Use of Tangent Mounts for Diamond Machining Optics

Abstract

A fundamental requirement for precision diamond machining is the use of a proper part support technique. Various fixturing techniques have been used during diamond machining to minimize or duplicate the strain that the part will be subjected to during use. These techniques include: three-point support, one-point support, potting, collet chucking, and vacuum chucking. During the production of a 15-inch-diameter reflaxicon, its two components, a ring axicon and center axieon, were assembled in tangent mounts and supported using a vacuum chuck. The tangent mount reduced the fixturing strain by increasing the distance the strain must propagate through, and by increasing the rigidity of each component relative to the spindle fixture. Non-flatness error of approximately 40 μin (1 μm) in the support flange of the tangent mount resulted in less than 2 μin (.05 μm) distortion in the optical surface.