Papers by Author: Wei Xiao Tang

Abstract: The ecological structures of some organisms that could resist environmental vibration naturally (such as dragonfly, woodpecker and legs of cursorial animals) uncovered by biologists inspire people a new approach to overcome the above problem. In this paper, a new shock isolation system consisting of a pedestal, a rubber layer, an air spring and a shearing viscoelastic damper is designed, fabricated, and characterized to avoid the performance deterioration and physical damage of mechanical manufacturing devices from external mechanical excitations. The nonlinear dynamics model of the platform is developed and the dynamic characteristics are analyzed using numerical analysis. The displacement and velocity response are obtained. The results demonstrate that the stiffness and damping characteristic of the platform change with excitation frequency. The vibration isolation effectiveness will be greatly enhanced.

Abstract: A review of research on the vibration control technology inspiration from the biological vibration damping mechanisms is described. First the important concept and background of the bionic vibration damping technology are briefly introduced. Then the basic theories and its applications in the engineering fields are elaborated from three aspects: vibration damping mechanisms of the creatures own the good ability to withstand the ambient vibrations, mechanical models of biological prototypes and its application progress in the practical occasions.

Abstract: High-speed milling (HSM) has advantages in high productivity high precision and low production cost. Thus it can be widely used in the manufacture industry. However, when the speed of spindle-tool reaches a higher speed range, the gyroscopic effect will become an important part of its stable milling. In this paper, a dynamics model of HSM system was proposed considering the influence of gyroscopic moment due to high rotating speed of end milling. Finite element model (FEM) is used to model the dynamics of a spindle-milling system. It obtains the trajectory of central point in face milling with considering gyroscopic effects through the dynamics model at high speeds. Then the cutting force model will be corrected by the trajectory of face milling. Then the stability lobes diagrams (SLD) was elaborated. Cutting thickness effects have non-negligible impact on stability limitation.

Abstract: High-speed milling (HSM) has advantages in high productivity high precision and low production cost. Thus it can be widely used in the manufacture industry. However, when the speed of spindle-tool reaches a higher speed range, the gyroscopic effect will become an important part of its stable milling. In this paper, a dynamics model of HSM system was proposed considering the influence of gyroscopic moment due to high rotating speed of end milling, and solution it. Then, the natural frequencies of end-milling model were researched by using analyse software. And analysis the stability of end-milling that considered gyroscopic effects under different speeds, obtain the Campbell Diagram. Get the trajectory of one point in end face milling. Then draw the fitting trajectory and ideal trajectory of the point in milling. Compare the actual trajectory, fitting trajectory and the ideal trajectory. So it can provide a basis for stability prediction of high speed milling.

Abstract: A combined numerical and experimental study is performed to analyze the feasibility of using heat pipe cooling in milling applications. In this model, it is assumed that the end mill is subjected to a static heat source which verifies the analysis and feasibility of using heat pipe cooling in milling operations. The performance of heat pipe mill model is approximated using a solid cylinder model of pure conduction. Both the numerical and experimental studies show that the use of a heat pipe in a mill can reduce the temperature field significantly.

Abstract: High-speed milling (HSM) has advantages in high productivity high precision and low production cost. Thus it can be widely used in the manufacture industry. However, when the speed of spindle-tool reaches a higher speed range, the gyroscopic effect will become an important part of its stable milling. In this paper, a dynamics model of HSM system was proposed considering the influence of gyroscopic moment due to high rotating speed of end milling. Finite element model (FEM) is used to model the dynamics of a spindle-milling system. It obtains the trajectory of central point in face milling with considering gyroscopic effects through the dynamics model at high speeds. Then the cutting force model will be corrected by the trajectory of face milling. So it can provide a basis for stability prediction of high speed milling.

Abstract: The cutting temperature is a key factor which directly affects thermal distortion, the machined part’s dimensional accuracy, as well as the tool wear in machining process. Aiming to effectively remove the cutting heat yields in machining process, the cutting tool with heat pipe cooling has been developed in recent years. This research focuses on developing a clear understanding of the temperature distribution in end mill embedded with heat pipe. Mathematical model is developed based on the heat transfer theory and the metal-cutting theory. 3-D finite element models are set up. The thermal boundary conditions are properly set, and contrasts of the temperature field in end mill with and without embedded heat pipes by numerical simulations are given.

Abstract: Semi-discretization method is applied to construct stability chart and performance contour in the parametric space for milling processes. The method creates a mapping of the system responses in a finite dimensional state space. Based on the discipline of that, the smaller the largest absolute value (μmax) of the characteristic multipliers of the mapping is, the faster the system converges to zero, minimization of μmax leads to optimal stable limit. The optimal limits are obtained by using stability chart and performance contours. Additional, a novel analytical method for selection of optimal depth of cut (axial depth of cut) is presented. An example of 2-DOF down-milling model is employed to demonstrate the method. It is shown that the spindle speeds corresponding to the optimal depths of cut locate the left side of the resonant spindle speeds, and the optimal cutting parameters pair (spindle speed and depth of cut) can be used to offer high finishing accuracy in precision machining.

Abstract: Chatter problems occurring during high speed milling affect the quality of the finished workpiece and, to a lesser extent, the tool life and the spindle life. Therefore, the prediction of stable milling regions is a critical requirement for high speed milling operations. In this paper, a dynamic model of a high speed spindle system considering the multi-mode dynamics is elaborated for the purposed of stability prediction. A stability lobes diagram (SLD) shows the boundary between chatter-free machining operations and unstable processes, in terms of axial depth of cut as a function of spindle speed. These diagrams are used to select chatter-free combinations of machining parameters. The proposed method enables a new stability lobes diagram to be established that takes into account the effect of spindle speed on multi-mode dynamic behavior.

Abstract: High-speed milling (HSM) which is characterized as high productivity and low power consumption can be widely used in the manufacture industry. However, while the speed of spindle-tool reach the high speed range, the prediction of its stable milling faces more difficulties, as the gyroscopic effects become prominent. In this paper, a dynamics model of HSM system was set up considering the influence of gyroscopic moment due to high rotating speed of spindle-tool. Then a method was proposed by transforming time-varying stiffness system into fixed-step time invariant one. Finally the stability lobes diagrams (SLD) was elaborated. The results shows that the gyroscopic effects due to high rotating speed have non-negligible impact on the stability limitation, which must be considered for the predicting of stability limit in the high speed milling.