Papers by Author: Yu Shan Lu

Abstract: In order to get the convex surface with phyllotactic pattern, the convex surface with phyllotactic pattern on end face of work-piece and its mask were designed based on the phyllotactic theory of biology, the surface was fabricated by electrolytic etching method, and also the fabricating processes were investigated .The results show that the convex surface with phyllotactic pattern can be fabricated by electrolytic etching method , and under the condition of room temperature (25°C), composite etching liquid which composed of NaCl,NaNO₃,Na₃PO₄,etc., has better performance than the pure NaCl etching fluid, and in the current density of 15A/dm², the etching rate was 3.292μm/min by composite etching liquid when steel 45 is etched. This technology can be used for fabricating the end grinding wheel with the phyllotactic pattern of abrasive clusters.

Abstract: In order to improve the lubricating performance of the headface sliding bearing, a new kind of the bionic headface sliding bearing, which has defined lubricating dimple pattern, has been designed based on the phyllotactic theory, and fabricated with UV lithography method and electrolytic technology. A electrolytic experiment of the dimple has been done and analyzed about the influence of the electrolytic time to the electrolytic depth against the different phyllotactic parameters. The analytical results indicate that the phyllotactic parameters influence the lubricating dimple arrangement configuration, so as to improve lubricating performance of the bearing. The increasing diameter of the dimple and the decreasing phyllotactic parameter c can increase the density of the lubricating dimple. Electrolytic experimental results show that the reasonable electrolytic fabricating can reduce the faults of defined lubricating dimple arrangement on the bearing surface.

Abstract: In order to resolve the theorized design problems on the bionic non-smooth drag reduction surface of an arc-shaped revolution body, which mainly include the structure morphology and spatial arrangement of the non-smooth point, a kind of designing method on the bionic non-smooth drag reduction surface is presented based on biological phyllotactic theory, and the mathematical equation of the arrangement of the non-smooth point on the arc-shaped drag reduction surface has been established, the effects of the phyllotactic parameters on the arrangement form and density of the non-smooth point have been discussed, and the arrangement of the non-smooth point on an arc-shaped revolution body surface has been designed by using a 3D software. Research results have shown that the arrangement density of the non-smooth points increases with the decreasing of the phyllotactic coefficient, and the area ratio of the no-smooth point to the surface of revolution body increases with the geometric parameter of the non-smooth point.

Abstract: In order to make the material removal distribution on polishing silicon surface more non-uniform during the chemical mechanical polishing (CMP), a kind of the bionic polishing pad with phyllotactic pattern has been designed based on phyllotaxis theory, and by polishing experiment, the effects of the phyllotaxis parameters on material removal distributions on silicon wafer surfaces are investigated. The research results show that the material removal distribution of polishing silicon surface more uniform and the edge rounding of polishing wafer can be decreased when the phyllotaxis parameters of the polishing pad are reasonably selected.

Abstract: In order to obtain the contact pressure distribution between the hard disc substrate and the polishing pad and its effects on the profile of polished substrate surface, the elastic contact mechanical model and mathematical equations on the chemical mechanical polishing of the hard magnetic disc substrate are established, and also the relevant boundary conditions are put forward. The contact pressure distribution is calculated with FEM, the polishing experiments are carried out and the surface profiles of polished substrates are obtained. The study results show that the contact pressure distribution on the substrate surface is non-uniformity and the contact pressure in the substrate edge present biggish undulation. Choosing properly the Young’s modulus of the polishing pads and decreasing its Poisson’s ratios can make the uniform area of the contact pressure distribution enlarging and improve the flatness of polished substrate.