Step by Step Assistance

Saturday, 30 March 2013

An assembly line is to be designed to operate 11.9 hours per day and supply a steady demand of 510

An assembly line is to be designed to operate 11.9 hours per day and supply a steady demand of 510 units per day. Here are the tasks and their performance times:

TASK PRECEDING
TASKS
PERFORMANCE TIME
(SECONDS)
TASK PRECEDING
TASKS
PERFORMANCE TIME
(SECONDS)
a 36 g d 15
b 48 h e 48
c 40 i f 20
d a 10 j g 10
e b 28 k h, i 60
f c 20 l j, k 15

 
Required:

(a) What is the workstation cycle time?

  Cycle time seconds per unit  

(b) What is the theoretical minimum number of workstations? (Round your answer to the next whole number.)

  Minimum number of workstations  
 
(c) Assign tasks to workstations using the longest operating time. (Leave no cells blank - be certain to enter "0" wherever required.)

Work station Task Idle time
I b-a
II c-e-d
III h-f-g
IV i-k
V j-l


(d) What is the efficiency of your line balance? (Round your answer to 1 decimal place. Omit the "%" sign in your response.)

  Efficiency %  
 
(e) Suppose demand increases by 10 percent. How would you react to this? Assume that you can operate only 11.9 hours per day. (Round your answers to the nearest whole number.)

  Reduce cycle time to seconds per unit. Another option is to work
  minutes overtime.


Explanation:

The following tasks are to be performed on an assembly line:

The following tasks are to be performed on an assembly line:

TASK SECONDS TASKS THAT MUST PRECEDE
A 18          
B 12           A
C 10           B
D 14           B
E 26           C
F 28           D
G 15           E-F
H 15           G

 
The workday is 8.75 hours long. Demand for completed product is 900 per day.
 
Required:
(a) Find the cycle time. (Round your answer to 1 decimal place.)

  Cycle time seconds per unit  
 
(b) What is the theoretical number of workstations? (Round your answer to the next whole number.)

  Number of workstations  
 
(c) Balance the line using the longest-operating-time rule. (Leave no cells blank - be certain to enter "0" wherever required. Round your answers to 1 decimal place.)

Work station Task Idle time
I A-B
II D-C
III F
IV E
V G-H

 
(d) What is the efficiency of the line balanced as in (c)? (Round your answer to 1 decimal place. Omit the "%" sign in your response.)

  Efficiency %  
 
(e) Suppose that demand rose from 900 to 1,000 units per day. What would you do? (Round your answer to the nearest whole number.)

  Reduce cycle time to seconds, which may require rebalancing the line.
 
(f) Suppose that demand rose from 900 to 1,100 units per day. What would you do? (Round your answer to the nearest whole number.)

  Reduce cycle time to seconds, which may require rebalancing the line.


Explanation: