Material removal by slurry erosion in the robot polishing of optics by polishing slurry nozzles

Robot polishing is increasingly being used in the production of high-end glass work pieces such as astronomy mirrors, lithography mirrors, laser gyroscopes or high-precision coordinate measuring machines. The quality of optical components such as lenses or mirrors can be described by shape errors and surface roughness. Whilst the trend towards sub nanometre level surfaces finishes and features progresses, matching both form and finish coherently in complex parts remains a major challenge. With increasing optic sizes, the stability of the polishing process becomes more and more important. Polishing agent nozzles supply the polishing process with sufficient polishing agent and it is assumed that this slurry erosion has an influence on the material removal. To investigate this, a static test set-up was built. The primary aim of this paper is to point out and raise awareness of the problem of slurry erosion in glass polishing and the influence of slurry erosion by conventional polishing nozzles is shown. From an angle of 30 degrees, the nozzle turns into a fluid jet tool and removes material independently.