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Q1. Consider a process consisting of three tasks in a machine-paced (conveyor) l

ID: 390262 • Letter: Q

Question

Q1. Consider a process consisting of three tasks in a machine-paced (conveyor) line and a wage rate of $15 per hour. Each task is assigned to a single worker.

Assume there is unlimited demand for the product.)

Tasks

processing time (minutes

1

10

2

12

3

8

a.How much is the process capacity, in units per hour?

b.How much is the total idle time?

c.Compute the efficiency of the line.

d.What is the cost of direct labor ($/unit)?

Now tasks 2 and 3 are combined and assigned to 4 workers, and task 1 is assigned to 2 workers, as shown below:

Tasks

Number of workers

1

2,

2,3

4

e.How much is the process capacity, in units per hour?

f.How much is the total idle time?

g.Compute the efficiency of the line.

h.What is the cost of direct labor ($/unit).

Tasks

processing time (minutes

1

10

2

12

3

8

Explanation / Answer

(a)

Task 2 having the highest cycle time is the bottleneck and its capacity = 60/12 = 5 units per hour. This is also the capacity of the entire process.

(b)

Idle time in task 1 = 12 - 10 = 2 minutes
Idle time in task 2 = 12 - 12 = 0 minutes
Idle time in task 3 = 12 - 8 = 4 minutes

So, total idle time in a cycle = 2+0+4 = 6 minutes

(c)

Efficiency = 1 - idle time / (no of stations x cycle time) = 1 - 6/(3*12) = 5/6 = 0.833 or 83.33%

(d)

Cost of direct labor = total wages per unit of time / the flow rate

= ($15 x 3) / 5

= $9 per unit

--------------------------------------

(e)

Process capacity = min (12, 12) = 12 per hour

(f)

Since both the stations (1 and 2,3) are having equal capacity, there is no idle time.

(g)

Efficiency = 100% (as there is no idle time)

(h)

Cost of direct labor = total wages per unit of time / the flow rate

= ($15 x (4+2)) / 12

= $7.5 per unit

Tasks # workers Effective Processing time per unit Effective capacity 1 2 10 / 2 = 5 minutes 60/5 = 12 per hr. 2,3 4 (8+12) / 4 = 5 minutes 60/5 = 12 per hr.