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Question
Station | Task | Time (seconds) | Time left (seconds) | Ready tasks |
A,B,C,D | ||||
1 | B | 66. | A,C,D | |
C | 25. | 41. | A,D | |
A | 20. | 21. | D,E | |
D | 10. | 11. | E,F | |
2 | E | 55. | 41. | F,G |
F | 30. | 11. | G | |
3 | G | 25. | 71. | H |
H | 40. | 31. | ||
Summary Statistics | ||||
Cycle time | 96 | seconds | ||
Time allocated (cycle time * #) | 288 | seconds/cycle | ||
Time needed (sum of task times) | 235 | seconds/unit | ||
Idle time (allocated-needed) | 53 | seconds/cycle | ||
Efficiency (needed/allocated) | 81.59722% | |||
Balance Delay (1-efficiency) | 18.40278% | |||
Min (theoretical) # of stations | 3 |
Key Term: Assembly-line balancing
49) A company is trying to balance production between 3 workstations on an assembly line. Currently there are 5 tasks that need to be performed. These tasks, ABCDE, have required times of 2 minutes, 4 minutes, 1 minutes, 3 minutes, and 10 minutes, respectively. The assembly line needs to produce 40 units per day to meet demand and can work for up to 8 hours each day.
(a) What is the required cycle time?
(b) What is the theoretical minimum # of workstations?
(c) Assign the tasks according to the shortest task time heuristic.
Answer:
(a) Required cycle time = Production time available/Units required = 8 hours * 60 minutes / 40 units = 12 minutes
(b) Minimum # of workstations = Sum of task times/Cycle time
= (2 + 4 + 1 + 3 + 10)/12 = 1.667 stations = 2 stations
(c) Workstation A would be assigned Task C for a total of 1 minute, Task A for a total of 3 minutes, Task D for a total of 6 minutes, Task B for a total of 10 minutes. Task E cannot be assigned because 10 + 10 > 12 minutes. Therefore Task E would be assigned to station B for a total of 10 minutes. Station C would have no assignment.
The assignment method of Part (c) creates the optimum assignment (2 workstations = theoretical minimum), so the third workstation is not needed.
Key Term: Assembly-line balancing
50) An assembly line is assigned as follows. Station 1- task A, B, and C. Station 2- task D. Station 3- task E and F. The task times are 7, 3, 2, 9, 4, and 5 minutes respective to A, B, C, D, E, and F. (Assume that there is no precedence relationships between the tasks, i.e. they can be performed in any order)
(a) Calculate the efficiency.
(b) What would the assignment of tasks to stations be using the shortest processing time heuristic (assuming the current maximum station time remains the cycle time)?
Answer:
(a) Efficiency = Sum of task time / (# Stations ∗ Longest Station duration)
= (7 + 3 + 2 + 9 + 4 + 5)/(3 ∗ 12)= 83.3%
(b) Station 1 would be assigned task C for a total of 2 minutes, task B for a total of 5 minutes, Task E for a total of 9 minutes. Task F cannot be assigned because the total would be 14 minutes which is greater than the 12 maximum. Therefore Station 2 would be assigned task F for a total of 5 minutes and task A for a total of 12 minutes. Finally station 3 would be assigned task D for a total of 9 minutes.
Key Term: Assembly-line balancing
Answer
This answer is hidden. It contains 0 characters.
Related questions
Q:
________ is an approach that seeks efficiency of operations through the integration of all material acquisition, movement, and storage activities.
Q:
Logistics management can provide a competitive advantage through improved customer service.
Q:
Channel assembly, which sends components and modules to be assembled by a distributor, treats these distributors as manufacturing partners.
Q:
One classic type of negotiation strategy is the market-based price model.
Q:
________ involves delaying any modifications or customization to the product as long as possible in the production process.
Q:
A carpet manufacturer has delivered carpet directly to the end consumer rather than to the carpet dealer. The carpet manufacturer is practicing which of the following?
A) postponement
B) cross-docking
C) channel assembly
D) drop shipping
E) float reduction
Q:
Describe ABC inventory analysis in one sentence. Identify three policies that may be based upon the results of an ABC analysis.
Q:
Which of the following is a function of inventory?
A) to decouple various parts of the production process
B) to provide a selection of goods for anticipated customer demand and to separate the firm from fluctuations in that demand
C) to take advantage of quantity discounts
D) to hedge against inflation
E) All of the above are functions of inventory.
Q:
Work-in-process inventory is devoted to maintenance, repair, and operating materials.
Q:
Consider a firm with an annual net income of $20 million, revenue of $60 million and cost of goods sold of $25 million. If the balance sheet amounts show $2 million of inventory and $500,000 of property, plant & equipment, how many weeks of supply does the firm hold?
A) 12.50
B) 5.20
C) 2.60
D) 0.08
E) 4.16
Q:
________ is the process of sending returned products back up the supply chain for value recovery or disposal.
Q:
The Institute for Supply Management:
A) establishes laws and regulations for supply management.
B) is an agency of the United Nations charged with promoting ethical conduct globally.
C) publishes the principles and standards for ethical supply management conduct.
D) prohibits backward integration into developing economies.
E) grants Ph.D. degrees in purchasing.
Q:
Because the supply chain has become so electronic and automated, opportunities for unethical behavior have been greatly reduced.
Q:
As the number of facilities increases, total logistics costs tend to follow a curve that first declines, then rises. Why?
A) Transportation and inventory costs first decline steeply, then rise, while facility costs always rise.
B) Transportation costs always decline, but eventually the rise in facility and inventory costs outweigh the declining transportation costs.
C) Facility costs first decline steeply, then rise, while transportation and inventory costs always rise.
D) Transportation costs first decline steeply, then rise, while facility and inventory costs always rise.
E) Inventory costs first decline steeply, then rise, while transportation and facility costs always rise.
Q:
Distribution management focuses on which of the following?
A) the outbound flow of products
B) incoming materials
C) allocation of demand among suppliers
D) setting dividend rates
E) balancing an assembly line
Q:
Designing distribution networks to meet customer expectations suggests three criteria: (1) rapid response, (2) cost, and (3) service.
Q:
As the number of facilities increases, total logistics costs tend to follow a curve that first rises, then declines.
Q:
Describe how the visual workplace can increase information flow, improve efficiency, and eliminate non-value-adding activities. Support your argument with a few examples.
Q:
"Visual workplace" is a term coined by Hawthorne, and it refers to the need for proper lighting at employee workstations.
Q:
________ are drawings used to analyze movement of people or material.
Q:
Methods analysis employs which of the following charts in its analysis of the movement of workers and materials?
A) micro-motion chart
B) flow diagram
C) activity chart
D) man-machine chart
E) movement chart
Q:
Often called human factors, the study of work is known as ________.
Q:
Identify five limitations of job expansion.
Q:
Station
Task
Time (hours)
Time left (hours)
Ready tasks (#followers) A(6),B(4) 1
A 4.
B(4),C(4),D(2) C
2.
2.
B(4),D(2) 2
B
6.
2.
D(2),E(2),F(2) 3
D
6.
2.
E(2),F(2) 4
E
3.
5.
F(2) F
3.
2.
G(1) 5
G
5.
3.
H(0) H
1.
2. Summary Statistics Cycle time
8
hours Time allocated (cycle time * #)
40
hours/cycle Time needed (sum of task times)
30
hours/unit Idle time (allocated-needed)
10
hours/cycle Efficiency (needed/allocated)
75% Balance Delay (1-efficiency)
25% Min (theoretical) # of stations
4 (b) The cycle time is 160/20 = 8 hours; (c) This line requires at least 30/8 = 3.75 or 4 stations; (d) A and C are in Station 1; B is in Station 2; D is in Station 3; E and F occupy Station 4; and G and H are in Station 5. (e) Efficiency is 30/40 = .75 or 75 percent.
Key Term: Assembly-line balancing
45) Hemo-tech, Inc., a biomedical technology and research laboratory, produces a standard blood filtering device on an assembly-line basis. Six basic tasks are performed along the assembly line. The time to perform each task and the tasks that must immediately precede each task are in the table below. Twenty pumps per 450-minute day must be produced by the assembly line.
Q:
Station
Task
Time (seconds)
Time left (seconds)
Ready tasks A,C,D 1
A 22.
C,D,B D
22.
0.
C,B 2
B
36.
36.
C,E C
26.
10.
E 3
E
70.
2.
F 4
F
30.
42. Summary Statistics Cycle time
72
seconds Time allocated (cycle time * #)
288
seconds/cycle Time needed (sum of task times)
234
seconds/unit Idle time (allocated-needed)
54
seconds/cycle Efficiency (needed/allocated)
81.25% Balance Delay (1-efficiency)
18.75% Min (theoretical) # of stations
4 Key Term: Assembly-line balancing
43) You have been asked to balance a flow shop assembly operation to achieve an output rate of 80 units per eight-hour day. Task times and precedence relationships are shown in the table below.
Q:
Task
Description
Predecessor(s)
Time (min.) A
Place circuit into circuit frame
--
50 B
Solder circuit connections to central circuit control
A
0.70 C
Place circuit assembly in device frame
B
0.40 D
Attach circuit assembly to device frame
C
0.30 E
Place and attach display to frame
--
0.30 F
Place and attach keypad to frame
--
0.20 G
Place and attach top body of device to frame
E, F
0.35 H
Place and attach battery holder to frame
D
0.40 I
Place and attach bottom body of device to frame
G, H
0.60 J
Test device
I
0.30 a. Draw the precedence diagram for this problem.
b. What is the sum of the task times?
c. What cycle time will allow the production of 200 units over a ten-hour day?
d. What is the theoretical number of workstations needed?
e. Balance this assembly line using the heuristic most following tasks and the heuristic longest operation time.
f. How do these two solutions differ? Which do you prefer; why?
Answer: The sum of the task times is 4.05 minutes. The cycle time for 200 units output is 600/200 = 3 minutes. The theoretical minimum number of stations is 4.05/3 = 1.35 or 2. Both solutions use two stations and have 67.5% efficiency--no preference. Most Following Tasks
Station 1: A, B, C, E, F, D, G; idle time = 0.25
Station 2: H, I, J; idle time = 1.70
Longest Operation Time
Station 1: A, B, C, E, D, H, F; idle time = 0.20
Station 2: G, I, J; idle time = 1.75
Key Term: Assembly-line balancing
42) A company is designing a product layout for a new product. It plans to use this production line eight hours a day in order to meet a schedule of 400 units per day. The tasks necessary to produce this product are detailed in the table below. Task
Predecessor
Time (seconds) A
-
50 B
A
36 C
-
26 D
-
22 E
B, D
70 F
C, E
30 a. Draw the network described in the table.
b. Without regard to a production schedule, what is the minimum possible cycle time (in seconds) for this situation; what is the maximum?
c. What is the required cycle time (in seconds) in order to meet the schedule?
d. What is the theoretical minimum number of workstations needed to meet the schedule?
e. Balance this line using longest processing time.
f. What is the efficiency of the balance obtained in part e?
Answer: The network diagram appears below. Minimum cycle time is 70 seconds (the longest task time); maximum cycle time is 234 seconds (sum of the task times). Required cycle time is 480/400 = 1.2 minutes or 72 seconds (which is barely feasible). The theoretical minimum number of stations required is at least 234/72 = 3.25 or 4.
Q:
Convey the mission of the store by carefully selecting the position of the lead-off department.
Key Term: Retail layout
17) Briefly explain what "slotting" is. What ethical issues might arise with regard to slotting?
Answer: Slotting is the practice of manufacturers paying for retail shelf space. Many small firms question the legality and ethics of slotting fees, claiming the fees stifle new products, limit their ability to expand, and cost consumers money.
Key Term: Slotting fees
18) What is a servicescape? How is it related to the retail layout problem? What are the three elements of servicescape for dealing with these human issues?
Answer: Servicescape describes the physical surroundings in which a service takes place, and how they affect customers and employees. Rather than design a retail space strictly for profitability, managers must consider how the surroundingsthe layouthave a humanistic effect on customers and employees. The three elements are ambient conditions; spatial layout and functionality; and signs, symbols, and artifacts.
Key Term: Servicescape
Section 5 Warehouse and Storage Layouts
1) Cross-docking processes items as they are received, rather than placing them in storage.
Answer: TRUE
Key Term: Cross-docking
2) Balancing low-cost storage with low-cost material handling is important in which of the following?
A) fixed-position layout
B) process-oriented layout
C) office layout
D) repetitive and product-oriented layout
E) warehouse layout
Answer: E
Key Term: Warehouse layout
3) Which of the following reduces product handling, inventory, and facility costs, but requires both (1) tight scheduling and (2) accurate inbound product information?
A) phantom-docking
B) random stocking
C) ASRS
D) customizing
E) cross-docking
Answer: E
Key Term: Cross-docking
4) The major problem addressed by the warehouse layout strategy is:
A) minimizing difficulties caused by material flow varying with each product.
B) requiring frequent close contact between forklift drivers and item pickers.
C) addressing trade-offs between space and material handling.
D) balancing product flow from one work station to the next.
E) locating the docks near a convenient access point to the closest highway.
Answer: C
Key Term: Warehouse layout
5) The concept of customizing in a warehouse layout:
A) is possible, but it causes serious loss of oversight of the quality function.
B) cannot be considered seriously in today's high efficiency factories.
C) is theoretically sound, but several years away in practice.
D) incorporates value-added activities in warehouses.
E) locates stock wherever there is an open location.
Answer: D
Key Term: Customizing
6) ASRS stands for which of the following?
A) automated storage and retrieval system
B) automated storage and recovery system
C) automated scan and recognize system
D) automated scan and retail system
E) automated scan and retrieval system
Answer: A
7) Which of the following is TRUE of random stocking?
A) Because items are stocked randomly, accurate inventory records are not necessary.
B) Its results always minimize handling costs.
C) Products have their own permanent storage spot.
D) Each pick can be of only one product.
E) None of the above is true.
Answer: E
Key Term: Random stocking
8) Cross-docking means which of the following?
A) Avoid placing materials or supplies in storage by processing them as they are received.
B) The same docks can be used either incoming or outbound shipments.
C) The same dock is used to unload and then reload the same truck.
D) Warehouse docks are designed in the shape of a cross.
E) Docks are placed in the warehouse according to the direction (north, south, east, or west) from which the truck is arriving.
Answer: A
Key Term: Cross-docking
9) ________ avoids placing materials or supplies in storage by processing them as they are received for shipment.
Answer: Cross-docking
Key Term: Cross-docking
10) What is cross-docking? What are some of its benefits for manufacturing facilities, distribution centers, and retailers such as Walmart?
Answer: Cross-docking avoids placing materials or supplies in storage by processing them as they are received. In a manufacturing facility, product is received directly by the assembly line. In a distribution center, labeled and presorted loads arrive at the shipping dock for immediate rerouting, thereby avoiding formal receiving, stocking/storing, and order-selection activities. Because these activities add no value to the product, their elimination is 100% cost savings. For retailers such as Walmart, cross-docking reduces distribution costs and speeds restocking of stores, thereby improving customer service.
Key Term: Cross-docking
Section 6 Fixed-Position Layout
1) The dominant problem associated with the fixed-position layout is that workers are fixed in position, and they cannot be reassigned.
Answer: FALSE
Key Term: Fixed-position layout
2) The fixed-position layout would be MOST appropriate in which of the following settings?
A) a fast-food restaurant
B) a doctor's office
C) a casual dining restaurant
D) a cruise ship assembly facility
E) a washing machine assembly line
Answer: D
Key Term: Fixed-position layout
3) For which of the following operations would a fixed-position layout be MOST appropriate?
A) assembling automobiles
B) producing TV sets
C) constructing a highway tunnel
D) refining of crude oil
E) running an insurance agency
Answer: C
Key Term: Fixed-position layout
4) Because problems with fixed-position layouts are so difficult to solve well onsite, operations managers:
A) virtually never employ this layout strategy.
B) utilize this approach only for construction projects such as bridges and office towers.
C) increase the size of the site.
D) often complete as much of the project as possible offsite.
E) utilize this layout only for defense contractors.
Answer: D
Key Term: Fixed-position layout
5) Which of the following is NOT one of the factors complicating the techniques for addressing the fixed-position layout?
A) The volume of materials needed is dynamic.
B) At different stages of a project, different materials are needed; therefore, different items become critical as the project develops.
C) Takt times at workstations are dynamic.
D) There is limited space at virtually all sites.
E) All of the above are complicating factors.
Answer: C
Key Term: Fixed-position layout
6) The project remains in one place and workers and equipment come to that one work area in a(n) ________ layout.
Answer: fixed-position
Key Term: Fixed-position layout
7) The techniques for addressing the fixed-position layout are complicated by what three factors? What is an alternative strategy to address these?
Answer:
(1) There is limited space at virtually all sites.
(2) At different stages of a project, different materials are needed; therefore, different items become critical as the project develops.
(3) The volume of materials needed is dynamic.
An alternative strategy is to complete as much of the project as possible offsite.
Key Term: Fixed-position layout
Section 7 Process-Oriented Layout
1) A process-oriented layout is the traditional way to support a product differentiation strategy.
Answer: TRUE
Key Term: Process-oriented layout
2) Job lots are groups or batches of parts processed together.
Answer: TRUE
Key Term: Job lots
3) Process-oriented layouts typically have low levels of work-in-process inventory.
Answer: FALSE
Key Term: Process-oriented layout
4) The most common tactic to arrange departments in a process-oriented layout is to minimize material handling costs.
Answer: TRUE
Key Term: Process-oriented layout
5) Which type of layout features departments or other functional groupings in which similar activities are performed?
A) process-oriented
B) product-oriented
C) fixed-position
D) mass production
E) unit production
Answer: A
Key Term: Process-oriented layout
6) One of the major advantages of process-oriented layouts is:
A) high equipment utilization.
B) large work-in-process inventories.
C) flexibility in equipment and labor assignment.
D) smooth and continuous flow of work.
E) small work-in-process inventories.
Answer: C
Key Term: Process-oriented layout
7) The main issue in designing process-oriented layouts concerns the relative positioning of:
A) safety devices.
B) departments or work centers.
C) raw materials.
D) entrances, loading docks, etc.
E) supervisors to their employees.
Answer: B
Key Term: Process-oriented layout
8) Which of the following is NOT an information requirement for solving a load-distance problem to design a process layout?
A) a list of departments or work centers
B) a projection of work flows between the work centers
C) the distance between locations
D) a list of product cycle times
E) the cost per unit of distance to move loads
Answer: D
Key Term: Process-oriented layout
9) The major problem addressed by the process-oriented layout strategy is:
A) the movement of material to the limited storage areas around the site.
B) how to design a continuous flow process.
C) the provision of low-cost storage with low-cost material handling.
D) minimizing difficulties caused by material flow varying with each product.
E) balancing product flow from one work station to the next.
Answer: D
Key Term: Process-oriented layout
10) The most common tactic followed in process-layout planning is to arrange departments or work centers so they:
A) minimize the cost of skilled labor.
B) maximize the machine utilization.
C) are equally allocated within the available space.
D) minimize the costs of material handling.
E) produce a perfectly balanced assembly line.
Answer: D
Key Term: Process-oriented layout
11) A big advantage of a process-oriented layout is:
A) its flexibility in equipment and labor assignments.
B) its low cost.
C) the simplified scheduling problem presented by this layout strategy.
D) the ability to employ low-skilled labor.
E) its high equipment utilization.
Answer: A
Key Term: Process-oriented layout
12) The disadvantages of process-oriented layout come from:
A) the use of special purpose equipment.
B) machine maintenance, which tends to seriously degrade the capacity of the entire system.
C) the use of specialized material handling equipment.
D) the need for stable demand.
E) the flexibility of general-purpose equipment.
Answer: E
Key Term: Process-oriented layout
13) The typical goal used when developing a process-oriented layout strategy is to:
A) minimize the distance between adjacent departments.
B) minimize the material handling costs.
C) maximize the number of different tasks that can be performed by an individual machine.
D) minimize the level of operator skill necessary.
E) maximize job specialization.
Answer: B
Key Term: Process-oriented layout
14) A process layout problem consists of 4 departments, each of which can be assigned to one of four rooms. The number of different solutions to this problem is ________, although all of them may not have different material handling costs.
A) 1
B) 4
C) 16
D) 24
E) unknown
Answer: D
Key Term: Process-oriented layout
15) Solving a load-distance problem for a process-oriented layout requires that:
A) the difficulty of movement be the same for all possible paths.
B) pickup and setdown costs vary from department to department.
C) the cost to move a load be the same for all possible paths.
D) takt time be less than 1.
E) Proplanner software examines all possible department configurations.
Answer: A
Key Term: Process-oriented layout
16) ________ layouts deal with low-volume, high-variety production with like machines and equipment grouped together.
Answer: Process-oriented
Key Term: Process-oriented layout
17) Explain how a load-distance model helps solve problems in process layout.
Answer: The problem in process layout is to arrange departments or work centers so as to minimize the costs of material handling. The load-distance model calculates the amount shipped multiplied by the cost per load of these movements from department to department, and so it can find that set of departmental space assignments that minimizes the aggregate material handling cost.
Key Term: Process-oriented layout
18) Departments A, B, C, and D need to be assigned to four rooms 1, 2, 3, and 4. These rooms are arranged in a row, in that order, with 20 meters between each. The departmental work flows are contained in the table below.
(a) What is the material handling total of assigning A-1, B-2, C-3, D-4?
(b) What is the material handling total of assigning A-1, B-3, C-4, D-2? Flow Matrix Dept. A
Dept. B
Dept. C
Dept. D Dept. A
0
30
5
20 Dept. B
5
0
40
20 Dept. C
0
10
0
40 Dept. D
10
5
0
0 Answer:
(a) The material handling total of A-1, B-2, C-3, D-4 is 5500. Details: 1-2 (A-B): 20 30 + 20 5 = 700; 1-3 (A-C): 40 5 + 400 = 200; 1-4 (A-D): 60 20 + 6010 = 1800; 2-3 (B-C): 20 40 + 20 10 = 1000; 2-4 (B-D): 40 20 + 40 5 = 1000; and 3-4 (C-D): 20 40 + 20 0 = 800. The sum of these six elements is 5500.
(b) The material handling total of A-1, B-3, C-4, D-2 is 5400 (which is also the optimal solution). Details: 1-2 (A-D): 20 20 + 20 10 = 600; 1-3 (A-B): 40 30 + 40 5 = 1400; 1-4 (A-C): 60 5 + 60 0 = 300; 2-3 (B-D): 20 20 + 20 5 = 500; 2-4 (C-D):40 40 + 40 0 = 1600; and 3-4 (B-C): 20 40 + 20 10 = 1000. These six elements sum to 5400.
Key Term: Process-oriented layout
19) There are three work centers (A, B, and C) behind the financial aid counter at a nearby university. They can each fit into any of three office spaces (1, 2, and 3) off the corridor behind the desk. There is no student contact in these areas, only workers. The distance 1-2 is 20 feet, 2-3 is 30 feet, and 1-3 is 50 feet. The matrix of work (trips per day) at the three centers are shown in the following table. Remember that each trip must be a round-trip (from 1 to 2 and back, for example). A
B
C A
--
20
0 B
45
--
25 C
60
0
-- (a) How many possible assignments are there? List them.
(b) Calculate the total distance traveled in each of these assignments.
(c) Which assignment minimizes distance traveled?
Answer: (a) There are 3! = 6 assignments, listed in the table below. (b) The cost, in feet, of each assignment appears in the table below. (c) The lowest cost assignment is A-2, B-1, C-3. A
B
C
Cost 1
2
3
10,100 1
3
2
10,400 2
1
3
8,700 2
3
1
8,800 3
1
2
11,100 3
2
1
10,900 Key Term: Process-oriented layout
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?
Answer: Load-distance = AB: 30(35) + AC: 5(20) + AD: 40(30) + AE: 50(70) + AF: 20(0) + BC: 20(100) + BD: 5(60) + BE: 20(160) + BF: 15(10) + CD: 10(50) + CE: 35(0) + CF: 5(60) + DE: 15(80) + DF: 10(20) + EF: 10(110) = 1050 + 100 + 1200 + 3500 + 0 + 2000 + 300 + 3200 + 150 + 500 + 0 + 300 + 1200 + 200 + 1100 = 14,800 meters. The current assignment costs: 14,800($4) =$59,200.
Key Term: Process-oriented layout
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
- Answer: There are 6 possible assignments and the distance traveled for each scenario is 110(Distance A-B) + 195(Distance C-B) + 180(Distance A-C) = total distance.
A(1)-B(2)-C(3) = 110(4000) + 195(6000) + 180(5000) = 2510K
A(1)-B(3)-C(2) = 110(5000) + 195(6000) + 180(4000) = 2440K
A(2)-B(1)-C(3) = 110(4000) + 195(5000) + 180(6000) = 2495K
A(2)-B(3)-C(1) = 110(6000) + 195(5000) + 180(4000) = 2355K
A(3)-B(2)-C(1) = 110(6000) + 195(4000) + 180(5000) = 2340K
A(3)-B(1)-C(2) = 110(5000) + 195(4000) + 180(6000) = 2410K
Subgroup A should be assigned terminal 3, subgroup B to terminal 2, and subgroup C to terminal 1 to minimize the distance travelers must go.
Key Term: Process-oriented layout
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.
Answer: FALSE
Key Term: Work cell
2) The work cell improves layouts by reducing both floor space and direct labor cost.
Answer: TRUE
Key Term: Work cell
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.
Answer: FALSE
Key Term: Focused work center
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
Answer: B
Key Term: Work cell
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.
Answer: B
Key Term: Work cell
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.
Answer: A
Key Term: Takt time
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
Answer: B
Key Term: Work cell
8) A(n) ________ is a special product-oriented arrangement of machines and personnel in what is ordinarily a process-oriented facility.
Answer: work cell
Key Term: Work cell
9) ________ is the pace (frequency) of production necessary (time per unit) to meet customer orders.
Answer: Takt time
Key Term: Takt time
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.
Answer: A focused work center is a permanent or semi-permanent product-oriented arrangement of machines and personnel. It moves production to a large work cell that remains part of the present facility. A focused work center may be appropriate when a firm has identified a family of similar products that have a large and stable demand.
Key Term: Focused work center
11) Why do work cells increase the utilization of equipment and machinery?
Answer: Work cells increase the utilization of equipment and machinery because of better scheduling and faster material flow.
Key Term: Work cell
12) What are the advantages of focused factories?
Answer: Focused factories are better able to stay in tune with their customers, produce quality products, and operate at higher margins.
Key Term: Focused factory
13) Identify the four requirements for cellular production.
Answer: (1) identification of families of products, often through the use of group technology codes or equivalents; (2) a high level of training, flexibility, and empowerment of employees; (3) being self-contained, with its own equipment and resources; (4) testing (poka-yoke) at each station in the cell
Key Term: Work cell
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?
Answer: Takt time = 420 minutes / 200 units required = 2.1 minutes
Key Term: Takt time
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?
Answer: The cell has 7.5 6 = 45 hours (or 2700 minutes) of work time each week. Takt time = 2700 / 120 = 22.5 minutes.
Key Term: Takt time
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?
Answer: (a) Takt time = 420 minutes / 80 units = 5.25 minutes. (b) Total operation time is 1.0 + 1.8 + 2.4 + 2.5 + 1.4 = 9.1 minutes. Workers required = 9.1 / 5.25 = 1.73 or 2.
Key Term: Takt time
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?
Answer:
(a) Takt time = 420 / 140 = 3 minutes/unit.
(b) Total operation time = 3.0 + 1.8 + 2.4 + 2.5 + 1.4 = 11.1 minutes. A minimum of four workers are required (11.1 / 3 = 3.7).
Key Term: Takt time
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.
Answer:
(a) Takt time = (6 hours/day * 20 days/month)/(250 units/month) = .48 hours per computer (or 28.8 minutes)
(b) Total operation time = 2+5+1 = 8 hours. Workers required = operation time / takt time = 8/.48 = 16.67 = 17 workers required
Key Term: Takt time
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?
Answer:
(a) Total operation time = Workers required takt time = 10(7 minutes) = 70 minutes
(b) Time worked = Takt time Units Delivered # workers = 7 minutes (68) 10 =4760 minutes = 79.33 hours
(c) 10 workers 8 hours/day = 80 hours per day are available. From (b), only 79.33 are required, so the workers can meet demand.
Key Term: Takt time
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.
Answer: FALSE
2) The biggest advantage of a product layout is its flexibility to handle a varied product mix.
Answer: FALSE
3) The minimum number of workstations depends upon the set of task times and the precedence chart, but not the number of units scheduled.
Answer: FALSE
Key Term: Cycle time
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.
Answer: FALSE
Key Term: Cycle time
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.
Answer: TRUE
Key Term: Cycle time
6) Product-oriented layouts tend to have high levels of work-in-process inventories.
Answer: FALSE
7) One drawback of a product-oriented layout is that work stoppage at any one point ties up the whole operation.
Answer: TRUE
8) Cycle time is the maximum time that the product is allowed at each workstation.
Answer: TRUE
Key Term: Cycle time
9) Heuristics are problem-solving procedures that mathematically optimize the solution.
Answer: FALSE
Key Term: Heuristic
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
Answer: C
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
Answer: B
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.
Answer: C
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.
Answer: D
Key Term: Fabrication line
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.
Answer: E
Key Term: Assembly-line balancing
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.
Answer: E
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
Answer: E
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
Answer: D
Key Term: Assembly-line balancing
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.
Answer: D
Key Term: Assembly-line balancing
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.
Answer: B
Key Term: Cycle time
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
Answer: B
Key Term: Cycle time
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
Answer: C
Key Term: Cycle time
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.
Answer: D
Key Term: Cycle 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
Answer: A
Key Term: Cycle time
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
Answer: C
Key Term: Assembly-line balancing
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
Answer: D
Key Term: Assembly-line balancing
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
Answer: C
Key Term: Heuristic
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.
Answer: E
Key Term: Heuristic
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
Answer: D
Key Term: Heuristic
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
Answer: C
Key Term: Assembly-line balancing
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
Answer: C
Key Term: Assembly-line balancing
31) A(n) ________ line is a machine-paced product-oriented facility for building components.
Answer: fabrication
Key Term: Fabrication line
32) ________ is the maximum time that the product is allowed at each workstation.
Answer: Cycle time
Key Term: Cycle time
33) Explain what the purpose of assembly-line balancing is. Describe briefly how it is done.
Answer: Assembly-line balancing attempts to put equal amounts of work into each of the workstations that assemble a product. The technique begins with a task list and precedence chart; to this is added demand data, from which cycle time can be computed. This is the maximum time that a product is allowed at each workstation. Then the theoretical number of workstations is calculated. Each required task is then assigned into a workstation, often based on one of the five common heuristic rules.
Key Term: Assembly-line balancing
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.
Answer:
(1) Cycle time = Production time available per day / Units required per day;
(2) Minimum number of workstations = The total of all task times for the product / Cycle time
(3) Efficiency = The total of all task times for the product / [(Actual # of workstations)(Largest assigned cycle time)]
Key Term: Assembly-line balancing
35) Identify the five common layout heuristics used to assign tasks to workstations in assembly-line balancing.
Answer: (1) longest task (operation) time; (2) most following tasks; (3) ranked positional weight; (4) shortest task (operation) time; (5) least number of following tasks
Key Term: Heuristic
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.
Answer: No, they should not be surprised. Efficiency is the ratio of actual work needed per unit to time available. Work needed is clearly the same in both cases as the product is the same. Work available is also the same, since both lines have the same number of stations and the same maximum assigned cycle time (which determines daily output). Once cycle time and number of stations are known, so is efficiency, no matter what tasks are assigned to what stations within that framework.
Key Term: Assembly-line balancing
37) What are the advantages and disadvantages of product-oriented layouts?
Answer:
The advantages of a product-oriented layout are:
The low variable cost per unit usually associated with high-volume, standardized products
Low material handling costs
Reduced work-in-process inventories
Easier training and supervision
Rapid throughput
The disadvantages are:
The high volume required because of the large investment needed to establish the process
Work stoppage at any point can tie up the whole operation.
The process flexibility necessary for a variety of products and production rates can be a challenge.
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 Answer: The theoretical minimum number of workstations is 3. Balance places ABDF in station 1, C in station 2, E in station 3, and G in station 4. The solution uses four stations, not three. The POM for Windows solution is shown below. Idle time is distributed 10, 180, 60, and 110 per station. There are 360 seconds of idle time in the system. Efficiency is 70.0%.
Q:
Use prominent locations for high-impulse and high-margin items.
Q:
Operations Management, 11e (Heizer/Render)
Section 1 The Strategic Importance of Layout Decisions
1) The objective of layout strategy is to develop an effective and efficient layout that will meet the firm's competitive requirements.
Answer: TRUE
Key Term: The strategic importance of layout decisions
2) Which of the following is NOT one of McDonald's "seven major innovations"?
A) the Happy Meal
B) drive-through windows
C) breakfast menus
D) play areas
E) self-service kiosks
Answer: A
3) The objective of layout strategy is to:
A) minimize cost.
B) develop an effective and efficient layout that will meet the firm's competitive requirements.
C) maximize flexibility.
D) minimize space used.
E) maximize worker satisfaction.
Answer: B
4) Identify McDonald's seven major innovations.
Answer: The seven major innovations are indoor seating, drive-through windows, breakfast menus, play areas, the "Made by You" kitchen system, the self-service kiosk, and the 21st century look.
5) In what specific areas does the layout decision establish a firm's competitive priorities?
Answer: Layout decisions establish a firm's competitive priorities in regard to: capacity, processes, flexibility, and cost, as well as quality of work life, customer contact, and image.
Section 2 Types of Layout
1) The layout approach that addresses trade-offs between space and material handling is called the fixed-position layout.
Answer: FALSE
Key Term: Warehouse layout
2) The ________ layout's main objective is to equalize the task time for each station.
A) work cell
B) fixed position
C) office
D) job shop
E) product oriented
Answer: E
3) A hospital's layout most closely resembles which of the following?
A) product oriented
B) work cell
C) job shop
D) project
E) retail
Answer: C
Key Term: Process-oriented layout
4) What layout strategy deals with low-volume, high-variety production?
A) fixed-position layout
B) retail layout
C) warehouse layout
D) office layout
E) process-oriented layout
Answer: E
Key Term: Process-oriented layout
5) "A special arrangement of machinery and equipment to focus on production of a single product or group of related products" describes what layout type?
A) fixed-position layout
B) intermittent production
C) job shop
D) work cell
E) warehouse layout
Answer: D
Key Term: Work cell
6) A good layout requires determining:
A) material handling equipment.
B) capacity and space requirements.
C) environment and aesthetics.
D) cost of moving between various work areas.
E) all of the above
Answer: E
7) Which of the statements below best describes office layout?
A) positions workers, their equipment, and spaces/offices to provide for movement of information
B) addresses the layout requirements of large, bulky projects such as ships and buildings
C) seeks the best personnel and machine utilization in repetitive or continuous production
D) allocates shelf space and responds to customer behavior
E) deals with low-volume, high-variety production
Answer: A
Key Term: Office layout
8) To develop a good facility layout, what must be determined?
Answer: You need to consider the following to determine a good layout: material handling equipment, capacity and space requirements, environment and aesthetics, flows of information, and cost of moving between various work areas.
9) Identify the seven fundamental layout strategies. Describe the use of each one very briefly.
Answer:
Q:
Weight
X coord
Y coord Project A
1
50
10 Project B
1
15
60 Project C
1
40
60 Project D
1
30
20 Sum Average 33.75
37.5 Weighted Average 33.75
37.5 b.