Comparison of robot arm orientations in measuring precision optics

Abstract

In precision optics manufacturing metrology is of particular importance. Especially for measuring freeform optics only few technologies are available, since the complex surface shape demands a high degree of freedom from the measuring device. Hence freeform surfaces are mostly measured using expensive coordinate measuring machines. At the TC Teisnach Optik we have been working on a metrology system for variable freeform surfaces using an industrial robot. This approach is challenging, since a regular industrial robot is not designed to meet the positioning accuracy needed for measuring precision optics. In this contribution we tested the possible accuracy of the robot without the use of additional accuracy improving extensions when positioning the device under test in respect to the measuring equipment. Therefore, we used a plane lens as the specimen which the robot places respecting to a dial gauge with different orientations of the robot arm. Thus, we tested the measurement accuracy in order to see the impact of the robot orientation on the positioning accuracy.