Deterministic micro asperities show potential for enhancement of lubrication in conformal contacts as found in many bearing and seal designs. Several manufacturing methods have been proposed for deterministic micro asperities. Of these, laser texturing has emerged as the most viable option. This paper proposes the LIGA MEMs manufacturing method as an alternative. Using LIGA, surfaces with patterned micron sized surface features of arbitrary cross section (cylindrical, hex, triangular, etc.) can be fabricated from electroplated nickel, gel-cast silicon nitride, or plastic. The resulting asperities can be positive (protuberances) or negative (recesses) and can have heights (depths) from 1–1000 microns and be patterned over surface areas up to about In this paper, the LIGA method is used to fabricate a sample thrust bearing surface with a hexagonal array of positive asperities. The resulting asperities are 550 μm in average diameter, 165 μm in edge-to-edge spacing and have heights of 3–100 μm. Surface metrology indicates submicron accuracy of form and 13 nm Ra roughness on the asperity tops (land). Tribology testing in a nonpressurized oil bath indicates full film conditions and shows a 14–22% reduction in friction coefficient for a thrust surface covered with the micro asperities. A model confirms the experimental trends and indicates the potential to further reduce the friction coefficient by about 60% through optimization of the asperity geometry and layout.
Deterministic Micro Asperities on Bearings and Seals Using a Modified LIGA Process
Contributed by the International Gas Turbine Institute (IGTI) of THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS for publication in the ASME JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Paper presented at the International Gas Turbine and Aeroengine Congress and Exhibition, Amsterdam, The Netherlands, June 3–6, 2002; Paper No. 2002-GT-30289. Manuscript received by IGTI, December 2001, final revision, March 2002. Associate Editor: E. Benvenuti.
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Stephens, L. S., Siripuram , R., Hayden , M., and McCartt, B. (March 2, 2004). "Deterministic Micro Asperities on Bearings and Seals Using a Modified LIGA Process ." ASME. J. Eng. Gas Turbines Power. January 2004; 126(1): 147–154. https://doi.org/10.1115/1.1619430
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