A New Spiral Path Used in Optical Fabrication

Abstract

Spiral is a common path for small tool optical fabrication. Usually discrete control points are calculated by increasing the polar angle by a fixed value, however, the space between control points in the outer zone becomes too large to perform accurate machining sometimes, especially for large workpieces. Meanwhile in the inner zone, the control points are too dense. In this research, a new spiral is proposed, which consists of many discrete control points. With the growth of control points, the new spiral become larger and larger. The new spiral path can reduce middle frequency surface error which is concentric circle shape or radicalized pattern because of lack of regularity.