Old Oregon Wood StoreCase Analysis

Preparation Assembly Finishing Packaging

Tom Surowski Leon Davis

George Brown

Cathy Stark

Process for Old Oregon Wood Store

General information• Process shows general allotment of people• One person is required for each step• Each person can do each task – Timing shown in next slide• May or may not optimal solution

Time taken in each stage for each person

Fastest way to manufacture with the crew:

Stage Preparation Assembly Finishing Packaging

Tom 100 60 90 25

George 80 80 60 10

Leon 110 90 80 10

Cathy 120 70 100 25

Using Hungarian method for assignment

Column reduction Row reduction

20 0 30 15

0 20 0 0

30 30 20 0

40 10 40 15

5 0 30 15

0 20 0 0

30 30 20 0

30 0 30 5

Min value: 5Intersection: 20, 0

0 0 25 15

0 25 0 5

25 30 15 0

25 0 25 5

Final table:

Assignment:

Stage Preparation Assembly Finishing Packaging

Tom 100

George 60

Leon 10

Cathy 70

Total Time 100 70 60 10

From the allocation, Total time = 100+70+60+10 = 240Assuming 8 working hours a day, total number of tables = 480/100 = 4.8 tables

If another person Randy is added

Timing for Randy

Stage Preparation Assembly Finishing Packaging Back up

Tom 100 60 90 25 0

George 80 80 60 10 0

Leon 110 90 80 10 0

Cathy 120 70 100 25 0

Randy 110 80 100 10 0

New assignment table after joining of Randy

To balance the table, we have to add a dummy column

Solving using Hungarian method:

Stage Preparation Assembly Finishing Packaging Back up

Tom 60

George 80

Leon 80

Cathy Back up

Randy 10

Total time 80 60 80 10

If Randy is hired, Total time = 80+60+80+10 = 230Saving of time = 240-230 = 10 with Cathy as back up

Moving Cathy

• Cathy’s first preference is finishing• Cathy’s second preference is preparation• Ignore Randy

Assignment in which Cathy is given finishing

Stage Preparation Assembly Finishing Packaging

Tom 100 60 90 25

George 80 80 60 10

Leon 110 90 80 10

Cathy 120 70 100 25

Assigning remaining 3jobs to remaining 3 persons:

Stage Preparation Assembly Finishing Packaging

Tom 60

George 80

Leon 10

Cathy 100

Total time 80 60 100 10

Total time:80+60+100+10= 250

Stage Preparation Assembly Finishing Packaging

Tom 100 60 90 25

George 80 80 60 10

Leon 110 90 80 10

Cathy 120 70 100 25

Assignment in which Cathy is given preparation

Stage Preparation Assembly Finishing Packaging

Tom 60

George 60

Leon 10

Cathy 120

Total time 120 60 60 10

Assigning remaining 3jobs to remaining 3 persons:

Total time = 120+60+60+10 = 250

Utilizing Packaging function

• We can combine packaging and finishing operation to utilize packaging function• Considering 5 crew member i.e. Randy is included

Stage Preparation Assembly Finishing & Packaging

Back up Total time

Tom 100 60 115 0 275

George 80 80 70 0 230

Leon 110 90 90 0 290

Cathy 120 70 125 0 315

Randy 110 80 110 0 300

• George is taking least time. So he can complete the table alone• Table made by George is = 480/230 = 2.09• Time taken by other crew members = 100+80+90 = 270• Bottleneck process is preparation (100 min)• Table made by other crew member = 480/100 = 4.8• Total number if table produced = 4.8 + 2.09 = 6.89• Crew can make almost 7 table a day

Solver approach

Job-Employee Assignment Problem

Time of each assignment

Tom George Leon Cathy

Preparation 100 80 110 120

Assembly 60 80 90 70

Finishing 90 60 80 100

Packaging 25 10 10 25

Tom George Leon Cathy Job Available Job Assigned

Preparation 1 0 0 0 1 = 1

Assembly 0 0 0 1 1 = 1

Finishing 0 1 0 0 1 = 1

Packaging 0 0 1 0 1 = 1

Emp. Available 1 1 1 1

= = = =

Emp. Assigned 1 1 1 1

Total time 240

Job

Job

Employee

Employee

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