Machine Tool Monitoring in discrete manufacturing can be performed using Digital Twins of the manufacturing process. Some ARs of machine tools are presented in following videos performing AR operation using Unity, C#, ISO 841: 2001, ISO 6983-1: 2009 and AI based on domain knowledge:

Twin Turret Lathe 3-Axes Milling Machine 5-Axes Milling Machine Virtual Factory

MDT Terminal Development and Retrofitting Manual Data Input (MDT) terminals are used to integrate conventional manufacturing machines within the manufacturing system and beyond. Possibilities extend to concepts given in eERP detailed above. Machine Tool Retrofitting is done to convert the conventional machine into a computer numerical control (CNC) machine. The following URLs show the retrofitting of CNC milling machine into a modern AR supported CNC milling machine: