文摘
Demand continues for the supply of machine tools with improved accuracy and productivity. This necessitates machine structures and spindle assemblies with much higher static and dynamic stiffness than are currently available, together with very low levels of thermal drift. The medium term accuracy of oil hydrostatic bearings has traditionally been limited by the thermal effects and although aerostatic bearings have relatively good thermal characteristics they suffer from a low relative stiffness and load capacity. New concepts are therefore required, and the authors describe a programme which is using fundamental principles to develop a new improved generation of porous bearings.