On Enhancing Legacy CNC Machine Tools for Process Monitoring and Cloud Integration in Industry 4.0

Industry 4.0 approaches in manufacturing rely on extensive data to create digital twins. Modern CNC machine tools can provide such data via built-in systems. However, legacy CNC machines, still prevalent in SMEs, lack these features. This paper focuses on enhancing legacy CNC machines towards process monitoring and integration into a cloud manufacturing ecosystem. The proposed methodology, demonstrated on a specific turning center, begins with instrumenting the machine and using a DAQ device to capture and synchronize analog signals e.g. for motor speed, torque and vibration. Next, a software application developed following a Service Oriented Architecture, operates on a single producer service to accumulate sensor data, group it into buffers, and distribute it in near-real time to other software components. These include a process monitoring service using a CNN to predict quality parameters, a bridge service to transmit streaming data via Server Sent Events and a web-based visualization interface.