Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and decoration.Thus,the fabrication of hie...Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and decoration.Thus,the fabrication of hierarchical micro/nanograting structures is important for these applications.In this study,a strategy for machining hierarchical micro/nanograting structures is developed by controlling the tool movement trajectory.A coupling Euler-Lagrange finite element model is established to simulate the machining process.The effect of the machining methods on the nanograting formation is demonstrated,and a suitable machining method for reducing the cutting force is obtained.The height of the nanograting decreases with an increase in the tool edge radius.Furthermore,optical variable devices(OVDs)are machined using an array overlap machining approach.Coding schemes for the parallel column unit crossover and column unit in the groove crossover are designed to achieve high-quality machining of OVDs.The coloring of the logo of the Harbin Institute of Technology and the logo of the centennial anniversary of the Harbin Institute of Technology on the surface of metal samples,such as aluminum alloys,is realized.The findings of this study provide a method for the fabrication of hierarchical micro/nanograting structures that can be used to prepare OVDs.展开更多
In this paper,optimum positioning of cylindrical cutter for five-axis flank milling of non-developable ruled surface is addressed from the perspective of surface approximation.Based on the developed interchangeability...In this paper,optimum positioning of cylindrical cutter for five-axis flank milling of non-developable ruled surface is addressed from the perspective of surface approximation.Based on the developed interchangeability principle,global optimization of the five-axis tool path is modeled as approximation of the tool envelope surface to the data points on the design surface following the minimum zone criterion recommended by ANSI and ISO standards for tolerance evaluation.By using the signed point-to-surface distance function,tool path plannings for semi-finish and finish millings are formulated as two constrained optimization problems in a unified framework.Based on the second order Taylor approximation of the distance function,a sequential approximation algorithm along with a hierarchical algorithmic structure is developed for the optimization.Numerical examples are presented to confirm the validity of the proposed approach.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.52035004,52105434).
文摘Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and decoration.Thus,the fabrication of hierarchical micro/nanograting structures is important for these applications.In this study,a strategy for machining hierarchical micro/nanograting structures is developed by controlling the tool movement trajectory.A coupling Euler-Lagrange finite element model is established to simulate the machining process.The effect of the machining methods on the nanograting formation is demonstrated,and a suitable machining method for reducing the cutting force is obtained.The height of the nanograting decreases with an increase in the tool edge radius.Furthermore,optical variable devices(OVDs)are machined using an array overlap machining approach.Coding schemes for the parallel column unit crossover and column unit in the groove crossover are designed to achieve high-quality machining of OVDs.The coloring of the logo of the Harbin Institute of Technology and the logo of the centennial anniversary of the Harbin Institute of Technology on the surface of metal samples,such as aluminum alloys,is realized.The findings of this study provide a method for the fabrication of hierarchical micro/nanograting structures that can be used to prepare OVDs.
基金Supported by the National Natural Science Foundation of China(Grant Nos.50775147 and 50835004)the National Basic Research Program of China("973"Project)(Grant No.2005CB724103)the Science&Technology Commission of Shanghai Municipality(Grant No.07JC14028)
文摘In this paper,optimum positioning of cylindrical cutter for five-axis flank milling of non-developable ruled surface is addressed from the perspective of surface approximation.Based on the developed interchangeability principle,global optimization of the five-axis tool path is modeled as approximation of the tool envelope surface to the data points on the design surface following the minimum zone criterion recommended by ANSI and ISO standards for tolerance evaluation.By using the signed point-to-surface distance function,tool path plannings for semi-finish and finish millings are formulated as two constrained optimization problems in a unified framework.Based on the second order Taylor approximation of the distance function,a sequential approximation algorithm along with a hierarchical algorithmic structure is developed for the optimization.Numerical examples are presented to confirm the validity of the proposed approach.
