Ilinois Furniture, Inc., produces all types of office furniture. The \"Executive
ID: 426941 • Letter: I
Question
Ilinois Furniture, Inc., produces all types of office furniture. The "Executive Secretary" is a chair that has been designed using ergonomics to provide comfort during long work hours. The chair sells for $130. There are 480 minutes available during the day, and the average daily demand has been 54 chairs. There are eight tasks: Performance Time Task Must Follow Task Listed Below Task mins A, B F G This exercise only contains parts b, c, d, e, f, and g. b) The cycle time for the production of a chair 8.89 minutes (round your response to two decimal places). c) The theoretical minimum number of workstations (round your response up to the next whole number). d) The assignment of tasks to workstations should be: (Hint: Number workstations sequentialy in terms of precedence relationships and combine any applicable tasks.) Task Workstation Number Station 1 Station2 Station 1 Station 3 Station 4Explanation / Answer
b) Given,
Demand = 54 units / 480 mins
Average throughput rate = 480/54 = 8.89 mins
So, cycle rate = 8.89 mins
c) Minimum number of workstations= sum of total task times / cycle time
= (6+7+6+6+5+6+8+6)/8.89= 50/8.89= 5.624 workstations = 6 workstations
Task Table
Task
Task time
Predecessor
A
6
-
B
7
-
C
6
A,B
D
6
C
E
5
D
F
6
E
G
8
E
H
6
F,G
The total station time is nothing but the cycle time. So, total station time of each station is 8.89 mins
In order of precedence relationship (primary rule) and shortest performance time (secondary rule), tasks: A->B->C->D->E->F->G->H
Workstation 1:
First task =A
Time left= 8.89-6=2.89 mins
So, workstation 1: A
Workstation 2:
First task =B
Time left= 8.89-7 = 1.89 mins
So, workstation 2: B
Workstation 3:
First task=C
Time left= 8.89-6=2.89 mins
So, workstation 3: C
Workstation 4:
First task= D
Time left=8.89-6=2.89 mins
So, workstation 4: D
Workstation 5:
First task= E
Time left=8.89-5=3.89 mins
So, workstation 5: E
Workstation 6
First task= F
Time left=8.89-6=2.89 mins
So, workstation 6: F
No workstation is left for assignment of task G and H, if following the theoretical minimum rule.
Workstation 7 (going against the minimum workstation rule):
First task= G
Time left=8.89-8=0.89 mins
So, workstation 7: G
Workstation 8 (going against the minimum workstation rule):
First task= H
Time left=8.89-6=2.89 mins
So, workstation 8: H
Work Station
Tasks
Total task Time
Idle Time
1
A
6
2.89
2
B
7
1.89
3
C
6
2.89
4
D
6
2.89
5
E
5
3.89
6
F
6
2.89
7
G
8
0.89
8
H
6
2.89
Were you able to assign all the tasks to the theoretical minimum no of workstations: No
e) Total idle time = 2.89+1.89+2.89+2.89+3.89+2.89+0.89+2.89 = 21.12 mins
f) Total idle time over 8 hour work day = (21.12*480)/50 = 202.75 mins
g) Efficiency with 8 workstations = (sum of all tasks) / (no of workstations * Cycle time)
= (50)/ (8*8.89) = 0.703 or 70.3 %
Task
Task time
Predecessor
A
6
-
B
7
-
C
6
A,B
D
6
C
E
5
D
F
6
E
G
8
E
H
6
F,G