Determine the Merchants constant $$'C'$$ (shear angle relation) for aluminium from the following orthogonal machining data. Rake angle $${35^ \circ }$$ and an uncut chip thickness $$0.15mm,$$ the values of $${F_c}$$ and $${F_t}$$ are found to be $$200$$ and $$90$$ $$N$$ respectively. The average chip thickness is also measured and found to be $$0.3$$ $$mm,$$ width of cut $$2.5mm$$ and cutting velocity $$30m/min.$$

Calculate the $$MRR$$ and Specific cutting pressure for the following cutting conditions
Work material : steel,
Tool material : $$HSS,$$
Depth of cut : $$1.6mm,$$
Feed : $$0.8mm/rev$$
Cutting speed $$=5.5m/min$$ and power consumed $$=0.67$$ $$kW$$

Find the percentage change in cutting speed required to give a $$50\% $$ reduction in tool life (that is required tool life is half of the original tool life ) when the value of the tool life exponent $$n=0.125$$ or $$1/8$$.

A tube is orthogonally machined in lathe to reduce its length under the following conditions.
Outside diameter of the tube : $$100mm,$$
Inside diameter of the tube $$=96$$ $$mm$$
$$RPM$$ of the work piece $$=120,$$
Longitudinal feed $$=0.5mm/rev$$
Cutting ratio $$=0.3,$$
Tangential force $$=800N,$$
Axial force $$=600N$$
Calculate the chip velocity in $$m/min$$ and the total power consumption in $$KW$$