Q&A Hero

Question

conveying the mission of the store by careful selection in the positioning of the lead-off department

27) Consider the five ideas for determining the overall arrangement of most retail stores. How are these ideas implemented (a) in a supermarket, and (b) in a fine department store? (Please consider the entire store--not just the areas where merchandise is displayed.)

Answer: (Suggested response) The five ideas are: 1. locating the high-draw items around the periphery of the store; 2. using prominent locations for high-impulse and high-margin items; 3. distributing what are known in the trade as "power items" to both sides of an aisle, and dispersing them to increase the viewing of other items; 4. using end aisle locations because they have a very high exposure rate; 5. conveying the image of the store by careful selection in the positioning of the lead-off department. Supermarkets make more use of aisles, where ideas 3 and 4 are featured. Department stores are meandering, so there's less use of end-caps. Both types of retail seem to follow ideas 1 and 5. Idea 2 seems to be implemented with impulse items near the checkouts for both retail types. The supermarket's straight lines convey its strategy of low cost; the department store's display areas convey its focus on image, browsing, etc.

28) Briefly explain what "slotting" is. Why is slotting considered a "controversial" practice? What ethical issues might arise with regard to slotting?

Answer: Slotting is the practice of manufacturers paying for retail shelf space. It is controversial because some managers approve of the practice, but others do not. Ethical issues involved with slotting are (1) such payments might be considered bribery, (2) such payments cost consumers more, and (3) such payments may interfere with efficient and profitable use of retail space.

29) 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. 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/functionality, and signs, symbols, and artifacts.

30) What is cross-docking? Why is it appropriate for some forms of warehouse layout?

Answer: Cross-docking avoids placing materials or supplies in storage by processing them as they are received for shipment. It avoids storing the product, saves space and receiving time, and speeds up shipment to the ultimate destination.

31) What are the two basic types of product layouts? Explain how they are alike, and how they are different.

Answer: The two types are fabrication lines and assembly lines. Fabrication lines build components on a series of machines, while assembly lines put the fabricated parts together at a series of workstations. Fabrication lines tend to be machine paced and require mechanical changes to facilitate balance, while assembly lines tend to be paced by work tasks assigned to individuals or to workstations and are therefore balanced by moving tasks from one individual to another.

32) Explain what the purpose of assembly line balancing is. Describe briefly how it is done. Explain how assembly line balancing supports the needs of product layout.

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 speed at which the line must move. Then the theoretical number of stations is calculated. Each required task is then assigned into one workstation. This approach holds down the amount of idle time in a product layout, and leads to higher utilization of the plant, and to higher volume of output.

33) Define the following terms that occur in assembly line balancing: cycle time, minimum number of workstations, and efficiency.

Answer: Cycle time is the ratio of allowed work time to units scheduled. The theoretical minimum number of workstations in an assembly line is determined by dividing the total task-duration time for the product by the cycle time. The efficiency of a line balance is determined by dividing the total task time assigned by the product of the number of workstations times the cycle time.

34) What is the role of heuristics in solving layout problems? Provide a brief example, drawing from manufacturing situations, retailing situations, or other service situations.

Answer: Heuristics are used in problems too complex to model explicitly, such as assembly line balancing problems, fixed-position layouts, office layouts, and retail layouts. All of these layout types are quite complex, featuring very large numbers of alternative solutions and no single numeric objective for evaluating them.

35) 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 cycle time. Once cycle time and number of stations are known, so is efficiency, no matter what tasks are assigned to what stations within that framework.

36) What are the advantages and disadvantages of product layouts?

Answer:

The advantages of a product 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

That work stoppage at any point halts the whole operation

A lack of flexibility when handling a variety of products or production rates

Essay

1) 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?

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%.