Deterministic Micro Asperities on Bearings and Seals Using a Modified LIGA Process
Deterministic Micro Asperities on Bearings and Seals Using a Modified LIGA Process
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DOI：
10.1115/1.1619430
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发表时间：
2002
影响因子：
1.5
通讯作者：
L. S. Stephens;R. Siripuram;Matthew A. Hayden;Bianca McCartt
中科院分区：
文献类型：
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作者：
L. S. Stephens;R. Siripuram;Matthew A. Hayden;Bianca McCartt
确定性微凸体显示出在许多轴承和密封设计中发现的共形接触中增强润滑的潜力。已经提出了几种用于确定性微凸体的制造方法。其中，激光纹理已成为最可行的选择。本文提出了LIGA MEMs制造方法作为替代。使用LIGA，具有任意横截面（圆柱形、六边形、三角形等）的图案化微米尺寸表面特征的表面。可以由电镀镍、凝胶铸造氮化硅或塑料制成。所得的凸体可以是积极的（突起）或消极的（凹进），可以有高度（深度）从1-1000微米，并在表面面积高达约150 mm × 150 mm的图案。在本文中，LIGA方法是用来制造一个样品的推力轴承表面与正凸体的六边形阵列。所得微凸体的平均直径为550 μm，边到边间距为165 μm，高度为3-100 μm。表面计量表明，亚微米精度的形式和13纳米Ra粗糙度的凹凸顶部（土地）。在非加压油浴中的摩擦学测试表明全膜条件，并显示覆盖有微凸体的推力表面的摩擦系数降低14-22%。一个模型证实了实验趋势，并表明通过优化微凸体的几何形状和布局，有可能进一步降低摩擦系数约60%。
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 150 mm X150 mm. 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.