It’s all about the finishing touches. To replicate glass and plastic lenses for optical and medical applications – while retaining complex geometries and optofunctional areas in the range of a few millimeters – mold inserts made of steel or carbides have to be finished by polishing. These complex components must be polished in specific shapes to fit localized cavities or grooves, so rotating polishing pads are very limited, according to a researcher from the University of Bremen in Germany. Conference attendees register on the first day of Optifab 2009 in Rochester, NY. The technical presentations were already in full swing, but the exhibition hall would not open until the following day. Photo by Laura S. Marshall. But a new abrasive polishing process for finishing complex mold geometries to optical quality has been developed. In a presentation at Optifab 2009, Bremen’s Heiko Schulte described this new technique: In the area of contact between polishing pad and workpiece surface, the required relative velocity is realized exclusively by vibrational motion. Schulte, who worked at Bremen with Oltmann Riemer and Ekkard Brinksmeier, said the new method's applications include LED optics and cylindrical lens arrays for high-performance diode lasers, and can be used for non-optical tool manufacturing as well. Abrasive vibrational polishing allows freedom in polishing pad geometry, Schulte said, adding that this will enable, "in the future, very complex workpiece shapes." He and his colleagues are working on two-dimensional abrasive vibrational polishing; their goal is to achieve deterministic polishing with the abrasive vibrational method. Laura S. Marshall laura.marshall@laurin.com