Lens centering by servo turning

Modern high performance lenses require a high precision machined housing, well centered to the optical axis of the Jens. This is fundamental for a highly precise and efficient assembly process. The required tolerances are in a range of some µm to sub µm. The aim is to reach the best coincidence between optical axis of the Jens and its mechanical axis. Usually it is necessary to detect the centering errors and adjust the Jens in accordance to a turning axis [1]. The new idea is to machine the Jens housing by servo turning, without any adjustment to reach the coincidence between the optical axis and the mechanical axis of the Jens. For this technology servo turning and a suitable measurement system- well referenced to the machine coordinate system - is essential. In this paper the realized machine setup, based on an ultraprecision lathe, the measurement data processing and CNC programming is described. The achieved tolerances on centered lenses are documented and technological limits are discussed.