Chapter 06 – Process Selection and Facility Layout
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CHAPTER 06
PROCESS SELECTION AND FACILITY LAYOUT
Teaching Notes
Facility layout involves physical placement of departments and/or arrangement of equipment within a
plant or a service facility. A good layout should lead to smooth flow of material, reduction of inventories,
and effective utilization of space.
The material in this chapter can be divided into four areas:
1. Process types, process selection, and automation.
2. Classification of production systems and (corresponding) types of layouts.
3. Line balancing.
4. Designing process layouts.
This chapter provides a good lead-in for the following chapter on design of work systems because it
1. Steps in salt production for Morton are:
a. Inject water into salt caverns below the surface and let the salt deposits dissolve in the water.
b. Pump the resulting brine to the surface.
c. Boil the brine and let the liquid evaporate leaving salt crystals and residual moisture.
d. Dry the salt to remove the residual moisture.
e. Store the salt in silos.
f. Move the salt to dedicated production areas.
g. Produce the cans by forming a cylinder (two sheets of chipboard are glued together).
h. Roll the cylinder into a continuous tube.
i. Cut the tubes into can-size pieces.
j. Assemble and glue the separate pieces constituting the can.
k. Fill the cans with salt.
l. Load the filled cans on pallets and store them in inventory.
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2. Quality is checked during different stages of the production process.
a. Check salt for purity using chemical analysis.
3. The company may not have updated its equipment because of the high cost of investment in new
machinery.
4. Salt production would be a low variety, high volume operation, which would place it as a
repetitive production or continuous flow in the product-process matrix.
5. (3,800,000 cans per year) x (26 ounces of salt per can) = 98,800,000 ounces per year.
6. Suggested improvements include the following:
a. Application of Statistical Process Control (SPC) to reduce the cost of quality.
b. Develop a plan to overhaul the existing equipment and to purchase new equipment as a joint
effort among finance, purchasing, and manufacturing areas.
c. Synchronize production, distribution, and capacity planning to ensure that there is sufficient
capacity in the silos to handle the incoming salt from brine production.
Reading: Foxconn Shifts Its Focus to Automation
1. As Foxconn increases its use of automation, jobs should be created in robot manufacturing
2. Foxconn’s shift to automation may make it likely that some companies will reconsider
outsourcing in favor of using automation because the companies doing the outsourcing should be
able to use the same automation to cut their own labor costs. In addition, transportation costs from
China to the U.S. have been increasing. On the other hand, Foxconn has developed expertise in
product design, quality control, etc. that may allow it to retain the work. Reasons for staying with
Foxconn include a well-established supply chain along with the production and design experience
of Foxconn personnel. Some reasons for leaving include increased labor costs in China, increased
transportation costs from China to the U.S., and shorter lead-times if these products were
produced in the U.S. instead of in China.
Reading: A Safe Hospital Room of the Future
1. Student answers will vary regarding which of the sixteen features they observed in the hospital
rooms that they stayed in or visited.
2. Student answers will vary regarding which of the sixteen features they did not observe in the
hospital rooms that they stayed in or visited.
Reading: Designing Supermarkets
This reading provides the student with an example of how a supermarket is laid out and why the
arrangement is done in a particular or specific way. It is a nice change of pace from the typical
manufacturing layout article.
Chapter 06 – Process Selection and Facility Layout
Answers to Discussion and Review Questions
1. Process selection refers to the ways organizations choose to produce or provide their goods and
2. There are five basic process types:
a. Job shop: Job shop is used when a low volume and a large variety of goods or services are
needed. Job shop involves intermittent processing, high flexibility, skilled workers, relatively
large work-in-process inventory, and general-purpose machinery. An example is a tool and
activities generally are not repeated. Equipment flexibility, level of worker skills, and work-
in-process inventory can range from very low to very high. Examples include construction of
a dam or a bridge, conversion of the production system from a job shop to group technology,
and installing and implementing a new inventory and bar coding system.
3. Advantages: Uniform output (low variability); boredom and fatigue are not factors; and machines
4. Numerically controlled (N/C) machines are programmed to follow a set of processing instructions
based on mathematical relationships. Robots have movable arms that enable them to handle a
wide variety of tasks such as welding, assembly, loading and unloading machines, painting, and
5. See Question #4 above for a description of a FMS. Flexible manufacturing systems often appeal
to managers who hope to achieve both the flexibility of a job shop and the productivity of
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15. 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 line will quickly come
16. Job sequence usually determines the arrangement of equipment in a product layout. In a process
17. The subway system is essentially a fixed-path arrangement—a product layout. Its advantages are
often low operating cost, more efficient handling, and low cost per unit moved. On the other
hand, a bus system is more flexible in terms of varying routes. This can be desirable if there are
18. Fixed-path material handling equipment in supermarkets includes the belts at the checkouts that
move items up to the cashier, the roller conveyors that transport boxes of groceries outside to
19. Heuristic approaches are rules designed to guide decision-makers to satisfactory decisions by
20. Nonmanufacturing environments do not usually lend themselves to product layouts because they
tend to involve more processing variety than many manufacturing environments do.
21. 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. That is, inventories of parts were on hand and
specialized machinery, workers, and material handling equipment were arranged specifically for
22. 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
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Education.
requirements to determine what will be needed and a certain amount of effort to obtain an optimal
(or satisfactory) 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 (particularly in process layouts).
23. In cellular manufacturing, machines are grouped into cells. The basis for grouping can be
24. Group technology involves items that have similar design or processing requirements and
25. Although we treated the task completion times as fixed when balancing assembly lines, it is more
realistic to assume variable task times whenever humans are involved. 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. In addition, workstation slack time also can be used for slower or
less experienced workers who take longer than normal to complete a task.
Taking Stock
1. The three major trade-offs in process selection are:
a. Flexibility vs. efficiency in facility layout. A product layout is designed to provide efficient
operations, while a process layout is designed to provide a variety of products, thus offering a
flexible system.
2. If we rebalance the assembly line too frequently, then the cost of making the adjustments
3. In process selection, we must make sure that manufacturing group(s), maintenance, engineering,
technical support, marketing, process design specialists, quality, and finance (especially if we
4. In layout design, we must make sure that manufacturing group(s), maintenance, engineering,
technical support, process design specialists, quality, finance (especially if we need capital to
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5. Technology has tremendous impact on process selection due to changes in computer related
technology and associated capabilities. The level of automation continues to change in
companies, thereby affecting layout decisions. For example, newer machinery is smaller;
therefore, the size of the machinery affects the work area size and ultimately the layout of the
facility.
Critical Thinking Exercises
1. Student answers will vary. Some possible answers follow:
a. If an operations manager purchased equipment that polluted the surrounding community, this
2. Factories—type of machines, skill level of the employees, level of automation, inventories, and
safety.
3. a. Some of the risks of automating a production process are that sufficient output may not
occur to offset the high costs of automation, future products might require more flexibility
4. When demand is low, the single server operation should be able to keep up with that demand. For
example, if the assembly time is 1 minute and demand is 240 customers per day (or 480 minutes),
then the server would have capacity of 480 customers per day (480 minutes per day/1 minute per
customer). Therefore, the one server operation would have sufficient capacity. However, if
demand increases to 960 customers per day, the one server operation has insufficient capacity to
meet demand. To meet the demand of 960 customers per day, Chipotle’s would have to consider
using at least two workers and dividing the total work content between the two servers for a cycle
time of 0.5 minutes per customer (480 minutes per day/960 customers per day = 0.5 minutes per
customer). When demand is low, a single server operation should have sufficient capacity. Using
more servers to increase capacity would lead to underutilized capacity. When demand grows, the
number of servers on the line must increase to keep up with the demand. Now, we all know that
demand at a restaurant fluctuates throughout the day. As demand fluctuates throughout the day,
Chipotle’s should be adjusting the capacity to attain high levels of utilization and to be able to
meet that demand.
Chapter 06 – Process Selection and Facility Layout
Solutions
1. Given: For all 17 tasks, the longest task time is 2.4 minutes. The sum of all 17 task times is 18
minutes. Operating time per day = 450 minutes.
a. Minimum cycle time = length of longest task, which is 2.4 minutes per unit (this was given).
Maximum cycle time = task times = 18 minutes per unit (this was given).
b. Range of output (depends on the minimum and maximum cycle times):
units
5.187
4.2
450
:.min 4.2@
Chapter 06 – Process Selection and Facility Layout
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2. Given: Desired output rate = 33 1/3 units per hour. Operating time = 60 minutes per hour. We
are given the tasks and their times (in minutes) shown below.
0.7
0.5
g
b
a
a. Use the most following tasks heuristic, and in the case of a tie, use the greatest positional
weight heuristic to break the tie. Before assigning tasks, we must determine the number
of following tasks for each task. Then, we must determine the positional weight for each
task. Positional weight for a task = the sum of task times for itself and all of its following
tasks.
Task
Positional Weight
a
6.0
b
4.6
c
1.6
d
2.2
e
2.3
f
1.0
g
1.5
h
0.5
Example calculations for determining positional weight:
Task a is followed by all 7 other tasks.
The positional weight for Task a = 1.4 + 0.5 + 0.6 + 0.7 + 0.8 + 0.5 + 1.0 + 0.5 = 6.0.
Task c is followed by 2 tasks: Tasks f & h.
The positional weight for Task c = 0.6 + 0.5 + 0.5 = 1.6.
Task d is followed by 2 tasks: Tasks g & h.
The positional weight for Task d = 0.7 + 1.0 + 0.5 = 2.2.
0.6
0.8
0.5
0.5
1.4
c
f
e