Advanced Materials Research Vols. 139-141

Abstract: Combining the machining process simulation on UG NX software and the mathematically analysis, a new solving method for the tooth crest curve equation of spiral bevel gears is proposed in this paper. The steps are as follows:1) Establishing the gear blank cone equation in the original coordinate system; 2) Finding the gear convex and concave profile equations in the new coordinate system; 3) Integrating the original coordinate system and the new one through geometric transformation and then deducing the tooth crest curve equations on both sides. The equations will help calculate the cutter’s position and pose in addendum chamfering process, with the chamfer automation achieved.

Abstract: This paper presents an efficient method for deforming B-spline surfaces, based on the surface energy minimization. Firstly, using an analogy between the B-spline surface patch and the thin-plate element of the finite element method, and applying external forces on the surface with some given geometric constraints, the forces can locate on part of the surface or the surface. Then, the energy of the B-spline surface can change with the change of the forces. Finally, a new B-spline surface is generated by solving an optimization problem of change of the energy. The forces can be a single force, a distributed force and set of isolated force. The method can accomplish easily local deformation and total deformation of the B-spline surface.

Abstract: On the basis of analyzing the geometric characteristics of the helical groove, the interfer -ometry method for its processing is discussed. This paper establishes a mathematical model of the helical groove, using differential geometry theory and numerical analysis. This research analyzes the impact of machine adjustment parameters (i.e. setting angle) on the geometry specification (i.e. Rake angle) of the helical groove. The simulation examples are done by CAD (Computer Aided Design), and the reasonable adjustment of machine parameters will be obtained by computer simulation and statistical analysis. This will reduce the time for design, the number of trial samples, and production costs. This study provides a precise 3D helical cutter model which can be used in areas such as finite element analysis (FEA) and virtual cutting tests.

Abstract: As general CAM software, PowerMill encounter some problems in NC programming for mould-electrode. This paper introduces a system which can significantly improve the efficiency and quality of programming. In the system, the macro, which is a operate recorder of PowerMIll, is used to record the excellent examples of mould-electrode processing. Then the system picks up the key parameters from the macro and save them in the standard processing database. The standard processing database is open database and can save many kinds of processing for various mold-electrodes. When a new mold-electrode which is similar with what is saved in the database to be processed, the system can process it automatically. The system is developed on VB6.0 and includes a standard processing database of mold-electrode and a friendly interface.

Abstract: Precision cutting, considering the time, cost and flexibility of the production, has been one of the major goals in manufacturing. Nowadays with helping of a lot of modern technology including many of instruments with high accuracy or of many researches focused on using new technological tools such as linear motors, laser and piezoelectric actuators in cutting operations to decrease the basic parts errors (straightness, roundness, diameter error, etc.) for commercial CNC lathes in a cheaper way, but errors always happened after manufacturing between the geometry of the parts which the designer wants to get and the actual parts after manufacturing .In this research Taguchi method is used to design optimal parameters for the high-speed CNC milling machine to reduce parts geometric errors for manufacturing with cheaper cost, economic with using available instruments on the industrial partners.

Abstract: In order to solve the engineering application problems of parametric rapidly in design of wind turbine tower, an automatic design method of wind turbine tower is put forward first, and the automatic design model was built through analyzing the key parameters and parameters’ calculation relation in different cases: same taper tower design and variable taper tower design. The key parameters, height, diameter and wall thickness of the tower, are mainly considered. Then, an automatic design system of the wind turbine tower is developed and realized according to the model. Finally, the system effectiveness is verified through taking a wind turbine for example. The results show that the system can enhance the design efficiency and shorten the cycle times at the same time.

Abstract: A design-analysis and simulation approach of complex ball-end cutter was proposed by using computer graphics and OpenGL control in this paper. The mathematical models of rake face and flank face of a complex ball-end cutter were built as the simulation condition. A computer-aided design and simulation processing system of complex tool was presented through pre-modeling OpenGL control. Some 3D simulation models of complex ball-end cutter including spiral cylinder, ball-head (including rake face, chip groove, first flank face and second flank face) and grinding wheel were created respectively. According to mathematical models and VC++ software platform, transformation and machining animation simulations of ball-end cutter were designed and realized visually using OpenGL control interface technique. The results of Three-dimensional design and simulation will offer sufficient theory foundation for virtually manufacturing ball-end cutter.

Abstract: The Johnson-Cook yielding criteria model, the initial damage model and the progressive damage and failure constitute model have been introduced into the constitutive equations of the rotating band. By using the penalty function method, the dynamic contact model has been introduced and an explicit dynamics finite element model has been established. The process of the rotating band impacting the throat bore was molded based on the elastic-plastic contact finite element theory. The rotating band pulling in and impacting the throat bore was simulated by the numerical computation. The dynamic responses of the rotating band and the projectile were obtained. And the stress distribution of the throat bore was studied. The influences of the engraving process on the interior ballistics were studied through the numerical computation.

Abstract: A comprehensive tolerancing system is presented with its design principle, system architecture and key functions. The following functional modules, automatic generation of dimension chain, equivalent variational mechanism (EVM) modeling and visualized 3D tolerance analysis, are described in detail. Design intent is expressed by assembly tolerance specifications, which may be added to the model and used in computing predicted quality levels. A comprehensive method, based on equivalent replacement, has been developed for modeling variations in 3D mechanical assemblies. The models are constructed of common engineering elements: dimension chain, kinematic joints, assembly datums, dimensional and geometric feature tolerances, and assembly tolerance limits. The method is consistent with engineering design practice and is well suited for integration with commercial CAD systems. To make the tolerancing system robust and efficient, new functionalities are added to well-known CAD software and simulation environment. Tested by many samples, this system shows good robustness and practicability.

Abstract: Digital composite structures definition is the basis for the data integration of CAD, CAE and CAM for composite structures. The key of digital composite structures definition is the modeling of material structures. In this paper the procedure of material structures modeling and contents of laminate lay-up definition data have been summarized briefly. Today composite structures can not be analyzed with true fiber orientations. True fiber orientations of discrete triangle elements have been used to approximate the final state of ply fibers and a XML file has been used to describe laminate lay-up definition data. Furthermore, automatic mapping of fiber orientation data to the finite element mesh based on user specified tolerances has been used to obtain the automatic data transfer from CAD software to CAE software. Finally, the data integration of the CAD software with two manufacturing systems has been presented.