Ultra-Precision Mothod of Joining a Polygon Mirror Using a Shrink Fitter : Effect of Out-of-Roundness of Joining Surfaces on the Flatness of Mirror Surfaces

Abstract

In a previous paper, a new simple and ultra-precision method of joining a polygon mirror onto a SiC self-acting air bearing has been developed by using a shrink fitter as a new machine element. In this new joining method, mirror surfaces were deformed beyond a desired flatness of 100 nm, because of contact pressure applied at inner surface of the polygon mirror. This distortion of the mirror surfaces is considerably affected by form errors or surface accuracy of the joining surfaces and sizes of the polygon mirror. Therefore a secondary cut after the joining is needed to finish the mirror surfaces to the desirable level. In order to dispense with the secondary cut, we must know how the form errors affect the deformation of the mirror surfaces. In this paper, we considered only an out-of-roundness as the form error. The effect of the out of-roundness on the deformation of the mirror surfaces was examined theoretically and experimentally. The calculated profiles of the mirror surfaces were in agreement with the experimented ones. In addition, the range of the out-of- roundness, in which the mirror surfaces were not deformed seriously, was shown in a 3-dimensional diagram.