| Hardened steel material Cr12MoV is common material of the components of automotive panel die. Automobile die plays a very important role in the manufacture and batch production of auto parts. With the development of manufacturing technology, automobile die develops toward large scale, precision and digitization. Comparing with other molds, automobile panel die has the characteristics of large size, large depth uniformity, high surface quality requirements, and complex process and so on. Therefore, in the process of processing automobile panel die, the car mold will not be allowed the connection of the connection is not smooth, rigid poor, uneven margin and other phenomena. C utting chatter can affect the dimensional accuracy and surface quality of machined parts in machining process. Supported by National Natural Science Foundation Major Project " Technical basis and application of machining Large high quality hardened steel die which used in car cover "(project number: 51235003).According to flutter problems of machine tool technology system in machining hardened steel material Cr12MoV,stability characteristics of cutting tool in milling process under different conditions were analyzed basing on the milling dynamic model and the mathematical model of process damping, which reveals the mechanism of the process damping and obtains the stable domain of the milling cutter.In the first place, the regenerative chatter in metal cutt ing is analyzed, which provides basis for establishing the dynamic model of milling cutter; On the basis of the above theory, a single degree of freedom and two degrees of freedom tool stability model is established to reveal the vibration characteristics of the tool; The feedback transfer function of dynamic milling system is obtained, and the milling force dynamic equation is transformed into the system characteristic value to solve the problem, and the relation between the limit depth and speed is obtained.Secondly, according to the formation mechanism of process damping, the factors that affect the damping size in milling process are explored, and the three main parameters are the workpiece material, the blade edge radius and the blade angle; Stress coefficient is calculated by energy method. The indentation force coefficient is only related to the material. When the indentation force coefficient of material is known, the coefficient of the damping coefficient and the cutting depth can be predicted under different tool geometry and cutting conditions; the calculation model of the flank pressing volume of a circular blade is given; compressed volume is calculated for solving indentation force coefficient.Finally, the dynamic characteristics of the tool in milling process are analyzed, and the simulation model of the circular edge milling cutter is established, and the modal parameters of the milling cutter are obtained, stable field of milling cutter is calculated; Milling hardened steel Cr12MoV experiments are carried out, the stability limit of experimental are recorded and tool dynamic characteristics are observed at the same time, the milling stability region which agrees with the law of the simulation results is obtained. |
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