Question

QRS Corp. is designing a product layout for a new product. They plan to use this production line ten hours a day in order to meet forecasted demand of 900 units per day. The following table describes the tasks necessary to produce this product:

Task	Time (Secs)	Immediate Predecessor
a	34	none
b	20	a
c	10	b
d	16	b
e	10	c
f	24	d,e
g	38	f

For output to equal forecasted demand, what will be the idle time at the fourth workstation of the assembly line that uses the least number of workstations?

Answer 1

Step1 :

Draw Prededence adiagram

step 2:

Calculate desired output rate = Demand per day / No. of hours in day = 900/10 = 90 unit per hour

Step3 :

Calculate Cycle time

Cycle time = 1/ Desired output = 1/90 hour = 60*60/90 sec = 40 sec per unit

Step4

Calculate Minimum no of workstation

TM = Sum of all task time /(Cycle time ) = 152/40 = 3.8 = 4 workstation

So Minimum number of workstation should be 4

Step 4 :

Assigning tasks to 4 Workstation without violating the predecessor relationship and sum of the processing time in any workstation should not be greater than cycle time ( 40 Sec)

Output

For 4th Workstation Idle time is 2 Seconds