Papers by Author: Nan Li

Abstract: Two kinds of methods for the control of the gap between pressing tool head and support in CNC incremental forming have been discussed (i.e. pressing path adjustment method and support shape adjustment method), and whose effects on forming accuracy are analyzed by using the Finite Element Analyses. The methods for the generation of pressing paths and supports have been given for the two forming method of the pressing path adjustment and support shape adjustment, and the Finite Element Analysis models have been built for them respectively. The method of digital simulations for the two forming cases mentioned above based on the ANSYS/LS-DYNA software has been presented and the forming precision of the two forming methods are analyzed through the comparison of digital simulation results.

Abstract: On the basis of the analysis for the reason that causes the errors of the vertex offset, the accuracy improvement method for the STL offset model which was generated by the vertex offset algorithm was proposed by using the surface subdivision algorithm based on the center of gravity on triangular facets. The offset point of the center of gravity was generated by offset the center of gravity along the normal vectors of the triangular facets on which the center of gravity is located, and the new triangular facets are formed by connecting the offset points of the center of gravity and the offset vertexes of the triangular facets so that the more accurate offset model to be built. The case study shows that the proposed algorithm has higher accuracy than the existing vertex offset algorithm.

Abstract: The method of laser inner engraving path generation and simulation for crystal glass is presented based on STL(Stereo Lithography) model. To generate the laser exposure points that are adaptive to the surface of model, the contour lines are obtained by cutting the STL model with unequal distance using a series of plans that are perpendicular to Z-axis. Then the contour lines are offset and scattered, and then the path is generated by sorting and connecting each discrete point in order. Simultaneously, simulation method of laser inner engraving for crystal glass is also proposed. The case studies show that the method can primely realize the engraving path generation and the simulation for the laser inner engraving of crystal glass, and that the system runs stably and reliably.