Question

Digital Eye must design an assembly line to produce a new line of slim digital cameras. Assembling a single camera requires the completion of nine distinct tasks, and information about each of these tasks is provided below:

Task	Immediate Predecessors	Task Duration (Seconds)
A	None	20
B	A	15
C	A	20
D	B	12
E	B	8
F	B	15
G	D,E	30
H	C,F	25
I	G,H	9

This assembly line will operate 8 hours a day to produce 600 digital cameras daily. Digital Eye will use the Longest Processing Time Rule (LPT) to create the design.  Please draw the precedence diagram and show me your line balancing steps!!

1.1 What is the cycle time of Digital Eye’s assembly line, in seconds?

1.2. How many workstations are required by this design and what tasks will be done at which workstations?

1.3 Which workstation enjoys the maximum idle time? How efficient is this design?

1.4 How does the actual number of workstations required by this design compare to its theoretical minimum number of workstations?

Answer 1

Solution:-

(1):-

Daily demand = d = 600 units for every day

Hours available every day = 8 hours

Seconds available every hour = an hour x 60 seconds x 8 every day = 28,800 seconds

All out Time available = TA = 28,800 seconds out of each day

Cycle time = CT = Available time/Demand = TA/D = 28800/600 = 48 seconds for every unit

Cycle time = 48 seconds for every unit

(2):-

All out Task Time = ∑Ti = 154 seconds

Minimum number of laborers required = Total work time/CT = ∑Ti/CT = 154/48 = 3.21

Minimum number of work station required = 3.21 work stations.

The system portrayal of sequential construction system is as per the following:

Allocations:

Work stations	Activities	Time	Idle time
I	g , f	45	3
II	h , e , i	42	6
III	a, c	40	8
IV	b, d	27	21

(3):-

Work station IV appreciates the most extreme inert time of 21 sec. The proficiency is 154/192 =0.802. The line is theoritically adjusted however the seuence of tasks with respects their workstations isn't proper.

The task with most prominent position weight or biggest number of following assignments ought to have been usedr for smooth work process

(4):- There is no contrast between the hypothetical and useful number of stations because of the gigantic equalization postpone which the line offers.

There is ( 192-154=38 sec. ) postpone which makes it conceivable to do it in a 4 WS line.

"The cycle time as asked in part a is 48 sec. while the number of workstations asked in part b are 4."

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