1. A product will be manufactured in a U-shaped cell. According to a market study, the product daily demand will be approximately 480 units. The cell will operate 8 hours/day. The tasks that should be carried out are shown in the following table:
a) Draw the line balancing in order to minimize the number of workstations.
b) Determine the total idle time, the lead time, and the work-in-process.
c) Make an outline of the cell layout indicating what tasks will be carried out in each station, and make a Gantt chart of the cell's operation.
2) Boxed-Goods Inc. packages replacement-parts kits. The company packages 10 kinds of kits. Each kit has between 4 and 8 kinds of parts, and the total parts count for a kit is between 20 and 55. As an example, a kit with 1 part J, 9 part Ks, 3 part Ls, 14 part Ps, and 7 part Rs would have a total parts count of 34, and be comprised of five different kinds of parts. Parts range in size from an average 1 inch on a side to 4 inches on a side. Kits are hand-packaged in batches according to customer order. A typical order is for 10,000 kits. The packaging rate is a function of kit size: roughly 1.5 seconds per part, plus 20 seconds; thus, for example, a 20-piece kit takes 50 seconds.
Task Duration (s) Precedence
A 16 -
B 18 A
C 13 B
D 14 -
E 10 D
F 12 C
G 7 C
H 11 E
I 14 E
J 17 F, G, H, I
K 11 J
L 20 K
The problem facing Boxed-Goods is that occasionally a worker makes a mistake resulting in an incorrect parts count or wrong kind of part in a kit. Suggest at least two poka-yoke procedures that might eliminate the parts-count problem, the wrong-part problem, or both at once. State any assumptions about the parts necessary for the procedures to work. Discuss the pros and cons of each procedure in terms of time, cost, quality, and flexibility.
3) In a production cell dedicated to the production of a product family, the following data corresponding to 10 working days have been obtained (the working time is 2417). The theoretical production was 90 units per day.
|
Day
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
|
Breakdowns (h)
|
-
|
2
|
-
|
-
|
5
|
-
|
3
|
-
|
-
|
6
|
|
Setup time (h)
|
-
|
-
|
3
|
-
|
-
|
3
|
-
|
-
|
3
|
-
|
|
Defects (units)
|
7
|
6
|
8
|
2
|
1
|
9
|
6
|
5
|
5
|
6
|
|
Total production (units)
|
70
|
65
|
85
|
80
|
63
|
70
|
73
|
68
|
72
|
67
|
In order to avoid defects, a poka-yoke device and a source inspection project were carried out. The next day, after implementation of those strategies, data from 10 working days were collected:
|
Day
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
|
Breakdowns (h)
|
3
|
-
|
-
|
4
|
-
|
1
|
-
|
7
|
-
|
1
|
|
Setup time (h)
|
-
|
-
|
3
|
-
|
-
|
3
|
-
|
-
|
3
|
-
|
|
Defects (units)
|
16
|
14
|
11
|
11
|
8
|
8
|
5
|
5
|
3
|
2
|
|
Total production (units)
|
81
|
70
|
65
|
67
|
72
|
80
|
83
|
71
|
67
|
69
|
a) How has this changed the overall equipment efficiency (OEE) rate?
b) Were the strategies worthwhile? Why not?