Ch 8 - Facility Layout

Question 1

What does layout decisions entail?

Answer 1

Determining the placement of departments, work groups within the departments, workstations, machines, and stock-holding points within a production facility.

The objective is to arrange these elements in a way that ensures a smooth work flow (in a factory) or a particular traffic pattern (in a service organization).

Question 2

Which are the input to layout decisions?

Answer 2

1. Specification of the objectives and corresponding criteria to be used to evaluate the design. The amount of space required and the distance that must be traveled between elements in the layout are common basic criteria.
2. Estimates of product or service demand on the system.
3. Processing requirements in terms of number of operations and amount of flow between the elements in the layout.
4. Space requirements for the elements in the layout.
5. Space availability within the facility itself or, if this is a new facility, possible building configurations.

Question 3

Which are the three basic types of formats by which departments are arranged in a facility?

Answer 3

The formats by which departments are arranged in a facility are defined by the general pattern of workflow. There are three basic types (workcenter, assembly line, and project layout) and one hybrid type (manufacturing cell).

Question 4

Workcenters

Answer 4

A workcenter (also called a job-shop or functional layout) is a format in which similar equipment or functions are grouped together, such as all lathes in one area and all stamping machines in another. A part being worked on then travels, according to the established sequence of operations, from area to area, where the proper machines are located for each operation. This type of layout is typical in hospitals, for example, where areas are dedicated to particular types of medical care, such as maternity wards and intensive care units.

Question 5

Assembly line

Answer 5

An assembly line (also called a flow-shop layout) is one in which equipment or work processes are arranged according to the progressive steps by which the product is made. The path for each part is, in effect, a straight line. Assembly lines for shoes, chemical plants, and car washes are all product layouts.

Question 6

Manufacturing cell

Answer 6

A manufacturing cell groups dissimilar machines to work on products that have similar shapes and processing requirements. A manufacturing cell is similar to a workcenter in that cells are designed to perform a specific set of processes, and it is similar to an assembly line in that the cells are dedicated to a limited range of products. (Group technology refers to the parts classification and coding system used to specify machine types that go into a cell.)

Question 7

Project layout

Answer 7

In a project layout, the product (by virtue of its bulk or weight) remains at one location. Manufacturing equipment is moved to the product rather than vice versa. Construction sites and movie lots are examples of this format.

Question 8

Hybrids

Answer 8

Many manufacturing facilities present a combination of two layout types. For example, a given production area may be organized as a workcenter, while another area may be an assembly line. It is also common to find an entire plant arranged according to product flow—for example, a parts fabrication area followed by a subassembly area, with a final assembly area at the end of the process. Different types of layouts may be used in each area, with workcenters used in fabrication, manufacturing cells in subassembly, and an assembly line used in final assembly.

Question 9

What is systematic layout planning?

Answer 9

Systematic layout planning (SLP) is A technique for solving process layout problems when the use of numerical flow data between departments is not practical. The technique uses an activity relationship diagram that is adjusted by trial and error until a satisfactory adjacency pattern is obtained.

Question 10

What is a common assembly line desing?

Answer 10

The most common assembly line is a moving conveyor that passes a series of workstations in a uniform time interval called the workstation cycle time (which is also the time between successive units coming off the end of the line).

Question 11

What is Assembly-line balancing?

Answer 11

The problem of assigning tasks to a series of workstations so that the required cycle time is met and idle time is minimized.

Question 12

What is the Precedence relationship?

Answer 12

The required order in which tasks must be performed in an assembly process.

Question 13

Determine the required workstation cycle time (C), using the formula

Answer 13

C = Production time per day /Required output per day (in units)

Question 14

Often, the longest required task time defines the shortest possible workstation cycle time for the production line. This task time is the lower time bound unless it is possible to split the task into two or more workstations. There are several ways we may be able to accommodate the 40-second task in a 36-second cycle (i.e. reducing time). Possibilities are:

Answer 14

1. Split the task. Can we split the task so that complete units are processed in two workstations?
2. Share the task. Can the task somehow be shared so an adjacent workstation does part of the work? This differs from the split task in the first option because the adjacent station acts to assist, not to do some units containing the entire task.
3. Use parallel workstations. It may be necessary to assign the task to two workstations that would operate in parallel.
4. Use a more skilled worker. Because this task exceeds the workstation cycle time by just 11 percent, a faster worker may be able to meet the 36-second time.
5. Work overtime. Producing at a rate of one every 40 seconds would create 675 per day, 75 short of the needed 750. The amount of overtime required to produce the additional 75 is 50 minutes (75 × 40 seconds/60 seconds).
6. Redesign. It may be possible to redesign the product to reduce the task time slightly.

Question 15

What does the Mixed-model line balancing involve?

Answer 15

Mixed-model line balancing involves scheduling several different models to be produced over a given day or week on the same line in a cyclical fashion. This approach is used by JIT manufacturers such as Toyota. Its objective is to meet the demand for a variety of products and to avoid building high inventories.

Question 16

What are the benefits of cellular layouts?

Answer 16

1. Better human relations. Cells consist of a few workers who form a small work team; a team turns out complete units of work.
2. Improved operator expertise. Workers see only a limited number of different parts in a finite production cycle, so repetition means quick learning.
3. Less in-process inventory and material handling. A cell combines several production stages, so fewer parts travel through the shop.
4. Faster production setup. Fewer jobs mean reduced tooling and hence faster tooling changes.

Question 17

Shifting from a workcenter layout to a cellular layout entails three steps:

Answer 17

1. Grouping parts into families that follow a common sequence of steps. This step requires developing and maintaining a computerized parts classification and coding system. This is often a major expense with such systems, although many companies have developed shortcut procedures for identifying parts families.
2. Identifying dominant flow patterns of parts families as a basis for location or relocation of processes.
3. Physically grouping machines and processes into cells. Often, there will be parts that cannot be associated with a family, and specialized machinery that cannot be placed in any one cell because of its general use. These unattached parts and machinery are placed in a “remainder cell.”

Question 18

What is the objective of a retail service layout (as is found in stores, banks, and restaurants)?

Answer 18

it is to maximize net profit per square foot of store space.

Operationally, this goal is often translated into such criteria as “minimize handling cost” or “maximize product exposure.”

In a retail setting, the layout is designed to increase sales rather than minimize cost, as done in a manufacturing layout.

Question 19

What is servicescape?

Answer 19

. The term servicescaperefers to the physical surroundings in which the service takes place and how these surroundings affect customers and employees.

Question 20

Which are the 3 elements that must be considered in the servicescape?

Answer 20

The servicescape has three elements that must be considered:

• the ambient conditions;
• the spatial layout and functionality; and
• the signs, symbols, and artifacts.

Question 21

The term ambient conditions

Answer 21

The term ambient conditions refers to background characteristics such as the noise level, music, lighting, temperature, and scent that can affect employee performance and morale as well as customers’ perceptions of the service, how long they stay, and how much money they spend. Although many of these characteristics are influenced primarily by the design of the building (such as the placement of light fixtures, acoustic tiles, and exhaust fans), the layout within a building also can have an effect. Areas near food preparation will smell like food, lighting in a hallway outside a theater must be dim, tables near a stage will be noisy, and locations near an entrance will be drafty.

Question 22

spatial layout and functionality

Answer 22

Two aspects of the spatial layout and functionality are especially important: planning the circulation path of the customers and grouping the merchandise. The goal of circulation planning is to provide a path for the customers that exposes them to as much of the merchandise as possible while placing any needed services along this path in the sequence they will be needed.

Question 23

Special mention is in order for a few guidelines derived from marketing research and relating to circulation planning and merchandise grouping:

Answer 23

1. People in supermarkets tend to follow a perimeter pattern in their shopping behavior. Placing high-profit items along the walls of a store will enhance their probability of purchase.
2. Sale merchandise placed at the end of an aisle in supermarkets almost always sells better than the same sale items placed in the interior portion of an aisle.
3. Credit and other nonselling departments that require customers to wait for the completion of their services should be placed either on upper floors or in “dead” areas.
4. In department stores, locations nearest the store entrances and adjacent to front- window displays are most valuable in terms of sales potential.

Question 24

Signs, symbols, and artifacts

Answer 24

Signs, symbols, and artifacts refer to the parts of the service that have social significance. As with the ambiance, these are often a characteristic of the design of the building, although the orientation, location, and size of many objects and areas can carry special meaning. As examples,
∙ Bank loan officers are easily identified because their desks are typically located in glass-walled offices in the bank.
∙ A person seated at the standup desk closest to the entrance is usually in charge of greeting customers and directing them to their destination.
∙ In a workcenter store, the tiled areas may indicate the aisles for travel, while carpeted areas indicate departments for browsing.

Question 25

What about office layout?

Answer 25

The trend in office layout is toward more open offices, with personal work spaces separated only by low divider walls. Companies have removed fixed walls to foster greater communication and teamwork. Signs, symbols, and artifacts, as discussed in the section on service layout, are possibly even more important in office layout than in retailing. For instance, the size and orientation of desks can indicate the importance or professionalism of the people behind them