Operations chapt 16
Identify three major sources of variability.
1. Poor production processes that allow employees and suppliers to produce improper quantities or late or non-conforming units 2. Unknown customer demands 3. Incomplete or inaccurate drawings, specifications, and bills of material
What are the goals of JIT partnerships?
1. Removal of unnecessary activities, such as receiving, incoming inspection, and paperwork related to bidding, invoicing, and payment. 2. Removal of in-plant inventory by delivery in small lots directly to the using department as needed. 3. Removal of in-transit inventory by encouraging suppliers to locate nearby and provide frequent small shipments. 4. Obtain improved quality and reliability through long-term commitments, communication, and cooperation.
Lead time for computers is 5 days with daily demand of 25 and safety stock of 5 computers. If management wants to use 10 kanbans how many computers should each one hold?
13
Lead time for cakes is 2 days with daily demand of 10 cakes and a safety stock of ½ a day. Each container (kanban) holds 1 cake. What is the correct number of kanbans?
25
Lead time for computers is 7 days with daily demand of 5 computers and a safety stock of 1 day. Each kanban holds 8 computers. What is the correct number of kanbans?
5
A bakery uses 5 kanban containers that each hold 5 cakes. If daily demand is 20 cakes and lead time is 1 day determine the safety stock.
Correct 5 = (20 + SS)/5, thus safety stock = 5 cakes
A bakery uses 5 kanban containers that each holds 3 cakes. Daily demand is 10 cakes and safety stock is 5 cakes. What is the lead time?
Correct 5 = (5 + 10LT)/3; LT = 1 day
A bakery uses 6 kanban containers that each hold 4 cakes. If safety stock is 2 cakes and lead time is 11 days, determine daily demand.
Correct 6 = (2 + 11d)/4; d = (24 - 2)/11 = 2 cakes per day
Which one of the following scenarios represents the use of a kanban to reduce inventories?
Correct A "customer" work center signals to the "supplier" workstation that more parts are needed.
Differentiate between a push and a pull system.
Correct A push system dumps orders on the next downstream workstation, regardless of timeliness and resource availability. A pull system uses signals to request production and delivery from upstream stations to the station that has production facilities available. In a pull system, materials or parts are pulled where they are needed when they are needed.
If the goals of JIT partnerships are met, which of the following is a result?
Correct In-transit inventory falls as suppliers are located closer to facilities.
Identify the inventory tactics appropriate for a JIT environment.
Correct Inventory tactics for a JIT environment include a pull system to move inventory, ever smaller lots, just-in-time deliveries from suppliers, deliveries directly to point of use, performance to schedule, setup reduction, and group technology.
Which one of the following statements is TRUE regarding JIT inventory?
Correct It is the minimum inventory necessary to keep a perfect system running.
A manufacturer took the following actions to reduce inventory. Which of these is generally not accepted as a JIT action?
Correct It picked the supplier that offered the lowest price based on quantity discounts.
Identify JIT scheduling tactics.
Correct JIT scheduling tactics include communicate schedules to suppliers; make level schedules; freeze part of the schedule; perform to schedule; seek one-piece-make and one-piece-move; eliminate waste; produce in small lots; use kanbans; and make each operation produce a perfect part.
Identify some of the signals that kanban systems use.
Correct Kanban systems use a wide variety of signals. These include cards, lights, an empty position, an empty tote tray, or a rag over a rack adjacent to a storage area.
Identify the layout tactics appropriate for a JIT environment.
Correct Layout tactics for a JIT environment include build work cells for families of products, include a large number of operations in a small area, minimize distance, design little space for inventory, improve employee communication, use poka-yoke devices, build flexible or movable equipment, and cross-train workers to add flexibility.
How are lean operations and the Toyota Production System (TPS) alike? How are they different?
Correct Lean operations and TPS are basically synonymous, and the two terms are often used interchangeably. Lean operations places more emphasis on understanding the customer; TPS places more emphasis on employee learning and empowerment in an assembly-line environment.
Describe level schedules. What purpose do they serve?
Correct Level schedules act on frequent small batches rather than a few large batches; the small batches are always changing. The practice matches each day's production to the demand for that day.
If a factory wants to cut its current lot size in half, by what proportion must setup cost change?
Correct Setup cost must be cut to one fourth its current value.
Which one of the following statements is TRUE about the kanban system?
Correct The customer workstation signals to the supplier workstation when production is needed.
A grocery store is attempting to implement a kanban system. Which of the following would not be an application of kanbans?
Correct The meat department stocking up on turkeys before Thanksgiving.
Identify Ohno's Seven Wastes.
Correct The seven are: overproduction, queues, transportation, inventory, motion, overprocessing, and defective product.
Which of the following is specifically characterized by a focus on continuous improvement, respect for people, and standard work practices?
Correct Toyota Production System (TPS)
Concerning relationships with suppliers, which of the following combinations is critical to the success of JIT?
Correct close relationships with trust
In JIT partnerships, suppliers have several concerns. Which of the following is NOT such a concern?
Correct customers' infrequent engineering changes
Which of the following is not a goal of JIT partnerships?
Correct inspect all incoming shipments to ensure zero defects
Characteristics of just-in-time partnerships do NOT include:
Correct large lot sizes to save on setup costs and to gain quantity discounts.
Which one of the following is a characteristic of a JIT partnership?
Correct removal of incoming inspection
Which one is NOT an application of lean principle in services?
Correct securing more inventory to prepare for disruption in production
How can a reduction of in-transit inventory be encouraged?
Correct supplier location near plants
Which one of the following is not a benefit of JIT implementation?
Correct variability increase
JIT makes quality cheaper because:
JIT prevents long run of defects
Which of the following is specifically characterized by continuous and forced problem solving via a focus on throughput and reduced inventory?
Just in time
Labor cost for set-up is $500/hour. If the plant plans on level material use and operates 50 days per year, determine the time it takes to setup. annual demand: 5000 daily production: 1000 lot size : 700 annual holding costs per unit: 25$
S = Q^2 ∗ H ∗ (1 - d/p)/(2D) = 700^2 ∗ 25 ∗ (1 - 5000/50/1000)/(2 ∗ 5000) = $1102.5 $1102.5/$500 = 2.205 hours
Waste is anything that does not add value from the consumer's perspective.
T
A repetitive manufacturing firm is planning on level material use. The following information has been collected. Currently, the firm operates 250 days per year. annual demand: 22,000 daily demand: 88 daily productin: 250 desired lot size (2 hr production) 63 holding cost per unit : $50 a. What is the setup cost, based on the desired lot size? b. What is the setup time, based on $40 per hour setup labor?
a. s=(Q^2 * H * (1-d/p)/2D) = (63^2 x 50 (1-88/250)/ 2 * 22,000) and S = $2.92 b. setup time : = 4.38 minutes
Which of the following is NOT a goal of JIT partnerships?
all of theese are removal of unnecessary activities removal of in-plant inventory removal of in-transit inventory obtain improved quality and reliability Correct All of these are goals of JIT partnerships.
Which of the following is TRUE regarding the steps to reducing setup times?
all of these The standardization of both tooling and work procedures is advantageous to setup time reduction. Answers: The first step involves performing as much setup preparation as possible while the process/machine is operating. The cycle of steps is repeated until setup time is reduced to under a minute. The standardization of both tooling and work procedures is advantageous to setup time reduction. Move material closer and improve material handling are done before operator training.
Just-in-time systems make demands on layouts, including the need for:
all of these cross-trained, flexible employees. distance reduction. increased flexibility. reduced space and inventory. cross-trained, flexible employees.
What does the Japanese word "kanban" mean? What is a kanban?
card Kanban is the Japanese word for card that has come to mean "signal." A kanban system moves parts through production by means of a "pull" from a signal.
A(n) ________ is a concept that results in material being produced only when requested and moved to where it is needed just as it is needed.
exact match pull system
A push system means providing the next station with exactly what is needed when it is needed.
false
Because most services cannot be inventoried, there is little place for JIT to help service organizations achieve competitive advantage.
false
Customer demand will always remain an unknown, so it is not considered a source of variability.
false
Employee empowerment is unnecessary in the Toyota Production System, because automation and powerful information systems reduce the need for employee creativity and decision making.
false
In a JIT system, product inspection adds value by identifying defective items.
false
JIT brings about competitive advantage by faster response to the customer regardless of cost.
false
JIT systems carry inventory just in case something goes wrong.
false
Increasing inventory exposes variability in production processes.
falsr
Which one of the following is NOT a layout tactic in a JIT environment?
fixed equiptments
When suppliers are encouraged to locate near manufacturing plants, the goal of the JIT partnership is to reduce ________ inventory.
in-transit
Kanban is associated with all EXCEPT which of the following?
increased material handling
Excess bags of basic commodities such as flour and sugar that are stored in a restaurant's kitchen represent which of the following wastes?
inventory
Which of the following is specifically characterized by the elimination of waste through a focus on exactly what the customer wants?
lean operations
________ involve scheduling products so that each day's production meets the demand for that day.
level schedules
Which of the following is characteristic of lean operations?
low space requirement s
The ________ is the time between the arrival of raw materials and the shipping of finished products.
manufacturing cycle time
Which of the following is an illustration of employee empowerment?
no one knows the job better than those who do it
Which of the following is generally found in most Lean environments?
pull systems
The number of kanbans should be equal to which of the following?
the ration of demand during lead time + safety stock to consider size
Manufacturing cycle time is best defined as the:
time from raw materials receipt to finished produt exit
Handling material more than once is an example of the waste called ________.
transportation
A common JIT layout tactic is to minimize distance.
true
A kanban system requires that the process has little variability in lead time because shortages impact the entire production system.
true
A scheduler may find that freezing the portion of the schedule closest to the due dates allows the production system to function and the schedule to be met.
true
Cross-training is a common JIT layout tactic to improve flexibility.
true
Hidden problems are generally uncovered during the process of reducing inventory.
true
JIT suppliers have concerns that the JIT firm's demands for small lot sizes are simply a way of transferring holding cost from the JIT firm to the suppliers.
true
Many suppliers feel that having a variety of customers is better than being tied to long-term contracts with one customer.
true
One goal of JIT partnerships is the removal of in-plant inventory by delivery in small lots directly to the using department as needed.
true
TPS stands for Toyota Production System.
true
The 5Ss-sort/segregate, simplify/straighten, shine/sweep, standardize, and sustain/self-discipline-are important to lean production because they act as a means to reduce waste.
true
The Toyota Production System requires that activities have built-in, automatic tests to signal problems.
true
The first step in reducing setup times is the separation of setup into preparation activities and actual setup, so that as much work as possible can be done while the machine or process is operating.
true
The quality management tool called poka-yoke is not relevant to JIT systems.
true
Variability in manufacturing can occur because engineering drawings or specifications are incomplete or inaccurate.
true
When implemented as a comprehensive operations strategy, JIT, TPS, and lean systems sustain competitive advantage and result in increased overall returns.
true
