Dynamic milling force model considering vibration and tool flank wear width for monitoring tool states in machining of Ti-6AI-4V

In aviation industry, difficult-to-machine materials (Ti-6Al-4V) are widely applied due to its excellent performance. However, dramatic dynamic milling force and cutting temperature generated in machining of Ti-6AI-4V result in excessive tool wears, which produce vibration, shorten tool life, deteriorates workpiece surface quality et al. To investigate above problems, the dynamic milling forces including tool vibration and tool flank wear width for tool state monitoring in machining of Ti-6AI-4V is proposed by theoretical and experimental method. In this process, the intricate interplay between tool and workpiece in the engagement zone is elucidated by analyzing the contact state and cutting force considering vibration and tool wear. Then, the dynamic milling forces can be divided into rake face shear force and tool flank face friction force. Subsequently, instantaneous uncut chip thickness considering vibration and tool wear are analyzed and the time-varying shear forces on tool rake face are determined. Next, the tool dynamic wear mechanism is investigated, in further, friction force model considering tool and workpiece vibration is constructed under elastic contact and plastic flow state. Meanwhile, a dynamic milling force model taking into account vibration and tool flank wear width is proposed based on elastic-plastic mechanics theory. Simultaneously, a model is developed to map dynamic milling forces and tool flank wear width for monitoring tool wear status. Finally, the proposed model is tested by different experiments, and the results demonstrate that the calculated milling forces closely match that measured and the average errors are 3.5 % and 5.75 % in X, Y direction, in addition, the average discrepancies of the calculated tool flank wear width based on dynamic milling forces in X, Y directions are 8.7 % and 8 % compared with that measured, respectively.