Papers by Keyword: Micro Pattern

Abstract: The effectiveness of gas turbines can be improved significantly by decreasing the friction losses. Compared to smooth surfaces riblet-structures have been proven to reduce skin friction in turbulent flow up to 10 %. For the technical application on compressor blades in turbo machines, micro riblet-structures with a riblet width between 20 μm and 120 μm and a depth of the half width are required. Furthermore, the application on compressor blades needs ideal riblet-geometries with an aspect ratio of 0.5, trapezoid groove geometry and a shape accuracy of the compressor blade about 10 μm. This paper presents the relevant influencing factors on the overall shape accuracy as well as the riblet geometry in five axes grinding of riblet-structures on double curved compressor blades. The results show, that the shape accuracy is affected by the CAD data and the macro-geometry of the grinding wheel. Therefore, specialized requirements on the CAD data were defined in order to increase the shape accuracy. To decrease the influence of the grinding wheel geometry on the overall shape geometry, a method adjusting the grinding wheel geometry on double curved surfaces was developed. Furthermore, the effect of the 5 axes kinematic on the aspect ratio and the profile wear was examined.

Abstract: Smart processing for ceramics structure tectonics is new strategy of science and engineering to create novel functional materials with special patterns and morphologies. In this lecture, various investigations to develop the functionally structured materials by using smart processes of stereo- lithography will be introduced. For example, photonic crystals with periodic arrangements in dielectric constants are strong candidates of artificial functional materials to control electromagnetic wave energies effectively. Special modifications of dielectric micro patterns to harmonize electromagnetic waves in terahertz frequency ranges with molecule vibrations of various biochemical solutions will be introduced as investigative results of artificial photosynthesis.

Abstract: Recently, ultra-precision machining of components and dies for information and communication industries, such as fresnel mirrors, diffraction lens, and die for super high intensity reflective sheet is one of the major target. To machine three-dimensional micro patterns, such as super high-intensity reflective sheets, ultra-precision and mirror surface fabrication processes are required. It has been reported, however, that continuous cutting, such as turning or shaping, is more suitable to ultra-precision machining. Many researchers have studied the manufacturing process of reflective sheet dies to obtain high form accuracy and surface quality. In this paper, ultra-precision shaping system was developed to fabricate micro patterns mechanically. In order to estimate performance of the shaping system, micro V-shaped grooves and tetrahedron pattern arrays for a super high intensity reflective sheet was applied. Also, a new measuring technology to inspect form and machining errors of a machined tetrahedron patterns was proposed. The results show that shaping system has a positioning accuracy of x, y, z axis with 100, 10, 10nm resolution, respectively. Micro V-shaped grooves could be machined at various depths and micro tetrahedron patterns with a good quality were obtained as well.