GATE2020-ME-2: 45

Question

Bars of $250$ mm length and $25$ mm diameter are to be turned on a lathe with a feed of $0.2$ mm/rev. Each regrinding of the tool costs Rs. $20$. The time required for each tool change is $1$ min. Tool life equation is given as $VT^{0.2} = 24$ (where cutting speed $V$ is in m/min and tool life $T$ is in min). The optimum tool cost per piece for maximum production rate is Rs. _______ (round off to $2$ decimal places).