e uhesorial BRegineering Fall 2017Dr S Siddiqui Memory Aid O

e uhesorial BRegineering Fall 2017.Dr. S Siddiqui Memory Aid OT 1.65 1.98 95.5 200 2.33 258 95 98 g time per day Cycle time Output rate Cycle time Desired output rate St Cycle time Percentage of idle time-Idle time per cycle X Cycle time × 100 N Efficiency = Natal×Cycletime-Idle time 100 Nanal × Cycle time Efficiency 100%-percent idle time Processing time needed TC FCVC Units of capacity Prcsing time capacity per unit Vc -x v IT FC HE ND

Solution

Answer to question 4 :

The precedence diagram as follows :

                                                                                                                   T

                                                                                U

                                        V

                                                                               W

                                         X

                                                                                                                    Y

                                                                                                                   Z

The possible paths and their corresponding durations as follows :

T-U-W-Y-Z = 15 + 14 + 6 + 10 + 21 = 66

T-V-X-Y-Z = 15 + 7 + 8 + 10 + 21 = 61

Cycle time of each path will be determined by maximum duration of activity lying on that path

It is activity Z which has the maximum duration 21 seconds lying on both the paths.

Thus maximum sensible cycle time = 21 seconds/ unit

MAXIMUMM SENSIBL CYCLE TIME = 21 SECONDS/ UNIT

Appropriate cycle time for 8 hours operating time = 480 minutes/ 960 units = 0.5 minutes/ unit = 30 seconds/ unit

APPROPRIATE CYCLE TIME = 30 SECONDS/ UNIT

Minimum number of workstations required to achieve above cycle time of 30 seconds

= Total duration of all activities together / Cycle time of 30 seconds

= ( 15 + 14 + 7 + 6 + 8 + 10 + 21) / 30

= 81/30

= 2.7 ( 3 rounded to nearest whole number )

MINIMUM NUMBER OF WORKSTATIONS REQUIRED WILL BE 3

The balanced workstations are done in such a way that total duration of any workstation shall not exceed cycle time of 30 seconds.

Accordingly, Balanced workstations as follows :

WORKSTATION

ACTIVITIES

TOTAL DURATION ( SECONDS )

1

T, U

15 + 14 = 29

2

W

6

3

V,X,Y

7 + 8 + 10 = 25

4

Z

21

Note : Required number of workstations of 4 > Minimum number of workstations of 3

T
U	V
W	X
Y
Z