Applied Mechanics and Materials Vols. 494-495

Abstract: Based on the principle of Single Point Incremental Forming (SPIF) and Double Side Incremental Forming (DSIF), A new Three Point Incremental Forming (TPIF) prototype device was developed to improve the forming accuracy. The mechanical structural components and the control system were designed and the TPIF prototype device was assembled. A TPIF trial example proved that this TPIF device can realize more forming accuracy than SPIF and DSIF. This TPIF prototype device provides a good platform for further study of the three point incremental forming.

Abstract: In order to solve deformation problem of large size hydrostatic thrust bearing under different load. Simulation model of fan cavity hydrostatic thrust bearing, three-dimensional mathematical model in guide rail is set up. Using CFD principle, FIUENT and ANSYS Workbench software, temperature field, pressure field and deformation field of hydrostatic bearing is simulated. Hydrostatic bearing deformation under different load conditions can be simulated and the lubrication characteristic is forecast in advance through this method. It provides valuable theoretical basis for hydrostatic bearing structure parameter optimization of oil cavity and worktable.

Abstract: Turbine main shaft is one of the most important components for wind turbines. Nowadays, the main shafts of megawatt wind turbine have been mainly manufactured by forging technology. Although forged spindle has good performance, forging process is so complicated that it generally takes long production cycle and high cost. This paper has been undertaken in an attempt to describing a novel method of gravity casting to manufacture wind turbine. It has been found that some performances such as the tensile strength and the yield strength of the casted main shaft are higher than those of the forging standard ones, while other performances dependent on various positions of the sampling present different performance distribution.

Abstract: The liquid metal filling and solidification process of aluminum engine cylinder head in different gating system during casting process was simulated by casting simulation software MAGMAsoft. The simulation results showed that the best pouring process contains the bottom note type casting and the placement of combustion chamber side, so that we could obtain a simple modeling process, and significantly shorten the trial production cycle, as well as the trial cost of the piston, and improve the quality of the cylinder head.

Abstract: Static bearing capacity and static stiffness of pressure equalizing groove cross section with the same width and depth are researched in this paper, it can conclude that the trapezoidal section has the maximum static bearing capacity and static stiffness, while air consumption rate of unit load is the lowest. When compound structure annular hydrostatic thrust bearing has had the optimizing parameters, compared with the single structure one, the bearing capacity had a substantial increasing.

Abstract: Cutting forces is one of the important physical phenomena in metal cutting process. It directly affects the surface quality of machining, tool life and cutting stability. The orthogonal experiments of cutting forces and influence factors with indexable and solid end mill were accomplished and the predictive model of milling force was established during high speed end milling 7050-T7451 aluminum alloy. The paper makes research mainly on the influence which the cutting speed, cutting depth and feed have on the cutting force. The experimental results of single factor showed that the cutting forces increase earlier and drop later with the increase of cutting speed, and the cutting speed of inflexion for 7050-T7451 is 1100m/min. As axial cutting depth, radial cutting depth and feed rate increase, the cutting force grows in different degree. The cutting force is particularly sensitive to axial cutting depth and slightly to the radial cutting depth.

Abstract: Introducing the design of a large turning table. The table structure is combined with three-body, double-ring hydrostatic guide-way consists of inner and outer rings, it has the advanced features of high carrying capacity, high rigidity, high precision and good holding of the second fitting precision. Table rigidity and former six-stage modal shape are resulted by the finite element analysis, the result proves the rationality of the design. The design has been applied to the 25m vertical lathe successfully and obtained a good effect. The design solved lots of questions such as casting and machining and transport of a large table, it has reduced the cost greatly.

Abstract: In order to solve the lubrication problem of the hydrostatic center rest, a optimal design concerning structure of hydrostatic center rest is studied. ANSYS has been used to compute three-dimensional stress and deformation fields of hydrostatic center rest. This research analyzes the stress and deformation of hydrostatic center rest, and it has revealed its stress and deformation distribution law. Results indicate that a characteristic will be improved by optimal design and the reliability of a hydrostatic center rest can be predicted through this method.

Abstract: In order to analyze the nonlinear dynamics of milling chatter, first we develop a cutting vibration signal acquisition and analysis system based on Labview platform; extract the phase and the maximum Lyapunov exponent of cutting vibration signal. We analyze characteristic value of vibration signals under different cutting conditions, and then online forecast milling chatter.

Abstract: The burr formation and control is one key technology of achieving precision and ultra-precision machining and automatic machining. Based on the theory of system engineering, the metal cutting burr formation, control and removal technology system are constructed in the paper. Then, the basic principles of burr control are presented. Combined with precision and ultra-precision machining and automatic machining, the active control methods and technologies of burr are presented. They are the modified design of parts structure, the option of tool geometry parameters, the adjustment of cutting data and processing technologies optimization etc. So, these methods lay a solid foundation on achieving minimum burrs.