Design and manufacture of an aerostatic spindle bearing system with carbon fiber-epoxy composites

Abstract

Recently, aerostatic bearing systems are widely used in various fields in which high precision and high speed are required because of their advantages such as low friction and low heat generation. However, the aerostatic bearing systems have low radial and axial stiffnesses and poor damping properties due to low viscosity of air, and consequently have a low starting value of whirl vibration if heavy metallic spindles are employed. As the carbon fiber-epoxy composite material has excellent properties for structures, owing to its high specific modulus, high damping and low thermal expansion, the vibrational and thermal characteristics as well as the starting value of the whirl of spindles will be improved if the proper design and manufacturing methods for the composite spindle are developed. In this paper, a high speed aerostatic spindle was designed and manufactured using high madulus carbon fiber-epoxy composite material for the first time. The design method of the composite spindle and joining method of the composite spindle to the steel sleeves for aerostatic bearing mounting were developed. Using the developed aerostatic spindle bearing system, its static and dynamic characteristics were compared with those of a comparable stainless steel aerostatic spindle.