An $$HSS$$ drill of $$20mm$$ diameter with $$5mm$$ cone height is used to drill a through hole in a steel work-piece of $$50mm$$ thickness. Cutting speed of $$10m/min$$ and feed rate of $$0.3mm/rev$$ are used. The drilling time, in seconds, neglecting the approach and over travel, is ______________

A disc of $$200$$ $$mm$$ outer and $$80$$ $$mm$$ inner diameter is faced at a feed of $$0.1$$ $$mm/rev$$ with a depth of cut of $$1$$ $$mm.$$ The facing operation is undertaken at a constant cutting speed of $$90$$ $$m/min$$ in a $$CNC$$ lathe. The main (tangential) cutting force is $$200$$ $$N$$

Assuming approach and over-travel of the cutting tool to be zero, the machining time in $$min$$ is

A disc of $$200$$ $$mm$$ outer and $$80$$ $$mm$$ inner diameter is faced at a feed of $$0.1$$ $$mm/rev$$ with a depth of cut of $$1$$ $$mm.$$ The facing operation is undertaken at a constant cutting speed of $$90$$ $$m/min$$ in a $$CNC$$ lathe. The main (tangential) cutting force is $$200$$ $$N$$

Neglecting the contribution of the feed force towards cutting power, the specific cutting energy in $$J/m{m^3}$$ is

In a shaping process, the number of double strokes per minute is $$30$$ and the quick return ratio is $$0.6,$$ If the length of the stroke is $$250mm,$$ the average cutting velocity in $$m/min$$ is