Toshiba

ANNISA TRINEZIA 2911137

Case: Designing Toshibas Notebook Computer Assembly Line Production Production of the subnotebook was scheduled to begin in 10 days, with initial production was at 150 units per day, increasing to 250 units per day, and eventually 300 units per day. Assumptions: Assembly lines staffed by 10 operators at a 14.4 meter long. Maximum operator is 12. Operating hour 7.5 hours. 1 notebook = 2, 10 operators. From exhibit 6A.18 we know that there are 10 stations. Sum of Task Times (T) = 1258 Cycle Time = 2 minutes = 120 Station

1

2

3

4

Task Time

110

114

101

107

Opn. #

Time (Sec)

1

100

2

6

3

4

4

50

5

13

6

16

7

13

8

16

9

6

10

26

11

10

12

13

13

23

14

6

15

6

16

13

17

4

18

15

19

11

20

8

21

8

22

8

23

13

24

6

25

13

26

8

27

13

28

4

1

ANNISA TRINEZIA 2911137

5

6

7

8

9

10

103

107

108

93

310

105

29

6

30

13

31

6

32

8

33

11

34

6

35

11

36

10

37

10

38

16

39

6

40

13

41

6

42

6

43

5

44

23

45

18

46

18

47

8

48

10

49

18

50

10

51

11

52

8

53

33

54

22

55

6

56

58

57

8

58

8

59

8

60

6

61

5

62

31

63

208

64

71

65

5

66

75

67

10

68

15

Assumed that opn. # 63 can produce 3 units at the same time in parallel. But this opn. Still have to wait unit from station 8 and so on, so the bottleneck is in station 2, which is the longest station takes 114

2

ANNISA TRINEZIA 2911137

a) Daily Capacity 1 day operation = 7.5 hours = 27000 (T) = 1258 Bottleneck is in Station 2 = 114 Daily Capacity = 27000 = 236 units / day 114

b) Efficiency of the line at the maximum capacity Efficiency =

Sum of Task Times (T) Number of Workstations (Nt) X Cycle Time (C)

= 1258 = 1.103 = 110 % 10 X 114 c) Redesigned to Operate 300 units / day Cycle Time = 27000 = 90 300 Assumption: In opn.# 63 station 9 the hardware test is performed in parallel on three different units. But this opn. Can not divide three because the process is not held at the same time. Therefore;

Nt = 1258 = 13.9 or 14 workstations 90 Adding 4 workstations means adding 4 more operators. Therefore need to be added 1 operator each, except Station 11 because the longest task is loading the software already done by the hardware test. In other words, operator only add in Station 1, Station 12, and 13 at Station 14. So, without overtime use, to fulfill 300 units / day need to add 4 workstations and 4 operators. Efficiency

=

1258 = 0.998 = 99.8% 14 X 90

3

ANNISA TRINEZIA 2911137

Make Balance the Line using Cycle Time 90

Station

1

2

3

4

5

Task Time

Opn. #

Remaining Unassigned Time

Number of  Operator

80

10

2

90

-

1

90

-

1

81

9

1

75

15

1

Sum of Task Time

1

50

2

3

3 4

2 25

5

13

6

16

7

13

8

16

9

6

10 11

26 10

12

13

13

23

14

6

15

6

16

13

17

4

18 19

15 11

20

8

21

8

22

8

23

13

24

6

25

13

26 27

8 13

28

4

29

6

30

13

31 32

6 8

33 34

11 6

35

11

36

10

37

10

4

ANNISA TRINEZIA 2911137

Station

6

7

8

9

10 11 12 13 14

Opn. #

Task Time

38

16

39

6

40

13

41 42

6 6

43

5

44 45

23 18

46

18

47

8

48

10

49

18

50 51

10 11

52 53

8 33

54

22

55

6

56

58

57 58

8 8

59

8

60

6

61

5

62

31

63

208

64

71

65 66

5 75

67

10

68

15

Sum of Task Time

Remaining Unassigned Time

Number of  Operator

75

15

1

82

8

1

80

10

1

88

2

1

36

54

1

208

automatic

76

14

1

85

5

1

15

65

1

5

ANNISA TRINEZIA 2911137 Issues to be Considered

If Toshihiro using this new assembly line, issues that need to be consider are: 1. cost for adding 4 workstations 2. Cost for adding 4 operators 3. Assembly line layout Assuming that the production and sales reach 300/day with selling price for $100 each, then the company will get revenue $30.000/day. 14 operators are working everyday for 7.5 hours without overtime use. Assuming each operator salary is $5/hour, and then the company has to pay $37.5 to each operator per day, or $525 for 14 operators. The company will get $29.475/day. But this is not including another operating expense, cost of goods sold and another expense. The comparison between design new assembly line with adding more stations and operators should be compared with using same assembly line without adding stations and operators but using overtime. To produce 300 unit/day with old assembly line which consists of 10 stations that can fit for until 12 operators, it takes for 11 operators and overtime for 2.5 hours. Assuming that overtime payment is $3/hour, then: 11 operator/day $37.5 x 11 Overtime payment $3 x 2.5 x 11

$412.5 $82.5 $495 It will be cheaper for the company to use overtime with 11 operators than to design new assembly line, adding more stations and hire more operators. The assembly line layout also needs to be considered. The assembly line consisted of a 14.4 meter conveyor belt and separated at 1.2 meter intervals for 10 workstations. If the company design new assembly line with 14 workstations but still with the same length of conveyor, then the interval is shorter than before, about 1 meter for 14 workstations. Position of the operators also needs to be considered, because if the operators dont feel comfortable then they cant work well. Especially in station 1 because there are 2 operators working there.

6