With the advent of the 4th industrial revolution, advanced digital manufacturing technologies are actively developed to strengthen manufacturing competitiveness. Smart factories require a real-time digital twin including a Cyber-Physical System (CPS) of machines and processes and intelligent technologies based on the CPS. To predict machining quality and optimize machines and processes, it is necessary to analyze the cutting force during machining. Therefore, for real-time digital twin, a fast cutting force simulation model that receives information such as the positions of the feed axes in short time intervals from the CNC and calculates the cutting force until the next information is input is required. This paper proposes a voxel-based fast cutting force simulation in NC milling for real-time digital twin. The proposed simulation model quickly calculates the cutting force by using only information of voxel elements removed by each tool edge without complicated Cutter-Workpiece Engagement (CWE) and chip thickness calculations in previous studies. To verify the performance of the developed simulation, experimental machining was performed and the measured cutting force and simulated cutting force were compared. It was demonstrated that the proposed model can successfully predict the cutting force 3.5 times faster than the actual process.

Along with the recent spread of 3D printing technology, researchers have developed various materials and equipment, now widely disseminated among individuals and industries. However, most of the current metal 3D printers generate the cutting paths using cutting software only, which doesn’t consider heat input of the plasma or laser. In the wire arc additive manufacturing (WAAM) system, a projection algorithm is created through the CATIA application programming interface. Different from the existing cutting algorithm, this algorithm converts a two-dimensional (2D) image into a three-dimensional (3D) structure by orthogonal projection and a voxel algorithm that expresses a 3D finite volume element. To fix the (x, y) coordinates and the z (Height) coordinate to be on the 2D plane, the projection algorithm models the 3D geometry orthogonal to the 2D plane. The bead modeling data and the step-over values generating the laminate shape were determined. The core of the voxel algorithm that models the free-shape lamination obtains the point location of the wire arc, considering the bead size and the distance between the layer spacing and the voxel center point (According to the processing conditions). Finally, the correct projection and voxel algorithms are selected using a lamination path-acquisition strategy.