Operations Management: Processes and Supply Chains, 12e (Krajewski)
Chapter 6 Lean Systems
6.1 Continuous Improvement Using a Lean Systems Approach
1) The just-in-time (JIT) philosophy is the belief that cutting inventory and removing non-value-added
activities in operations can eliminate waste.
2) Kaizen is the Japanese term for continuous improvement.
3) In a lean system, large inventories are not considered a type of waste, because they prevent operator
wait times.
4) In a lean system, an item that is manufactured before it is needed is not considered waste, because it
helps keep material flowing through the system.
5) In manufacturing systems, one way to achieve continuous improvement can be to maintain low
inventories, and periodically cut safety stocks almost to zero.
6) In a lean system, the key to continuous improvement is the understanding that excess capacity or
inventory hides problems on the shop floor and thus prevents waste sources from being identified and
eliminated.
7) In lean systems, work-in-process inventory is a direct result of overproduction and waiting.
8) Long production runs, poor material flows, and processes that are not tightly linked to one another can
cause over 90% of a product’s lead time to be spent waiting.
9) The just-in-time (JIT) system is a(n):
A) management system of people and procedures to fulfill all delivery deadlines.
B) production system of small-lot manufacturing to reduce work-in-process inventory.
C) materials management system for removing all inventories.
D) integrated system of managing resources, information, and decision processes to eliminate waste.
10) Regarding the Eight Types of Waste that must be eliminated to implement lean systems, excessive
movement and material handling of product between processes is part of which general waste category?
A) Motion
B) Transportation
C) Inappropriate Processing
D) Underutilization of Employees
11) Regarding the Eight Types of Waste that must be eliminated to implement lean systems, using
expensive high precision equipment when a simpler machine would suffice is part of which general
waste category?
A) Motion
B) Overproduction
C) Inappropriate Processing
D) Defects
12) Which of the following statements is true with regard to the eight types of waste that must be
eliminated to implement lean systems?
A) Jobs with excessive motion should be redesigned.
B) Work-in-process inventory is the direct result of underutilization of employees.
C) Manufacturing an item before it is needed helps an organization detect and reduce defects.
D) Product damage and deterioration result from using expensive high precision equipment.
13) Regarding the Eight Types of Waste that must be eliminated to implement lean systems,
manufacturing an item before it is needed is part of which general waste category?
A) Inappropriate Processing
B) Waiting
C) Inventory
D) Overproduction
14) Continuous improvement with lean systems:
A) involves navigating a ship over treacherous rocks.
B) requires periodically increasing lot sizes or workforce levels to uncover problems.
C) entails systematically stressing the system and focusing on problem areas.
D) focuses exclusively on internal operations without addressing relationships with customers and
suppliers.
15) What did the production manager say to the pile of scrapped material?
A) “Hello muda.”
B) “Hello fadduh.”
C) “We need more kanbans.”
D) “JIT II Brute?”
16) ________ is the philosophy that waste can be eliminated by cutting unnecessary inventory and
removing non-value-adding activities in operations.
17) The Japanese term for continuous improvement in quality and productivity is ________.
18) An operator standing idly by his workstation because a previous process with quality issues was
delayed is an example of ________.
19) List and briefly define the eight types of waste (or muda) that often occur in firms which must be
eliminated in implementing lean systems.
Answer: Refer to Table 6.1 in the text.
1. Overproduction Manufacturing an item before it is needed, making it difficult to detect defects and
creating excessive lead times and inventory.
6.2 Strategic Characteristics of Lean Systems
1) Just-in-time (JIT) systems need close relationships with suppliers.
2) JIT II refers to a form of supplier partnership that places a supplier representative, who is empowered
to plan and schedule the replenishment of materials from the supplier, in the customer’s plant on a full–
time basis.
3) In lean systems, the need for single-digit setups is driven by the desire for small lot sizes.
4) Push systems are often used in firms with highly repetitive processes and well defined work flows of
standardized items.
5) Firms that have highly repetitive processes and well-defined work flows of standardized items often
use the pull method.
6) Just-in-time (JIT) systems rely on inspectors to inspect quality into the product.
7) Quality at the source is a philosophy whereby defects are caught and corrected where they are created.
8) Automatically stopping the process when something is wrong and then fixing the problems on the line
itself as they occur is called jidoka.
9) A power cord that can be plugged in only one way is an example of a poka-yoke.
10) Takt time is the cycle time needed to match the rate of production to the rate of sales.
11) Takt time is the cycle time needed to maximize utilization of an organization’s workers and
equipment.
12) A firm that averages sales of 320 units for every 480-minute shift it runs has a takt time of 90 seconds.
13) Heijunka is the leveling of production load by both volume and product mix.
14) Mixed-model assembly is a type of assembly that produces a mix of models in smaller lots.
15) Productivity tends to increase when components are standardized because each worker performs a
standardized task or work method more often each day.
16) Five S practices can enable workers to visually see everything differently, prioritize tasks, and achieve
a greater degree of focus.
17) Five S practices can be applied to both manufacturing and service settings and can include offices,
work spaces, tool rooms, and shop floors.
18) Preventive maintenance is typically given very low priority in just–in-time systems.
19) One tactic of Total Preventive Maintenance (TPM) is to make workers responsible for routine minor
maintenance of their own equipment.
20) While lean systems work very well for manufacturing systems, they cannot be applied to service
systems.
21) Toyota sets up all of its operations as experiments and teaches employees at all levels how to use the
trial and error method of problem solving.
22) In the Toyota Production System, when a work station needs more material, it is obvious to both the
worker and the supplier that material is needed. Further, the amount needed must be understood as well
as the delivery time for replenishment.
23) In the Toyota Production System, services and goods are pushed to the next available person or
machine to maintain smooth, rapid flow.
24) Lean systems try to:
A) produce a product in anticipation of demand.
B) maximize the value added by each of its activities.
C) organize production in large lots to minimize the number of setups.
D) reduce the labor content in all processes.
25) Companies using lean systems generally have:
A) many suppliers to ensure that material shortages never occur.
B) suppliers that are located nearby to decrease delivery lead time.
C) suppliers that are willing to accept short-term contracts.
D) suppliers who are low-cost producers.
26) Lean systems maintain inventory in small lot sizes because small lot sizes:
A) increase pipeline inventory, allowing the organization to buffer against demand uncertainties.
B) increase the quality level of the product.
C) enable schedules to use machine capacities more efficiently.
D) increase manufacturing lead time because of the increase in waiting time.
27) The goal of single-digit setups is to have a setup time:
A) of less than one shift.
B) of less than one hour.
C) of less than 30 minutes.
D) of less than 10 minutes.
28) The lean system concept will not work without the proper environment. Which one of the following
characteristics is most common to firms that have successfully implemented a lean system?
A) uniform assembly schedules
B) specialized workforce
C) high rates of machine failures
D) longer setup times
29) There are many requirements for the successful implementation of the lean system of production.
Which one of the following is not such a requirement?
A) uniform assembly schedule
B) short setup time
C) low machine failure and low defects
D) substantial natural resources
30) Using customer demand to activate production of an item or service is called:
A) the andon method.
B) the pull method.
C) the jidoka method.
D) the push method.
31) A method in which production of an item begins in advance of customer needs is called:
A) the andon method.
B) the pull method.
C) the jidoka method.
D) the push method.
32) Automatically stopping the process when something is wrong and then fixing the problems on the
line itself as they occur is known as:
A) andon.
B) muda.
C) jidoka.
D) poka-yoke.
33) Mistake-proofing is known by the term:
A) andon.
B) muda.
C) jidoka.
D) poka-yoke.
34) Items to be assembled that fit together only the proper way are an example of:
A) andon.
B) jidoka.
C) poka-yoke.
D) muda.
35) In lean systems, if a defective product is found, which of the following is generally not done?
A) The production line is stopped.
B) The defective unit is passed on to the next workstation.
C) The defective unit is returned to the worker responsible for creating the defect.
D) The production line is made aware of the problem without necessarily stopping the line.
36) The takt time of a process is defined as:
A) the cycle time needed to match the rate of production to the rate of consumption.
B) the total time required to move an item through a process.
C) the time required to change a machine to run a new model.
D) the lead time necessary to notify maintenance that a problem has occurred in an operation.
37) The production of 240 units during a 480-minute work shift results in a takt time of:
A) 24 seconds.
B) 30 seconds.
C) 120 seconds.
D) 240 seconds.
38) A takt time of 90 seconds generates a process output of:
A) 40 units per hour.
B) 30 units per hour.
C) 4 units per hour.
D) 90 units per hour.
39) The production of 150 units during a 480-minute work shift results in a takt time of:
A) 150 seconds.
B) 192 seconds.
C) 120 seconds.
D) 18.8 seconds.
40) Justin Thyme used to run one batch each of 500 As, 300 Bs and 100 Cs every month but now he runs a
batch of 5 As, 3 Bs, and 1 C every half day with the use of:
A) single-digit setups.
B) andon lights.
C) mixed-model assembly.
D) push method.
41) Lean systems use the standardization of components because standardization:
A) decreases the demand for each component.
B) increases repeatability.
C) increases lot sizes more easily.
D) decreases repeatability.
42) Weeding out unnecessary items, neatly arranging what’s left, and cleaning the work area are
components of:
A) a Kanban system.
B) a constraint management system.
C) mixed-model assembly.
D) a 5S program.
43) “When in doubt, weed it out” describes which 5S element?
A) Sort
B) Straighten
C) Shine
D) Standardize
44) Which of the following statements about the Toyota Production System is best?
A) Toyota has built a learning organization over the course of 50 years.
B) The key to success for Toyota is the set of tools and procedures readily apparent on a plant tour.
C) The four principles that form the basis to TPS are impossible to replicate.
D) Toyota has 23 manufacturing plants in North America alone.
45) The four bolts that hold the passenger seat in a pickup truck are tightened in a clockwise order
beginning with the front right bolt, in 24 seconds. This production factoid illustrates which of the
following principles of the Toyota Production System?
A) All work must be specified as to content.
B) Every customer-supplier connection must be direct and unambiguous.
C) The pathway for every service and product must be direct.
D) Any improvements to the system must be made in accordance with the scientific method.
46) The rack at my assembly station that holds rear view mirrors is empty, so a runner wheels it away
and replaces it with a new rack, fully populated with rear view mirrors. This production factoid
illustrates which of the following principles of the Toyota Production System?
A) All work must be specified as to content.
B) Every customer-supplier connection must be direct and unambiguous.
C) The pathway for every service and product must be direct.
D) Any improvements to the system must be made in accordance with the scientific method.
47) Management at Pepman has decided to switch from a push system to a pull system of manufacturing.
They are a large repetitive manufacturer of bicycles. Which one of the following is most likely to occur?
A) The cycle time will increase, resulting in higher inventory levels.
B) The space required will increase due to the increase in the number of units that require rework.
C) The decrease in WIP inventory levels will reduce the space requirements.
D) The workers at any given process will produce units before they are needed by the subsequent
process.
48) ________ refers to a form of supplier partnership that places a supplier representative, who is
empowered to plan and schedule the replenishment of materials from the supplier, in the customer’s
plant on a full-time basis.
49) A(n) ________ is a group of activities needed to readjust a process between successive lots of items.
50) ________ refers to the goal of having a setup time of fewer than 10 minutes.
51) The ________ method activates production of a service or item based on customer demand.
52) Automatically stopping the process when something is wrong and then fixing the problems on the
line itself as they occur is called ________.
53) ________ refers to mistake-proofing methods aimed at designing fail-safe systems that minimize
human error.
54) A lean system’s ________ refers to the cycle time needed to match the rate of production to the rate of
sales or consumption.
55) ________ is the leveling of production load by both volume and product mix.
56) A ________ assembly line produces a mix of models in smaller lots.
57) ________ is a methodology consisting of five workplace practices that are conducive to visual controls
and lean production.
58) The list of five S practices includes ________, ________, ________, ________ and ________.
59) ________ practices include early testing of machine parts that may need to be replaced and making
workers responsible for routine minor maintenance of their own equipment.