Bernd Schulz

Dynamically optimized air bearings manufactured with the laser beam

The use of air bearings as friction free devices is state of the art in measurement machines. However in many applications air bearings cannot be used because of their insufficient dynamic characteristics. This disadvantage occurs in common air bearings because of pockets and chambers that are worked into the surface in order to improve their static behavior. Air bearings with optimized static and dynamic characteristics have been developed at the Lehrstuhl fuer Feingeraetebau der TU Muenchen in 1986. However the reliable production of these air bearings was very difficult because of high sophisticated working steps. In 1995 a new technique was developed and patented to manufacture dynamically optimized air bearings. This new technique allows a mainly automated production of the bearings without loosing any performance. The key is to bring a large number of nozzles with aid of a laser beam. The combination of this new manufacturing tool and the knowledge of more than 40 years of research has lead to air bearings with best dynamic behavior at a lower production price.

Segmented air bearing in micronozzle technology for the project SOFIA

Since 1986 there is a cooperation between NASA and DARA, Germanys space agency, to develop a flying telescope three times the size and ten times the light gathering ability of its predecessor -- the Kuiper Airborne Observatory. This project is called SOFIA -- Stratospheric Observatory for Infrared Astronomy. The 2.5 meter telescope for the visible through the infrared and the sub-millimeter wavelengths to the microwaves will be mounted in a modified Boeing 747-SP with a cavity at the port side behind the wings. It can be opened at stratospheric altitudes of around 41,000 feet, above 99.9 percent of the interfering water vapor. When not in use, the telescope will be sheltered from environment by a door in the fuselage. Vibrations of the aircraft would spoil the telescopes images. Therefore the telescope has to be isolated from the aircrafts structure. One promising solution for the rotational uncoupling is a segmented spherical air bearing with a bearing sphere diameter of 1.2 meter, which carries the telescope on a thin air cushion. In this paper a new technology of air bearings with micro nozzles manufactured with the aid of a laser is presented. The innovation is rooted in the unique combination of excellent static and dynamic characteristics. These types of air bearings were developed at the Lehrstuhl fur Feingeratebau und Mikrotechnik at the Technical University of Munich, and they are produced in series by the AeroLas GmbH, Munich.