Modeling And Simulation For Chatter Stability Of Milling Process Including The Effect Of Nonlinear Process Damping

Because of having both advantage of high precision and high efficiency, high performance milling has been widely used in aerospace, rail transportation, automotive and other important fields. Chatter is the key factor to restrict high performance milling. Deeply research on milling dynamics, analyze the characteristics and the rules for milling dynamics, adapt and optimize reasonable process parameters, then, non-chatter high performance milling can be achieved. Process damping significantly affects and enhances the critical axial depth of cut especially at low cutting speeds, so it is crucial for the high performance machining of the difficult-to-machine material in aerospace field such as titanium, nickel-based alloys. This paper focuses on the process damping in the milling dynamics, the main research contents are as follows.Based on the cylindrical helical milling model, this paper presents the milling dynamics model considering regeneration in the simplified milling system, a two degree of freedom vibration system. Based on this milling dynamics model, analyze the process damping mechanism, discuss the relationship between process damping with cutting speed, model and solve the ploughing force in the process damping. Then, the milling dynamics model considering the process damping is set up, and solved by numerical method.This paper presents an improved semi discretization simulation method to solve the milling dynamics model considering process damping based on the classical semi discretization method. The improved semi discretization method utilize the dichotomy method, and the result is more faster than the classical method. Utilizing the improved semi discretization method, the simulation program module is developed though Matlab GUI software.Picking the chatter milling point and stable milling point in the chatter stable lobes diagram, research and analyze the two points nonlinear condition by the tool vibration displacement time diagram and the phase diagram, and further research the process damping affect in the milling.Last, the cutting force coefficient and the modal parameter are identified through milling test and modal test respectively, all these data are used in the numerical simulation. In the chatter stable milling test, get each stable milling and chatter milling point data, the chatter is identified through the force instrument and the software. The chatter stable milling test validate the simulation of the milling dynamic considering process damping.