Output details

Modeling and validation of polishing tool influence functions for manufacturing segments for an extremely large telescope

The “Influence Function” (IF) characterises the 3D morphology of the material-removal from a polishing tool acting on a single location. The global removal is simply the time-weighted super-position of moving IFs, and the stability or variability of IFs becomes the determining factor in process predictability (“convergence”). This paper reports on new quantitative methods of numerically-modelling IFs, both on the bulk surface, and in the complex domain where the IF overlaps the edge of the part, then reports on experimental validation of the model. This gives the basic data to optimise the removal process using optimisation techniques, and also circumvents the need for time-consuming experiments. It therefore has a direct impact both on process setup-time and on convergence, and hence overall commercial competitiveness