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20) An insurance claims processing center has six work centers, any of which can be placed into any of six
physical departmental locations. Call the centers 1, 2, 3, 4, 5, and 6, and the departments A, B, C, D, E, and
F. The current set of assignments is A-3, B-1, C-6, D-2, E-4, and F-5.
The (symmetric) matrix of departmental distances, in meters is shown below.
1
2
3
4
5
6
1
--
5
30
20
15
20
2
--
40
15
10
10
3
--
50
20
5
4
--
10
35
5
--
5
6
--
The matrix of work flow (estimated trips per day) is among centers is shown below.
A
B
C
D
E
F
A
--
15
20
0
30
0
B
20
--
50
0
160
10
C
0
50
--
30
0
30
D
30
60
20
--
70
0
E
40
0
0
10
--
60
F
0
0
30
20
50
--
The firm estimates that each trip costs approximately $4. What is the cost of the current assignment?
21) An airport is trying to balance where to place the three subgroups (local (A), regional (B), and national
(C)) for an airline. The distance between terminals and the number of trips that travelers make between
subgroups for flight connections per day are listed. Find the assignment that minimizes the distance
travelers must walk.
Airline
A
B
C
Trips to A
-
60
80
Trips to B
50
-
120
Trips to C
100
75
-
Terminal
1
2
3
Distance to Terminal 1
-
4000
5000
Distance to Terminal 2
4000
-
6000
Distance to Terminal 3
5000
6000
-
Section 8 Work Cells
1) The work cell layout, a special arrangement of machinery and personnel to focus on the production of
a single product or group of related products, is for manufacturing applications and has no relevance to
services.
2) The work cell improves layouts by reducing both floor space and direct labor cost.
3) A focused work center is well suited to the production of a large family of products requiring similar
processing, even if their demands are not very stable.
4) Which of the following is NOT an advantage of work cells?
A) reduced direct labor cost
B) decreased equipment and machinery utilization
C) heightened sense of employee participation
D) reduced raw material and finished goods inventory
E) reduced investment in machinery and equipment
5) Balancing a work cell is done:
A) before the work cell equipment is sequenced.
B) as part of the process of building an efficient work cell.
C) before takt time is calculated.
D) so that each assembly line workstation has exactly the same amount of work.
E) to minimize the total movement in a process layout.
6) Mathematically, takt time is:
A) total work time available divided by units required.
B) units required divided by workers required.
C) a fictional time increment similar to a therblig.
D) workers required divided by total operation time required.
E) units required divided by total work time available.
7) Which of the following is NOT one of the requirements of cellular production?
A) testing (poka-yoke) at each station in the cell
B) adequate volume for high equipment utilization
C) a high level of training, flexibility, and empowerment of employees
D) being self-contained, with its own equipment and resources
E) identification of families of products, often through the use of group technology codes or equivalents
8) A(n) ________ is a special product-oriented arrangement of machines and personnel in what is
ordinarily a process-oriented facility.
9) ________ is the pace (frequency) of production necessary (time per unit) to meet customer orders.
10) "Having a focused work center is like having a plant within a plant." Discuss. Include in your
discussion what conditions make focused work centers appropriate.
11) Why do work cells increase the utilization of equipment and machinery?
12) What are the advantages of focused factories?
13) Identify the four requirements for cellular production.
14) A work cell is required to make 200 computerized diagnostic assemblies (for installation into hybrid
automobiles) each day. The cell currently works an eight hour shift, of which seven hours is available for
productive work. What is takt time for this cell?
15) A work cell is scheduled to build 120 digital light processor (DLP) assemblies each week. These
assemblies are later installed into home theater projection systems. The work cell has 7.5 hours of
productive work each day, six days per week. What is takt time for this cell?
16) A work cell is required to make 80 computerized diagnostic assemblies (for installation into hybrid
automobiles) each day. The cell currently works an eight hour shift, of which seven hours are available
for productive work. These assemblies require five operations, with times of 1.0, 1.8, 2.4, 2.5, and 1.4
minutes each. (a) What is takt time for this cell? (b) How many workers will be needed?
17) A work cell is required to make 140 computerized diagnostic assemblies (for installation into hybrid
automobiles) each day. The cell currently works an eight hour shift, of which seven hours is available for
productive work. These assemblies require five operations. Standard times for these operations are:
Operation A, 3.0 minutes, B, 1.8 minutes, C, 2.4 minutes, D, 2.5 minutes, and E, 1.4 minutes.
(a) What is takt time for this cell?
(b) How many workers will be needed to achieve this schedule?
18) Brandon's computer shop has hired a consultant to help apply operations management techniques to
increase profits. Currently the shop sells most of its computers to a high-end customized online retailer
and sales are steady at 250 per month. A single work cell produces the computers. To produce the
computer, three operations are required. First the parts must be assembled, next software must be
installed, and finally the computer must be safely packed and labeled for shipping. These operations take
2 hours, 5 hours, and 1 hour respectively. If there are 6 available work hours each day and the shop
operates 20 days per month find:
(a) the takt time, and
(b) the number of workers Brandon should hire.
19) A manufacturing work cell has a takt time of 7 minutes. Exactly 10 workers are required. Suppose that
the work cell delivers 68 units each day.
(a) What is the total operation time?
(b) What is the amount of time worked during the day for all 10 workers combined?
(c) If the plant is open for only 8 hours per day, can the staff meet demand?
Section 9 Repetitive and Product-Oriented Layout
1) A fabrication line and an assembly line are both types of repetitive and product-focused layout, but
only the fabrication line utilizes workstations.
2) The biggest advantage of a product layout is its flexibility to handle a varied product mix.
3) The minimum number of workstations depends upon the set of task times and the precedence chart,
but not the number of units scheduled.
4) A product requires 24 separate tasks, and the sum of those task times is 14 minutes. If the cycle time is
2 minutes, then at least 12 workstations will be needed.
5) If the schedule calls for the production of 120 units per day and 480 minutes of production time are
available per day, the cycle time would be 4 minutes.
6) Product-oriented layouts tend to have high levels of work-in-process inventories.
7) One drawback of a product-oriented layout is that work stoppage at any one point ties up the whole
operation.
8) Cycle time is the maximum time that the product is allowed at each workstation.
9) Heuristics are problem-solving procedures that mathematically optimize the solution.
10) Which one of the following is NOT common to repetitive and product-oriented layouts?
A) a high rate of output
B) specialized equipment
C) ability to adjust to changes in demand
D) low unit costs
E) standardized products
11) A product-oriented layout would be MOST appropriate for which one of the following businesses?
A) fast food
B) steel making
C) insurance sales
D) clothing alterations
E) a grocery store
12) The assumptions necessary for a successful product-oriented layout include all EXCEPT which of the
following?
A) adequate volume for high equipment utilization
B) standardized product
C) volatile product demand
D) adequately standardized supplies of raw materials and components
E) All of the above are appropriate assumptions.
13) Which of the following is TRUE regarding fabrication lines?
A) They are the same thing as assembly lines.
B) They are the same thing as focused factories.
C) They are a special type of process-oriented layout.
D) They are usually machine-paced as opposed to worker-paced.
E) They require completely different line balancing techniques than do assembly lines.
14) The central problem in product-oriented layout planning is:
A) minimizing material handling within workstations.
B) minimizing labor movement between workstations.
C) equalizing the space allocated to the different workstations.
D) maximizing equipment utilization.
E) minimizing the imbalance in the workloads among workstations.
15) Which of the following is a disadvantage of product-oriented layout?
A) There is a lack of flexibility necessary for handling a variety of products.
B) High volume is required because of the large investment needed to establish the process.
C) Work stoppage at any one point can tie up the whole operation.
D) There is a lack of flexibility necessary for handling a variety of production rates.
E) All of the above are disadvantages of product-oriented layouts.
16) Which of the following is one of the main advantages of a product-oriented layout?
A) high customer exposure rates
B) employability of highly skilled labor
C) high flexibility
D) low capital cost
E) low variable cost per unit
17) In a product-oriented layout, what is the process of deciding how to assign tasks to workstations?
A) station balancing
B) process balancing
C) task allocation
D) assembly-line balancing
E) work allocation
18) In assembly-line balancing, the theoretical minimum number of workstations is:
A) the ratio of the sum of all task times to cycle time.
B) always (when a fraction) rounded upward to the next larger integer value.
C) not always possible to reach when tasks are actually assigned to stations.
D) all of the above.
E) none of the above.
19) In assembly-line balancing, cycle time (the ratio of available production time to scheduled
production) is the:
A) minimum time that a product is allowed at each workstation.
B) maximum time that a product is allowed at each workstation.
C) inverse of the minimum number of workstations needed.
D) sum of all the task times divided by the maximum number of workstations.
E) equivalent of the maximum task time among all tasks.
20) A production line is to be designed to make 500 El-More dolls per day. Each doll requires 11 activities
totaling 16 minutes of work. The factory operates 750 minutes per day. What is the required cycle time for
this assembly line?
A) 0.5 minutes
B) 1.5 minutes
C) 2 minutes
D) 5,500 minutes
E) 4.26 minutes
21) A production line is to be designed for a job with four tasks. The task times are 2.4 minutes, 1.4
minutes, 0.9 minutes, and 1.7 minutes. After line balancing, the largest possible assigned cycle time is
________ minutes, and the smallest possible assigned cycle time is ________ minutes.
A) 1.8; 1.4
B) 1.6; 0.9
C) 6.4; 2.4
D) 2.4; 0.9
E) 6.4; 0.9
22) Cycle time is computed as:
A) desired output divided by the daily operating time.
B) daily operating time divided by the product of desired output and the sum of job times.
C) the product of desired output and the sum of job times divided by daily operating time.
D) daily operating time divided by the scheduled output.
E) 1.00 minus station time.
23) Four hundred and eighty minutes of production time are available per day. Scheduled production is
120 units per day. What is the required cycle time?
A) 4 minutes
B) 5 minutes
C) 6 minutes
D) 7 minutes
E) 8 minutes
24) A production line is to be designed for a product whose completion requires 21 minutes of work. The
factory works 400 minutes per day. Can an assembly line with five workstations make 100 units per day?
A) yes, with exactly 100 minutes to spare
B) no, but four workstations would be sufficient
C) no, it will fall short even with a perfectly balanced line
D) yes, but the line's efficiency is very low
E) cannot be determined from the information given
25) Four hundred and eighty minutes of production time are available per day. The schedule calls for the
production of 80 units per day. Each unit of the product requires 30 minutes of work. What is the
theoretical minimum number of workstations?
A) 2
B) 3
C) 4
D) 5
E) 6
26) Which of the following is NOT a heuristic rule for assigning tasks to workstations in a product
layout?
A) longest tasks first
B) in order of most number of following tasks
C) median tasks first
D) shortest tasks first
E) in accordance with positional weight
27) If a layout problem is solved by use of heuristics, this means that:
A) there is no other way to solve the problem.
B) no computer software is available.
C) the problem has only a few alternatives to evaluate.
D) no optimum solution exists.
E) a satisfactory, but not necessarily optimal, solution is acceptable.
28) Which of the following is a common heuristic for assembly line balancing?
A) first come, first served
B) least preceding tasks
C) earliest due date first
D) ranked positional weight
E) most preceding tasks
29) An assembly line consists of 21 tasks grouped into 5 workstations. The sum of the 21 task times is 85
minutes. The largest assigned cycle time is 20 minutes. What is the efficiency of this line?
A) 4.2 percent
B) 17 percent
C) 85 percent
D) 100 percent
E) 21 percent
30) An assembly line consists of 158 tasks grouped into 32 workstations. The sum of all task times is 105
minutes. The largest assigned cycle time is 4 minutes. What is the efficiency of this line?
A) 8 percent
B) 21 percent
C) 82 percent
D) 100 percent
E) 81 percent
31) A(n) ________ line is a machine-paced product-oriented facility for building components.
32) ________ is the maximum time that the product is allowed at each workstation.
33) Explain what the purpose of assembly-line balancing is. Describe briefly how it is done.
34) Identify the formulas for the following terms that occur in assembly line balancing: (1) cycle time, (2)
minimum number of workstations, and (3) efficiency.
35) Identify the five common layout heuristics used to assign tasks to workstations in assembly-line
balancing.
36) Assembly line balancing has just been used to solve a product layout problem. Two solutions look
especially attractive to the plant managers. Both solutions make the same output per day, and both have
the same number of workstations. The managers were going to break the tie by looking at line efficiency,
but discovered that both lines had the same efficiency as well. Should they have been surprised at this?
Explain.
37) What are the advantages and disadvantages of product-oriented layouts?
38) Develop a solution for the following line balancing problem, allowing a cycle time of 5 minutes.
a. Draw the precedence diagram for the set of tasks.
b. Calculate the theoretical minimum number of workstations.
c. Balance this line using the longest task time heuristic.
d. What tasks are assigned to which stations?
e. Does the solution have the minimum number of stations? Explain.
f. How much idle time is there, summed over all workstations?
g. What is the efficiency of this line?
Work Task
Task Time
(seconds)
Task Predecessor(s)
A
70
-
B
60
A
C
120
B
D
60
-
E
240
C, D
F
100
A
G
190
E, F
