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Aiming at the influence of noise, vibration, and force on machining efficiency and machining quality in the process of milling, this paper proposed an improved particle swarm optimization algorithm. The algorithm could optimize the multi-objective and multi-parameter integration model and obtain the optimal milling parameters under the specified milling conditions, so as to reduce milling noise, vibration, and force and improve machining efficiency. First, based on the theory of all factor experiment, the milling experiment of TC4 titanium alloy was carried out, and the relevant milling noise, vibration, and force signals were obtained. Then, based on the response surface analysis method, the influence of milling parameters on noise, vibration, and force was studied. Finally, a multi-objective optimization model based on maximum metal removal rate, minimum noise, minimum vibration, and minimum force was established, and the improved particle swarm optimization algorithm was used to solve the optimal milling parameters. The result shows that when the milling speed is 24.9588 m/min, the feed speed is 9.9324 mm/min, and the milling depth is 1 mm, the optimal milling state within the constraint conditions can be achieved.

Abstract. The dynamic force equilibrium equations of the cup of crowned tapered roller bearing under the combined loads condition are established in this paper, considering the centrifugal forces of each roller, the forces of the rib/roller end contact and the contact forces between crowned tapered roller and raceway. The equations are solved based on the Newton iteration method to analysis the dynamic load distribution of crowned tapered roller bearings. The load distribution and contact deformation of tapered roller bearing with three kinds of crowned rollers, such as rollers with straight profile, circular crowned profile and logarithmic crowned profile, are analyzed according to the Palmgren's formula and the numerical method based on influence coefficient method respectively. The results show that the Almgren's formula can be applied to calculation of the dynamic load distribution approximatively, while the numerical method must be used in contact deformation calculation for the crowned tapered roller bearing.