Thin-walled Multi-frame Structure And Efficient Milling Stability Study

With characteristics of light mass, high intensity and perfect dynamic performance, the monolithic construction components are used more and more widely in aero, electronic and mold industries. As there are many complex characteristics such as thin-wall, varying thickness, complex curved face and big metal allowance in the monolithic construction components, chatter is an unavoidable phenomenon in all machining processes, causing a reduction in productivity and low quality of finished workpieces. Study on the maching vibration and cutting stability of the monolithic construction components is very important. This paper has theoretically analyzed the chatter and stability cutting of the monolithic construction components firstly. A three-dimensional chatter stability model is presented analytically in this article. Then built the FEM dynamic mechanistic analysis model of milling process. Finally conducted a simulation analysis of milling process. By large quantity of simulations and tests, some important conclusions have been gained. The main work in this paper is concluded as follows.1. Built the dynamic force model of milling thin-walled structure components in detail. In this paper, several dynamic force models are built for milling of aeronautical parts that include thin walls and thin floors. This paper sets up dynamic force models for spiral end mills and bull-nose end mills during milling the thin floors. The model is verified with milling experiment. Based on the model, a dynamic model of the milling system of thin-walled parts is established by considering the machine subsystem, the tool subsystem and the workpiece subsystem. This will be helpful to estimate the cutting forces more accurately and to predict the chatter vibration.2. Studied the milling dynamic characteristics of the thin-walled structure components. Based on the dynamic model of the milling system of thin-walled parts established in the previous paper, the FEM dynamic mechanistic analysis model of milling process is built theoretically. Then a kind of simplified model has been proposed in this paper, and large quantity simulations have been carried out based on the simplified model. The simulation results have been concluded.3. Studied the modal analysis of the thin-walled structure component. The modal analyses are carried out in every machining location. Based on it, modal parameters have been gained which will be helpful to the stability anslysis.4. Studied the chatter in the machining processes. The properties and mechanism of machining vibration have been studied. Then the definition of stability and the prediction method of stability criterion are presented based on it.5. Studied the stability limits of high-speed milling considering the flexibility of the workpiece and the machine. Aimed to bull-nose mill, the dynamic milling force model taking account of regenerative chatter are deduced, and high speed cutting stability is investigated according to dynamic milling force model, then the stability criterion and the ultimate axial depth of cut are studied. Finally, the stability lobes are drawn, and simulated the effect of different modal parameters on stability based on stability lobes.The studies of this paper will be a guide for no chatter milling of the monolithic construction components.