Side-Wall Surface Quality Assessment for Micro-End Milling

Abstract

Mechanical micro-end milling helps in creating complex three dimensional structures without a restriction on work-piece material. So far, the surface quality assessment achieved in mechanical micro-end milling has mainly focused on the bottom milled surface of the machined part. In this paper, surface quality of the side-wall created by mechanical micro-end milling on stainless steel (SUS 304) and aluminum alloy (Al 6061) is studied. The surface quality thus achieved is assessed by considering three surface assessment factors namely average surface roughness, form error and burr height under various cutting conditions. The cutting parameters varied for machining were spindle speed, feed/tooth, radial depth of cut, and axial depth of cut. The optimal cutting conditions were evaluated for the three surface evaluation factors according to the material and cutting conditions. The surface roughness values were found to have a turning point at a particular spindle speed for both the materials and were affected by spindle speed, feed/tooth and axial depth of cut. The form error was observed to be lesser for higher axial depth of cut due to an increase in the relative tool stiffness. The burr formation was influenced mainly by feed/tooth with an increase in burr height due to the plowing effect at lowest feed rate and pushed uncut chip at highest feed rate.