Digitization and virtualization represent key factors in the era of Industry 4.0. Digital twins (DT) can certainly contribute to increasing the efficiency of various productive sectors as they can contribute to monitoring, managing, and improvement of a product or process throughout its life cycle. Although several works deal with DTs, there are gaps regarding the use of this technology when a Flexible Manufacturing System (FMS) is used. Existing work, for the most part, is concerned with simulating the progress of manufacturing without providing key production data in real-time. Still, most of the solutions presented in the literature are relatively expensive and may be difficult to implement in most companies, due to their complexity. In this work, the digital twin of an FMS is conceived. The specific module of an ERP (Enterprise Resources Planning) system is used to digitize the physical entity. Production data is entered according to tryouts performed in the FMS. Sensors installed in the main components of the FMS, CNC (computer numerical control) lathe, robotic arm, and pallet conveyor send information in real-time to the digital entity. The results show that simulations using the digital twin present very satisfactory results compared to the physical entity. In time, information such as production rate, queue management, feedstock, equipment, and pallet status can be easily accessed by operators and managers at any time during the production process, confirming the MES (manufacture execution system) efficiency. The low-cost hardware and software used in this work showed its feasibility. The DT created represents the initial step towards designing a metaverse solution for the manufacturing unit in question, which should operate in the near future as a smart and autonomous factory model.

Accompanying the changes in production strategies focused on the intensive use of information technologies, electronic manufacturing represents one of the first moves towards the development of intelligent factories, the main guideline of Industry 4.0. One of the great challenges of manufacturing companies is the acquisition of data in an integrated manner from CNC devices of different manufacturers. In this context, taking advantage of the fact that standards such as MTConnect and OPC-UA contribute to creating the path towards the development of the new industrial era, this paper presents the architecture of a framework implemented in the form of an internet-based client-server model for monitoring and teleoperation of CNC machine tools, which has attributes compliant with Industry 4.0. The concept of the framework was carried out through a methodological approach that involved the use of IDEF0 diagrams and the axiomatic design methodology for the refinement of the model. The computational implementation was based on the integration of servers in the form of services through the proposed CyberDNC web system. It was evaluated and validated through use cases focused on the connectivity between a CNC lathe with the servers, and those with the available web clients.

When used in pocket roughing, both the direction-parallel and the contour-parallel tool path strategies usually create critical cutting regions in corners and narrow slots, which can be problematic to machine. The utilization of a trochoidal tool path has been proposed recently in order to avoid these problems. In this work, a method for generating trochoidal tool paths for 2½D pocket milling using a medial axis transform is proposed. In order to achieve this goal, first the pocket and islands are represented as polygons, and the medial axis transform is calculated as a series of points. The points are then sorted and grouped by an algorithm that generates the trochoidal path whenever the desired radial depth of cut is attained. In the proposed method, machining time is reduced through a pixel-based simulation, adjusting the tool path to the remaining material. The tool path generation method allows the control of the maximum radial depth of cut, avoiding the momentary increments in radial depth of cut, since those increments are problematic when machining hard materials or when high speed machining. Also, a cutting tool selection and area segmentation method using different tool sizes are used.