Finish turning on a CNC turning center with a bed in polymer concrete

Finish turning of AISI 420B stainless steel was widely investigated under dry, minimum quantity of lubricant and wet cutting conditions, using inserts in coated carbides on turn-ing centers equipped with polymer concrete and cast iron beds. The machining tests was performed using a cutting speeds equal to 235 m/min, depths of cut of 0.4 mm and feed per revolution of 0.08 mm/rev. The workpiece surface finish and tool wear versus cutting time were measured and related to the morphological features of worn tools observed on both the flank and the rake face surfaces by SEM. It was observed that both the lubrication-cooling technique and the bed materials strongly affect the tool wear and the surface finish, due to the different shearing mechanisms operating during cutting under different lubrication-cooling conditions