Development of a force controlled orbital polishing head for free form surface finishing

Polishing is the last and the most essential process step to guarantee the required form accuracy and especially the surface roughness in the production of steel molds. This is true for polishing of molds for optics manufacturing as well as mold making in the field of aviation, automotive or consumer products. One of the characteristics of the production is that in most cases the finishing is done by manual labor which is extremely time consuming and cost intensive. Moreover the polishing result is crucially depending on the worker's skill and education. To overcome these limitations Fraunhofer IPT is developing a fully automated polishing cell which realizes a completely automated and reproducible finishing process. By this means an important competitive advantage for high-wage countries will result. A standard six-axis industrial robot with a novel force controlled orbital polishing head will support the manual processing. In this paper, the mechanical setup of the de veloped orbital polishing head as well as its control system is described, starting from an analysis of the polishing process and the derivation of the requirement specification.