Procedure for computer-controlled milling of accurate surfaces of revolution for millimeter and far-infrared mirrors

We discuss a simple method for milling accurate off-axis parabolic mirrors with a computer-controlled milling machine. For machines with a built-in circle-cutting routine, an exact paraboloid can be milled with few computer commands and without the use of the spherical or linear approximations that have been discussed in other mirror-cutting procedures in the literature. The method given here can be adapted easily to cut offaxis sections of elliptical or spherical mirrors.