Wear-based aspherics generator based on a novel elliptical rotator

Derived from an earlier development (fabrication of ultrapre- cise surfaces using a tube; patent pending (FAUST)), a new fabrication technique to produce on- and off-axis optical surfaces of revolution is presented. Although based on a shape-copying method, it is possible to generate different types of surfaces with the same machining tool. Load- controlled point-contact machining is applied using a small tool that is guided along a predetermined tool path, not requiring an in-process tool- path control. This fabrication technique constitutes a self-correcting pro- cess and is characterized by an advantageous error propagation be- tween tool path and workpiece shape. The characteristics of this fabrication technique are discussed together with its application for the generation of on- and off-axis surfaces with conic sections as generators (''conic surfaces''). We present the design of a first setup for production of conic surfaces that facilitates the generation of all kinds of conic sur- faces on the same machine, featuring a pantograph enabling the produc- tion of different scales of the surfaces. A discussion of first experimental data is also presented. © 1998 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(98)03408-4)