New perspectives in hydrodynamic radial polishing techniques for optical surfaces

Abstract

In order to overcome classic polishing techniques, a novel hydrodynamic radial polishing tool (HyDRa) is presented; it is useful for the corrective lapping and fine polishing of diverse materials by means of a low-cost abrasive flux and a hydrostatic suspension system that avoids contact of the tool with the working surface. This tool enables the work on flat or curved surfaces of currently up to two and a half meters in diameter. It has the advantage of avoiding fallen edges during the polishing process as well as reducing tool wear out and deformation. The functioning principle is based on the generation of a high-velocity, high-pressure, abrasive emulsion flux with radial geometry. The polishing process is repeatable by means of the control of the tool operational parameters, achieving high degrees of precision and accuracy on optical and semiconductor surfaces, with removal rates of up to 9 mm3/hour and promising excellent surface polishing qualities. An additional advantage of this new tool is the possibility to perform interferometric measurements during the polishing process without the need of dismounting the working surface. A series of advantages of this method, numerical simulations and experimental results are described.

New results in hydrodynamic radial polishing using HyDRa

“…A new hydrodynamic polishing tool based on a stable, radially symmetric abrasive flux that floats above the working surface has been developed (1,3,9) in order to face new challenges in membrane and freeform optics. With this tool it is possible to accomplish most stages of the polishing process.…”

HyDRa: polishing with a vortex

“…As the demands of producing large and increasingly complex aspheric optics become more common, the need of developing deterministic, subaperture polishing tools that can meet up to these new challenges has motivated us to develop a hydrodynamic, noncontact polishing tool (HyDRa) [1,2]. This tool belongs to the fluid-jet polishing (FJP) family, first developed by Fähnle et al [3].…”