Non-Invasive Milling Force Monitoring Through Spindle Vibration with Lstm and Dnn in Cnc Machine Tools

•A convenient method to monitor milling force of machine tool non-invasively is proposed, which can predict milling force based on spindle vibration in real-time.•A hybrid neural network combining long and short-term memory network and deep neural network are used to build the mapping between milling force and spindle vibration in data-driven manner.•The milling force prediction accuracy using hybrid NN is improved at least by 16.7% compared with existing data-driven prediction methods.