Question

A single point cutting tool with a nose radius of $0.4mm$ was used to turn a component in a lathe employing feed rate of $0.3mm/rev$. If the feed rate is double, the ideal surface roughness (peak-to-valley height) produced on the components will increase by a factor of

• A. $2$
• B. $4$
• C. $8$
• D. $16$

Answer 1

The correct option is B $4$

The max peak to valley height:
$R_t=\frac{f^2}{8r}$
As the feed rate is increased by $2$ times th roughness value will increase by $4$ times.
$R=0.4mm,f=0.3mm/rev$
Surface roughness,
$h=\frac{f^2}{8r}$
If feed rate is double
$h_1=\frac{(2f{)}^2}{8R}=\frac{4f^2}{8R}=4h$