Line A

Current production capacity is 315 units/day

This capacity now has to be increased to 420 units/day.

No. of workers working on Line A are 7

Activity Activity Time

Predecessor

1 30 None2 50 None3 40 14 50 15 20 26 10 37 10 4,58 20 29 10 610 40 911 20 712 30 713 50 914 50 1015 10 1116 40 8,12

Total 480  

Workstation cycle time = 7*60*60/420 = 60

Minimum number of workstations = 8

Assuming that we require 1 worker per workstation, we then require to hire one extra worker to meet the minimum requirement

Considering that we make use of 8 work stations,

Activity

No. of tasks followed

Activity Time

Predecessor

1 12 30 None2 7 50 None3 5 40 14 5 50 15 5 20 26 4 10 37 4 10 4,58 1 20 29 3 10 610 1 40 911 1 20 712 1 30 713 0 50 914 0 50 10

15 0 10 1116 0 40 8,12

Total   480  

Following the precedence table, we are able to identify that the distribution across the work stations will be as follows:

Work Station

Activities

Actual Time

Idle Time

1 2 50 102 1,5 50 103 4 50 104 3,6,7 60 05 8,9,12 60 06 10,11 60 07 13,15 60 08 14,16 90 -30

Using the Ideal cycle time as 60 seconds, we can see that an extra 30 seconds of work is required at Station 8. This is unfavourable and we will require employees to either work overtime or we could add one more work station to the list. If we add another workstation, we will then require a total of 2 new hires, to meet the demand of 7+2 = 9 work stations, which would need 9 employees.

Work Station

Activities

Actual Time

Idle Time

1 2 50 102 1,5 50 103 4 50 104 3,6,7 60 05 8,9,12 60 06 10,11 60 07 13,15 60 08 14 50 109 16 40 20

Hence, hiring of 2 new employees would help Line A achieve its new target

Line B

New output required = 210 units/day

No. of workers on Line B = 2

Currently, tasks are organized as follows:

Activity

Activity Time

Predecessor

a 40 Noneb 50 Nonec 70 ad 20 ae 50 af 40 b,cg 60 eh 30 d,f,g

Total 360  

Cycle time = 7*60*60/210 = 120

Minimum workstations required = 360/120 = 3

Assuming that 1 worker is need per workstation, we will need to hire 1 additional worker to meet the minimum requirements.

Using a precedence table to analyse the process flow for Line B

Activity

No. of tasks followed

Activity Time

Predecessor

a 6 40 Noneb 2 50 Nonec 2 70 ad 1 20 ae 2 50 af 1 40 b,cg 1 60 eh 0 30 d,f,g

Total   360  

Following this precedence table, we are able to see that the distribution of activities across these work stations would be

Work Station

Activities

Actual Time

Idle Time

1 a,c 110 102 b,d,e 120 03 f,g,h 130 -10

Now we can re-assign the tasks on the last workstation and increase the total number of workstations to 4. But this would require hiring of two additional workers, which would not be

possible since only 3 workers can be hired in total for Lines A and B, and given that Line A will already be hiring 2 more people, only 1 more can be hired for Line B which is already been taken in to meet the minimum production requirement.

Hence, the three employees on Line B will have to work overtime.

If we change the cycle time to 130, then we get the equation,

130 = New time required * 60/210

New time required = 455 mins or 7 hours and 35 mins

This would imply that due to the inability to introduce an extra worker, all the three workers on Line B will have to work an overtime of 35mins to meet the minimum requirements of Line B.