Experimental and Numerical Investigations of Laser Beam Polishing of Quartz Glass Surfaces

摘要

The aim of laser beam polishing is to achieve an even surface finish in the shortest possible time without changing the contour of the material. Laser radiation acts as a topology-independent sub-aperture tool. Analyses of influences on the process, interaction between laser radiation and the quartz glass as well as comprehensive evaluation of the results with regard to surface quality, and manipulation of tensions and mechanical properties support the development of an industrially applicable laser polishing technology. The polishing process was investigated with the commercial FE-software SYSWELD for calculation of the time- and location-dependence of temperature and stress distribution in the plate. The application of the laser beam polishing process requires extensive adaptation of the material models used. The application of simulation is suitable to optimize the process parameters of the targeted temperature and residual stress state. The design, execution and evaluation of the experiments for laser beam polishing are performed with the help of statistical methods. These show that power and persistence (i.e. dwell time) are the most significant factors. Temperature, as one of the main parameters, is measured accurately either punctually or linearly with a pyrometer and two-dimension-ally with an infrared camera. In a defined temperature range a polishing process without stock removal is achievable.