1. Explain the importance of process selection in system design.
- Process selection refers to deciding on the way production of goods or services will be organized. It
has major implications for capacity planning, layout of facilities, equipment, and design of work systems.
Capacity and process selection are interrelated, and are often done in production. They affect facility
and equipment choices, layout, and work design.
2. Briefly describe the five process types, and indicate the kinds of situations in which each would be
used.
- There are five basic process types:
a. Jobshop: Jobshop is used when a low volume and a large variety of goods or services are needed. It
usually operates on a relatively small scale. A manufacturing example of a job shop is a tool and die
shop that is able to produce one-of-a-kind tools. A service example is a veterinarian’s office, which is
able to process a variety of animals and a variety of injuries and diseases.
b. Batch: Batch processing is used when a moderate volume of goods or services is desired, and it can
handle a moderate variety in products or services. The skill level of workers doesn’t need to be as high
as in a job shop because there is less variety in the jobs being processed. Examples of batch systems
include bakeries, which make bread, cakes, or cookies in batches; movie theaters, which show movies
to groups (batches) of people; and airlines, which carry planeloads (batches) of people from airport to
airport
c. Repetitive: This type of a process that involves higher volumes of more standardized goods or
services. The standardized output means only slight flexibility of equipment is needed. Skill of workers is
generally low. Examples of this type of system include production lines and assembly lines
d. Continuous: This type of a process involves a very high volume of highly standardized goods or
services. These systems have almost no variety in output and no need for equipment flexibility. The
machines are dedicated to perform specified tasks. Examples of a continuous process include
petroleum refining, steel manufacturing, and sugar manufacturing.
e. Project: Designed to be used s used for work that is nonroutine, with a unique set of objectives to be
accomplished in a limited time frame. These activities are not repeated. Equipment flexibility and worker
skills can range from low to high. Examples include a simple to complicated construction of a dam or a
bridge, launching a new product or service, publishing a book.
3. Briefly discuss the advantages and disadvantages of automation.
- Automation is machinery that has sensing and control devices that enable it to operate automatically.
Advantages of automation includes higher production rates and increased productivity, more efficient
use of materials, better product quality and improved safety. While the disadvantages of automation
include worker displacement, the worker may be displaced geographically. Also it includes high capital
cost and a higher level of maintenance needed than with a manually operated machine.
4. Briefly describe computer-assisted approaches to production.
- Numerically controlled (N/C) machines are programmed to follow a set of processing instructions
based on mathematical relationships that tell the machine the details of the operations to be performed.
The instructions are stored on a device such as magnetic tape or microprocessor.
- A flexible manufacturing system (FMS) is a group of machines that include supervisory computer
control, automatic material handling, and robots or other automated processing equipment.
Reprogrammable controllers enable these systems to produce a variety of similar products.
- Computer-integrated manufacturing (CIM) is a system that uses an integrating computer system to link
a broad range of manufacturing activities, including engineering design, flexible manufacturing systems,
purchasing, order processing, and production planning and control.
5. What is a flexible manufacturing system, and under what set of circumstances is it most appropriate?
- Flexible manufacturing systems often appeal to managers who hope to achieve both the flexibility of a
job shop and the productivity of repetitive processing.
6. Why is management of technology important?
- It is very important for an organization to manage its technology strategically because when it is not
well managed, it might result into a big loss in the organization. Managing technology involves planning,
designing, optimizing, operation and control of technological products
7. Why might the choice of equipment that provides flexibility sometimes be viewed as a
management cop-out?
- Managers sometimes view flexible systems as a barrier. They opt for such systems without having
complete understanding of future needs, that their lack of knowledge is offset by the flexible nature of
the system. But such systems are more expensive to install and maintain. The flexibility provided by
such systems may not be needed.
8. What are the trade-offs that occur when a process layout is used? What are the trade-offs that
occur when a product layout is used?
- The trade-offs between product layouts and process layouts include the following:
a. Process layout has more equipment flexibility.
b. Process layout generally requires higher skilled workers.
c. Product layout involves higher volume manufacturing.
g. For a product layout, the flow of work is linear, while for process layout, the flow of work is mixed
depending on the product produced.
h. There is more dependency between workstations for a product layout.
i. Preventive maintenance and machine reliability are more important in a product layout because
equipment breakdowns may involve shutting down a workstation, which may in turn result in shutting
down downstream workstations.
9. List some common reasons for redesigning layouts.
- The most common reasons for redesign of layouts include:
1. Inefficient operations.
2. Accidents or safety hazards.
3. Changes in the design of products or services.
4. Introduction of new products or services.
5. Changes in methods or equipment.
6. Changes in environmental or other legal requirements.
10. Briefly describe the two main layout types.
- Process layouts (functional layouts) are designed to process items or provide services that involve a
variety of processing requirements. Product layout is the opposite of the process layout. Rather than
have a specific section for each group of tools and supplies, the product layout is an assembly line. The
trade-offs that occur when a process layout is used
11. What are the main advantages of a product layout? The main disadvantages?
- The main advantages of product layouts includes potentially high rate of output, low unit costs, low
training costs, low unit cost for material handling, high utilization of labor and equipment, accounting,
purchasing, and inventory control are routine. While the main disadvantages of product layouts includes
repetitive jobs with little opportunity for personal satisfaction or creativity, workers may have little interest
in maintaining equipment or in the quality of output and incentive plans tied to individual output are
impractical.
12. What are the main advantages of a process layout? The main disadvantages?- The main advantages of process layouts are they can handle a variety of processing requirements;
they are less vulnerable to equipment failures than product layouts, individual incentive systems are
possible. While the main disadvantages of process layouts are work-in-process inventory costs can be
high, routing and scheduling must be done for each new job, equipment utilization rates are usually low,
accounting, inventory control, and purchasing generally are more involved than is the case with a
product layout.
13. What is the goal of line balancing? What happens if a line is unbalanced?
- Line balancing is the process of assigning tasks to workstations in such a way that the workstations
have approximately equal time requirements. And if a line is unbalanced there will be undesirable in
terms of inefficient utilization of labor and equipment and because they may create morale problems at
the slower stations for workers who must work continuously.
14. Why are routing and scheduling continual problems in process layouts?
- Routing and scheduling are continual problems in a process layout because a variety of jobs pass
through the system, and they tend to differ in terms of routing and scheduling requirements. Product
layouts typically handle items with little or no variety
15. Compare equipment maintenance strategies in product and process layouts.
- With a product layout, equipment breakdown has serious implications because the separate pieces of
equipment are closely tied together. If one piece of equipment fails, the lines will quickly stop.
Preventive maintenance to reduce the failure rate is advisable. A process layout contains matched
equipment so that if one particular piece of equipment fails, it can usually be shifted to another piece of
the equipment. Process layouts utilize more skilled workers who tend to take better care of the
equipment than the lower skilled workers do in a product layout system
16. Briefly outline the impact that job sequence has on each of the layout types.
- Job sequence usually determines the arrangement of equipment in a product layout. In a process
layout, job sequences vary, so there is much less influence on equipment arrangement. Because of
differences in job requirements, sequencing is a continual task in a process layout.
17. The City Transportation Planning Committee must decide whether to begin a long-term project to
build a subway system or to upgrade the present bus service. Suppose you are an expert in fixed path
and variable-path material-handling equipment, and the committee seeks your counsel on this
matter. What are the advantages and limitations of the subway and bus systems?
- Bus service is the better option where task will be complete on time with systematic movements of
equipment. The bus service equipment consists of variable path material handling. The advantage of
bus service consists of low cost project, low investments and material handing is easier. The
disadvantage consists of high utilization of equipment which can cause breakdown. Skillful operator is
required to upgrade the bus service.
The subway system will require fixed material handling where building the subway system is fixed and
all other equipment are moved as needed. The disadvantage of subway system is the usage of heavy
equipment which require high skill operator. The fixed path equipment does not have the huge storage
system to accommodate equipment. The advantage of subway system consists of minimum handling of
equipment. It helps the people to use new transport line.
18. Identify the fixed-path and variable-path material-handling equipment commonly found in
supermarkets.
- Fixed-path material handling equipment in supermarkets includes the belts at the checkouts which
move items up to the cashier, the roller conveyors which transport boxes of groceries outside to pick up
areas, conveyors in the meat department to move carcasses from storage to cutting tables, roller
conveyors to off-load goods from trucks and move them to storage. Variable-path material handling
equipment includes grocery carts, “trucks” and “jeeps” used to transport baked goods from storage to
display shelves, and movable racks to transport baked goods from ovens or from deliveries to the
bakery counter.
19. What are heuristic approaches, and why are they used in designing layouts?
- Heuristic approaches are rules designed to guide decision-makers to satisfactory decisions by
reducing the number of alternatives that must be considered. They don’t yield optimal solutions
necessarily. They usually are employed when there is a problem involving an exceedingly large number
of potential solutions.
20. Why are product layouts atypical in service environments?
- Nonmanufacturing environments do not usually lend themselves to product layouts because they tend
to involve more processing variety than many manufacturing environments do.
21. According to a study by the Alliance of American Insurers, it costs more than three times the
original purchase price in parts and labor to reconstruct a wrecked Chevrolet. Explain the reasons
for this large discrepancy in terms of the processes used to assemble the original car and those
required to reconstruct the wrecked car.
- The original car probably was one of a large number of similar cars produced on an assembly line,
which was set up to speed the flow of work. Inventories of parts were on hand and specialized
machinery, workers, and material handling equipment were arranged specifically for the job. Because of
this repetitive processing, the unit cost of the car was relatively low due to the high volume, low variety
processing. Reconstructing a car essentially is a cross between job shop processing and a project, with
none of the economies of repetitive processing. The work would progress at a slow rate, and probably
with a certain amount of backtracking. Obviously, reconstruction of a car would cost more.
22. Name some ways that a layout can help or hinder productivity.
-Layout can lead to high productivity if it contributes to a smooth flow of work with high utilization of
labor and equipment. Creating a layout requires careful consideration of future work requirements to
determine what will be needed and a certain amount of effort to obtain an optimal layout. A poor layout
will hinder productivity with bottlenecks and lower utilization of labor and equipment than is necessary,
and will require more handling or movement between work stations than is necessary.
23. What is cellular manufacturing? What are its main benefits and limitations?
- Cellular manufacturing is a process of manufacturing which is a subsection of just-in-time
manufacturing and lean manufacturing encompassing group technology. Advantages of such systems
include relatively short throughput time, reduced material handling, less work-in-process inventory, and
reduced setup time.
24. What is group technology?
- Group technology involves items that have similar design or processing requirements and grouping
them into part families for cellular manufacturing. It also includes a coding system for items.
25. Explain the consequences of task time variability on line balancing.
- The lower the level of automation, the higher the variability of task times will be. If the assembly line
consists of tasks with variable completion times, it will be more difficult to balance the line. To deal with
variability of task times, we can require a minimum amount of slack to be available at each workstation.
As the variability of task times increases, we can increase the minimum slack available at each
workstation.