Determine the number of vacuum purges required to reduce a vessel’s oxygen concentration from 21% to 5.0% if the nitrogen contains: .0 ppm of oxygen ppm of oxygen assume vacuum goes to 20 torr

Aturning operation is performed with following conditions: rake angle of 12°, a feed of 0.35 mm/rev, and a depth of cut of 1.1 mm. the work piece is aluminum alloy 6061 with t6 heat treatment (a16061-t6). the resultant chip thickness was measured to be 1.0 mm. estimate the cutting force, fc. use shear stress of 207 mpa and coefficient of friction on the tool face of 0.6.