Statistical variation of porous aerostatic bearings

Abstract

This study investigates the statistical variation of the performance of porous aerostatic bearings. A novel Repeatability Performance Parameter ($R_{pp}$) is introduced to quantify bearing performance similarity across key performance variables, such as air gap height, bearing load capacity, stiffness, air flow, and air gap pressure distribution. An automated high precision measurement setup was developed to measure these parameters.

Four sample bearing sets, consisting of three commercially available and one in-house manufactured, were analyzed. Surface roughness and planarity of the samples were evaluated using coherence scanning interferometry. Load capacity, air film stiffness, and pressure distribution were measured under varying loads.

The results highlight significant variability in bearing performance both within and between manufacturers, emphasizing the need for improved manufacturing repeatability. The findings contribute to the advancement of aerostatic bearing technology by providing a quantitative assessment of bearing performance similarity.