60) All improvements to the Toyota Production System must be made using the ________ method.
61) The pathway for every service and product in the Toyota Production System must be ________ and
________.
62) In the Toyota Production System, all work must be completely specified as to ________, ________,
________ and ________.
63) What are the supply chain implications of the lean system emphasis on close supplier ties?
64) What are the supply chain implications of the lean system emphasis on small lot sizes?
Answer: Small lot sizes reduce average inventory levels (relative to large lots) throughout the entire
supply chain. Small lots also pass through the system more quickly, because they do not keep materials
65) What is the difference between the “push” and “pull” methods of material flow? Which method does
lean systems use?
66) What are some of the approaches used to achieve the high quality levels associated with lean
systems?
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67) Explain the meaning of the term takt time, and use a numerical example to illustrate.
68) With respect to lean systems, what is the advantage of standardized components?
69) List and briefly define the 5S Practices that serve as an enabler and essential foundation of lean
systems.
70) What are the four underlying principles of the Toyota Production System?
Answer: The four underlying principles are: (1) all work must be completely specified as to content,
sequence, timing and outcome; (2) every customer–supplier connection must be direct, unambiguously
71) Briefly discuss the House of Toyota, including its origin and key points.
Answer: The House of Toyota is a graphic presentation of all the essential elements of lean systems that
make the Toyota Production System (TPS) work well. It was originally used by Toyota to define TPS to its
72) An item sells at a rate of 240 units per day. If a plant works one shift per day (480 minutes), what takt
time is required for the plant to meet this demand?
73) A plant‘s manufacturing process has a takt time of 90 seconds per unit. This results in a process
output of how many units per hour?
74) An item is used in Process B at a rate of 150 units per day. Process A works one shift per day (480
minutes) and supplies Process B’s requirements. What takt time is required in Process A to meet Process
B’s demand?
75) What is the output for a process that has a takt time of 1.25 minutes per unit?
76) An item sells at a rate of 600 units per day. If a plant works two shifts per day (480 minutes each shift),
what takt time is required for the plant to meet this demand?
77) A plant‘s manufacturing process has a takt time of 72 seconds per unit. This results in a process
output of how many units per hour?
6.3 Designing Lean System Layouts
1) One benefit of a lean system is that it reduces space requirements.
2) Options for achieving line-flow layouts in a lean system include assigning one worker to operate
several different machines in a line and creating cells to produce similar product groups called families.
3) An OWMM arrangement reduces labor requirements but increases inventory.
4) Group technology collects similar parts into families and organizes machine tools into separate cells.
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5) Combining parts or products with similar characteristics into families and setting machines aside for
their production is known as:
A) the one-worker, multiple machines (OWMM) method of production.
B) the standardized component method of manufacturing.
C) group technology.
D) the flexible workforce approach to manufacturing.
6) A ________ is a workstation in which a worker operates several different machines simultaneously to
achieve a line flow.
7) ________ is the combining of parts or products with similar characteristics into families and setting
aside groups of machines for their production.
8) What is group technology and what advantages are accrued from its use?
Answer: The theory is to group parts or products into families and set aside groups of machines for their
production. By dedicating these groups of machines to specific part families, the overall setup time
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9) How can group technology be used in a service setting? Provide an example and describe two
advantages of using this principle in a service setting.
Answer: The theory behind group technology is to group parts or products into families and set aside
groups of machines for their production. In a service setting, the parts are customers and the groups of
10) Explain how a line-flow strategy can be used to reduce or eliminate setups.
Answer: If line-flow volumes are high enough, a product layout can be used that eliminates setup
requirements entirely. Another tactic, the one-worker-multiple-machines (OWMM) approach, can also be
6.4 The Kanban System
1) A Kanban is a card used to control the flow of production in many just–in-time systems.
2) In a Kanban system, materials may be withdrawn without a withdrawal card if the operation requiring
the material is about to run out of work.
3) Some Kanban systems are set up without Kanban cards, and use the material containers or open spaces
in a work area to withdraw materials.
4) As the average processing time per container of parts increases, fewer containers are needed in a
Kanban system.
5) A Kanban system is an important mechanism for lean system management. Which one of the following
statements regarding the operation of a Kanban system is best?
A) A typical Kanban used in the JIT system includes information such as item number, unit price,
competitor‘s product name, and its price.
B) A Kanban can be used to set the order quantity but not the inventory level.
C) A Kanban and a container move as a pair once production begins at the fabrication process.
D) An empty container can be exchanged for a full container at the storage location even though no
Kanban is on the full container.
6) An important mechanism for lean systems is a Kanban system. Which one of the following statements
correctly describes the behavior of a two-card Kanban system?
A) A withdrawal Kanban is issued to authorize production in the fabrication process.
B) A production-ordering Kanban authorizes the assembly process to remove the materials from the
storage location.
C) The fabrication process produces certain units defined by the lot size and pushes them down to the
assembly process.
D) Containers must never be removed from the storage location without an authorizing withdrawal
Kanban.
7) Which one of the following statements regarding the Toyota production system is best?
A) It is particularly well suited for making irregularly used parts and customized “specials.“
B) It is a “push system,” with orders pushed out in anticipation of future requirements.
C) Each container has either a withdrawal or production-ordering Kanban.
D) It does not use poka yoke or 5S practices.
Case 6.1
The Edward James Toy Company uses a Kanban system to make plastic wheels that are a component of
several toys. The waiting time for a container of the wheels during production is 0.25 day; average
processing time is 0.15 day per container. Each container holds 200 wheels. The company uses 2,000
wheels a day in the production of its products.
8) Use the information in Case 6.1. Using a policy variable of 5%, calculate the number of Kanban
containers needed for the wheels.
A) three or fewer
B) four or five
C) five or six
D) seven or more
9) Use the information in Case 6.1. How many Kanban containers would be required if a 10% policy
variable is used?
A) three or fewer
B) four or five
C) five or six
D) seven or more
Case 6.2
The Jewel Golf Club Company, which recently began using a Kanban system, has had problems with
high inventory levels of one of the handle grips used to make several versions of its clubs. Daily demand
for the grip is 3,000 units, average waiting time during production is 0.20 day, processing time is 0.10 day
per container, and a container holds 150 grips.
10) Use the information in Case 6.2. How many Kanban containers would Jewel require if a 5% policy
variable is used?
A) three or fewer
B) four or five
C) six or seven
D) eight or more
11) Use the information in Case 6.2. How many Kanban containers would Jewel require if a 10% policy
variable is used?
A) three or fewer
B) four or five
C) five or six
D) six or seven
12) Which of the following actions would increase the number of containers in use in a Kanban system?
A) using larger containers that can hold more parts than before
B) less demand for the part held by the container
C) faster processing time for the part held by the container
D) increased waiting time for the container
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13) A ________ is a card used to control the flow of production through a factory.
14) A ________ is based on both a withdrawal card and a production-order card, to control inventory
quantities more closely.
15) In a ________ system based on other Kanban signals, an empty space signals a need to fill it.
16) What are the general operating rules for a single-card kanban system?
Answer: The operating rules for the single-card system are simple and are designed to facilitate the flow
of materials while maintaining control of inventory levels.
1. Each container must have a card.
2. The assembly line always withdraws materials from the fabrication cell. The fabrication cell never
pushes parts to the assembly line because, sooner or later, parts will be supplied that are not yet needed
for production.
17) How does Toyota’s two-card kanban system work?
Answer: Toyota uses a two-card system, based on a withdrawal card and a production-order card, to
control inventory quantities more closely. The withdrawal card specifies the item and the quantity the
user of the item should withdraw from the producer of the item, as well as the stocking locations for both
Learning Obj.: Understand Kanban systems for creating a production schedule in a lean system.
18) When determining the number of kanban containers, discuss the impact of alpha, the policy variable,
on the total amount of inventory in the system. If alpha is set equal to zero, is system inventory zero?
What would be required to achieve a system-wide inventory of zero?
Answer: The policy variable alpha adds safety stock to cover for unexpected circumstances, for example
a quality issue or delays in supply. Even if alpha is zero, there is still inventory in the system as dictated
19) Jones Electric Motors uses a Kanban system to make motors for several garage door companies in the
southeastern United States. The daily demand for motor housings used in manufacturing is 100 units.
The average waiting time for a container of parts is 0.2 day. The processing time for a container of
housings is 0.1 day, and a container holds 5 housings. If Jones wishes to use a 10% policy variable, how
many containers are needed?
20) Happiness, Inc. uses a Kanban system. The daily demand for the most critical part, the Smylie, is 400
units over an eight-hour production period. The average waiting time for a container of Smylies is 30
minutes. The processing time for a container filled with Smylies is 6 minutes, and a container holds 5
units. If the company wishes to use a 5% policy variable, how many containers are needed?
21) Degan’s Salad Dressings uses a Kanban system. The daily demand for corrugated boxes used in
packaging its dressings is 300 boxes. The average waiting time for a container of boxes is 0.25 day. The
processing time for a container of boxes is 0.1 day, and a container holds 10 boxes. If Burdell wishes to
use a 10% policy variable, how many containers are needed?
22) Champion Cooling Company uses a kanban system at their two locations in the Oklahoma City
Metroplex. The daily demand for fans is 2,000 at each location and management insists on using the same
alpha level (0.1) at both locations. Location Reno uses containers that hold 20 items and takes 0.04 of a
day to process a container. It takes 0.07 of a day to get a container filled and for it to wait during its cycle.
Location Western uses containers that hold 24 items and takes 0.02 of a day to process a container. It takes
0.08 of a day to get a container filled and for it to wait during its cycle. Which location has the higher level
of inventory? Assume that both locations round up to the next highest integer number of containers.