Question

Task	Task Time (seconds)	Tasks that must Precede
A	50	--
B	40	--
C	20	A
D	45	C
E	20	C
F	25	D
G	10	E
H	35	B,F,G

The above tasks must be performed on an assembly line in the sequence and times specified. The workstation cycle time is 72 seconds. Using the longest task time to balance the assembly line, the first workstation include, the second workstation include , the third workstation include , and the fourth workstation include . (For each blank write tasks in alphabetical order without space or comma. For example, if workstation 1 includes task A, task C and task E, write them as ACE, not A,C,E, A C E or CAE.)

Answer 1

The precedence diagram as follows :

A		B
C
D	E
F	G
H

Total duration of all tasks ( A through H )

= 50 + 40 + 20 + 45 + 20 + 25 + 10 + 35 seconds

= 245 seconds

Theoretical minimum number of workstations

=Total duration of all tasks / Cycle time

= 245/ 72

= 3.40 ( 4 rounded to nearest whole number )

MINIMUM NUMBEROF WORKSTATIONS = 4

b)The assignment of tasks to workstations should be done in such a way so that total duration of all tasks in any workstation shall not exceed cycle time of 72 seconds. Predecessor successor relationship also has to be maintained which means that a successor activity cannot feature before a predecessor activity .

Longest operation time rule put preference in choosing first the task with longest operating time .

Accordingly allotment of tasks to workstations as follows :

Workstation	Tasks	Total duration ( seconds )
1	AC	50 + 20 = 70
2	B	40
3	DF	45 + 25 = 70
4	EGH	20+10+35 = 65