor dimensional accuracy, surface quality, and various defects, a process monitoring system with an appropriate information visualization interface has been required. In the recent technological mega-trend, the 4th industrial revolution, the digital twin technology has received much attention to effectively monitor the process and transfer relevant information to operators. Therefore, in this paper, the interactive digital twin for a directed energy deposition (DED) process, which is one of representative metal 3D printing processes, is developed. First, the DED equipment digital twin is developed by creating a 3D model of the DED machine, and the motions of virtual components are synchronized with physical ones of the machine by attaching an inertial measurement unit (IMU) sensor to the DED head. Next, the DED process digital twin is developed by pooling objects based on the measured shape of the actual deposited parts. Finally, the DED equipment and process digital twins are combined together to simulate exactly the same as the actual system. Furthermore, the process monitoring function is realized by displaying temperature, shape and size of the melt-pool that are measured by a pyrometer and a CCD camera, respectively. In addition, the diagnosis results of the health state of the DED process are shown in the interactive digital twin.