Study on Surface Roughness in Turning (Part 1)

Plain Carbon Steels

Abstract

The factors to affect the surface quality in turning can be classified into two categories, that is, controllable and uncontrollable factors. The most serious problem of the latter is built-up edge.Without such the disturbance, surface roughness produced conforms quite well to the theoretical value calculated by tool shape and feed which are so-called controllable factors.
Whether the surface finish produced is free from the disturbance depends upon the cutting conditions, of caurse. Thus, there exists two separate domains of cutting conditions (cutting speed and feed, actually) which yield nearly theoretical roughness and highly disturbed, respectively, the former being defined "normal region" and the latter "abnormal".
This report stresses upon a methodological study to establish the machining standards in view of surface finish in turning plain carbon steels (0.15 C0.55 C). The boundaries of aforementioned domains are experimentally figured out for the respective steels.
Within the normal region the surface roughness produced can be described by the theoretical or slightly modified formula. With regard to the abnormal region conceivable factors to affect the surface roughness are investigated experimentally.