I cannot find the rest of the answers to this problem! If someone could also exp

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I cannot find the rest of the answers to this problem! If someone could also explain how to find idle time that would be very helpful

Some tasks and the order in which they must be performed according to their assembly requirements are shown in the following table. These are to be combined into workstations to create an assembly line. The assembly line operates 10.0 hours per day. The output requirement is 1,200 units per day PRECEDING PRECEDING SECONDS) TASK (SECONDS) 19 12 20 F. G H, I 15 a. What is the workstation cycle time? Workstation cycle time 30 seconds per unit b. Balance the line using the longest task time based on the 1,200-unit forecast, stating which tasks would be done in each workstation. (Leave no cells blank be certain to enter "O" wherever required.) Idle Time A C 8 E F I D GHJ K L c. For b, What is the efficiency of your line balance? (Round your answer to 2 decimal place.) 87.78% d. After production was started, Marketing realized that they understated demand and must increase output to 1,350 units. What action would you take? Be specific in quantitative terms, if appropriate. (Input all amounts as positive values. Round down "cycle time" value to the next smallest integer and overtime" to nearest whole number.) (Click to select)cycle time to seconds or work minutes of overtime

Explanation / Answer

Activity

Predecessor

Duration (week)

A

None

19

B

A

27

C

A

7

D

B

12

E

B

20

F

C

7

G

C

11

H

D

9

I

E

14

J

F, G

7

K

H, I

15

L

J, K

10

Demand = D =1200 units per day

Available hours = 10 hours per day
Available time (seconds) = 10 x 60 x 60 = 36,000 seconds

Total Work time = 158 seconds

a.

Determine Cycle Time

Cycle time of the Line = Available time (seconds)/Demand

Ct = 36000/1200 = 30 seconds

So assembly must be capable of processing units once every 30 seconds.

Cycle time gives idea of how frequently the products are processed by assembly line.

b.

Determine number of workstation required:

Number of workstation required in assembly line depends on the cycle time and total work content that is total amount of time required to produce the product.

So for assembly line number of workstation required is as follows:

Number of workstation = (total work content)/(required cycle time)

Number of workstation required = 158/30 = 5.27

Actual number of workstations required are 6 workstations.

Arrange the tasks according to longest tasks first as shown below:

Activity

Predecessor

Duration (week)

B

A

27

E

B

20

A

NONE

19

K

H, I

15

I

E

14

D

B

12

G

C

11

L

J, K

10

H

D

9

C

A

7

F

C

7

J

F, G

7

Applying largest candidate rule to balance the line:

Work Elements Assigned to Stations According to the Largest Candidate Rule

The activity B and E require A to be completed first, so pass to next highest activity, A, next feasible activity is C which require A to be completed. The combined work time of A and C is 19 + 7 = 26, which is less than Ct = 30 seconds. First workstation is A + C

Again go through table, B is feasible activity, and requires
A, which form workstation #1, thus select activity B as its work time is 27, no more task can be added to the B. The work station #2 consists of Activity B.

Again go through table, E is feasible task with duration 20 sec., next feasible task F (7) requires C to be completed. Thus, WS#3 consists of E+F.

Similarly WS#4 : I, 14 (requires E to be completed) and D, 12 (requires B to be completed)

Similarly, other workstations are determined as follows:

Workstation

Tasks

Work Time (CW­)

Cycle Time (Ct)

Idle = Ct + CW

1

A, C

19 + 7

26

30

4

2

B

27

27

30

3

3

E, F

20 + 7

27

30

3

4

I, D

14 + 12

26

30

4

5

G, H, J

11 + 9 + 7

27

30

3

6

K, L

15 + 10

25

30

5

Idle time for workstation = Cycle time - Workstation cycle time

C.

Efficiency of assembly line = Total work time/(no. of workstation x Cycle time)

Efficiency = 158/(6 x 30)

Efficiency = 87.78%

D

Revised Demand = 1350 units

Revised Cycle Time = 36000/1350 = 26.67 seconds

Reduce the cycle time of assembly to 26 seconds.

Activity

Predecessor

Duration (week)

A

None

19

B

A

27

C

A

7

D

B

12

E

B

20

F

C

7

G

C

11

H

D

9

I

E

14

J

F, G

7

K

H, I

15

L

J, K

10

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