s. The work principle of indexing mechanism with globoidal cam is depicted firstly. Equations of the contour surface and the conjugate contact line are deduced by rotating matrix operators. The value of roughness becomes very small by high speed machining, so it can replace the grinding. At last, kinematics analyze and motion simulation are carried out.

As a new tool of statistical analysis, Copula is introduced to build reliability model for structural system consisting of identical components, by which the complex feature of failure dependence can be depicted. Aiming at symmetric structure systems, typical failure-dependence mechanism of components is discussed firstly. Considering the failure-dependence mechanism, modeling steps based on Gauss Copula and Archimedean Copulas are put forward, in which the twin stress, components strength are chosen as the basic variables and the safety margins are chosen as the analytic variables. Compared with Gauss Copula, Archimedean Copulas have powerful capability of describing the failure-dependence mechanism owing to the adjustable parameters can be determined according to the rank correlation coefficient and the information about the critical failure point. Archimedean Copula-based reliability models are applicable to non-normal situations. A numerical example is given to show that the new method is reasonable and feasible. Copula-based reliability models can give a new path for reliability analysis of complex systems with failure-dependence.

In order to achieve higher speed and better efficiency of the plastic buckle molding, Imageware, the reverse design software, was adopted in this paper to process the point cloud data of the plastic buckle, mesh feature lines and reconstruct the surface,and then the reconstructed plastic buckle model was imported into UG and saved in STL format with the powerful surface repair function of UG to suture discontinuous surfaces. Mold Wizards of UG, the mold design module, was used to create mold assembly model, design parting surface, generate three-dimensional solid model of molding parts according to STL format saved previously and eventually the injection-molded plastic buckle was analyzed with Moldflow / MPI. As was indicated, the optimized design parameters tally with the experimental results basically.