Analysis of the colleting method of producing spherical surfaces in contact lens blanks using finite element and...

In contact lens manufacturing, the collet chuck is one of the most common methods of holding a lens blank in a lathe in order to cut a back optic zone. In this method the lens blank is compressed by a colleting force, and the effects of this force on the back optic zone radius of the lens blank are not well known. If these effects are known, improved back optic zone radius dimensions may be obtained. In this paper, the finite element and experimental results obtained for the effects of colleting on the back optic zone radius are presented and discussed.