Question

(a) Allan's job shop takes order for making spare parts for textile manufacturing equipment. The operation milling and involves first milling and then finishing. Table Q4(a) presents the data of processing times for each job. (i) Determine the sequencing rule using First Come First Serve (FCFS) and Johnson's Rule. (4 marks) (ii) Make a work schedule on a Gantt chart using FCFS rules indicating the makespan. (6 marks) (iii) Make a work schedule on a Gantt chart using Johnson's rules indicating the makespan. (6 marks) (iv) Explain which sequencing rule Allan would use minimising the processing time based on the makespan and the idle time. (2 marks) Table Q4(a) Processing time Jobs (Hour) Milling Finishing M 6 N 8 P |a 5 12 3

Answer 1

Date: / 201 ling Time Finishing Time Booho * first Sequence using using First come Sexved - M-N-O-P- Q I Makesban Table MILLING I FINISHING I FINISHING INIME OUT TIME ITIME OUT TIME Jobs Idle time for Finishing 0 o o+6= 6 6 16+5=111 6 16+8=14114_114+4=18 14 14+4=18 18 18+3=21 - 18 18+5=23 23 23+2= 25 2 23.23 42-25 25 25+3=28 Q Idle time for finishing = 6+3 +2= 11 hours Idle time for milling = (28-25) = 3 hours Total makespan => 28 hours

Udo * . omni Sequence using Johnson's Rule & Q-M-N-O-P Makesban Table Job MILLING I FINISHING Idle Team TIN OUT IN OUT for Finishin TIME TIME TIME TIME o o Tota=212 2+3=51 12+6=8 1 8 18+5=13 18+8=16|16 1 16+4=20 0 16 16+4= 20 20 20+3=23 P 20 20+5=25 25 25+2=27 2 Tolle Time for Milling = (27-25) d = 2 hours : Idle Time for finishing = 2+3+3+2 - lo housse Total Makespan= lo hours d) 'Since total makesban, for idle time for milling and finishing in Johnson's xule is less as compared to first comes first served rule, so Allan must choose Johnson's rule for sequencing

FIRST COME FIRST SERVED M IDLE IDLE 5 6 7 MILLING FINISHING IDLE IDLE IDLE IDLE P Q IDLE 14 IDLE 23 21 28

10 JOHNSON'S RULE 13 IDLE MILLING FINISHING Q IDLE IDLE Q IDLE IDLE M IDLE IDLE N 0 IDLE IDLE IDLE P 25 16 20 23 78

All the parts have been done as shown.