Advanced Materials Research Vols. 314-316

Abstract: In order to improve the cleaning effect and efficiency of the aluminum package used for carrying electronic aluminum liquid a new cleaning machine of aluminum package was put forward. Three standard cutters is used in new equipment to mill the inner cylindrical surface and end surface by moving in an epicyclic way. The cutting efficiency could be enhanced due to the appropriate capability carried by the cutters. The radial adjusting device of the cutter disk make the processing range flexible, thus increase the applicability of the equipment. Based on the analysis and research on the cutting devices of the new-structure aluminum package cleaning machine and the simulated to the machine processing it is demonstrated that the strength and stiffness of the cutting devices are qualified, and the design of the cleaning machine tool is practical.

Abstract: The structure and working principles of impact mole system were analyzed, and the dynamic simulation model of working impact mole system was built by using the theories of aerodynamics and aerothermodynamic. The Hammerhead impact mole was simulated by means of MATLAB language and its system simulation tool SIMULINK, and the correctness of simulation model was verified. The results show that the simulation approach provides the theoretical evidence for analyzing the kinetic parameters of working impact mole and its application in actual projects.

Abstract: The aim of this paper is to present a finite element method to predict buckling characteristics of paper honeycomb sandwich panels with composite skins under dynamic axial compression via ANSYS/LS-DYNA. First of all, some problems of the conventional method using honeycomb plate theory, sandwich laminboard theory and equivalent panel theory were pointed out. In order to develop an effective predicting method, by assuming appropriate periodic boundary condition on the edges, a simplified finite element model on hexagonal structure of a unit cell for sandwich panels was developed utilizing the 3D finite element method. The effective Young's modulus of the cellular wall was obtained from the result of the test on the honeycomb core. Several useful conclusions are drawn about the axial crushing of honeycomb sandwich composites and unit cell and can be used to guide the design of composite structures. The paper further attempts to explain numerical results are well consistent with the corresponding experimental ones.

Abstract: Obtaining a uniform thickness of the final product using thermoforming is difficult, and the thickness distribution depends strongly on the distribution of the sheet temperature. In this paper, the time-dependent temperature distribution of the total sheets in the storing process was studied because the temperature after the storing process is the initial temperature of the preheating process. An analysis code for simulating the storing process was developed under the condition that the thermal conductivity caused by contact resistance between sheets was assumed as a large value. In this study, the number of sheets in the storing room was adjusted for finding out the effect of it. The analysis results show that maximum temperature difference between sheets was significantly different when adjusting the number of sheets in the storing room. The temperature distribution of the total sheets and the method for analysis in this study will be used to optimize the storing process for higher quality of final products.

Abstract: Thermoforming is one of the most versatile and economical processes available for shaping polymer products. To improve the quality of final products, the temperature difference between surface and center of sheet should be continuously minimized. But, the temperature difference between surface and center of sheet can not be freely reduced because of low thermal conductivity of sheet materials. In this paper, an analysis model was developed under the condition that the inputted heat flux was expressed by an exponential function form. In the following step, an optimal design was carried out using a 3rd order polynomial. The optimal results show that the developed method can be used to reduce the temperature difference between surface and center of sheet by adjusting the parameter of time-dependent heat flux.

Abstract: The material removal rate (MRR) of micro-detonation of striking arc machining (MDSAM) is studied. The orthogonal experimental design and regression analysis method are employed to build the empirical model and the influencing laws of processing parameters on impact force are educed. Experimental results show that the material removal rate decreases with the increment of working distance and increases with the growth of working current, working gas pressure and pulse width. The exponential type empirical model with feature of simple and reliable consists with experiment results well. The research can offer an important reference for the predication and control of material removal rate in the process of micro-detonation machining of striking arc.

Abstract: Springback is a common phenomenon in sheet metal forming, caused by the elastic redistribution of the internal stresses during unloading. The aim of this search is to investigate the wave of material parameters on the results of forming and springback of sheet metal. A finite element model of cylinder bending benchmark of NUMISHEET’2002 was proposed firstly to simulate bending and springback with contact evolution between tools and blank based on static implicit method. The simulation results agree well with the experiment. Then the effects of the wave of material parameters on forming and springback results are investigated using orthogonal design simulation. Eight factors are investigated with the orthogonal label. The results show the factors have different effects on both the forming and springback. And the significance of the factors is shown through direct analysis of the results.

Abstract: Because of unbalanced axial force of cross wedge rolling asymmetric shaft-parts causing the rolling play and not stably, it is key factors to restrict application in asymmetric shaft-parts of cross wedge rolling. Axial force balance depends on technical parameters. So the influence regularities of axial force to technical parameters is researched in this paper by Ansys-Ls/Dyna finite element software. Finite element model is authenticated by experiment of rolling force, and the influence regularities of axial force of cross wedge rolling asymmetric shaft-parts is get. It will provide a theoretical basis for choosing reasonable parameters in mold design of cross wedge rolling asymmetric shaft-parts.

Abstract: Blank shape design is the prerequisite and foundation of optimization for the closed forming the high-neck flange. This paper obtained the design formulas of blank size with analyzing the mathematical model of flank blank based on the principle of volume invariably during the rolling process.The blank of a special flange was designed by this method which was validated by the numerical simulation under the DEFORM software. The results indicate that the product is qualified with the blank shape based on this method. These research conclusions can provide scientific basis for forming the high-neck flange with rolling method.

Abstract: The strong demand for increasing productivity and workpiece quality in milling process makes the machine-tool system operate close to the limit of its dynamic stability. Milling cutters with variable pitch angles can be very effective in improving stability against chatter for certain speed ranges, which will be predicted by the model presented here. The present paper deals with the design of structural geometry of variable pitch end mills in detail. Based on the analysis of tooth engagement factor, which is expressed and extended in the paper, an approach is proposed to design variable pitch end mill with high milling stability. The certain speed ranges with high milling stability are given.