A machine operator has to perform two operations, turning and threading, on a number of different jobs. The time required to perform these operations (in minutes) for each job is known. Determine the order in which the jobs should be processed in order to minimize the total time required to turn out all the jobs. - |JOB|Time for turning (min)|Time for threading (min)| |-|-|-| |1|3|8| |2|12|10| |3|5|9| |4| 2| 6| |5| 9| 3| |6| 11| 1|

Also determine the total processing time and idle times for turning and threading operations. -

Mumbai University > MECH > Sem 7 > Operations Research

Marks: 10 M

Year: May 2014

Using Johnson’s algorithm to determine sequence of jobs:

Sequence: 413256

Total processing time: 43mins

Idle time for turning machine = 43 – 42 = 1min

Idle time for threading machine = 2 + 42-38 = 6mins