Experiments on the Iridescent Reflection Light from the Machined Surface

Study on Generation of Iridescent Surface II

Abstract

The present paper describes some experimental verifications of the diffraction theory on iridescence from the machined surface which was reported in the previous paper. The brass disks are machined under various cutting conditions, that is, by two kinds of lathe, by four cutting tools of different material and with different tool feeds. Surface profiles are mesured by a surface roughness meter and photographic recordings of diffracted spectra are obtained by an optical diffractometer for each surface. The effects of cutting condition are investigated to find the best condition for making clear iridescent surface.
The surface should have the roughness curve which consists of exactly periodic feed marks. Pitch error of feed and waviness of the surface cause a decrease of saturation of iridescent color. The use of a diamond lathe i.e., a fine turning lathe with precision sliding bearing, is the most preferable for the purpose.