Question

A 97 mm diameter bar is turned in one pass on a lathe machine to 90 mm. A minimum tool life of 9 hrs is desired when a feed of 0.38 mm/rev is given. What is the tool life exponent for these conditions? The appropriate tool life equation is
$T=\frac{(1.9{)}^8}{v^9{f}^8{d}^6}\text{where}T\text{(min)},$
$v\text{(m/min)},f\text{(mm/rev)}\text{and}d\text{(mm)}.$

• A. 0.111
• B. 0.125
• C. 0.167
• D. 0.391

Answer 1

The correct option is A 0.111

Compare the tool life equation with standard tool life equation,

$T=\frac{k}{v^1{f}^{1/n_1}{d}^{1/n_2}}=\frac{(1.9{)}^8}{v^9{f}^8{d}^6}$

$\frac{1}{n}=9$

$\Rightarrow$ $n=0.111$ (tool life exponent)