(a) What do you mean by machinibility ? Discuss the factors which come into play while evaluating the machinability of any metal. Also describe machinability index.
(b) Brass components 80 mm long and 55 mm diameter were turned taking a depth of cut 1.25 mm. Using the following data find out the speed that minimizes the machining cost and determine corresponding tool life. Also estimates the cutting speed for maximum production .
Labour + Overhead charges = Rs 20/- per hour
Reconditioning cost of tool = Rs 1 per edge
Tool changing time = 6 mins
Loading and Unloading time of job = 20 sec
Feed = 0.2 mm/rev
C = 300
n = 0.25