精密旋削面の虹むら

抄録

The iridescent unevenness of a precisely turned surface is investigated by a ray-tracing procedure with reference to the pitch unevenness of turned grooves. The surface is illuminated at an oblique angle with a linear light source which is crossed at right angles to the cylindrical axis of the surface, and the image of the light source focussed by the surface is observed in the direction of diffraction. The image is smooth parabolic when no pitch unevenness is present on the surface. The image calculated on the assumption of sinusoidal pitch unevenness arises disturbance of the image corresponding to the change of pitch. When the surface is illuminated with a white light source, this disturbance turns into iridescent unevenness. A surface having sinusoidal unevenness of pitch is worked by a lathe provided with a periodically variable feed device connected to the tool slide, and the theoretical result is confirmed. The pitch unevenness tolerable in the existence of iridescent unevenness differs depending to the intensity of iridescence on the surface.