Question

Problem 4

Frank’s Fine Furniture makes tables, desks, bookcases, and other office furniture. At the North California facility, they make tables. All parts of the table are purchased except for the tabletop that is fabricated at the plant. Tables are made to order for dealers who FAX orders into the sales department. Orders are processed from the order database on FIFO basis.

The first step in the process is to cut the top ¾ pressboard. It takes one worker 20 minutes to cut each top. Four workers work in the cutting work center each with his own cutting equipment. At the same time the plastic laminate that goes on top of the table (the finished surface) is cut from stock. There are four other workers each with their own equipment in this work center. It takes one worker 30 minutes to cut this material.

The next step is to glue the plastic laminate to the pressboard top. The contact cement is applied to the top surface of the pressboard and the bottom surface of the laminate. There is one worker who applies the glue to both surfaces. It takes him 5 minutes to apply the glue. After the glue has been applied the two pieces are lined up and pressed together. There is one worker who does that and it takes her 6 minutes to complete that step. After pressing together, the assembled top must be set aside for 30 minutes to allow the glue to dry. There is unlimited space in this drying area.

The finished tabletop is then attached to the leg assembly that is purchased from a nearby metalworking firm. It takes a team of two workers working together for 10 minutes to attach the leg assembly to the tabletop. There are two such teams in this assembly area.

Finally the table is packed and shipped by one team of two workers working together who take 4 minutes to pack and ship one finished table.

1. Draw a process flow diagram for the material flow at frank’s manufacturing plant including all work centers and their capabilities, inventory and information flow.

	Time for each unit(minutes)	Service rate (units/hour)	# servers	Capacity (units/hour)
Cutting board	20	3	4	12
Cutting plastic	30	2	4	8
Glue	5	12	1	12
Press	6	10	1	10
Dry	30	2	Infinite	Infinite
Assemble	10	6	2	12
Shipping	4	15	1	15

2. What is the Bottleneck in Frank’s plant? Explain (Short answer)
3. How many tables can be produced in an 8 hour days?
4. What are the Cycle and the throughput Times for this process?
5. If one additional worker and tools were added to the bottleneck, how many tables could the line produce in an 8 hour day?

Answer 1

a) The flow diagram will be as below with below details of each operation, like its lead time, service rate and capacity etc.

	Cutting Board -20 min		Cutting Plastic - 30 min						Dry - 30 min		Assembly - 10 min
	Cutting Board -20 min		Cutting Plastic - 30 min		Glue - 5 min		Press - 6 min		Dry - 30 min				Shipping - 4 min
	Cutting Board -20 min		Cutting Plastic - 30 min						Dry - 30 min		Assembly - 10 min
	Cutting Board -20 min		Cutting Plastic - 30 min						Dry - 30 min
									Dry - 30 min
									Infinite
Service Rate Units/Hour	3		2		12		10		2		6		15
Servers	4		4		1		1		infinite		2		1
Capacity (Unit/Hour)	12		8		12		10		infinite		12		15

b) Bottleneck in the process = the operation with lowest capacity per hour = Cutting plastic operation is with lowest capacity per hour = 8 units per hour.

c) Number of tables can be produced in an 8 hour days = 8 hour * capacity per hour = 8 * 8 = 64 nos.

The Cycle time of the process = highest lead time of the operations = Plastic Cutting operation = 30 minutes / 4 server = 7.5 minutes.

d) The throughput Times for this process = Total lead time for making one table = 105 minutes., as below

Cutting Board -20 min

Cutting Plastic - 30 min

Dry - 30 min

Asembly - 10 min

Cutting Board -20 min

Cutting Plastic - 30 min

Glue - 5 min

Press - 6 min

Dry - 30 min

Shipping - 4 min

Cutting Board -20 min

Cutting Plastic - 30 min

Dry - 30 min

Assembly - 10 min

Cutting Board -20 min

Cutting Plastic - 30 min

Dry - 30 min

Dry - 30 min

Total

Through put Time

20

30

5

6

30

10

4

105

e) If one additional worker and tools were added to the bottleneck, then capacity at bottleneck will be as below

• The server at bottle neck will be 5, then service rate 2 unit per hour, then capacity = 2 * 5= 10 units per hour.
• Then number of tables could the line produce in an 8 hour day = 8 * 10 = 80 tables.